考虑岩体劣化的库岸典型危岩体破坏过程与长期稳定性分析

自三峡库区蓄水以来，岸坡消落带岩体劣化趋势明显，加速了岩质岸坡向欠稳定和不稳定发展，潜在崩塌涌浪灾害威胁长江航道安全。以三峡库区板壁岩为例，采用抗剪强度折减法分析在岩体劣化工况下危岩体的破坏过程与长期稳定性。结果表明：在自然工况下，板壁岩危岩体处于稳定状态；在库水+岩体劣化工况下，中部锁固段处拉应力集中，拉张裂缝逐步向顶部主控裂缝及底部基破碎带延展并相互贯通，可能发生滑移-剪切破坏；在库水+岩体劣化+强降雨极端工况下，约40个水文周期后，岩体强度下降30%,板壁岩危岩体的稳定性系数降至约1.14,处于欠稳定状态，建议进行工程防治，提高危岩体稳定性，以保障航道安全。研究结果可为三峡库区板壁岩及类似危岩体的防灾减灾工作提供科学合理的依据。

Failure process and long-term stability analysis of typical unstable rock mass in the Three Gorges Reservoir area considering rock mass deterioration

Since the Three Gorges Reservoir went into service, the rock mass in the hydro-fluctuation belt of the bank slope has obviously deteriorated, which accelerates the instability of the bank slope. The potential debris avalanche threatens the safety of the Yangtze River waterway. The Banbiyan unstable rock mass in the Three Gorges Reservoir area was studied using the shear strength reduction method to analyze the failure process and long-term stability of the unstable rock mass under rock deterioration. The results show that the Banbiyan unstable rock mass is stable under natural working conditions. Under reservoir water and rock mass deterioration, the tensile stress is concentrated at the central section. The tensile cracks gradually penetrate up and down, extending to the prominent controlling cracks at the top and the bottom base fracture zone. Slip-shear failure may occur. Under the condition of reservoir water combined with rock mass deterioration and heavy rainfall, the strength of the rock mass decreases by 30% after about 40 hydrological cycles, and the stability coefficient of the Banbiyan unstable rock mass decreased to about 1.14, which is an under-stable state. It is suggested to carry out engineering prevention and control to improve the stability of dangerous rock mass to ensure the safety of the waterway. The research results can provide a scientific and reasonable basis for disaster prevention and mitigation of the Banbiyan and similar unstable rock masses in the Three Gorges Reservoir area.