基于底摩擦试验的硬岩岩质边坡变形过程及破坏机制研究

A study of deformation process and failure mechanism of hard rock slope based on the bottom friction test

针对不同倾向、不同倾角条件下,边坡变形破坏特征不同但缺乏相互对比分析研究的现状,在充分考虑硬岩岩质边坡变形破坏特征的基础上,配制硬岩相似材料,采用底摩擦试验方法,分析不同倾向、不同倾角边坡变形破坏模式,并借助PIVlab技术进行分析。结果表明:顺倾和反倾边坡变形破坏模式和破坏范围有明显区别。在45°坡度条件下,当顺倾边坡倾角由30°→45°→60°→80°转换时,变形破坏模式由滑移-拉裂→轻微滑移-弯曲(或滑移-剪切)→未有明显变形(整体稳定)→浅表部倾倒-拉裂逐渐演化。在45°坡度、反倾边坡条件下,变形破坏模式由岩层倾角30°和45°条件下无明显变形,逐渐向60°和80°条件下的倾倒-拉裂演化。当岩层倾角较陡时,反倾边坡破坏范围相对顺倾边坡更大,倾倒弯曲转折端更深。PIVlab结果反映出不同结构边坡条件下,不同位置的速度和位移矢量特征不同,且与宏观观察结果相吻合。研究成果能够为同类边坡的稳定性评价和治理设计提供一定参考。

The deformation and failure characteristics of slopes are different under different inclination and dip angles and their comparative analyses and studies are lacking.On the basis of fully considering the deformation and failure characteristics of hard rock slopes,hard rock similar materials are prepared,and the deformation and failure modes of slopes with different inclination and dip angles are analyzed with the bottom friction test method,and are analyzed with the PIVlab technology.The results show that there are obvious differences between the deformation failure mode and the failure range of down-dip and anti-dip slopes. Under the condition of 45° slope, when the dip angle of the down-dip slope changes from 30° to 45°, 60°, and 80°, the deformation and failure mode gradually evolves from slip-tensile to slight slip-bending (or slip-shear), no obvious deformation (overall stability), and to shallow toppling tensile crack. Under the condition of 45° slope and the anti-dip slope, the deformation failure mode gradually evolves from no obvious deformation under the conditions of 30° and 45° rock formation dip angles, and to dumping-cracking under the conditions of 60° and 80°. When the dip angle of the rock formation is steep, the damage range of the anti-dip slope is larger than that of the down-dip slope, and the turning end of the toppling bend is deeper. The results of PIVlab reflect that the speed and displacement vector characteristics of different positions are different under different structural slope conditions, which are consistent with the macroscopic observations, and the deformation zone characteristics are described according to the calculation results. This study can provide some reference for the stability evaluation and treatment design of similar slopes.