Volume 13,Issue 6,2015 Table of Contents
2015, 13(6):1025-1030.
Abstract:
With the r apid development o f meso scale numer ical at mospher ic model WRF in r ecent y ears, its application is wider and w ider. In or der to ex plain the mechanism, r eveal the develo pment directio n and pr ov ide refer ence for r elated fields research2 er s, WRF model sy stem is int roduced, it is discussed that the influence o f parameterized phy sical pr ocesses, data assimilatio n and reasonable spat ial scale o n the simulation effect o f WRF model. Related studies have shown that: ( 1) differ ent par ameter2 ized phy sical processes need to be chosen in different reg ion and different time; ( 2) the common data assimilation method is 3DVar data assimilatio n at present, hybr id data assimilatio n may be a better met ho d to impr ove the simulatio n effect of WRF model; ( 3) reasonable spat ial scales need to be cho sen because not the hig her hor izo nt al reso lution, t he better simulat ion effect for a ll research; ( 4) WRF mo del has g oo d simulat ion effect , hig h pr ediction accuracy , there is mo re w ide applicat ion.
With the r apid development o f meso scale numer ical at mospher ic model WRF in r ecent y ears, its application is wider and w ider. In or der to ex plain the mechanism, r eveal the develo pment directio n and pr ov ide refer ence for r elated fields research2 er s, WRF model sy stem is int roduced, it is discussed that the influence o f parameterized phy sical pr ocesses, data assimilatio n and reasonable spat ial scale o n the simulation effect o f WRF model. Related studies have shown that: ( 1) differ ent par ameter2 ized phy sical processes need to be chosen in different reg ion and different time; ( 2) the common data assimilation method is 3DVar data assimilatio n at present, hybr id data assimilatio n may be a better met ho d to impr ove the simulatio n effect of WRF model; ( 3) reasonable spat ial scales need to be cho sen because not the hig her hor izo nt al reso lution, t he better simulat ion effect for a ll research; ( 4) WRF mo del has g oo d simulat ion effect , hig h pr ediction accuracy , there is mo re w ide applicat ion.
2 Effects of precipitation downscaling method on evapotranspiration simulation of land surface model
2015, 13(6):1031-1035.
Abstract:
In order to recognize the effects of precipitation intensity and duration on the evapotranspiration, temporal downscaling simulation of daily precipitation in Changbaishan area is conducted using the weather generator of IBIS ( Integrated Biosphere Simulator) model and a precipitation downscaling model based on precipitation intensity and duration. The calculated hourly precipitation is used as the meteorological drive and evapotranspiration is simulated using the IBIS model. The results show that the precipitation intensity simulated by the weather generator of IBIS model is obviously lower, leading to a higher evapotranspi 2 ration, while the results from the precipitation downscaling model match the observation data well. The accuracy of evapotrans2 piration simulation can be improved with the accurate precipitation downscaling. In addition, through the comparison of evapo2 transpiration variation under different schemes of precipitation intensity and duration based on two precipitation events in 2004, stronger precipitation intensity and shorter precipitation duration can decrease the total evapotranspiration and the proportion of canopy interception evaporation, and increase the proportion of soil evaporation and plant transpiration under the same daily pre 2 cipitation.
In order to recognize the effects of precipitation intensity and duration on the evapotranspiration, temporal downscaling simulation of daily precipitation in Changbaishan area is conducted using the weather generator of IBIS ( Integrated Biosphere Simulator) model and a precipitation downscaling model based on precipitation intensity and duration. The calculated hourly precipitation is used as the meteorological drive and evapotranspiration is simulated using the IBIS model. The results show that the precipitation intensity simulated by the weather generator of IBIS model is obviously lower, leading to a higher evapotranspi 2 ration, while the results from the precipitation downscaling model match the observation data well. The accuracy of evapotrans2 piration simulation can be improved with the accurate precipitation downscaling. In addition, through the comparison of evapo2 transpiration variation under different schemes of precipitation intensity and duration based on two precipitation events in 2004, stronger precipitation intensity and shorter precipitation duration can decrease the total evapotranspiration and the proportion of canopy interception evaporation, and increase the proportion of soil evaporation and plant transpiration under the same daily pre 2 cipitation.
2015, 13(6):1036-1039.
Abstract:
The principle of parameter selections in the hydrologic frequency calculation is that the theoretical frequency curve matches with the empirical points. In this paper, three fitting evaluation applications and their advantages and disadvantages in the hydrologic frequency calculation are investigated, including Excel, frequency calculation software, and set pair analysis. T he Excel method and frequency calculation software use the sum of deviation square as the parameter selection criteria but it is in2 sensitive. According to connection number and the amount of a, b and c, the fitting degree between the frequency curve and measured points is analyzed by set pair analysis. This is a new way to evaluate the fitting of frequency curve quantitatively, which can avoid the subjective arbitrariness of current curve fitting methods.
The principle of parameter selections in the hydrologic frequency calculation is that the theoretical frequency curve matches with the empirical points. In this paper, three fitting evaluation applications and their advantages and disadvantages in the hydrologic frequency calculation are investigated, including Excel, frequency calculation software, and set pair analysis. T he Excel method and frequency calculation software use the sum of deviation square as the parameter selection criteria but it is in2 sensitive. According to connection number and the amount of a, b and c, the fitting degree between the frequency curve and measured points is analyzed by set pair analysis. This is a new way to evaluate the fitting of frequency curve quantitatively, which can avoid the subjective arbitrariness of current curve fitting methods.
2015, 13(6):1040-1044.
Abstract:
In order to investigate the climate change in the M ahai Basin of the Qinghai 2T ibet Plateau under the conditions of glob2 al warming, the variations of annual precipitation and temperature data in the Mahai Basin were analyzed using the accumulative anomaly method, Mann2Kendall test, and wavelet analysis. T he results suggested that ( 1) annual precipitation is stable from 1970 to 2010 while annual temperature has an increasing trend; ( 2) annual precipitation has a decreasing trend before 2001 and increases after that, while annual temperature has a decreasing trend before 1995 and increases after that; ( 3) the primary oscil2 lation periods of annual precipitation are 15 and 30 years while the primary oscillation period of annual temperature is 26 years; and (4) annual precipitation has different dry 2wet cycles while annual temperature has different hot2cold cycles under different time scales. The variations of precipitation and temperature are different under different time scales, and the variations are lower when the time scale is smaller.
In order to investigate the climate change in the M ahai Basin of the Qinghai 2T ibet Plateau under the conditions of glob2 al warming, the variations of annual precipitation and temperature data in the Mahai Basin were analyzed using the accumulative anomaly method, Mann2Kendall test, and wavelet analysis. T he results suggested that ( 1) annual precipitation is stable from 1970 to 2010 while annual temperature has an increasing trend; ( 2) annual precipitation has a decreasing trend before 2001 and increases after that, while annual temperature has a decreasing trend before 1995 and increases after that; ( 3) the primary oscil2 lation periods of annual precipitation are 15 and 30 years while the primary oscillation period of annual temperature is 26 years; and (4) annual precipitation has different dry 2wet cycles while annual temperature has different hot2cold cycles under different time scales. The variations of precipitation and temperature are different under different time scales, and the variations are lower when the time scale is smaller.
2015, 13(6):1045-1050.
Abstract:
In recent years, seasonal droughts occur frequently in the hilly area of central Sichuan, resulting in serious impacts on the agricultural production in Sichuan. According to the daily meteorological data of eight meteorological stations from 1960 to 2011 in this area, the relative humidity index in the national standards was selected as the drought index, and linear trend meth2 od, Morlet wavelet, and inverse distance weighting interpolation method were used to investigate the spatial and temporal distri 2 bution of seasonal drought frequency and intensity. The results indicated that ( 1) drought frequency and intensity have large differences in different seasons, and they are significantly higher in spring and winter than those in summer and autumn, and drought occurs mainly in spring and winter; (2) on the temporal distribution, drought in spring and autumn tends to be worse while drought in summer and winter alleviates. Drought in spring has three cycle evolutions while drought in winter has 2 cycle evolutions; and ( 3) on the spatial distribution, the central hilly area of central Sichuan has high incidence of drought in spring and summer, while the northern hilly area of central Sichuan has the high incidence of drought in autumn and winter. This study can provide a theoretical basis for the drought control and mitigation measures in the hilly area of central Sichuan.
In recent years, seasonal droughts occur frequently in the hilly area of central Sichuan, resulting in serious impacts on the agricultural production in Sichuan. According to the daily meteorological data of eight meteorological stations from 1960 to 2011 in this area, the relative humidity index in the national standards was selected as the drought index, and linear trend meth2 od, Morlet wavelet, and inverse distance weighting interpolation method were used to investigate the spatial and temporal distri 2 bution of seasonal drought frequency and intensity. The results indicated that ( 1) drought frequency and intensity have large differences in different seasons, and they are significantly higher in spring and winter than those in summer and autumn, and drought occurs mainly in spring and winter; (2) on the temporal distribution, drought in spring and autumn tends to be worse while drought in summer and winter alleviates. Drought in spring has three cycle evolutions while drought in winter has 2 cycle evolutions; and ( 3) on the spatial distribution, the central hilly area of central Sichuan has high incidence of drought in spring and summer, while the northern hilly area of central Sichuan has the high incidence of drought in autumn and winter. This study can provide a theoretical basis for the drought control and mitigation measures in the hilly area of central Sichuan.
