隐伏断层作用下深厚覆盖层三维渗流分析

针对柴达木盆地深厚覆盖层及较大隐伏断层等不利地质条件严重影响坝基渗透稳定及大坝蓄水功能的问题，采用防渗墙来减少渗流量，并应用有限单元法对隐伏断层渗流特性、防渗措施及防渗墙渗控效果进行了分析。研究表明：哇沿水库采用70 m深悬挂式防渗墙可满足渗透稳定和大坝蓄水要求；若断层渗透系数较大，防渗墙需穿过透水断层，深入密实岩体内，插入深度需结合渗流量及岩体密实程度来综合确定；或对渗透系数较大的断层进行灌浆，减小其渗透系数，结合悬挂式防渗墙，减少渗流量；上述两种措施中防渗墙要避免将底端置于渗透性差异大的两种材料交界面处，以避免较大的防渗墙底部水力坡降导致的局部冲蚀，保证工程安全稳定的运行。研究成果可为柴达木盆地类似地质条件建坝提供技术支持和指导。

Three-dimensional analysis of seepage behavior in deep overburden layers with hidden faults

Unfavorable geological conditions such as deep overburden layers and large hidden faults in the Qaidam basin severely affect the seepage stability of the foundation and storage function of a dam. This study examines the cutoff wall measure for reducing seepage flow in a deep overburden layer with hidden faults, and uses a finite element method to analyze the seepage characteristics of this anti-seepage measure and its seepage control effect. Results show that adopting a suspended cutoff wall of 70 m deep, the Wayan reservoir meets the needs of seepage stability and water storage. If the seepage coefficient of a fault is large, the cutoff wall needs to pass through the fault and go deep into the dense rock mass, and its depth into the fault should be determined by combining the seepage flow rate and rock mass compactness. Also, we can decrease the permeability and seepage flow through grouting. For either of these two measures, the cutoff wall should avoid being extended into an interface of two materials widely different in permeability to prevent local erosion under the large hydraulic gradient around its tip, and its safe and stable operation must be ensured.