基于岩石长期强度特征的岩质边坡时效变形过程分析

基于对岩体流变特性的认识,从岩石材料内在物理力学性质受环境影响随时间劣化与岩石内部细观损伤积累的角度出发,通过引入岩体细观表征单元体的强度退化模型,开展岩质边坡的时效变形与破坏特征的研究。首先模拟了含顺坡软弱结构面边坡的时效破坏模式,分析了软弱结构面分布和强度劣化特性对边坡长期稳定性的影响；其次对一含有明显的软弱结构面的软硬互层岩质边坡,进行了时效变形破坏的实例分析。由于岩体的流变特性,岩体强度参数随时间的推移而逐渐衰减,致使边坡稳定程度降低。特别是对于含有明显的软弱结构面及软岩层的边坡,软弱结构面及软岩层的长期强度特性不容忽视。对含有明显的软弱结构面的软弱互层边坡蠕滑破坏的控制和治理,应在顾及时间效应的基础上,着重考虑长期强度、渗控和开挖卸荷等主要因素。研究成果可望对类似边坡的安全评价和设计提供一定的参考。

Time-dependent deformation of rock slopes based on long-term strength characteristics of rocks

Based on the knowledge of rheological characteristics of rocks, the strength degradation model is employed in the representative volume element to study the time-dependent deformation and failure of slopes in view of the physical essence that the mechanical properties of rocks are degraded with time and the meso-scopic damage accumulation due to the influence of environmental variation. The time-dependent deformation and failure of slopes with weak structural planes distributed along the slope surface is firstly simulated. The influence of spatial distribution and strength degradation characteristics of weak structural planes on the long-term stability of slopes is numerically investigated. Then the time-dependent failure of an existing slope with weak structural planes and alternatively distributed soft and hard rock layers is numerically investigated. Due to the rheological characteristics of rocks, the strength characteristics are degraded with time and the slope becomes more unstable. The long-term strength of weak structural planes and weak rocks plays an important role in the stability of rock slopes. The key factors such as long-term strength, seepage control and excavation-induced unloading should be thoroughly considered in the optimum design of slopes related to the safety of stabilization. The results obtained in this study may provide a meaningful guidance for the design and construction of other similar slopes.