6 Application of time2series model on the temperature variation analysis in Weihai in recent 50 years
2015, 13(6):1051-1055.
Abstract:
The time 2series model with the statistical methods, such as trend analysis, wavelet transforms, and Mann 2Kendall mu2 tation test, were used to analyze the annual variations of average, maximum, and minimum temperatures, seasonal variations and time 2frequency characteristics of annual average temperature, and to conduct mutation test of average temperatures in Weihai from 1964 to 2013. The results showed that ( 1) the annual average temperature in Weihai increased from 1964 to 2013 with an inclination rate of 0 1 35 e / ( 10a) ; ( 2) the inclination rates of seasonal temperature were 01427 e / ( 10a) , 0 1 268 e /( 10a) , 01241 e /(10a) , and 0 1 287 e / (10a), and the largest contribution to the average annual temperature in the area was spring; (3) spring temperature appeared the alternate variations with down2up 2down 2up2down trends, and spring was the season with the most significant variations; (4)the mutation of annual average temperature occurred in 1987; and (5) temperature in each season increased significantly after the mutation.
The time 2series model with the statistical methods, such as trend analysis, wavelet transforms, and Mann 2Kendall mu2 tation test, were used to analyze the annual variations of average, maximum, and minimum temperatures, seasonal variations and time 2frequency characteristics of annual average temperature, and to conduct mutation test of average temperatures in Weihai from 1964 to 2013. The results showed that ( 1) the annual average temperature in Weihai increased from 1964 to 2013 with an inclination rate of 0 1 35 e / ( 10a) ; ( 2) the inclination rates of seasonal temperature were 01427 e / ( 10a) , 0 1 268 e /( 10a) , 01241 e /(10a) , and 0 1 287 e / (10a), and the largest contribution to the average annual temperature in the area was spring; (3) spring temperature appeared the alternate variations with down2up 2down 2up2down trends, and spring was the season with the most significant variations; (4)the mutation of annual average temperature occurred in 1987; and (5) temperature in each season increased significantly after the mutation.
2015, 13(6):1056-1059.
Abstract:
Chaersen reservoir undertakes the important tasks for the hinggan league area, such as irrigation, flood control and so on, its flood forecasting is significance. Due to the hydrogeological condition and characteristics of rainfall distribution, it is diffi 2 cult to obtain a better simulation by the single model or a set of parameters. This paper used unit Xin canjiang model and API model to forecast Chaersen reservoir flood respectively, and analyzed the applicability of the two models in the region. T he re 2 sults showed that forecast results by the models all met the requirement of the operational, and especially the heavy flood effect is better; If the antecedent soil is moist, both models were applicable, particularly the Xin c anjiang; If the antecedent soil is drought and rainfall intensity was larger, the Xincanjiang model is not applicable, it was supposed to choose the API model to forecast. Therefore, it is necessary for us to choose proper model according to the hydrogeological conditions and the characteris2 tics of rainfall distribution to improve the flood forecast accuracy and to direct reservoir regulation, in order to improve the eco2 nomic effectiveness.
Chaersen reservoir undertakes the important tasks for the hinggan league area, such as irrigation, flood control and so on, its flood forecasting is significance. Due to the hydrogeological condition and characteristics of rainfall distribution, it is diffi 2 cult to obtain a better simulation by the single model or a set of parameters. This paper used unit Xin canjiang model and API model to forecast Chaersen reservoir flood respectively, and analyzed the applicability of the two models in the region. T he re 2 sults showed that forecast results by the models all met the requirement of the operational, and especially the heavy flood effect is better; If the antecedent soil is moist, both models were applicable, particularly the Xin c anjiang; If the antecedent soil is drought and rainfall intensity was larger, the Xincanjiang model is not applicable, it was supposed to choose the API model to forecast. Therefore, it is necessary for us to choose proper model according to the hydrogeological conditions and the characteris2 tics of rainfall distribution to improve the flood forecast accuracy and to direct reservoir regulation, in order to improve the eco2 nomic effectiveness.
2015, 13(6):1060-1064.
Abstract:
According to the precipitation data of seven representative precipitation stations in the Yishu River Basin from 1954 to 2010, the variation characteristics of precipitation were analyzed using the correlation coefficient, frequency analysis method, ac 2 cumulative anomaly method, M orlet wavelet method, M ann2Kendall method, and R/ S method. T he results showed that ( 1) there is a significantly positive correlation between the precipitation data series of each station, and the average annual precipitation in2 creases gradually from north to south, while the annual variation magnitude of precipitation decreases from north to south; (2) the occurrence frequencies of partial wet year and normal year are the highest; (3) the variations of annual precipitation have un2 dergone three wet phases, one normal phase, and four dry phases; ( 4) the first characteristic time scales of annual precipitation, flood season precipitation, and non2flood season precipitation are 12 a, 12 a, and 5 a, respectively, the second characteristic time scales are 16 a, 17 a, and 5 a, respectively, and the third characteristic time scales are 4~ 5 a, 4~ 5 a, and 3 or 10 a, respectively; and (5) annual precipitation, flood season precipitation, and non2flood season precipitation have a decreasing trend, and precipi 2 tation of most stations will have a strong decreasing trend in the future.
According to the precipitation data of seven representative precipitation stations in the Yishu River Basin from 1954 to 2010, the variation characteristics of precipitation were analyzed using the correlation coefficient, frequency analysis method, ac 2 cumulative anomaly method, M orlet wavelet method, M ann2Kendall method, and R/ S method. T he results showed that ( 1) there is a significantly positive correlation between the precipitation data series of each station, and the average annual precipitation in2 creases gradually from north to south, while the annual variation magnitude of precipitation decreases from north to south; (2) the occurrence frequencies of partial wet year and normal year are the highest; (3) the variations of annual precipitation have un2 dergone three wet phases, one normal phase, and four dry phases; ( 4) the first characteristic time scales of annual precipitation, flood season precipitation, and non2flood season precipitation are 12 a, 12 a, and 5 a, respectively, the second characteristic time scales are 16 a, 17 a, and 5 a, respectively, and the third characteristic time scales are 4~ 5 a, 4~ 5 a, and 3 or 10 a, respectively; and (5) annual precipitation, flood season precipitation, and non2flood season precipitation have a decreasing trend, and precipi 2 tation of most stations will have a strong decreasing trend in the future.
2015, 13(6):1065-1068.
Abstract:
Based on the monthly precipitation data of 25 meteorological stations in the Haihe River Basin from 1960 to 2010, the inter 2annual precipitation characteristics in the Haihe River Basin were analyzed using the linear regression and cumulative a 2 nomaly curve methods. T he probability distribution of precipitation was analyzed using the Pearson III curve method, and the spatial variation of precipitation was analyzed using the spatial interpolation method. T he results showed that (1) precipitation in the Haihe River Basin has a slightly decreasing trend in recent 51 years, and the decreasing trend is stable recently; ( 2) there is a trend with more wet years while less dry years in the Haihe River Basin and the trend is increasing; (3) seasonal variation of precipitation is obvious; and (4) precipitation decreases trend from the south to the north.
Based on the monthly precipitation data of 25 meteorological stations in the Haihe River Basin from 1960 to 2010, the inter 2annual precipitation characteristics in the Haihe River Basin were analyzed using the linear regression and cumulative a 2 nomaly curve methods. T he probability distribution of precipitation was analyzed using the Pearson III curve method, and the spatial variation of precipitation was analyzed using the spatial interpolation method. T he results showed that (1) precipitation in the Haihe River Basin has a slightly decreasing trend in recent 51 years, and the decreasing trend is stable recently; ( 2) there is a trend with more wet years while less dry years in the Haihe River Basin and the trend is increasing; (3) seasonal variation of precipitation is obvious; and (4) precipitation decreases trend from the south to the north.
2015, 13(6):1069-1074.
Abstract:
The Baishi reservoir is an important water supply reservoir in the west of Liaoning Province, therefore an objective e 2 valuation of water quality contributes to the protection of water resource and provides the basis for scientific management of res2 ervoir. In this paper, the physical and chemical tendency analysis of the total nitrogen, ammonia nitrogen, dissolved oxygen and permanganate index was conducted based on water samples in the front dam of Baishi reservoir using the seasonal Kendall test method. The results showed that the total nitrogen in the Baishi reservoir exceeds the standard and has a deteriorative trend, so the management of water quality in the Baishi reservoir needs to be further strengthened.
