Volume 12,Issue 1,2014 Table of Contents
2014, 12(1):1-6.
Abstract:
Based on the daily data of precipitation and temperature of 30 basic meteorological stations during the period 1956-2010, twelve indices characterizing extreme climate change have been selected to analyze the temporal changes in precipitation and temperature extremes in the Hai River Basin. As per many other parts of the world, the analysis shows an increase in the intensity, frequency and duration of high temperature extremes and a decrease in that of cold extremes. The intensity of short-time precipitation extremes shows an increase and the frequency of heavy precipitation shows a decrease. The consecutive wet days shows a decrease, while the consecutive dry days shows an increase in recent decades, thus the dry pattern has been aggravated in the basin. The annual high temperature extremes and short-time precipitation extremes have begun to frequently occur since 1990s from interdecadal variations, the rainfall of long-duration precipitation events has shown a decrease however. The general warm and dry trend and precipitation concentration will have a negative impact on the agriculture production and water resources development. Meanwhile, the increase of short-time precipitation extremes may exacerbate the risk of local flood disaster in mountainous area as well as urban waterlogging.
Based on the daily data of precipitation and temperature of 30 basic meteorological stations during the period 1956-2010, twelve indices characterizing extreme climate change have been selected to analyze the temporal changes in precipitation and temperature extremes in the Hai River Basin. As per many other parts of the world, the analysis shows an increase in the intensity, frequency and duration of high temperature extremes and a decrease in that of cold extremes. The intensity of short-time precipitation extremes shows an increase and the frequency of heavy precipitation shows a decrease. The consecutive wet days shows a decrease, while the consecutive dry days shows an increase in recent decades, thus the dry pattern has been aggravated in the basin. The annual high temperature extremes and short-time precipitation extremes have begun to frequently occur since 1990s from interdecadal variations, the rainfall of long-duration precipitation events has shown a decrease however. The general warm and dry trend and precipitation concentration will have a negative impact on the agriculture production and water resources development. Meanwhile, the increase of short-time precipitation extremes may exacerbate the risk of local flood disaster in mountainous area as well as urban waterlogging.
2014, 12(1):7-11.
Abstract:
The objective of this study is to evaluate the applicability of SWAT model to agricultural drought evaluation for regions without or lack of soil moisture data. For this purpose, the SWAT model was applied to simulate the hydrological process in the Bahe watershed of the upper Weihe River. The soil water content was obtained and it was used to calculate the relative soil moisture. The calculated relative soil moisture was regarded as the evaluation index of agricultural drought. The results showed that severe spring droughts occurred in 2001 and 2002 and summer drought occurred in 2003 in the Bahe watershed, which was in accordance with the actual conditions. . Therefore, SWAT model is applicable to agricultural drought evaluation for the area lack of soil moisture data.
The objective of this study is to evaluate the applicability of SWAT model to agricultural drought evaluation for regions without or lack of soil moisture data. For this purpose, the SWAT model was applied to simulate the hydrological process in the Bahe watershed of the upper Weihe River. The soil water content was obtained and it was used to calculate the relative soil moisture. The calculated relative soil moisture was regarded as the evaluation index of agricultural drought. The results showed that severe spring droughts occurred in 2001 and 2002 and summer drought occurred in 2003 in the Bahe watershed, which was in accordance with the actual conditions. . Therefore, SWAT model is applicable to agricultural drought evaluation for the area lack of soil moisture data.
2014, 12(1):12-15.
Abstract:
The plain reach of Zhang River is a wide and shallow sandy channel. Due to being cut-off for a long time, the recharge to groundwater decreased yearly, resulting in a gradual reduction of groundwater level and therefore affecting the water transmission efficiency of Yuecheng Reservoir to downstream cities. Based on the field survey and measured data, a channel leakage model for the plain reach of Zhang River was developed, and the leakage rates under different flow rates of reservoir were determined by a two-step method, including calibration step using the observed flow data and validation step using the water level data. The results showed that the leakage area per unit reach length varies significantly, indicating the wandering characteristics of the Zhang River. Moreover, it was suggested that the total leakage increases with the increasing of flow rate of reservoir; however, the proportion of total leakage to total flow decreases and tends to be stable. A comprehensive factor was introduced in the leakage model to reflect the effects of actual conditions on leakage coefficient, and the parameterization of the unknown factors is practical.
The plain reach of Zhang River is a wide and shallow sandy channel. Due to being cut-off for a long time, the recharge to groundwater decreased yearly, resulting in a gradual reduction of groundwater level and therefore affecting the water transmission efficiency of Yuecheng Reservoir to downstream cities. Based on the field survey and measured data, a channel leakage model for the plain reach of Zhang River was developed, and the leakage rates under different flow rates of reservoir were determined by a two-step method, including calibration step using the observed flow data and validation step using the water level data. The results showed that the leakage area per unit reach length varies significantly, indicating the wandering characteristics of the Zhang River. Moreover, it was suggested that the total leakage increases with the increasing of flow rate of reservoir; however, the proportion of total leakage to total flow decreases and tends to be stable. A comprehensive factor was introduced in the leakage model to reflect the effects of actual conditions on leakage coefficient, and the parameterization of the unknown factors is practical.
2014, 12(1):16-20.
Abstract:
In order to evaluate the effects of water source replacement quantitatively, joint allocation model of the external and local water resources was established and applied in the water-receiving areas of Haihe Basin of the 1st stage of South-to-North Water Transfer Project (SNWTP). Based on the analysis of the water source replacement process, different scenarios of water allocation were analyzed under the conditions of groundwater control and eco-environmental restoration in the water-receiving areas. The results showed that one third of intake water from the 1st stage of SNWTP is used to support the increasing urban water demand, and two thirds is used to replace the existing unreasonable water uses and to return to the agricultural and ecological construction. The water source replacement can improve the eco-environment conditions in the water-receiving areas. However, the conflict between water resources shortage and ecological deterioration cannot be solved for the 1st stage of SNWTP, and therefore other measures need to be conducted to optimize the profit of SNWTP, including water saving, pollution control, groundwater overdraft control, and reasonable allocation of various water sources.
In order to evaluate the effects of water source replacement quantitatively, joint allocation model of the external and local water resources was established and applied in the water-receiving areas of Haihe Basin of the 1st stage of South-to-North Water Transfer Project (SNWTP). Based on the analysis of the water source replacement process, different scenarios of water allocation were analyzed under the conditions of groundwater control and eco-environmental restoration in the water-receiving areas. The results showed that one third of intake water from the 1st stage of SNWTP is used to support the increasing urban water demand, and two thirds is used to replace the existing unreasonable water uses and to return to the agricultural and ecological construction. The water source replacement can improve the eco-environment conditions in the water-receiving areas. However, the conflict between water resources shortage and ecological deterioration cannot be solved for the 1st stage of SNWTP, and therefore other measures need to be conducted to optimize the profit of SNWTP, including water saving, pollution control, groundwater overdraft control, and reasonable allocation of various water sources.
2014, 12(1):21-25.
