某土石坝深厚覆盖层混凝土防渗墙深度优化研究  

Study on Depth Optimization of Concrete Cutoff Wall for an Earth-rock Dam on Deep Overburden

作　　者：支永艳 邓华锋[1] 段玲玲 ZHI Yongyan;DENG Huafeng;DUAN Lingling(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area(China Three Gorges University),Ministry of Education,Yichang 443002,Hubei,China)

机构地区：[1]三峡大学三峡库区地质灾害教育部重点实验室

出　　处：《水力发电》2019年第9期102-108,共7页Water Power

基　　金：国家自然科学基金资助项目(51679127);国家自然科学基金重点项目(51439003);三峡大学硕士学位论文培优基金项目(2019SSPY017)

摘　　要：针对某深厚覆盖层土石坝坝基进行了9种不同深度的悬挂式混凝土防渗墙方案对比计算分析,计算结果表明,防渗墙深度达到22 m时,大坝及坝基年渗流量小于坝址区多年平均径流量的2%的要求。在此基础上采用三维有限元对坝体和坝基渗流特性进行了整体分析验证,结果表明,采用沥青混凝土心墙和悬挂式混凝土防渗墙为主的防渗体系,可有效地降低坝体内部浸润线高度,浸润线在沥青混凝土心墙处骤降,大坝最高处浸润线降至排水层,下游出逸点位于下游排水体中下部;沥青混凝土心墙和混凝土防渗墙的渗透坡降均小于允许值80,坝体填筑材料和天然砂砾石层的水力梯度小于允许值0.15,均满足渗透稳定要求。For an earth-rock dam foundation on deep overburden,nine different depth schemes of suspended concrete cutoff wall are calculated and compared.The results show that,when the depth of cutoff wall reaches 22 m,the total seepage flow of dam body and dam foundation meets the requirement of less than the 2%of annual average runoff in dam site area.This basis,three dimensional finite element is used to analyze the seepage characteristic of dam body and dam foundation.The results show that,(a)the seepage prevention system combined with asphalt concrete core wall and suspended concrete cutoff wall can effectively reduce the height of phreatic line in dam body,the height of phreatic line drops suddenly in the position of asphalt concrete core wall to the horizon of drainage layer,and the downstream outflow points are located in the middle and lower part of downstream drainage body;and(b)both the seepage gradients of asphalt concrete core wall and concrete cutoff wall are less than the allowable values of 80,and both the hydraulic gradients of dam filling materials and natural sand gravel layer are less than the allowable values of 0.15,which meets the requirements of seepage stability.

关 键 词：深厚覆盖层 悬挂式防渗墙 渗流 渗透坡降 水力梯度 

分 类 号：TV543.82[水利工程—水利水电工程]