大渡河沙湾水电站厂房深基坑渗流反分析

Back Analysis on Seepage Flow in Deep Foundation Pit of Powerhouse at Shawan Hydropower Station on Dadu River

沙湾水电站工程厂房区地质条件复杂,基岩完整性差,地层中有较厚的夹沙层及岩溶层,覆盖层中存在大量渗漏通道并发育有承压水。为获得较大的发电水头,保证厂房建于基岩上,施工期开挖形成深基坑并导致大量渗水。针对厂房深基坑围堰范围纵横剖面建立了两个有限元模型,对地下水流场及渗透流量等进行了分析研究,论述了沙湾水电站深基坑围堰防渗的处理方法及效果,为类似工程提供参考。

In powerhouse area at Shawan hydropower station,geological conditions are complex.Bedrock integrity is poor,the rock mass is interbedded with thick sand layer and karstic formation,considerable seepage paths with confined water exist in overburden.To gain greater water head for power generation and ensure powerhouse to be founded on bedrock,considerable seepage water is caused by deep excavation of foundation pit during construction stage.Two finite element models are developed for longitudinal and cross sections of deep foundation pit cofferdam of powerhouse.Ground water flow field and seepage flow discharge are analyzed and researched by these two models.Watertight treatment and results of the deep foundation pit cofferdam are presented for the reference to the similar project.