Abstract:
Water conservancy project is one of the most important factors of the impacts from human activities on the flood. With the large-scale construction of water conservancy engineering projects all over the country in recent years, its effects become more obvious and vary for different types of flood in different regions. In this paper, the basic operation data of large, medium, and small water conservancy projects in the upstream of Fengman of the second Songhua River Basin were analyzed. Based on the flood classification of “Standard of Hydrology Information Forecast”, the impact rules between water conservancy projects and different types of floods were determined by the statistical method, and they were converted into the impact parameters of water conservancy projects. These parameters were added into the Xinanjiang model of flood simulation, and the impact degrees of water conservancy projects on different types of flood were then obtained in consideration of the requirement of prediction precision. The research can provide a new idea for study the impacts of human activities on flood.
Water conservancy project is one of the most important factors of the impacts from human activities on the flood. With the large-scale construction of water conservancy engineering projects all over the country in recent years, its effects become more obvious and vary for different types of flood in different regions. In this paper, the basic operation data of large, medium, and small water conservancy projects in the upstream of Fengman of the second Songhua River Basin were analyzed. Based on the flood classification of “Standard of Hydrology Information Forecast”, the impact rules between water conservancy projects and different types of floods were determined by the statistical method, and they were converted into the impact parameters of water conservancy projects. These parameters were added into the Xinanjiang model of flood simulation, and the impact degrees of water conservancy projects on different types of flood were then obtained in consideration of the requirement of prediction precision. The research can provide a new idea for study the impacts of human activities on flood.
2014, 12(1):26-31.
Abstract:
The flood and waterlogging disaster loss assessment is a very important component for the disaster relief work, which has important theoretical and practical significance for the research of disaster and its relief. According to the correlation analysis between the flood disaster loss and meteorological and hydrological elements, a correlation model between the area and property of flood disaster loss and historical meteorological and hydrologic factors was developed. The property loss rate and background data of permanent assets were used to evaluate the direct economic losses caused by flood disaster, which are useful for the pre-disaster preliminary assessment and post-disaster rapid assessment. In this paper, the flood of the middle reach of Huaihe River in Anhui Province in 2007 was analyzed, which provided similar assessment results of flood disaster loss with those reported data in reality. Therefore, the evaluation method is applicable and reliable.
The flood and waterlogging disaster loss assessment is a very important component for the disaster relief work, which has important theoretical and practical significance for the research of disaster and its relief. According to the correlation analysis between the flood disaster loss and meteorological and hydrological elements, a correlation model between the area and property of flood disaster loss and historical meteorological and hydrologic factors was developed. The property loss rate and background data of permanent assets were used to evaluate the direct economic losses caused by flood disaster, which are useful for the pre-disaster preliminary assessment and post-disaster rapid assessment. In this paper, the flood of the middle reach of Huaihe River in Anhui Province in 2007 was analyzed, which provided similar assessment results of flood disaster loss with those reported data in reality. Therefore, the evaluation method is applicable and reliable.
2014, 12(1):32-36.
Abstract:
Based on the average monthly precipitation data collected at 28 Level-4 sub-segments in the Haihe River Plain from 1956 to 2011, the variation characteristics of precipitation in the Haihe River Plain were analyzed using the methods of linear regression, Mann-Kendall trend test, and Morlet wavelets analysis method. The results showed that (1) the average precipitation in the Haihe River Plain varies spatially. The north and south have the most abundant rainfall, followed by the central coastal area, and the central piedmont has the least amount of rainfall; and (2) the average precipitation also varies temporally. Over 68.7% of the rainfall occurs in summer, while only about 2.5% occurs in winter. In addition, annual precipitation in the Haihe River Plain had an insignificant decreasing trend in the recent 56 years, which was caused by the obvious decreasing trend of precipitation in summer. Among the 28 Level-4 sub-segments, 12 of them showed a significant decreasing trend of precipitation, and they are mainly located in the Heilonggangyundong Plain and the piedmont plain in the northwest. Moreover, a few Level-4 sub-segments had an insignificant increasing trend of precipitation. In the recent 56 years, there was no significantly periodic change on the annual precipitation; however, there were a 4-year interval, a 7-year interval, and an 11-year interval occurring during the periods of 1956 to 1990, 1993 to 2011, and 1956 to 1980, respectively.
Based on the average monthly precipitation data collected at 28 Level-4 sub-segments in the Haihe River Plain from 1956 to 2011, the variation characteristics of precipitation in the Haihe River Plain were analyzed using the methods of linear regression, Mann-Kendall trend test, and Morlet wavelets analysis method. The results showed that (1) the average precipitation in the Haihe River Plain varies spatially. The north and south have the most abundant rainfall, followed by the central coastal area, and the central piedmont has the least amount of rainfall; and (2) the average precipitation also varies temporally. Over 68.7% of the rainfall occurs in summer, while only about 2.5% occurs in winter. In addition, annual precipitation in the Haihe River Plain had an insignificant decreasing trend in the recent 56 years, which was caused by the obvious decreasing trend of precipitation in summer. Among the 28 Level-4 sub-segments, 12 of them showed a significant decreasing trend of precipitation, and they are mainly located in the Heilonggangyundong Plain and the piedmont plain in the northwest. Moreover, a few Level-4 sub-segments had an insignificant increasing trend of precipitation. In the recent 56 years, there was no significantly periodic change on the annual precipitation; however, there were a 4-year interval, a 7-year interval, and an 11-year interval occurring during the periods of 1956 to 1990, 1993 to 2011, and 1956 to 1980, respectively.
2014, 12(1):37-41.
Abstract:
Regional water security is the basis of protection of the regional sustainable development. Based on the characteristics of water resources and specific situation of Anhui Province, a comprehensive evaluation index system of water security was developed, and AHP was used to evaluate the water security situation of Anhui Province from 2005 to 2010. The results suggested that the water security situation is between "unsafe" and "basically safe" in Anhui Province from 2005 to 2010 and thus water security situation is not optimistic. This conclusion was in coincidence with that determined by the set pair analysis, which indicated that AHP is feasible and reliable for water security evaluation. Finally, from the perspective of improving water security, some recommendations were proposed to promote savings, increase the utilization efficiency of water resources, and improve water quality.
Regional water security is the basis of protection of the regional sustainable development. Based on the characteristics of water resources and specific situation of Anhui Province, a comprehensive evaluation index system of water security was developed, and AHP was used to evaluate the water security situation of Anhui Province from 2005 to 2010. The results suggested that the water security situation is between "unsafe" and "basically safe" in Anhui Province from 2005 to 2010 and thus water security situation is not optimistic. This conclusion was in coincidence with that determined by the set pair analysis, which indicated that AHP is feasible and reliable for water security evaluation. Finally, from the perspective of improving water security, some recommendations were proposed to promote savings, increase the utilization efficiency of water resources, and improve water quality.
2014, 12(1):42-46.
