光照重力坝坝基断层影响及处理的三维数值模拟

200m级光照重力坝坝踵和坝趾分别存在较大规模的断层，为了分析和评价断层对重力坝应力位移和坝基稳定性的影响，以及建坝后由于围压变化导致的断层变形模量提高对坝体的影响，对重力坝典型坝段和坝基岩体的联合作用进行三维数值模拟。对两条断层分别进行浮值分析，用强度储备系数法计算受断层影响的坝基安全稳定性，并分别模拟对两条断层进行的不同方式加固处理措施进行模拟。研究结果表明，位于坝趾的F2断层对坝体应力位移状态影响较大，也是坝基稳定性的控制性因素之一，在进行固结灌浆处理提高强度后，不仅可以提高坝基稳定性，而且可使坝体应力状态得到改善。位于坝踵的F1断层开挖并回填混凝土处理不宜过深。同时，建坝后围压变化导致断层变形模量的提高对于坝体应力控制是有利的。

3D NUMERICAL SIMULATION OF IMPACT OF KEY FAULT AND FAULT ENHANCEMENT ON FOUNDATION ROCK MASS OF GUANGZHAO HIGH GRAVITY DAM

Two major faults are located in the heel and toe of Guangzhao gravity dam with height of 200 m. A nonlinear 3D numerical simulation is conducted on a typical monolith to analyze the impact of faults on stress-deformation status of the gravity dam and stability of the abutment. Simultaneously, the impact on the gravity dam, which is caused by the increase of fault deformation modulus induced by the variation of confining pressure after the dam completion, is also analyzed. Sensitivity analysis of faults is conducted; safety of abutment impacted by faults is calculated by strength reservation method; and different reinforcement methods on the two faults are simulated respectively. The results show that the F2 fault located near the dam toe makes a great impact on stress status of the dam, and it is a major factor to control stability of the dam. Not only is the stability increase, but also the stress status is improved after consolidation grouting. It is suggested that F1 fault near the heel should not be excavated deeply. The increase of fault deformation modulus, which is induced by the variation of confining pressure after the dam completion, has an advantageous impact on the stress status of dam.