某水电站洞室群开挖扰动区渗透特性演化及对渗流场影响

本文以某水电站左岸地下厂房洞室群工程开挖为依托,采用应变敏感渗透张量模型结合有限元分析方法对其左岸地下厂房洞室群开挖扰动区渗透特性演化规律进行了研究,并进行了考虑工程开挖扰动效应与否的情况下左岸厂房区域的渗流场分析研究.研究结果表明:厂房洞室群围岩由于开挖卸载导致的渗透系数变化率可达2~3个数量级,并且渗透系数开挖影响范围与开挖空间尺寸有一定的关系;地下厂房洞室群附近渗流场受开挖扰动效应影响较为显著,洞室群周围自由面有一定的下降;考虑开挖后,厂区渗漏总量有一定的增加、最大渗透坡降略有减小.研究成果可为水电站厂区渗流控制系统的优化设计提供相关的理论依据,同时也可为其它类似开挖工程提供参考.

Excavation-induced permeability variation and its influence in seepage field in caverns of hydropower station

In this paper,based on the excavation disturbed problems and then analyzed the seepage field when the exaction effects were taken into account or not of the caverns of underground powerhouse in the left bank of hydropower station,which using the strain-dependent permeability tensor model combine with finite element method.Researches show that: the change ratio ofpermeability of the rock around powerhouses up to 2~3 magnitudes and the size of influenced area related to excavation spatial dimensions;the excavation have a great impact on the seepage field especially near caverns,and free surface have been reduced;when consider the effect of excavation,the leakage of powerhouse be increased and maximum hydraulic gradient decreased slightly.Research achievements can provide relevant theoretical basis for optimization of seepage control system of powerhouse,and also provide references for other similar excavation.