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[摘要]
为缓解城市内涝,提高透水铺装渗蓄排功能,搭建填充多孔纤维棉为铺装基层的海绵体透水铺装系统,基于 室内模拟降雨的物理试验,构建 Hydrus-1D 数值模拟模型。在不同降雨强度和降雨间隔条件下,通过产流试验获 得透水铺装的产流曲线并利用 Hydrus-1D 软件进行模拟验证,分析纤维棉透水铺装结构对降雨径流水量的控制特 性,初步探究透水铺装结构的一维水动力过程,并利用数值模型模拟不同结构层比例下峰值流量削减效果及出流 特征。结果表明:在间隔天数为 1~7?d 时 Hydurs-1D 数值模型对海绵体透水铺装具有较好的拟合度;纤维棉透水 铺装能有效削减峰值流量,具有较好的出流延迟性能,对于排水过程有明显滞缓作用,降雨强度越小,间隔时间越 长,效果越显著,在强降雨条件下效果大大减弱。在试验条件下降雨间隔 3?d 能发挥该透水铺装最大蓄水性能,降 雨间隔 9?d 表现出最佳峰值流量削减效果。在降雨间隔 9?d 时,多孔纤维棉层与碎石层比例为 1∶3 时水路畅通效 果最佳。
[Key word]
[Abstract]
The rapid development of urbanization has led to a dramatic increase in the proportion of hardened subsurface, which has had a significant impact on urban water generation and concentration, leading to urban flooding, the urban heat island effect, and the rain island effect. The sponge city is a new type of rainwater management measure. Permeable paving, as a multi-layer infiltration media system, is one of the LID technologies commonly used in sponge city construction, which can effectively absorb rainwater, and achieve the urban water cycle of regulation and storage.To alleviate urban flooding and improve the infiltration, storage, and drainage performance of permeable paving, a sponge permeable paving system filled with porous fibre wool was built as the paving substrate, and a Hydrus-1D numerical simulation model was constructed based on indoor physical experiments to simulate rainfall. Under different rainfall intensities and rainfall intervals, the flow production curves of the permeable pavers were obtained through flow production tests and verified by simulation using Hydrus-1D software. The control characteristics of the fibre wool permeable paving structure on the amount of rainfall runoff were analyzed, the one-dimensional hydrodynamic process of the permeable paving structure was investigated, and the peak flow reduction effect and outflow characteristics under different structural layer ratios were simulated using the numerical model.The results showed that the Hydrus-1D numerical model can simulate the flow production process of sponge permeable paving well. The flow rate and total flow rate curves were well-fitted for intervals of 0 d,1 d, 3 d, 5 d, and 7 d. However, for the flow rate curve at 11 d intervals, the simulated curve was shifted to the right by a larger amount than the measured curve. The model also fitted the storage process well for the rainfall phase, and the simulated curve lagged behind the measured curve to a certain extent when the rainfall stopped. Fibre wool permeable paving could effectively reduce the peak flow rate and had a good outflow delay performance, which had a significant retarding effect on the drainage process. The lower the intensity of rainfall and the longer the interval days, the more significant the effect showed. The maximum water storage performance of the permeable paving was achieved at a rainfall interval of 3 days, and the best peak flow reduction was achieved at a rainfall interval of 9 days. At a rainfall interval of 9 days, the porous fibre wool layer to gravel layer ratio of 1∶3 showed the best effect in terms of smooth water circulation.The experiments showed that sponge permeable paving had a more obvious water control effect at rainfall intensities below heavy rainfall, effectively absorbing rainwater and reducing peak flows. However, the effect of water control under extreme rainfall conditions such as very heavy rainstorms is limited. Sponge permeable pavement flow production curve indicated that it had an obvious slowing effect on the drainage process while reducing runoff, and cutting peak flow so that the drainage process flow remained stable. In practice, the sponge-permeable pavement can reduce the impact on the urban sewage network during heavy rainfall and reduce the pressure on the urban network. The experiments also provided data support for the establishment of numerical simulation methods for urban subsurface runoff water control processes.
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