Abstract:
Assessment of climate change and land use/cover changes (LUCC) on hydrological processes is essential for the sustainable development of water resources, especially in the arid/semi-arid regions with limited water supplies. The Soil and Water Assessment Tool (SWAT) was used as a distributed hydrological model to quantify the effects of climate change and LUCC on seasonal variation of surface runoff and evapotranspiration in the Gulang River basin. The results suggested that the variation of precipitation and temperature is the major reason for the variation of evapotranspiration and surface runoff. Surface runoff is more sensitive to precipitation than temperature whereas temperature has a greater impact on evapotranspiration with an obvious seasonal variation. Moreover, LUCC can result in the variation of evapotranspiration and surface runoff as well. The increasing of forest or grass land can increase evapotranspiration but decrease surface runoff, the increasing of agricultural land can decrease evapotranspiration and surface runoff, and the increasing of rural residential area or bare land can increase both evapotranspiration and surface runoff significantly.
Assessment of climate change and land use/cover changes (LUCC) on hydrological processes is essential for the sustainable development of water resources, especially in the arid/semi-arid regions with limited water supplies. The Soil and Water Assessment Tool (SWAT) was used as a distributed hydrological model to quantify the effects of climate change and LUCC on seasonal variation of surface runoff and evapotranspiration in the Gulang River basin. The results suggested that the variation of precipitation and temperature is the major reason for the variation of evapotranspiration and surface runoff. Surface runoff is more sensitive to precipitation than temperature whereas temperature has a greater impact on evapotranspiration with an obvious seasonal variation. Moreover, LUCC can result in the variation of evapotranspiration and surface runoff as well. The increasing of forest or grass land can increase evapotranspiration but decrease surface runoff, the increasing of agricultural land can decrease evapotranspiration and surface runoff, and the increasing of rural residential area or bare land can increase both evapotranspiration and surface runoff significantly.
10 Second Time Supply and Demand Balance Analysis of Regional Water Resources Based on System Dynamics
2014, 12(1):47-49.
Abstract:
According to the present water resources conditions of Jiangsu Province, system dynamics simulation method was used to predict the water resources supply and demand balance in Jiangsu Province in 2020 and 2030 level year under different guarantee rates (50%, 75%, and 95%). On the basis, the first time supply and demand balance analysis of water resources was performed under the current conditions, and the second time supply and demand balance analysis of water resources was performed under the conditions of improved water supply capacity and water saving measures. The results showed insufficiency for the first time supply and demand balance analysis of water resources, and that the imbalance between supply and demand improves for the second time supply and demand balance analysis of water resources. The insufficiency can decrease 49.70% under the guarantee rate of 50% in 2020, and decrease 47.43% under the guarantee rate of 50% in 2030.
According to the present water resources conditions of Jiangsu Province, system dynamics simulation method was used to predict the water resources supply and demand balance in Jiangsu Province in 2020 and 2030 level year under different guarantee rates (50%, 75%, and 95%). On the basis, the first time supply and demand balance analysis of water resources was performed under the current conditions, and the second time supply and demand balance analysis of water resources was performed under the conditions of improved water supply capacity and water saving measures. The results showed insufficiency for the first time supply and demand balance analysis of water resources, and that the imbalance between supply and demand improves for the second time supply and demand balance analysis of water resources. The insufficiency can decrease 49.70% under the guarantee rate of 50% in 2020, and decrease 47.43% under the guarantee rate of 50% in 2030.
2014, 12(1):50-53.
Abstract:
Based on the land use, soil classification, and hydrological and meteorological data, the SCS model, developed by Soil Conservation Service (SCS), U.S.A., was applied to simulate the annual runoff depth and surface runoff under different frequencies in the platform of ArcGIS in the coastal region of Qinghuangdao and to determine the appropriate value of CN in the area. The results showed that the runoff depths were 194.21mm, 145.64mm, and 126.08mm during the wet, normal, and dry seasons, which can accurately reflect the actual rainfall-runoff relationship in the study area. Meanwhile, the surface runoff results were used to estimate the pollution loads under different runoff conditions in the coastal region of Qinghuangdao, which can provide reference for the simulation of spatial and temporal distribution of non-point source pollution and evaluation of environmental improvement in Beidaihe area of Qinghuangdao.
Based on the land use, soil classification, and hydrological and meteorological data, the SCS model, developed by Soil Conservation Service (SCS), U.S.A., was applied to simulate the annual runoff depth and surface runoff under different frequencies in the platform of ArcGIS in the coastal region of Qinghuangdao and to determine the appropriate value of CN in the area. The results showed that the runoff depths were 194.21mm, 145.64mm, and 126.08mm during the wet, normal, and dry seasons, which can accurately reflect the actual rainfall-runoff relationship in the study area. Meanwhile, the surface runoff results were used to estimate the pollution loads under different runoff conditions in the coastal region of Qinghuangdao, which can provide reference for the simulation of spatial and temporal distribution of non-point source pollution and evaluation of environmental improvement in Beidaihe area of Qinghuangdao.
2014, 12(1):54-58.
Abstract:
The water from a wastewater treatment plant in Tianjin still contains a large number of N and P as well as macromolecules which are hard to be degraded. The constructed wetland system is used to perform advanced treatment on the water from the wastewater treatment plant so that it can meet the standard of urban landscape water use. A pilot experiment is used to simulate the removal efficiency of the constructed wetland system on different kinds of pollutants. The results showed that (1) the wetland system of the inoculated microorganisms has a high removal efficiency of 84.7% on the suspended solids of tail water; (2) removal of suspended solids has a great correlation to matrix adsorption and physical precipitation; (3) the wetland system of the inoculated microorganisms has a good removal efficiency of 44.8% on COD of tail water, , and the addition of functional microbes can improve the removal ability on COD; (4) the wetland system of the inoculated microorganisms does not have a good removal efficiency on ammonia nitrogen and total nitrogen, which is about 12.3% and 35.5% respectively; (5) the addition of dissolved oxygen can contribute to the removal of ammonia nitrogen and total nitrogen; and (6) the wetland system of the inoculated microorganisms has a removal efficiency of 52.3% on total phosphorus, main relying on the matrix adsorption and physical precipitation.
The water from a wastewater treatment plant in Tianjin still contains a large number of N and P as well as macromolecules which are hard to be degraded. The constructed wetland system is used to perform advanced treatment on the water from the wastewater treatment plant so that it can meet the standard of urban landscape water use. A pilot experiment is used to simulate the removal efficiency of the constructed wetland system on different kinds of pollutants. The results showed that (1) the wetland system of the inoculated microorganisms has a high removal efficiency of 84.7% on the suspended solids of tail water; (2) removal of suspended solids has a great correlation to matrix adsorption and physical precipitation; (3) the wetland system of the inoculated microorganisms has a good removal efficiency of 44.8% on COD of tail water, , and the addition of functional microbes can improve the removal ability on COD; (4) the wetland system of the inoculated microorganisms does not have a good removal efficiency on ammonia nitrogen and total nitrogen, which is about 12.3% and 35.5% respectively; (5) the addition of dissolved oxygen can contribute to the removal of ammonia nitrogen and total nitrogen; and (6) the wetland system of the inoculated microorganisms has a removal efficiency of 52.3% on total phosphorus, main relying on the matrix adsorption and physical precipitation.