The Baishi reservoir is an important water supply reservoir in the west of Liaoning Province, therefore an objective e 2 valuation of water quality contributes to the protection of water resource and provides the basis for scientific management of res2 ervoir. In this paper, the physical and chemical tendency analysis of the total nitrogen, ammonia nitrogen, dissolved oxygen and permanganate index was conducted based on water samples in the front dam of Baishi reservoir using the seasonal Kendall test method. The results showed that the total nitrogen in the Baishi reservoir exceeds the standard and has a deteriorative trend, so the management of water quality in the Baishi reservoir needs to be further strengthened.
2015, 13(6):1075-1079.
Abstract:
Water quality evaluation includes the description of water state and variation process of water quality. Due to the char2 acteristics of water quality, such as fuzziness, uncertainty, and randomness, the variable pattern recognition model was applied to evaluate water quality dynamics. T he weight was determined using the coupling analytic hierarchy process and entropy method, so the original water quality data and scientific research can be combined together. T he Monte Carlo method was used to analyze the effects of index uncertainty on water quality evaluation, and the model was used to conduct monthly evaluation of water quality dynamics in the Biliu reservoir. The results showed that water quality in the Biliu reservoir is between level II and III, there are no significant changes between each month but water quality in August and September are worse, and the main pollu2 tion index is total nitrogen.
Water quality evaluation includes the description of water state and variation process of water quality. Due to the char2 acteristics of water quality, such as fuzziness, uncertainty, and randomness, the variable pattern recognition model was applied to evaluate water quality dynamics. T he weight was determined using the coupling analytic hierarchy process and entropy method, so the original water quality data and scientific research can be combined together. T he Monte Carlo method was used to analyze the effects of index uncertainty on water quality evaluation, and the model was used to conduct monthly evaluation of water quality dynamics in the Biliu reservoir. The results showed that water quality in the Biliu reservoir is between level II and III, there are no significant changes between each month but water quality in August and September are worse, and the main pollu2 tion index is total nitrogen.
2015, 13(6):1080-1083.
Abstract:
Factor analysis method can convert a number of water quality indexes to a few comprehensive indexes and eliminate the correlation between indexes, so it can provide more objective water quality evaluation results. The factor analysis method was used to conduct the comprehensive evaluation of water quality in the Liao River Basin from 2006 to 2012. The results showed that the main impact factors of water quality are DO, COD, permanganate value, BOD, volatile phenol, fluoride, petrole 2 um, followed by PH and ammonia nitrogen. On the basis, the variation trend of water quality in the Liao River Basin from 2006 to 2012 was obtained, which suggested that water quality has improved gradually from 2006 to 2011, while becomes bad in 2012, but the trend of variation range is small without impacts on the general trend. Finally, the entropy weight method was used to validate the evaluation results from the factor analysis, which indicated both assessment results are similar.
Factor analysis method can convert a number of water quality indexes to a few comprehensive indexes and eliminate the correlation between indexes, so it can provide more objective water quality evaluation results. The factor analysis method was used to conduct the comprehensive evaluation of water quality in the Liao River Basin from 2006 to 2012. The results showed that the main impact factors of water quality are DO, COD, permanganate value, BOD, volatile phenol, fluoride, petrole 2 um, followed by PH and ammonia nitrogen. On the basis, the variation trend of water quality in the Liao River Basin from 2006 to 2012 was obtained, which suggested that water quality has improved gradually from 2006 to 2011, while becomes bad in 2012, but the trend of variation range is small without impacts on the general trend. Finally, the entropy weight method was used to validate the evaluation results from the factor analysis, which indicated both assessment results are similar.
2015, 13(6):1084-1088.
Abstract:
Cuihu Lake in Kunming City is a plateau lake recharged by reclaimed water. Based on four periods of week2long diurnal monitoring water quality data in Cuihu Lake from May to October in 2013, the spatial and temporal distributions of water trans2 parency and the relationship between transparency and T ( water temperature), pH, DO, Chla ( Chlorophyll a) , TP, SS, COD Cr , N/ P, TN, NH 4 2N, DTP, and DTN were analyzed. Additionally, SD was considered as the dependent variable, multiple regression analysis was conducted for each water environment factor. The results indicated that the water transparency in Cuihu Lake is lower in the western area (averaged 33. 6 cm, with deeper water and fewer aquatic plants) and higher in the eastern area (aver2 aged 61. 5 cm, with more aquatic plants and better water quality). The correlation analysis and multiple regression analysis showed that water transparency is negatively correlated with T, pH, DO, Chla, TP, SS, and COD Cr ( p< 0. 01) , and positively cor2 related with N/ P and T N ( p< 0. 01) . Chla is the primary and important factor affecting water transparency in Cuihu Lake, and COD Cr , TP are two significant water quality factors to impact the algae growth in Cuihu Lake. The research results can provide scientific reference for the improvement of water transparency and landscape value in plateau lake recharged by reclaimed water.
Cuihu Lake in Kunming City is a plateau lake recharged by reclaimed water. Based on four periods of week2long diurnal monitoring water quality data in Cuihu Lake from May to October in 2013, the spatial and temporal distributions of water trans2 parency and the relationship between transparency and T ( water temperature), pH, DO, Chla ( Chlorophyll a) , TP, SS, COD Cr , N/ P, TN, NH 4 2N, DTP, and DTN were analyzed. Additionally, SD was considered as the dependent variable, multiple regression analysis was conducted for each water environment factor. The results indicated that the water transparency in Cuihu Lake is lower in the western area (averaged 33. 6 cm, with deeper water and fewer aquatic plants) and higher in the eastern area (aver2 aged 61. 5 cm, with more aquatic plants and better water quality). The correlation analysis and multiple regression analysis showed that water transparency is negatively correlated with T, pH, DO, Chla, TP, SS, and COD Cr ( p< 0. 01) , and positively cor2 related with N/ P and T N ( p< 0. 01) . Chla is the primary and important factor affecting water transparency in Cuihu Lake, and COD Cr , TP are two significant water quality factors to impact the algae growth in Cuihu Lake. The research results can provide scientific reference for the improvement of water transparency and landscape value in plateau lake recharged by reclaimed water.
2015, 13(6):1089-1092.
Abstract:
In this paper, the Chinese administrative division is regarded as the analysis unit, the vector data of Chinese administra 2 tive district map, Chinese forest coverage map, Chinese flora map, and Chinese vegetation zoning map are overlaid using the spa 2 tial analysis function of ArcGIS. T he information of vegetation zoning and flora, as well as forest coverage is obtained through the analysis of unit data. On the basis of Chinese vegetation zoning information using the second 2order cluster analysis method, the spatial disparities characteristics of vegetation are analyzed. The proportion of the first class, second class, and third class vegetation is 30B37B23, which reflects a strong spatial variation of vegetation distribution. The proportion of fourth class vege 2 tation is about 10%, which reflects the regional variation from the overall vegetation distribution. The first class vegetation mostly exists in the region of high latitudes, the second class is everywhere, and the third class is located in the region of low lat2 itudes.
In this paper, the Chinese administrative division is regarded as the analysis unit, the vector data of Chinese administra 2 tive district map, Chinese forest coverage map, Chinese flora map, and Chinese vegetation zoning map are overlaid using the spa 2 tial analysis function of ArcGIS. T he information of vegetation zoning and flora, as well as forest coverage is obtained through the analysis of unit data. On the basis of Chinese vegetation zoning information using the second 2order cluster analysis method, the spatial disparities characteristics of vegetation are analyzed. The proportion of the first class, second class, and third class vegetation is 30B37B23, which reflects a strong spatial variation of vegetation distribution. The proportion of fourth class vege 2 tation is about 10%, which reflects the regional variation from the overall vegetation distribution. The first class vegetation mostly exists in the region of high latitudes, the second class is everywhere, and the third class is located in the region of low lat2 itudes.
2015, 13(6):1093-1096.
Abstract:
With the increasingly prominent water environment pollution problem, the demand of water quality risk assessment is rapidly increasing as well. In this article, we chose the one 2dimensional steady state water quality model 2QUAL2K model, which has small data demand and is broadly applied to river network model, to simulate the water quality and evaluate the water quali 2 ty risk. In order to simplify the model development process, improve the calculation efficiency, optimize display effects of model results, and achieve the application in water quality risk assessment, we transformed the QUAL2K model into B/S architecture system integration, utilized ArcGIS platform to achieve the visually dynamic display of water quality simulation results and the 2 matic map production, and then proposed the water quality risk assessment method from the water quality risk probability based on time step water quality simulation results. The method can provide the decision 2making basis for the water environment man2 agement.
