密集缓倾软弱夹层影响下的坝基失稳破坏模式研究

Research on the Failure Mode of Dam Foundation under the Influence of Dense Gently Inclined Weak Interlayer

缓倾软弱夹层是影响坝基抗滑稳定的重要因素之一,密集发育的缓倾软弱夹层使坝基稳定问题变得更加复杂。开展关于密集缓倾软弱夹层影响下的坝基失稳模式研究,对复杂地基条件下的工程安全和坝基处理具有重要意义。本文以大藤峡水利工程泄水闸2个典型坝段为研究对象,分别采用地质力学模型和数值模拟方法进行研究。研究中充分考虑密集缓倾软弱夹层、断层等地质构造的不利影响,获得了闸室与坝基的破坏过程与破坏形态,确定了综合法稳定安全系数为KSC=3.30~4.18,揭示了大藤峡泄水闸坝基的破坏模式为浅层基岩的挤压屈服破坏,缓倾软弱夹层未形成滑移通道,坝基没有出现深层滑动失稳破坏。研究结果表明,坝踵区与坝趾区破坏较严重,是工程的薄弱部位,需采取工程措施进行加固。研究成果为工程加固方案设计提供了重要依据,为类似工程坝基稳定性研究提供借鉴与参考。

Gently inclined weak interlayer is one of important factors affecting anti-sliding stability of dam foundation.The densely developed gently inclined weak interlayer makes the stability of dam foundation more complicated.It is of great significance to engineering safety and treatment of dam foundation under complex foundation conditions to study the instability mode of dam foundation under the influence of dense gently inclined weak interlayer.In this paper,two typical dam sections of Datengxia Sluice Dam are studied by using geomechanical model and numerical simulation method respectively.In this study,the adverse effects of dense gently inclined weak interlayer and faults are taken into full consideration, and the failure process and form of the dam foundation are obtained. The stability safety factor of the comprehensivemethod is determined to be KSC=3.30~4.18. It is revealed that the failure mode of the dam foundation of Datengxia Sluice Gate is the compressionyield failure of shallow bedrock, and the gently inclined weak interlayer does not form a slip channel. No deep sliding failure occurs inthe dam foundation. The results show that the dam heel area and the dam toe area are the weak parts of the project, which needs to bestrengthened by engineering measures. The research results provide an important basis for the design of engineering reinforcement schemeand a reference for similar engineering dam foundation stability researches.