2014, 12(1):59-64.
Abstract:
According to the pollution control process of the first-stage construction in the Eastern Route (ER) of South-to-North Water Diversion Project (SNWDP), the inter-annual and annual variations of water quality of the south section of Yellow River along the ER of SNWDP were analyzed using two key indicators, permanganate index and ammonia. The analysis selected year 2000 as the planning year, and was performed for the first quarter from 2000 to 2013. The results showed that water pollution control achieved remarkable successes, and water quality along the ER of SNWDP showed significantly phased improvements over the past decade. In November 2012, the water quality at the control sections met the requirements of planning objectives and it stabilized since then, which laid a solid foundation for the water service of the first-stage engineering project in the ER of SNWDP in 2013.
According to the pollution control process of the first-stage construction in the Eastern Route (ER) of South-to-North Water Diversion Project (SNWDP), the inter-annual and annual variations of water quality of the south section of Yellow River along the ER of SNWDP were analyzed using two key indicators, permanganate index and ammonia. The analysis selected year 2000 as the planning year, and was performed for the first quarter from 2000 to 2013. The results showed that water pollution control achieved remarkable successes, and water quality along the ER of SNWDP showed significantly phased improvements over the past decade. In November 2012, the water quality at the control sections met the requirements of planning objectives and it stabilized since then, which laid a solid foundation for the water service of the first-stage engineering project in the ER of SNWDP in 2013.
2014, 12(1):65-68.
Abstract:
Study on the river ecological water demand is not only the foundation of optimal allocation of water resources，but also the security to maintain and improve the ecological system and realize the sustainable utilization of water resources. In this paper, on the basis of the conception and component of ecological water demand, the ecological water demand in Baoji section of Weihe River was estimated from the perspectives of ecological base flow, water requirement for sediment transport, and water requirement for self purification, which was 19.01×108 m3. Compared with the upstream water, a big gap in ecological water demand still exists. Therefore, some feasible suggestions were proposed including the increasing of upstream water, water saving and pollution control in the section, and establishment of an effective management system. The research results not only enrich the eco-environmental water demand theory, but also provide an important reference for the eco-environment construction and reasonable utilization of water resources.
Study on the river ecological water demand is not only the foundation of optimal allocation of water resources，but also the security to maintain and improve the ecological system and realize the sustainable utilization of water resources. In this paper, on the basis of the conception and component of ecological water demand, the ecological water demand in Baoji section of Weihe River was estimated from the perspectives of ecological base flow, water requirement for sediment transport, and water requirement for self purification, which was 19.01×108 m3. Compared with the upstream water, a big gap in ecological water demand still exists. Therefore, some feasible suggestions were proposed including the increasing of upstream water, water saving and pollution control in the section, and establishment of an effective management system. The research results not only enrich the eco-environmental water demand theory, but also provide an important reference for the eco-environment construction and reasonable utilization of water resources.
LIU Yong-hui
,
TIAN Ye
,
LIU Ao-ran
,
YANG Qing-hua
,
YANG Zhen-jing
,
ZHOU Ya-hong
,
GUO Zhao-xia
,
SUN Li-ming
2014, 12(1):69-72.
Abstract:
Based on the high-resolution sporopollen records of the section in the Yudaokou pasture of Weichang County, Hebei Province, the variations of climate and environment since 6000 a B.P. (14C dating is 5.7ka B.P. at the section bottom) in the Yudaokou area of Weichang County were analyzed. The regional features of sporopollen assemblages showed that the paleoclimate in the Yudaokou area experienced seven stages since 6000 a B. P.: cool and slightly wet - cool and dry- warm and slightly wet –warm and wet – warm and slightly wet –warm and wet - cool and slightly dry. Vegetation landscape was mainly coniferous forest - steppe vegetation, which was dominated with Pinus and Artemisia and scattered with a small amount of Betula, Quercus, and other deciduous trees and shrubs in the forest. The paleoclimate change pattern since the Holocene in the study area is similar to that in other regions of China.
Based on the high-resolution sporopollen records of the section in the Yudaokou pasture of Weichang County, Hebei Province, the variations of climate and environment since 6000 a B.P. (14C dating is 5.7ka B.P. at the section bottom) in the Yudaokou area of Weichang County were analyzed. The regional features of sporopollen assemblages showed that the paleoclimate in the Yudaokou area experienced seven stages since 6000 a B. P.: cool and slightly wet - cool and dry- warm and slightly wet –warm and wet – warm and slightly wet –warm and wet - cool and slightly dry. Vegetation landscape was mainly coniferous forest - steppe vegetation, which was dominated with Pinus and Artemisia and scattered with a small amount of Betula, Quercus, and other deciduous trees and shrubs in the forest. The paleoclimate change pattern since the Holocene in the study area is similar to that in other regions of China.
2014, 12(1):73-77.
Abstract:
In order to understand the influence of urban planning on urban water environment, SWMM (storm water management model) was used to analyze the relationship between urban planning mode and urban water environment in the Fuxi River watershed of Zigong. The results showed that the peak flow rate and peak concentration of TSS of urban runoff decreased by 58% and 55% respectively when the proportion of the planning impervious underlying surface decreased from 74% to 30%. Green roof, penetration square, and green roof + penetration square were beneficial to urban runoff control on the basis of planning land use layout with further reduction of peak rainfall runoff of 33%, 29%, and 64%, respectively and further reduction of TSS concentration of 26%, 15%, and 38%, respectively. The study results provided reference to the management of urban environment.
In order to understand the influence of urban planning on urban water environment, SWMM (storm water management model) was used to analyze the relationship between urban planning mode and urban water environment in the Fuxi River watershed of Zigong. The results showed that the peak flow rate and peak concentration of TSS of urban runoff decreased by 58% and 55% respectively when the proportion of the planning impervious underlying surface decreased from 74% to 30%. Green roof, penetration square, and green roof + penetration square were beneficial to urban runoff control on the basis of planning land use layout with further reduction of peak rainfall runoff of 33%, 29%, and 64%, respectively and further reduction of TSS concentration of 26%, 15%, and 38%, respectively. The study results provided reference to the management of urban environment.
2014, 12(1):78-81.
Abstract:
The transportation and diffusion of pollutants in water body are closely related to the water renewal time, so knowledge of the water renewal time of reservoir is useful for understanding the temporal and spatial distribution of pollutants. In this paper, a three-dimensional numerical model of hydrodynamics in the wide-shallow reservoir was developed based on EFDC, and then the model was validated using the field data. First, the validated model was used to simulate the flow velocity field at 365 days and water renewal time of wide-shallow reservoir in order to obtain the hydrodynamics characteristics. Then, the water renewal time of reservoir was simulated under the conditions of no wind in order to obtain the impacts of wind on the water renewal time of wide-shallow reservoir. The results can provide theoretical reference for the ecological regulation of wide-shallow reservoir.