With the increasingly prominent water environment pollution problem, the demand of water quality risk assessment is rapidly increasing as well. In this article, we chose the one 2dimensional steady state water quality model 2QUAL2K model, which has small data demand and is broadly applied to river network model, to simulate the water quality and evaluate the water quali 2 ty risk. In order to simplify the model development process, improve the calculation efficiency, optimize display effects of model results, and achieve the application in water quality risk assessment, we transformed the QUAL2K model into B/S architecture system integration, utilized ArcGIS platform to achieve the visually dynamic display of water quality simulation results and the 2 matic map production, and then proposed the water quality risk assessment method from the water quality risk probability based on time step water quality simulation results. The method can provide the decision 2making basis for the water environment man2 agement.
2015, 13(6):1097-1100.
Abstract:
Attribute reduction of rough set (RS) theory was applied to select the evaluation indexes of groundwater environment quality. AHP and entropy methods were used to decide the weight of each evaluation index, and the relative similarity degree of each sample was determined based on the combination method of TOPSIS and gray correlation. Then, the RS 2T OPSIS model was developed to perform the evaluation of groundwater environment quality. The evaluation model was applied to assess groundwater environment quality in the Huaihe River Basin. T he results showed that among 13 groundwater sampling sites, 2 sampling sites belong to level I, II, and III respectively and the remaining 5 sampling sites belong to level IV, which is consistent with the results obtained from the evaluation model with T OPSIS and gray correlation.
Attribute reduction of rough set (RS) theory was applied to select the evaluation indexes of groundwater environment quality. AHP and entropy methods were used to decide the weight of each evaluation index, and the relative similarity degree of each sample was determined based on the combination method of TOPSIS and gray correlation. Then, the RS 2T OPSIS model was developed to perform the evaluation of groundwater environment quality. The evaluation model was applied to assess groundwater environment quality in the Huaihe River Basin. T he results showed that among 13 groundwater sampling sites, 2 sampling sites belong to level I, II, and III respectively and the remaining 5 sampling sites belong to level IV, which is consistent with the results obtained from the evaluation model with T OPSIS and gray correlation.
2015, 13(6):1101-1104.
Abstract:
In this paper, a simplified equivalent model was proposed to analyze the sloshing fluid in the pipeline bridge. The water motion in a pipeline bridge is assumed to be inviscid, irrotational, compressible, and linear (small displacement) . T he transverse sloshing fluid in a pipeline bridge can be simplified as a fixed rigid mass M 0 and a mass2spring system ( M 1 , K 1 ) . According to the equivalence rule, the actual fluid ( computed by the finite element model) and its equivalent model have the same the first sloshing frequency and the same effects on the pipe. The approximate analytical formulae of the fixed mass M 0 , mass2spring oscillator (M 1 , K 1 ) , and its locations in the pipe were acquired by the least2squares and curve fitting algorithms. T he simplified equivalent fluid model and fininte element model were used to calculate the first natural frequency and seismic response of a pipeline bridege (fluid 2structure coupling system). The numerical results calculated by the two fluid models agreed well, which confirmed the validity and accuracy of the equivalent model. Therefore, the simplified model of sloshing fluid can analyze the seismic response of the support structure of pipeline bridge, which can provide reference of seismic resistance for the researchers and structural engineers.
In this paper, a simplified equivalent model was proposed to analyze the sloshing fluid in the pipeline bridge. The water motion in a pipeline bridge is assumed to be inviscid, irrotational, compressible, and linear (small displacement) . T he transverse sloshing fluid in a pipeline bridge can be simplified as a fixed rigid mass M 0 and a mass2spring system ( M 1 , K 1 ) . According to the equivalence rule, the actual fluid ( computed by the finite element model) and its equivalent model have the same the first sloshing frequency and the same effects on the pipe. The approximate analytical formulae of the fixed mass M 0 , mass2spring oscillator (M 1 , K 1 ) , and its locations in the pipe were acquired by the least2squares and curve fitting algorithms. T he simplified equivalent fluid model and fininte element model were used to calculate the first natural frequency and seismic response of a pipeline bridege (fluid 2structure coupling system). The numerical results calculated by the two fluid models agreed well, which confirmed the validity and accuracy of the equivalent model. Therefore, the simplified model of sloshing fluid can analyze the seismic response of the support structure of pipeline bridge, which can provide reference of seismic resistance for the researchers and structural engineers.
2015, 13(6):1105-1109.
Abstract:
The scheme design of numerical simulation on tilt angle Aand tilt angle Bof gill2piece applied the uniform experimental design theory. With the sediment velocity on the upper surface of gill 2piece 3 as the evaluation index, velocity flow field was sim2 ulated under different tilt angles of gill2piece through the adoption of Eulerian model provided by the Fluent software. The pro2 jection pursuit regression (PPR) was used to analyze the numerical simulation results. The results showed that the influence of angle B on the effect of water 2sediment separation in the gill 2piece separation device is the highest, followed by the tilt angle A. The velocity field of gill 2piece separation device is beneficial to increase water 2 sediment separation and the effect of water 2sedi 2 ment separation is the best under the combination of A = 60b and B = 45b.
The scheme design of numerical simulation on tilt angle Aand tilt angle Bof gill2piece applied the uniform experimental design theory. With the sediment velocity on the upper surface of gill 2piece 3 as the evaluation index, velocity flow field was sim2 ulated under different tilt angles of gill2piece through the adoption of Eulerian model provided by the Fluent software. The pro2 jection pursuit regression (PPR) was used to analyze the numerical simulation results. The results showed that the influence of angle B on the effect of water 2sediment separation in the gill 2piece separation device is the highest, followed by the tilt angle A. The velocity field of gill 2piece separation device is beneficial to increase water 2 sediment separation and the effect of water 2sedi 2 ment separation is the best under the combination of A = 60b and B = 45b.
2015, 13(6):1110-1113.
Abstract:
Form the static cone penetration model test of clay with low liquid limit, the relationships among the tip resistance, side friction, specific penetration resistance, dry density, and water content were determined as well as the variation law of the above parameters. T he results showed that (1) the tip resistance has good correlation with the specific penetration resistance, and the tip resistance is 0. 86~ 0. 92 times of the specific penetration resistance; (2) variation of the stress mechanism for the surround2 ing soil of probe is the main reason for the generation of critical depth; (3) under the same water content, the tip resistance has a logarithmic relationship with the dry density in the rectangular coordinate system, and there is a linear relationship between log tip resistance and log dry density; and ( 4) under the same dry density, the tip resistance has a negative correlation with wa 2 ter content, and the linear relationship between the tip resistance and water content becomes weaker with the increasing of dry density.
Form the static cone penetration model test of clay with low liquid limit, the relationships among the tip resistance, side friction, specific penetration resistance, dry density, and water content were determined as well as the variation law of the above parameters. T he results showed that (1) the tip resistance has good correlation with the specific penetration resistance, and the tip resistance is 0. 86~ 0. 92 times of the specific penetration resistance; (2) variation of the stress mechanism for the surround2 ing soil of probe is the main reason for the generation of critical depth; (3) under the same water content, the tip resistance has a logarithmic relationship with the dry density in the rectangular coordinate system, and there is a linear relationship between log tip resistance and log dry density; and ( 4) under the same dry density, the tip resistance has a negative correlation with wa 2 ter content, and the linear relationship between the tip resistance and water content becomes weaker with the increasing of dry density.
2015, 13(6):1114-1117.
Abstract:
The relative hydraulic conductivity of unsaturated soil is sensitive to the change of saturation, so it is hard to determine the relative hydraulic conductivity through experiments. Based on the generalized Darcy cs Law and van Genuchten cs model, a simplified numerical model for predicting the relative hydraulic conductivity of unsaturated soil was derived. T hrough the simple evaporation experiment and numerical analysis, the relative hydraulic conductivity with function of water saturation was ob2 tained. T he numerical results were compared with the observed experimental data, which suggested that this method has certain reliability and it has certain innovation in the aspects of the finite element back analysis of model parameters. However, the prac 2 tical accuracy of the new method needs further verification through experimental comparison.
The relative hydraulic conductivity of unsaturated soil is sensitive to the change of saturation, so it is hard to determine the relative hydraulic conductivity through experiments. Based on the generalized Darcy cs Law and van Genuchten cs model, a simplified numerical model for predicting the relative hydraulic conductivity of unsaturated soil was derived. T hrough the simple evaporation experiment and numerical analysis, the relative hydraulic conductivity with function of water saturation was ob2 tained. T he numerical results were compared with the observed experimental data, which suggested that this method has certain reliability and it has certain innovation in the aspects of the finite element back analysis of model parameters. However, the prac 2 tical accuracy of the new method needs further verification through experimental comparison.
2015, 13(6):1118-1123.
Abstract:
On the basis of creating water flow regime partitions in the impact zone of bottom2flow dissipation with step 2down floor and the theory of free turbulent jet flow, an empirical formula of time 2averaged dynamic water pressure in the impact zone was obtained under different incident angles. The distribution diagram of dynamic water pressure in the impact zone was ana 2 lyzed using matlab. The effects of step 2down floor on the dynamic water pressure under the same incident angle and flow rate, and the effects of incident flow rate on the dynamic water pressure under the same incident angle and step 2down floor were in2 vestigated, and the most vulnerable area to damage and abrasion in the impact zone was determined. A reservoir project was se 2 lected as the case study. The relevant parameters of the empirical formula were deduced based on the measured data to verify the feasibility of the empirical formula. With the knowledge of the bottom velocity, the abrasion resistance strength of concrete floor in the impact zone of bottom2flow dissipation was obtained. The research can provide reference for the strength classification of concrete floor of bottom2flow dissipation.
