基于应变软化的软弱夹层边坡渐进破坏

Progressive Failure of Slope with Weak Interlayer Strain Softening

含软弱夹层的顺层岩质滑坡是常见的地质灾害,研究其渐进破坏过程对于滑坡防治具有重要意义。基于软弱夹层的应变软化特性,推导了开挖工况下含软弱夹层的顺层岩质边坡渐进破坏的微分方程,并理论分析了渐进破坏的过程和阶段;对比摩尔-库伦本构模型下的数值计算结果,证明了应变软化摩尔-库伦本构模型能更准确地反映边坡软弱夹层的渐进破坏过程,并以实际工程案例进行了检验。研究结果表明:含软弱夹层的顺层岩质边坡的渐进破坏过程可分为初始、等速与加速变形3个阶段;在开挖工况下,破坏首先产生自坡脚,而后剪切破坏区不断扩展,沿软弱夹层延伸至坡顶,并在坡顶产生拉张破坏,边坡的整体破坏模式表现为滑移-拉裂式。

Researching the progressive failure of bedding rock landslide with weak interlayer,which is a common geological disaster,is of vital significance to the protection and treatment of landslides.In the light of the strain softening characteristics of weak interlayer,the differential equation reflecting the progressive failure process of bedding rock slope with weak interlayer under excavation condition is derived,and the process and stages of progressive destruction are revealed through theoretical analysis.Compared with the calculation results of Mohr-Coulomb constitutive model,the strain-softening Mohr-Coulomb constitutive model reflects more accurately the progressive failure of slope with weak interlayers,which is validated rational by an engineering example.The progressive failure of bedding rock slope with weak interlayer can be divided into three stages:initial deformation,constant speed deformation,and accelerated deformation.Under excavation condition,shear failure first occurs at the slope toe,and extends continuously to the top of slope along the weak interlayer;meanwhile,tensile failure occurs on the top of the slope.The overall failure of the slope is in a slip-crack mode.