The transportation and diffusion of pollutants in water body are closely related to the water renewal time, so knowledge of the water renewal time of reservoir is useful for understanding the temporal and spatial distribution of pollutants. In this paper, a three-dimensional numerical model of hydrodynamics in the wide-shallow reservoir was developed based on EFDC, and then the model was validated using the field data. First, the validated model was used to simulate the flow velocity field at 365 days and water renewal time of wide-shallow reservoir in order to obtain the hydrodynamics characteristics. Then, the water renewal time of reservoir was simulated under the conditions of no wind in order to obtain the impacts of wind on the water renewal time of wide-shallow reservoir. The results can provide theoretical reference for the ecological regulation of wide-shallow reservoir.
2014, 12(1):82-87.
Abstract:
Compared with the traditional determined hydrologic forecast, hydrologic ensemble forecast contains various uncertainties in the hydrologic forecast processes. Therefore, the accuracy and validity of hydrologic forecast have been improved theoretically. Meanwhile, the cognitive and predictive capabilities of the events such as storm, flood, and drought have been enhanced in the practical applications. The hydrologic ensemble forecast can provide more accurate and useful information in flood control, drought relief, and sustainable water resources management. In this paper, we firstly reviewed the history of hydrologic ensemble forecast, and then we summarized the research progresses in theory, methods, as well as the applications and operational hydrologic ensemble forecast. We focused on two research aspects of the pre-processing and post-processing issues in an effort to provide a useful platform for the development of hydrologic ensemble prediction. The perspectives and recommendations on this subject were provided. This paper is of important significance in the future development of hydrologic ensemble forecast research.
Compared with the traditional determined hydrologic forecast, hydrologic ensemble forecast contains various uncertainties in the hydrologic forecast processes. Therefore, the accuracy and validity of hydrologic forecast have been improved theoretically. Meanwhile, the cognitive and predictive capabilities of the events such as storm, flood, and drought have been enhanced in the practical applications. The hydrologic ensemble forecast can provide more accurate and useful information in flood control, drought relief, and sustainable water resources management. In this paper, we firstly reviewed the history of hydrologic ensemble forecast, and then we summarized the research progresses in theory, methods, as well as the applications and operational hydrologic ensemble forecast. We focused on two research aspects of the pre-processing and post-processing issues in an effort to provide a useful platform for the development of hydrologic ensemble prediction. The perspectives and recommendations on this subject were provided. This paper is of important significance in the future development of hydrologic ensemble forecast research.
2014, 12(1):88-93.
Abstract:
Land use / cover change (LUCC) fully reflects the interaction between human and nature, and especially the impacts of LUCC on runoff have received global attention. In this paper, the main research methods (comparative watershed method, statistical analysis method, model simulation method, and separation judgment method) and previous research progress of the impacts of LUCC on runoff were summarized, the impacts of variation of forest and urbanization on runoff were analyzed, the impacts of climate conditions and different land use/cover types on runoff and flood process were evaluated, the research progresses of quantitative assessment of the contribution rate of the above impacts were introduced, and the existing problems and future research trend of the impacts of LUCC on runoff were discussed.
Land use / cover change (LUCC) fully reflects the interaction between human and nature, and especially the impacts of LUCC on runoff have received global attention. In this paper, the main research methods (comparative watershed method, statistical analysis method, model simulation method, and separation judgment method) and previous research progress of the impacts of LUCC on runoff were summarized, the impacts of variation of forest and urbanization on runoff were analyzed, the impacts of climate conditions and different land use/cover types on runoff and flood process were evaluated, the research progresses of quantitative assessment of the contribution rate of the above impacts were introduced, and the existing problems and future research trend of the impacts of LUCC on runoff were discussed.
2014, 12(1):94-96.
Abstract:
Subsurface flow constructed wetland (SSFW) is drawing more and more attentions in ecological engineering due to its high load rate, bearing capacity against impact load, reliable treatment effects, less occupied land, and aesthetic effect. In the design of SSFW, hydraulic condition has significant and direct influences on the removal efficiency of pollutants. The research methods and progress on hydraulics of SSFW were illustrated in this paper. The characteristic parameters of hydraulics of SSFW and their impact factors were analyzed. The effects of construction, filter, plant, and inflow configuration of SSFW on the characteristics of hydromechanics were discussed, which can provide theoretical and technical support on hydraulic design of SSFW, increasing of hydraulic efficiency, and improvement of removal effects on pollutants.
Subsurface flow constructed wetland (SSFW) is drawing more and more attentions in ecological engineering due to its high load rate, bearing capacity against impact load, reliable treatment effects, less occupied land, and aesthetic effect. In the design of SSFW, hydraulic condition has significant and direct influences on the removal efficiency of pollutants. The research methods and progress on hydraulics of SSFW were illustrated in this paper. The characteristic parameters of hydraulics of SSFW and their impact factors were analyzed. The effects of construction, filter, plant, and inflow configuration of SSFW on the characteristics of hydromechanics were discussed, which can provide theoretical and technical support on hydraulic design of SSFW, increasing of hydraulic efficiency, and improvement of removal effects on pollutants.
2014, 12(1):97-100.
Abstract:
The 3D finite element method based on strength reduction method was used to analyze the slope stability of a slope reinforcement project under natural conditions. The dangerous zone and most dangerous sliding surface of the slope were determined. On the basis, two reinforcement schemes were proposed, including the fitting-slope reinforcement and anti-slide pile reinforcement. The slope stability was analyzed under the two reinforcement schemes. The results showed that the 3D finite element method based on strength reduction method can provide reliable analysis of slope stability for the three-dimensional slopes with weak interlining and complex geological conditions. The three-dimensional finite element numerical simulation is necessary in the selection of slope reinforcement scheme.
The 3D finite element method based on strength reduction method was used to analyze the slope stability of a slope reinforcement project under natural conditions. The dangerous zone and most dangerous sliding surface of the slope were determined. On the basis, two reinforcement schemes were proposed, including the fitting-slope reinforcement and anti-slide pile reinforcement. The slope stability was analyzed under the two reinforcement schemes. The results showed that the 3D finite element method based on strength reduction method can provide reliable analysis of slope stability for the three-dimensional slopes with weak interlining and complex geological conditions. The three-dimensional finite element numerical simulation is necessary in the selection of slope reinforcement scheme.
2014, 12(1):101-104.
Abstract:
Regional water quality structure is constituted by deep freshwater and shallow salt water in the east of North China Plain (NCP). Evidences showed that salinity of deep freshwater did not increase significantly when it was supplied by shallow saline water. To examine whether the clay-bearing soil can intercept the salt from water, this study conducted the permeability tests to analyze the dispersion effects of saline water flowing through the clay-bearing soil. The results showed that (1) clay-bearing soil can intercept most of salt in the saline water, which confirms the existence of salt-filtering phenomenon in the eastern deep aquitard of NCP; (2) the intercept capacity of clay-bearing soil increases with the decreasing of permeability and dispersivity. ; and (3) the possible reason of salt-filtering is that Na+ in saline water is adsorbed by solid colloid particles or has cation exchange interaction with some components absorbed by soil colloids.