On the basis of creating water flow regime partitions in the impact zone of bottom2flow dissipation with step 2down floor and the theory of free turbulent jet flow, an empirical formula of time 2averaged dynamic water pressure in the impact zone was obtained under different incident angles. The distribution diagram of dynamic water pressure in the impact zone was ana 2 lyzed using matlab. The effects of step 2down floor on the dynamic water pressure under the same incident angle and flow rate, and the effects of incident flow rate on the dynamic water pressure under the same incident angle and step 2down floor were in2 vestigated, and the most vulnerable area to damage and abrasion in the impact zone was determined. A reservoir project was se 2 lected as the case study. The relevant parameters of the empirical formula were deduced based on the measured data to verify the feasibility of the empirical formula. With the knowledge of the bottom velocity, the abrasion resistance strength of concrete floor in the impact zone of bottom2flow dissipation was obtained. The research can provide reference for the strength classification of concrete floor of bottom2flow dissipation.
2015, 13(6):1124-1127.
Abstract:
In this paper, the effects of hydraulic factors and sediment characteristics in turbid water on the abrasion state of tur2 bine were studied, the turbine flow index data of main power stations were analyzed, the test parameters, design parameters, and key issues of turbine abrasion test equipment were determined, the principle of rotating 2jet mode abrasion test was illustrated, and the overall structure design of the test equipment was developed. The test equipment can expand the applicable working conditions, adjust the grinding speed and grinding angle, and improve the efficiency of abrasion test.
In this paper, the effects of hydraulic factors and sediment characteristics in turbid water on the abrasion state of tur2 bine were studied, the turbine flow index data of main power stations were analyzed, the test parameters, design parameters, and key issues of turbine abrasion test equipment were determined, the principle of rotating 2jet mode abrasion test was illustrated, and the overall structure design of the test equipment was developed. The test equipment can expand the applicable working conditions, adjust the grinding speed and grinding angle, and improve the efficiency of abrasion test.
2015, 13(6):1128-1132.
Abstract:
In this paper, microwave drying of dredged sediment was carried out using domestic microwave oven in order to ex2 plore a new way of effective dry processing for dredge sediment. Effects of different sediment thicknesses and microwave power outputs on the drying characteristics of dredged sediment by microwave energy were discussed and the unit energy consumption was analyzed, and thin layer drying modelwas introduced to simulate the drying process. The results showed that the decreasing rate of dry basis moisture content reduced and the drying time extended with the increasing of sediment thickness successively the drying time shortened significantly with the increasing of the powers; and the maximum drying rate of 10 mm thick sediment was about 3. 0 times of that of 40 mm thick sediment. T he unit energy consumption analysis showed that the unit energy con2 sumption was lower under 280 W for different thicknesses of sediment, and energy utilization was more effective. Modified Page 2 I model was determined to be applicable to analyze the microwave drying of sediment through the analysis of experimental data, and the model had good fittings. Therefore, the model can be used to predict the drying time for different thicknesses of dredged sediment with different moisture contents.
In this paper, microwave drying of dredged sediment was carried out using domestic microwave oven in order to ex2 plore a new way of effective dry processing for dredge sediment. Effects of different sediment thicknesses and microwave power outputs on the drying characteristics of dredged sediment by microwave energy were discussed and the unit energy consumption was analyzed, and thin layer drying modelwas introduced to simulate the drying process. The results showed that the decreasing rate of dry basis moisture content reduced and the drying time extended with the increasing of sediment thickness successively the drying time shortened significantly with the increasing of the powers; and the maximum drying rate of 10 mm thick sediment was about 3. 0 times of that of 40 mm thick sediment. T he unit energy consumption analysis showed that the unit energy con2 sumption was lower under 280 W for different thicknesses of sediment, and energy utilization was more effective. Modified Page 2 I model was determined to be applicable to analyze the microwave drying of sediment through the analysis of experimental data, and the model had good fittings. Therefore, the model can be used to predict the drying time for different thicknesses of dredged sediment with different moisture contents.
24 Experimental research on creep characteristics of aquifer sand sediments in Xican under high stress
2015, 13(6):1133-1137.
Abstract:
For a better understanding of the mechanism of land subsidence in Xi can, a high2stress consolidation system was de 2 signed, and several tests on the medium2 to fine 2grained sand sediments were conducted under different stresses. T he variations of overlaying pressure and water table of confined aquifer were simulated using the system, and one 2dimensional creep deforma 2 tion tests were conducted under high stress. T he results showed that ( 1) the creep characteristics of aquifer sand is not only af2 fected by the magnitude of effective stress but also the stress history; (2) when the confined water level decreases, the compres2 sive deformation of sand samples shows obvious creep characteristics; (3) when the confined water level increases, the sand samples begin to expand but the creep characteristics are insignificant; and ( 4) according to the comparison of laser granularity analysis curve and scanning electron microscope before and after the tests, the creep deformation of aquifer sand is not only re 2 lated to the slip dislocation but also the fracture of sand sediments. The generalized Kelvin model was proposed to characterize the creep deformation of aquifer sand in Xi can based on the summary of experiments and deformation mechanism. The five rheo2 logical parameters in the generalized Kelvin odel were not constant but varied with the effective stress.
For a better understanding of the mechanism of land subsidence in Xi can, a high2stress consolidation system was de 2 signed, and several tests on the medium2 to fine 2grained sand sediments were conducted under different stresses. T he variations of overlaying pressure and water table of confined aquifer were simulated using the system, and one 2dimensional creep deforma 2 tion tests were conducted under high stress. T he results showed that ( 1) the creep characteristics of aquifer sand is not only af2 fected by the magnitude of effective stress but also the stress history; (2) when the confined water level decreases, the compres2 sive deformation of sand samples shows obvious creep characteristics; (3) when the confined water level increases, the sand samples begin to expand but the creep characteristics are insignificant; and ( 4) according to the comparison of laser granularity analysis curve and scanning electron microscope before and after the tests, the creep deformation of aquifer sand is not only re 2 lated to the slip dislocation but also the fracture of sand sediments. The generalized Kelvin model was proposed to characterize the creep deformation of aquifer sand in Xi can based on the summary of experiments and deformation mechanism. The five rheo2 logical parameters in the generalized Kelvin odel were not constant but varied with the effective stress.
2015, 13(6):1138-1142.
Abstract:
Pressure plate extractor is used to study the soil water characteristic curve of unsaturated remolded soil under different dry densities. The results showed that (1) when the sample has smaller dry density, the slope of soil water characteristic curve has higher variation during the low suction segment, the residual water rate is lower, and the moisture holding capacity is worse; ( 2) with the increase of suction, the decreasing range of moisture content becomes smaller with the increase of matrix suction and tends towards stability; ( 3) the power function has good results to fit the obtained data obtained; and ( 4) the soil water characteristic curve results are similar to those tested by VG model. At the same time, penetration tests were carried out for the soil samples under each suction effect using the micro penetrometer, and the relationships between matric suction and bearing capacity of the foundation, liquid index, and compression modulus were obtained.
Pressure plate extractor is used to study the soil water characteristic curve of unsaturated remolded soil under different dry densities. The results showed that (1) when the sample has smaller dry density, the slope of soil water characteristic curve has higher variation during the low suction segment, the residual water rate is lower, and the moisture holding capacity is worse; ( 2) with the increase of suction, the decreasing range of moisture content becomes smaller with the increase of matrix suction and tends towards stability; ( 3) the power function has good results to fit the obtained data obtained; and ( 4) the soil water characteristic curve results are similar to those tested by VG model. At the same time, penetration tests were carried out for the soil samples under each suction effect using the micro penetrometer, and the relationships between matric suction and bearing capacity of the foundation, liquid index, and compression modulus were obtained.
2015, 13(6):1143-1146.
Abstract:
Soil thermal parameters play an important role in estimating ground heat flux and investigating ground energy balance. In this paper, based on the measured soil temperature data, thermal diffusivity of shallow soil was estimated using the harmonic method and heat conductivity and convection method, and then the heat flux was calculated and compared with that measured by the heat flux plate to verify the applicability of the two methods. T he results showed that (1) the thermal diffusivities estimated by both the harmonic method and conductivity and convection method are reasonable; ( 2) the harmonic method can simulate the soil temperature of vertical profile better than the heat conductivity and convection method; and ( 3) the harmonic method under2 estimates the maximum heat flux during daytime and minimum heat flux at night, whereas the heat conductivity and convection method can perform good simulation of soil heat flux at night.