Regional water quality structure is constituted by deep freshwater and shallow salt water in the east of North China Plain (NCP). Evidences showed that salinity of deep freshwater did not increase significantly when it was supplied by shallow saline water. To examine whether the clay-bearing soil can intercept the salt from water, this study conducted the permeability tests to analyze the dispersion effects of saline water flowing through the clay-bearing soil. The results showed that (1) clay-bearing soil can intercept most of salt in the saline water, which confirms the existence of salt-filtering phenomenon in the eastern deep aquitard of NCP; (2) the intercept capacity of clay-bearing soil increases with the decreasing of permeability and dispersivity. ; and (3) the possible reason of salt-filtering is that Na+ in saline water is adsorbed by solid colloid particles or has cation exchange interaction with some components absorbed by soil colloids.
SHI Yu-zhi
,
ZHANG Bao-xiang
,
FAN Ming-yuan
,
YANG Xiao-feng
,
LIU Hai-jiao
,
ZHANG Ji-sheng
,
LIU Dong-mei
2014, 12(1):105-109.
Abstract:
Development and utilization of the unconventional water resources in the mine have important practical significance in improving ecological environment and saving water resources. In this paper, both Mann-Kendall and Spearman methods were applied to identify the variation characteristics of mining water inflow from 1982 to 2011 in the Feicheng Basin mining area, and the impact factors affecting mining gushing water were analyzed. The results showed that mining water inflow has a significant increasing trend, which is mainly affected by the hydrogeological conditions in the basin and is also correlated with coal mining yield and rainfall. The international water chemical analysis software, AquaChem5.1 was adopted to identify the characteristics of mining water quality, and the results showed that mining water has high hardness and sulfate content, which suggested that it is high-salinity and acid water. Based on the above analysis, the reasonable development and utilization mode of mining water was established to provide technical support for groundwater environment protection and sustainable utilization of water resources in the Feicheng Basin.
Development and utilization of the unconventional water resources in the mine have important practical significance in improving ecological environment and saving water resources. In this paper, both Mann-Kendall and Spearman methods were applied to identify the variation characteristics of mining water inflow from 1982 to 2011 in the Feicheng Basin mining area, and the impact factors affecting mining gushing water were analyzed. The results showed that mining water inflow has a significant increasing trend, which is mainly affected by the hydrogeological conditions in the basin and is also correlated with coal mining yield and rainfall. The international water chemical analysis software, AquaChem5.1 was adopted to identify the characteristics of mining water quality, and the results showed that mining water has high hardness and sulfate content, which suggested that it is high-salinity and acid water. Based on the above analysis, the reasonable development and utilization mode of mining water was established to provide technical support for groundwater environment protection and sustainable utilization of water resources in the Feicheng Basin.
2014, 12(1):110-113.
Abstract:
In order to resolve the complex seepage problem of the unconfined and confined aquifers in the Baliwan pumping station, several seepage stability control measures, such as underground continuous wall, drainage holes, horizontal drainage pipes, and relief wells, were applied to extend the seepage path, increase upstream head loss, and decrease downstream water level. The seepage field of the ground foundation was obtained using the three-dimensional seepage mathematical model, and the depth of underground continuous wall and the spacing of drainage holes, horizontal drainage pipes, and relief wells were also determined, which can optimize the seepage control measures. Therefore, the design difficulty of pumping stations was solved. The research results can provide reference for the seepage control design of pumping stations in the layered strata area in the plains.
In order to resolve the complex seepage problem of the unconfined and confined aquifers in the Baliwan pumping station, several seepage stability control measures, such as underground continuous wall, drainage holes, horizontal drainage pipes, and relief wells, were applied to extend the seepage path, increase upstream head loss, and decrease downstream water level. The seepage field of the ground foundation was obtained using the three-dimensional seepage mathematical model, and the depth of underground continuous wall and the spacing of drainage holes, horizontal drainage pipes, and relief wells were also determined, which can optimize the seepage control measures. Therefore, the design difficulty of pumping stations was solved. The research results can provide reference for the seepage control design of pumping stations in the layered strata area in the plains.
2014, 12(1):114-117.
Abstract:
In order to provide a scientific evaluation of regional difference of development level of water resource informatization, an evaluation index system of the development level of water resource informatization was developed from the perspectives of water resource infrastructure, water resource business application, and water resource information security environment based on the overall framework of water resource informatization construction and development mechanism of informatization. Meanwhile, the content, building principle, basis, and scope of the index system were described. The distinction and evaluation of the development level of water resource informatization in different regions can provide references for the water resource informatization in the future.
In order to provide a scientific evaluation of regional difference of development level of water resource informatization, an evaluation index system of the development level of water resource informatization was developed from the perspectives of water resource infrastructure, water resource business application, and water resource information security environment based on the overall framework of water resource informatization construction and development mechanism of informatization. Meanwhile, the content, building principle, basis, and scope of the index system were described. The distinction and evaluation of the development level of water resource informatization in different regions can provide references for the water resource informatization in the future.
2014, 12(1):118-121.
Abstract:
The optimal operation model for flood control of reservoir is a high-dimensional multimodal extremum problem in general, and intelligent optimization algorithm is usually used to solve such problems. Particle swarm optimization (PSO) algorithm is widely used in the optimal operation of reservoir due to its simplicity; however, there are shortcomings in the PSO algorithm such as premature convergence, low efficiency in global convergence, and deficiency in local search capability. Logistic equation and mutation operator are introduced to increase the diversity of population and convergence factor is introduced to improve the convergence rate during the iterative process. The improved PSO algorithm was applied in the optimal operation for flood control of the Dongzhen Reservoir and Mulanxi Watershed. The resulted showed that the maximum water level is 6.35 m and the maximum flow rate is 959.2m3/s at the pivotal watercourse. The solutions were much better than that obtained from the present reservoir control regulations (maximum water level of 6.93 m and maximum flow rate of 1139.5 m3/s) and that determined by the standard PSO algorithm (maximum water level of 6.51 m and maximum flow rate of 1066.3 m3/s).
The optimal operation model for flood control of reservoir is a high-dimensional multimodal extremum problem in general, and intelligent optimization algorithm is usually used to solve such problems. Particle swarm optimization (PSO) algorithm is widely used in the optimal operation of reservoir due to its simplicity; however, there are shortcomings in the PSO algorithm such as premature convergence, low efficiency in global convergence, and deficiency in local search capability. Logistic equation and mutation operator are introduced to increase the diversity of population and convergence factor is introduced to improve the convergence rate during the iterative process. The improved PSO algorithm was applied in the optimal operation for flood control of the Dongzhen Reservoir and Mulanxi Watershed. The resulted showed that the maximum water level is 6.35 m and the maximum flow rate is 959.2m3/s at the pivotal watercourse. The solutions were much better than that obtained from the present reservoir control regulations (maximum water level of 6.93 m and maximum flow rate of 1139.5 m3/s) and that determined by the standard PSO algorithm (maximum water level of 6.51 m and maximum flow rate of 1066.3 m3/s).
2014, 12(1):122-125.
Abstract:
The multi-level fuzzy evaluation method is commonly used for the early warning for dam safety, but this method has deficiencies. In this paper, the fuzzy inference method was introduced and the related theories of approximate inference based on the features of multiple implicational propositions were used to determine a multi-dimensional approximate fuzzy inference method for early warning of dam safety. Firstly, the dam conditions and dam safety warning were performed fuzzy classification based on the strong driving factors reflecting dam characteristics, and the speculative premise was developed using the summarized fuzzy conditional statement. Secondly, the dam conditions represented by the strong driving factors were the multiple inputs of fuzzy inference system, the dam safety warning was the single output of fuzzy inference system, and the response of dam safety warning was determined by the small premise composed of current factors based on the fuzzy inference rule. Finally, case studies were presented to analyze the application process of the method.
The multi-level fuzzy evaluation method is commonly used for the early warning for dam safety, but this method has deficiencies. In this paper, the fuzzy inference method was introduced and the related theories of approximate inference based on the features of multiple implicational propositions were used to determine a multi-dimensional approximate fuzzy inference method for early warning of dam safety. Firstly, the dam conditions and dam safety warning were performed fuzzy classification based on the strong driving factors reflecting dam characteristics, and the speculative premise was developed using the summarized fuzzy conditional statement. Secondly, the dam conditions represented by the strong driving factors were the multiple inputs of fuzzy inference system, the dam safety warning was the single output of fuzzy inference system, and the response of dam safety warning was determined by the small premise composed of current factors based on the fuzzy inference rule. Finally, case studies were presented to analyze the application process of the method.
2014, 12(1):126-130.
Abstract:
Under the current conditions that the subsequent flood cannot be predicted with high accuracy, the study on the historical storm flood information is important as it may provide valuable information to reduce the risk of reservoir flood control. In this paper, we developed a method to standardize the historical flood and selected the index system to reflect the flood characteristics on the basis of the formation mechanism of storm flood and available real-time information. Based on the gray correlation analysis theory, a dynamic identification approach of similar flood and an evaluation method of the extending effects of real-time flood forecasting process of similar flood were developed. The methods were applied to simulate the storm flood in the Chitan reservoir, which showed that the flood extending method has high efficiency to estimate the subsequent flood. Overall, the method is applicable, adaptable, and stable.
Under the current conditions that the subsequent flood cannot be predicted with high accuracy, the study on the historical storm flood information is important as it may provide valuable information to reduce the risk of reservoir flood control. In this paper, we developed a method to standardize the historical flood and selected the index system to reflect the flood characteristics on the basis of the formation mechanism of storm flood and available real-time information. Based on the gray correlation analysis theory, a dynamic identification approach of similar flood and an evaluation method of the extending effects of real-time flood forecasting process of similar flood were developed. The methods were applied to simulate the storm flood in the Chitan reservoir, which showed that the flood extending method has high efficiency to estimate the subsequent flood. Overall, the method is applicable, adaptable, and stable.
2014, 12(1):131-134.
Abstract:
There are a number of small reservoirs in China, but they are in poor security situation with the lack of effective security monitoring and out-of-date management, therefore they have high risk in safe operation. Over the years, the security identification for reservoirs mainly focuses on qualitative evaluation, and the quantitative assessment of operation risk and impact on downstream properties of dangerous reservoirs are missing. The operation risk of small reservoirs varies and remains uncertain, and the uncertainty is often interactive and interdependent. In this paper, the uncertainty of operation risk was considered as a grey system, and the grey theory and stochastic probability method were combined to develop the power function. The modified first-order second-moment method can convert the calculation of grey-stochastic probability into the calculation of general stochastic probability, which can better quantify the uncertainty of operation risk of reservoirs. The case studies of application of the above method demonstrate that the calculation can provide good guidance for the safe operation and reinforcement of small reservoirs.
There are a number of small reservoirs in China, but they are in poor security situation with the lack of effective security monitoring and out-of-date management, therefore they have high risk in safe operation. Over the years, the security identification for reservoirs mainly focuses on qualitative evaluation, and the quantitative assessment of operation risk and impact on downstream properties of dangerous reservoirs are missing. The operation risk of small reservoirs varies and remains uncertain, and the uncertainty is often interactive and interdependent. In this paper, the uncertainty of operation risk was considered as a grey system, and the grey theory and stochastic probability method were combined to develop the power function. The modified first-order second-moment method can convert the calculation of grey-stochastic probability into the calculation of general stochastic probability, which can better quantify the uncertainty of operation risk of reservoirs. The case studies of application of the above method demonstrate that the calculation can provide good guidance for the safe operation and reinforcement of small reservoirs.
30 Optimization Planning of Small or Medium Pumping Stations
along the Yangtze River Affected by Tides
2014, 12(1):135-137.
Abstract:
An optimal operation model of small or medium pumping stations along the Yangtze River affected by tides was developed on the basis of the objective function of least power consumption expense of the pumping stations, the decision variable of flow rate at each pumping station, and the constraint condition of pumped water quantity. The model was solved using the large-scale system of experimental optimization method. The results showed that under certain tidal and time-of-use power price conditions, the start-up mode of the pump station with nonadjustable working condition along the Yangtze River is mainly affected by the time-of-use power price. In order to decrease the operational cost of pumping stations, the flow rate should be reduced with high power price, and be increased with lower power price. The results can provide reference for the optimal management and operation of pumping stations affected by tides.
An optimal operation model of small or medium pumping stations along the Yangtze River affected by tides was developed on the basis of the objective function of least power consumption expense of the pumping stations, the decision variable of flow rate at each pumping station, and the constraint condition of pumped water quantity. The model was solved using the large-scale system of experimental optimization method. The results showed that under certain tidal and time-of-use power price conditions, the start-up mode of the pump station with nonadjustable working condition along the Yangtze River is mainly affected by the time-of-use power price. In order to decrease the operational cost of pumping stations, the flow rate should be reduced with high power price, and be increased with lower power price. The results can provide reference for the optimal management and operation of pumping stations affected by tides.
2014, 12(1):138-144.
Abstract:
For the safety problems of vibration in the pressure pipeline of high-lift pumping station, the approach of added water mass was proposed. A numerical model of pressure pipeline of pumping station was developed based on the fluid-solid interaction, and the modal parameters under different working conditions were identified based on the No.1 pressure pipeline of #2 pumping station in the first stage of Jingtai irrigated area. The displacement deformation of pressure pipeline and its vibration characteristics were analyzed. The results showed that (1) the vibration deformation stimulated by the pressure pipeline occurs at the inlet and outlet pipes of #4 machine; (2) the vibration amplitude of high-order vibration mode is larger than that of low-order vibration mode, and with the increasing of order, vibration deformation can also occur in the outlet pipe which is not easily to be vibrated; and (3) the inlet pipe of #8 machine does not affect the overall pipeline vibration. The results of finite element numerical simulation analysis were similar to those obtained from in-situ measurements. Consequently, the model with added water mass is simple and provides reliable results, and it has advantages in the fluid-solid coupling simulation of pressure pipelines.