Soil thermal parameters play an important role in estimating ground heat flux and investigating ground energy balance. In this paper, based on the measured soil temperature data, thermal diffusivity of shallow soil was estimated using the harmonic method and heat conductivity and convection method, and then the heat flux was calculated and compared with that measured by the heat flux plate to verify the applicability of the two methods. T he results showed that (1) the thermal diffusivities estimated by both the harmonic method and conductivity and convection method are reasonable; ( 2) the harmonic method can simulate the soil temperature of vertical profile better than the heat conductivity and convection method; and ( 3) the harmonic method under2 estimates the maximum heat flux during daytime and minimum heat flux at night, whereas the heat conductivity and convection method can perform good simulation of soil heat flux at night.
2015, 13(6):1147-1150.
Abstract:
ANSYS was used to perform the finite element analysis of unsteady seepage of seawall. T he osmotic pressure sequence and corresponding permeability parameters were collected to act as the input layer and output layer of the neural network, and the nonlinear mapping relationship between the osmotic pressure and permeability parameters of seawall was developed. Based on the results, the observed osmotic pressure sequence was put into the trained BP neural network to conduct the back analysis of the permeability parameters of seawall. The inversion results were analyzed using the finite element method, which showed that the simulated and measured osmotic pressures at the monitoring points are similar.
ANSYS was used to perform the finite element analysis of unsteady seepage of seawall. T he osmotic pressure sequence and corresponding permeability parameters were collected to act as the input layer and output layer of the neural network, and the nonlinear mapping relationship between the osmotic pressure and permeability parameters of seawall was developed. Based on the results, the observed osmotic pressure sequence was put into the trained BP neural network to conduct the back analysis of the permeability parameters of seawall. The inversion results were analyzed using the finite element method, which showed that the simulated and measured osmotic pressures at the monitoring points are similar.
2015, 13(6):1151-1155.
Abstract:
With the rapidly economic development in the Loess Plateau, the site has become a bottleneck restricting the develop2 ment of local economy, which leads to inevitable slope cutting and therefore a large number of catastrophic loess landslides. Ac 2 cording to the limit equilibrium theory of slope instability caused by excavation, the variation characteristics of stress, strain, and yield zone were analyzed under different scales. T he results showed that the excavation area forms horizontal load decrement, the top of slope is prone to the occurrence of tension crack, and the excavation can accelerate the formation of the yield surface from top to bottom. Finally, the excavation slope stability was analyzed under different scales. The research results are of scientific and guiding significance on the excavation slope in the loess area.
With the rapidly economic development in the Loess Plateau, the site has become a bottleneck restricting the develop2 ment of local economy, which leads to inevitable slope cutting and therefore a large number of catastrophic loess landslides. Ac 2 cording to the limit equilibrium theory of slope instability caused by excavation, the variation characteristics of stress, strain, and yield zone were analyzed under different scales. T he results showed that the excavation area forms horizontal load decrement, the top of slope is prone to the occurrence of tension crack, and the excavation can accelerate the formation of the yield surface from top to bottom. Finally, the excavation slope stability was analyzed under different scales. The research results are of scientific and guiding significance on the excavation slope in the loess area.
2015, 13(6):1156-1161.
Abstract:
A three 2dimensional water 2heat coupled numerical model was developed to simulate and analyze the evolution of seep2 age and temperature fields under different layout schemes of pumping and injection wells in the Yupinxuan food industrial park of Xi can. The results showed that ( 1) the variation of groundwater temperature field is not only associated with the natural groundwater flow field, but also affected by the layout of pumping and injection wells, and the layout with injection wells on the opposite side has greater effects on the geothermal field than that with the injection wells on the same side; ( 2) the greater the distance between wells is, the longer the thermal transfixion of pumping wells encounters; ( 3) from the point of view of re 2 charge, the layout with injection wells on the opposite side is better than the layout with injection wells on the same side; and ( 4) from the point of view of controlling transfixion, the layout with injection wells on the same side is better than the layout with injection wells on the opposite side. According to the specific conditions of test site, both layout schemes broke through the phenomenon of thermal transfixion, and the layout with injection wells on the opposite side was selected if only the effects of seepage field were considered.
A three 2dimensional water 2heat coupled numerical model was developed to simulate and analyze the evolution of seep2 age and temperature fields under different layout schemes of pumping and injection wells in the Yupinxuan food industrial park of Xi can. The results showed that ( 1) the variation of groundwater temperature field is not only associated with the natural groundwater flow field, but also affected by the layout of pumping and injection wells, and the layout with injection wells on the opposite side has greater effects on the geothermal field than that with the injection wells on the same side; ( 2) the greater the distance between wells is, the longer the thermal transfixion of pumping wells encounters; ( 3) from the point of view of re 2 charge, the layout with injection wells on the opposite side is better than the layout with injection wells on the same side; and ( 4) from the point of view of controlling transfixion, the layout with injection wells on the same side is better than the layout with injection wells on the opposite side. According to the specific conditions of test site, both layout schemes broke through the phenomenon of thermal transfixion, and the layout with injection wells on the opposite side was selected if only the effects of seepage field were considered.
2015, 13(6):1162-1167.
Abstract:
Permeability coefficient of saturated clay is an important parameter in hydrogeology, and its testing methods include la 2 boratory and in 2situ methods according to different testing sites. Darcy cs Law and Terzaghi consolidation theory are main theo2 ries applied in the testing methods. However, there is not a complete test system, and current testing methods and instruments have their own deficiencies and irrationality. In this paper, the history of measurement methods of permeability coefficient in the saturated clay is reviewed, the mechanism of the seepage in the saturated soil is discussed, and the laboratory and in 2situ testing methods are summarized. Besides the traditional testing methods, the new test methods to determine permeability coefficient, such as tracer method and consolidation curve, are introduced. Finally, the paper discusses how to determine permeability coeffi 2 cient in the saturated soil.
Permeability coefficient of saturated clay is an important parameter in hydrogeology, and its testing methods include la 2 boratory and in 2situ methods according to different testing sites. Darcy cs Law and Terzaghi consolidation theory are main theo2 ries applied in the testing methods. However, there is not a complete test system, and current testing methods and instruments have their own deficiencies and irrationality. In this paper, the history of measurement methods of permeability coefficient in the saturated clay is reviewed, the mechanism of the seepage in the saturated soil is discussed, and the laboratory and in 2situ testing methods are summarized. Besides the traditional testing methods, the new test methods to determine permeability coefficient, such as tracer method and consolidation curve, are introduced. Finally, the paper discusses how to determine permeability coeffi 2 cient in the saturated soil.
2015, 13(6):1168-1171.
Abstract:
In this paper, the development history and characteristics and formation mechanism of land subsidence in Nantong were analyzed, which suggested that land subsidence is related to groundwater level decline caused by excessive groundwater pumping. The results showed that the rate of land subsidence has positive correlation with groundwater level decline and the ar2 ea with high land subsidence rate is consistent with the area of high groundwater level decline rate. Finally, control measures of land subsidence prevention were proposed.
In this paper, the development history and characteristics and formation mechanism of land subsidence in Nantong were analyzed, which suggested that land subsidence is related to groundwater level decline caused by excessive groundwater pumping. The results showed that the rate of land subsidence has positive correlation with groundwater level decline and the ar2 ea with high land subsidence rate is consistent with the area of high groundwater level decline rate. Finally, control measures of land subsidence prevention were proposed.
2015, 13(6):1172-1176.
Abstract:
The landslide is the one of main geological disasters in Wangcang County of Sichuan Province. The occurrence of land2 slide in this county is primarily controlled by the factors such as lithology, topography. and precipitation. Based on 90 historical landslides in Wangcang County, a grey assessment system was developed using entropy thesis to analyze the distribution law of landslides and determine the zonation of landslide risk in Wangcang County. The results showed that the high occurrence of landslide is mainly located in the areas where the landscape type is medium mountain of tectonic erosion, the slope range is from 15 b to 60b, the precipitation is rich, or the stratum is the loose deposit. Additionally, 39 unstable slopes were used to verify the assessment accuracy, which suggested that the grey system based on the entropy thesis can provide reliable landslide risk as2 sessment.
The landslide is the one of main geological disasters in Wangcang County of Sichuan Province. The occurrence of land2 slide in this county is primarily controlled by the factors such as lithology, topography. and precipitation. Based on 90 historical landslides in Wangcang County, a grey assessment system was developed using entropy thesis to analyze the distribution law of landslides and determine the zonation of landslide risk in Wangcang County. The results showed that the high occurrence of landslide is mainly located in the areas where the landscape type is medium mountain of tectonic erosion, the slope range is from 15 b to 60b, the precipitation is rich, or the stratum is the loose deposit. Additionally, 39 unstable slopes were used to verify the assessment accuracy, which suggested that the grey system based on the entropy thesis can provide reliable landslide risk as2 sessment.
2015, 13(6):1177-1180.