For the safety problems of vibration in the pressure pipeline of high-lift pumping station, the approach of added water mass was proposed. A numerical model of pressure pipeline of pumping station was developed based on the fluid-solid interaction, and the modal parameters under different working conditions were identified based on the No.1 pressure pipeline of #2 pumping station in the first stage of Jingtai irrigated area. The displacement deformation of pressure pipeline and its vibration characteristics were analyzed. The results showed that (1) the vibration deformation stimulated by the pressure pipeline occurs at the inlet and outlet pipes of #4 machine; (2) the vibration amplitude of high-order vibration mode is larger than that of low-order vibration mode, and with the increasing of order, vibration deformation can also occur in the outlet pipe which is not easily to be vibrated; and (3) the inlet pipe of #8 machine does not affect the overall pipeline vibration. The results of finite element numerical simulation analysis were similar to those obtained from in-situ measurements. Consequently, the model with added water mass is simple and provides reliable results, and it has advantages in the fluid-solid coupling simulation of pressure pipelines.
2014, 12(1):145-148.
Abstract:
Dam deformation is influenced by a lot of factors. For those projects without long-term, continuous, and reliable monitoring data, the prediction precision of dam deformation based on the traditional MGM(1,n) model decreases with time. In this paper, the self-adaptive MGM(1,n) model was applied. The proposed model characterizes the interaction between each variable, and replaces the oldest information with new information, which can reflect the effects of random factors or perturbation on dam deformation. On the basis, the state transition probability matrix of the time series was determined by Markov chain, and the monitoring data and forecast data were analyzed to predict the dam deformation with a higher precision. Compared with the traditional MGM(1,n) model and self-adaptive MGM(1,n) model, the MGM-MC model has higher precision.
Dam deformation is influenced by a lot of factors. For those projects without long-term, continuous, and reliable monitoring data, the prediction precision of dam deformation based on the traditional MGM(1,n) model decreases with time. In this paper, the self-adaptive MGM(1,n) model was applied. The proposed model characterizes the interaction between each variable, and replaces the oldest information with new information, which can reflect the effects of random factors or perturbation on dam deformation. On the basis, the state transition probability matrix of the time series was determined by Markov chain, and the monitoring data and forecast data were analyzed to predict the dam deformation with a higher precision. Compared with the traditional MGM(1,n) model and self-adaptive MGM(1,n) model, the MGM-MC model has higher precision.
2014, 12(1):149-153.
Abstract:
Based on the preliminary design scheme of Jinfo Mountain concrete face rockfill dam located in Chongqing, the stress deformation distributions of the dam during the completion period and storage period were analyzed through the stress deformation calculation on the static plane. The study was focused on the effects of main rockfill porosity ratio and secondary rockfill materials on the stress deformation distribution of the face slab and toe slab of the dam and the deformation of the peripheral joint, which can form the basis for the selection of dam materials. The calculation results showed that the main rockfill porosity ratios of 20.1% and 19.1% are feasible, and the secondary rockfill dam materials with the ratios between the weak weathered zone silty sandstone and shale of 7:3 and 5:5 are feasible. The stress deformation of dam body, face slab, and toe slab is small with the main rockfill porosity ratio of 20.1% and the secondary rockfill dam materials with the ratio between the weak weathered zone silty sandstone and shale of 7:3.
Based on the preliminary design scheme of Jinfo Mountain concrete face rockfill dam located in Chongqing, the stress deformation distributions of the dam during the completion period and storage period were analyzed through the stress deformation calculation on the static plane. The study was focused on the effects of main rockfill porosity ratio and secondary rockfill materials on the stress deformation distribution of the face slab and toe slab of the dam and the deformation of the peripheral joint, which can form the basis for the selection of dam materials. The calculation results showed that the main rockfill porosity ratios of 20.1% and 19.1% are feasible, and the secondary rockfill dam materials with the ratios between the weak weathered zone silty sandstone and shale of 7:3 and 5:5 are feasible. The stress deformation of dam body, face slab, and toe slab is small with the main rockfill porosity ratio of 20.1% and the secondary rockfill dam materials with the ratio between the weak weathered zone silty sandstone and shale of 7:3.
2014, 12(1):154-157.
Abstract:
A proposed water transfer tunnel will be excavated with tunnel boring machine (TBM) in the surrounding type-III rock. The shotcrete and reinforced concrete segment serve as the initial support and permanent liner, respectively. The considerable internal and external water pressures are loaded on the liner, with the water head values of 110 m and 200 m, respectively. In this paper, in consideration of the contact relationship between segments, the contact relationship between segment and surrounding structure, and the cooperative working performance of reinforcement bars and concrete, the stress deformation characteristics of the liner under high water pressures are analyzed using the finite element method. The results showed that the external water pressure is the decisive load for the design of tunnel liner, and therefore a simplified model of segment liner design was proposed. The results suggested that it is feasible to use the reinforced concrete segment as tunnel lining under the conditions of the surrounding rock, support, and water pressure shown in the study.
A proposed water transfer tunnel will be excavated with tunnel boring machine (TBM) in the surrounding type-III rock. The shotcrete and reinforced concrete segment serve as the initial support and permanent liner, respectively. The considerable internal and external water pressures are loaded on the liner, with the water head values of 110 m and 200 m, respectively. In this paper, in consideration of the contact relationship between segments, the contact relationship between segment and surrounding structure, and the cooperative working performance of reinforcement bars and concrete, the stress deformation characteristics of the liner under high water pressures are analyzed using the finite element method. The results showed that the external water pressure is the decisive load for the design of tunnel liner, and therefore a simplified model of segment liner design was proposed. The results suggested that it is feasible to use the reinforced concrete segment as tunnel lining under the conditions of the surrounding rock, support, and water pressure shown in the study.
2014, 12(1):158-161.
Abstract:
Hydraulic hoist is used for the open and close of the lower head work gate of ship lift in Three Gorges Project. The hoist frame is safe if the traditional design method is applied, but it has heavy self weight. The structure of hoist frame was performed static analysis using the finite element software to obtain the distribution of equivalent stress. In order to improve the initial design of hoist frame, the topological optimization of structure was performed. Based on the objective function of self weight, the material distribution pseudo-density of the structure was obtained from the maximum structural stiffness with 25% decreasing of volume On the basis of topological optimization results and requirements for manufacture, the frame structure was improved by the measures such as local structural change, adding or removing reinforcing ribs, and modification of plate thickness. The modified results can not only meet the requirements of strength and stiffness, but also decrease the self weight effectively.
Hydraulic hoist is used for the open and close of the lower head work gate of ship lift in Three Gorges Project. The hoist frame is safe if the traditional design method is applied, but it has heavy self weight. The structure of hoist frame was performed static analysis using the finite element software to obtain the distribution of equivalent stress. In order to improve the initial design of hoist frame, the topological optimization of structure was performed. Based on the objective function of self weight, the material distribution pseudo-density of the structure was obtained from the maximum structural stiffness with 25% decreasing of volume On the basis of topological optimization results and requirements for manufacture, the frame structure was improved by the measures such as local structural change, adding or removing reinforcing ribs, and modification of plate thickness. The modified results can not only meet the requirements of strength and stiffness, but also decrease the self weight effectively.
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