Abstract:
Submerged pipeline project may encounter anti 2uplift break and embankment settlement and deformation. How to de 2 termine the anti 2uplift buried depth and ultimate settlement in the design is a key problem to be solved to ensure project safety. In this paper, a cross2river submerged pipeline was taken as an example, an optimal algorithm based on finite element method was proposed to obtain a more practical and reasonable anti 2uplift buried depth in consideration of the overlying soil layer inten2 sity, flood passage and erosion, and earthquake load. In addition, ground loss was simulated based on the ultimate shrinkage of pipeline, and the vertical ultimate settlement and displacement were obtained eventually. The results can provide the basis for the project design and subsequent settlement monitoring.
Submerged pipeline project may encounter anti 2uplift break and embankment settlement and deformation. How to de 2 termine the anti 2uplift buried depth and ultimate settlement in the design is a key problem to be solved to ensure project safety. In this paper, a cross2river submerged pipeline was taken as an example, an optimal algorithm based on finite element method was proposed to obtain a more practical and reasonable anti 2uplift buried depth in consideration of the overlying soil layer inten2 sity, flood passage and erosion, and earthquake load. In addition, ground loss was simulated based on the ultimate shrinkage of pipeline, and the vertical ultimate settlement and displacement were obtained eventually. The results can provide the basis for the project design and subsequent settlement monitoring.
2015, 13(6):1181-1184.
Abstract:
The evaluation index system of water security was developed using the Analytic Hierarchy Process (AHP) method. On the basis, a water security model was established using the projection pursuit method, and applied to perform the comprehensive evaluation of water security in the Lower Liao River Plain on the regional scale. The results showed that water security is safe in Fushun and Li 2 aoyang, relatively safe in Shenyang and Anshan, andunsafe in Jinzhou, Yingkou, Tieling, and Panjin. The water security evaluation mod2 el based on projection pursuit method is applicable and can be applied to assess regional water security.
The evaluation index system of water security was developed using the Analytic Hierarchy Process (AHP) method. On the basis, a water security model was established using the projection pursuit method, and applied to perform the comprehensive evaluation of water security in the Lower Liao River Plain on the regional scale. The results showed that water security is safe in Fushun and Li 2 aoyang, relatively safe in Shenyang and Anshan, andunsafe in Jinzhou, Yingkou, Tieling, and Panjin. The water security evaluation mod2 el based on projection pursuit method is applicable and can be applied to assess regional water security.
2015, 13(6):1185-1190.
Abstract:
On the basis of summarizing the attributes of urban ecosystem and analyzing its content of health, an evaluation indica 2 tor system was established using the frequency statistics. A fuzzy matter model was then developed using the Hamming ap2 proach degree to estimate the urban ecosystem health in Zhengzhou, Luoyang, and Xuchang (the first batch of the experimental units of water eco 2civilization construction in Henan Province) from 2000 to 2013 and analyze the impact factors of urban eco2 system health. The results showed that (1) the level of urban ecosystem health in Zhengzhou, Luoyang, and Xuchang is impro2 ving slightly, but some indexes tend towards worse; (2) the level of urban ecosystem health from high to low is Zhengzhou, Luoyang, and Xuchang, but the improving rate in Xuchang is the highest while the lowest in Zhengzhou; and ( 3) the health de 2 gree differs in different cities and the harmony between each index is low. Consequently, we should focus on the development of indexes with low health degree, improve the harmony between each index, and increase the health level of urban ecosystem.
On the basis of summarizing the attributes of urban ecosystem and analyzing its content of health, an evaluation indica 2 tor system was established using the frequency statistics. A fuzzy matter model was then developed using the Hamming ap2 proach degree to estimate the urban ecosystem health in Zhengzhou, Luoyang, and Xuchang (the first batch of the experimental units of water eco 2civilization construction in Henan Province) from 2000 to 2013 and analyze the impact factors of urban eco2 system health. The results showed that (1) the level of urban ecosystem health in Zhengzhou, Luoyang, and Xuchang is impro2 ving slightly, but some indexes tend towards worse; (2) the level of urban ecosystem health from high to low is Zhengzhou, Luoyang, and Xuchang, but the improving rate in Xuchang is the highest while the lowest in Zhengzhou; and ( 3) the health de 2 gree differs in different cities and the harmony between each index is low. Consequently, we should focus on the development of indexes with low health degree, improve the harmony between each index, and increase the health level of urban ecosystem.
2015, 13(6):1191-1196.
Abstract:
According to the relevant planning of South 2to 2North Water Transfer Project ( SNWTP), after the water supply for domestic and industrial uses from the first stage of the Middle Route Project, the regulating reservoirs in the water receiving district need to return the water supply for agricultural and ecological uses, and therefore the operation and management mode of regulating reservoirs needs be adjusted. Thirteen regulating reservoirs in the water receiving district in the Middle Route of SNWTP were selected to investigate their current management status, requirements for management adjustment, and existing problems. T he functional variation of regulating reservoirs, current management status and income of reservoir administration were analyzed. The new situation and main problems for the adjustment of operation and management mode of regulating reser2 voirs were analyzed, and suggestions for improvement were proposed, which can provide support for the normal operation and management of regulating reservoirs, exerting benefit of Middle Route of SNWT P, and optimal operation of water resources in the water receiving district of SNWTP.
According to the relevant planning of South 2to 2North Water Transfer Project ( SNWTP), after the water supply for domestic and industrial uses from the first stage of the Middle Route Project, the regulating reservoirs in the water receiving district need to return the water supply for agricultural and ecological uses, and therefore the operation and management mode of regulating reservoirs needs be adjusted. Thirteen regulating reservoirs in the water receiving district in the Middle Route of SNWTP were selected to investigate their current management status, requirements for management adjustment, and existing problems. T he functional variation of regulating reservoirs, current management status and income of reservoir administration were analyzed. The new situation and main problems for the adjustment of operation and management mode of regulating reser2 voirs were analyzed, and suggestions for improvement were proposed, which can provide support for the normal operation and management of regulating reservoirs, exerting benefit of Middle Route of SNWT P, and optimal operation of water resources in the water receiving district of SNWTP.
2015, 13(6):1197-1202.
Abstract:
Water resources consumption of hotels is very large. Based on the sample investigation of 11 hotels in Tianjin, the structure of water utilization and water balance test reports of 6 hotels were analyzed. The main factors affecting water con2 sumption in hotels were identified through the principal component analysis and correlation analysis. T he basal water use quotas of hotels with different levels were calculated using the statistical analysis methods, including simple average method, weighted 2 average method, secondary average method, and probabilistic evaluation method. According to the differences of water consump2 tion in different types of hotels, the accommodation coefficients for different types of hotels were introduced and obtained from scientific calculations. In order to guarantee the effective implementation of water quota management and achieve the satisfaction rate of 70% for each hotel, the basal water use quota was suggested as 500 L/( bed# d) for hotels in Tianjin, and the accommo2 dation coefficient was suggested between 0. 3 and 1. 6. Compared with the existing water use quotas, the suggested water use quota is rational and advanced.
Water resources consumption of hotels is very large. Based on the sample investigation of 11 hotels in Tianjin, the structure of water utilization and water balance test reports of 6 hotels were analyzed. The main factors affecting water con2 sumption in hotels were identified through the principal component analysis and correlation analysis. T he basal water use quotas of hotels with different levels were calculated using the statistical analysis methods, including simple average method, weighted 2 average method, secondary average method, and probabilistic evaluation method. According to the differences of water consump2 tion in different types of hotels, the accommodation coefficients for different types of hotels were introduced and obtained from scientific calculations. In order to guarantee the effective implementation of water quota management and achieve the satisfaction rate of 70% for each hotel, the basal water use quota was suggested as 500 L/( bed# d) for hotels in Tianjin, and the accommo2 dation coefficient was suggested between 0. 3 and 1. 6. Compared with the existing water use quotas, the suggested water use quota is rational and advanced.
2015, 13(6):1203-1206.
Abstract:
Through the analysis of reservoir capacity calculation methods such as grid method, section method, contour cubage method, and triangular mesh method, the use of C# language to realize the 3D visualization of reservoir capacity calculation sys2 tem was investigated under the environment of Visual studio. net 2010 and Arc GIS engine SDK10. 0, and the main sub function modules such as terrain data processing and view processing were discussed. The 3D visualization of reservoir capacity calcula 2 tion system based on Arc GIS can process the raw terrain data using the interface and algorithm advantage of Arc GIS, develop the 3D terrain model TIN rapidly, improve the computational efficiency, and avoid the precision loss in the traditional capacity calculation.
Through the analysis of reservoir capacity calculation methods such as grid method, section method, contour cubage method, and triangular mesh method, the use of C# language to realize the 3D visualization of reservoir capacity calculation sys2 tem was investigated under the environment of Visual studio. net 2010 and Arc GIS engine SDK10. 0, and the main sub function modules such as terrain data processing and view processing were discussed. The 3D visualization of reservoir capacity calcula 2 tion system based on Arc GIS can process the raw terrain data using the interface and algorithm advantage of Arc GIS, develop the 3D terrain model TIN rapidly, improve the computational efficiency, and avoid the precision loss in the traditional capacity calculation.
2015, 13(6):1207-1211.
Abstract:
In the construction of water diversion project, selection of management mode for project construction directly affects the management targets, such as quality, cost, and schedule of construction. In this paper, an evaluation index system of manage 2 ment mode selection in the water diversion project is constructed, a model is established using the fuzzy analytic hierarchy process ( FAHP), and the evaluation method and process of management mode selection in the water diversion project are illus2 trated. The minimum relative information entropy principle is introduced to the model, and the combined weights of indexes are determined based on the combination of the subjective weights and objective weights. T he index system is applied to evaluate a project in the Eastern Route of South2to2North Water Diversion, and the most suitable project management mode for this project is obtained. The results show that the management mode is reliable, and the system and model can provide new method and thoughts for the management mode selection in the water diversion project.
In the construction of water diversion project, selection of management mode for project construction directly affects the management targets, such as quality, cost, and schedule of construction. In this paper, an evaluation index system of manage 2 ment mode selection in the water diversion project is constructed, a model is established using the fuzzy analytic hierarchy process ( FAHP), and the evaluation method and process of management mode selection in the water diversion project are illus2 trated. The minimum relative information entropy principle is introduced to the model, and the combined weights of indexes are determined based on the combination of the subjective weights and objective weights. T he index system is applied to evaluate a project in the Eastern Route of South2to2North Water Diversion, and the most suitable project management mode for this project is obtained. The results show that the management mode is reliable, and the system and model can provide new method and thoughts for the management mode selection in the water diversion project.
2015, 13(6):1212-1217.
Abstract:
Interconnected river system network as a national water conservancy strategy was put forward in the new period, and its connotation and theory have become a hot topic in scientific research. T he purpose of this paper is to review the connotations of river2lake relationship and interconnected river system network and to investigate the key impact factors for the evolution of interconnected river system network. T he interconnected river system network belongs to the river 2lake relationship, and it is an important content of the research on the relationship between rivers and lakes. T he evolution of interconnected river system net2 work is mainly affected by the geological and geomorphological conditions, climate change, water and sediment inputs from other watershed, lake evolution, and human activities. In addition, the correct understanding of river 2lake relationship is the premise and foundation of the interconnected river system network project. The related theories of river 2lake relationship are the theoret2 ical basis to build the interconnected river system network project and to guide the construction of interconnected river system network project directly.
Interconnected river system network as a national water conservancy strategy was put forward in the new period, and its connotation and theory have become a hot topic in scientific research. T he purpose of this paper is to review the connotations of river2lake relationship and interconnected river system network and to investigate the key impact factors for the evolution of interconnected river system network. T he interconnected river system network belongs to the river 2lake relationship, and it is an important content of the research on the relationship between rivers and lakes. T he evolution of interconnected river system net2 work is mainly affected by the geological and geomorphological conditions, climate change, water and sediment inputs from other watershed, lake evolution, and human activities. In addition, the correct understanding of river 2lake relationship is the premise and foundation of the interconnected river system network project. The related theories of river 2lake relationship are the theoret2 ical basis to build the interconnected river system network project and to guide the construction of interconnected river system network project directly.
2015, 13(6):1218-1224.
Abstract:
Environmental change caused by climate change and human activities has great influence on the human water system, which has also been a major concern all over the world. In this paper, the research status of the impacts of climate change, hu2 man activities, and the combined action on the human water system was analyzed and summarized, and the key problems regard2 ing the current study were proposed from five aspects including impact mechanism, environmental change factors, impact of en2 vironment change on human system, comprehensive study on human2water system, and quantitative method for the impact on " integrated system". In order to solve the key problems, future research focus for the study was proposed. In addition, the prelim2 inary research ideas were put forward in order to provide reference for future work.
Environmental change caused by climate change and human activities has great influence on the human water system, which has also been a major concern all over the world. In this paper, the research status of the impacts of climate change, hu2 man activities, and the combined action on the human water system was analyzed and summarized, and the key problems regard2 ing the current study were proposed from five aspects including impact mechanism, environmental change factors, impact of en2 vironment change on human system, comprehensive study on human2water system, and quantitative method for the impact on " integrated system". In order to solve the key problems, future research focus for the study was proposed. In addition, the prelim2 inary research ideas were put forward in order to provide reference for future work.
42 Analysis of irrigation water requirement for maize and soybean in Siping region of Jilin Province
2015, 13(6):1225-1228.
Abstract:
Temporal distributions of precipitation and water requirements of maize and soybean during the growth period in Si 2 ping region were analyzed. Crop water requirement was computed using the Penman2 M onteith equation ( FAO 56 PM formula) and crop coefficients. Effective precipitation and water requirements ( ET c )for maize and soybean sin different hydrological years were analyzed using the P 2III distribution curve. Results showed that the average effective precipitation, water requirement ( ET c ), and water deficit are 423. 24, 503. 73, and 80. 49 mm respectively for maize, and 442. 62, 484. 18, and 41. 56 mm respec 2 tively for soybean in Siping region. During the wet year ( P= 25%) , normal year ( P= 50%), and dry year ( P= 75%), the effec 2 tive precipitation is 517. 47, 425. 60, and 352. 79 mm respectively, and the corresponding water requirement is 504. 88, 467. 83, and 506. 29 mm respectively for maize; whereas the effective precipitation is 540. 23, 452. 26, and 371. 42 mm respectively, and the corresponding water requirement is 434. 67, 498. 80, and 450. 77 mm respectively for soybean. Supplementary irrigations at the fast development stage of maize and at the blossom and productive stage of soybean are important for maintaining high yields in Siping region.
Temporal distributions of precipitation and water requirements of maize and soybean during the growth period in Si 2 ping region were analyzed. Crop water requirement was computed using the Penman2 M onteith equation ( FAO 56 PM formula) and crop coefficients. Effective precipitation and water requirements ( ET c )for maize and soybean sin different hydrological years were analyzed using the P 2III distribution curve. Results showed that the average effective precipitation, water requirement ( ET c ), and water deficit are 423. 24, 503. 73, and 80. 49 mm respectively for maize, and 442. 62, 484. 18, and 41. 56 mm respec 2 tively for soybean in Siping region. During the wet year ( P= 25%) , normal year ( P= 50%), and dry year ( P= 75%), the effec 2 tive precipitation is 517. 47, 425. 60, and 352. 79 mm respectively, and the corresponding water requirement is 504. 88, 467. 83, and 506. 29 mm respectively for maize; whereas the effective precipitation is 540. 23, 452. 26, and 371. 42 mm respectively, and the corresponding water requirement is 434. 67, 498. 80, and 450. 77 mm respectively for soybean. Supplementary irrigations at the fast development stage of maize and at the blossom and productive stage of soybean are important for maintaining high yields in Siping region.
2015, 13(6):1229-1232.
Abstract:
On the basis of general survey on the cracking situation at the crest of the Fosi Reservoir dam, a specific study on the cracks was conducted using the test boring and grouting methods. T he cause of cracks on the dam crest of the Fosi Reservoir was analyzed. The results suggested that (1) the cracks at the crest do not extend to the underlayer of the original gravel road, i. e. , no influence on the core wall, which indicates that the cracks on the concrete pavement are not caused by the non2uniform settlement between the core wall and dam shell; ( 2) T he non 2uniform distribution of the gravel layer material of the concrete road is the primary cause of the cracks, and the higher loading from the vehicles than the design loading of the road is the sec 2 ondary cause. M eanwhile, due to the existence of wave walls in the upstream of the crest, vehicles tend to move towards the downstream side, leading to the non 2uniform cracks on the dam crest; and ( 3) the cracks at the dam crest need to be fixed, the number of public vehicles needs to be limited, and more monitoring and perambulatory inspection are proposed to prevent the crack propagation.
On the basis of general survey on the cracking situation at the crest of the Fosi Reservoir dam, a specific study on the cracks was conducted using the test boring and grouting methods. T he cause of cracks on the dam crest of the Fosi Reservoir was analyzed. The results suggested that (1) the cracks at the crest do not extend to the underlayer of the original gravel road, i. e. , no influence on the core wall, which indicates that the cracks on the concrete pavement are not caused by the non2uniform settlement between the core wall and dam shell; ( 2) T he non 2uniform distribution of the gravel layer material of the concrete road is the primary cause of the cracks, and the higher loading from the vehicles than the design loading of the road is the sec 2 ondary cause. M eanwhile, due to the existence of wave walls in the upstream of the crest, vehicles tend to move towards the downstream side, leading to the non 2uniform cracks on the dam crest; and ( 3) the cracks at the dam crest need to be fixed, the number of public vehicles needs to be limited, and more monitoring and perambulatory inspection are proposed to prevent the crack propagation.
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