基于边坡岩土体劣化破坏的临界滑移面研究

基于边坡岩土体劣化破坏机理,提出了一种边坡临界滑移面的确定方法。该方法通过有限元数值模拟对边坡岩土体进行多次弹塑性计算与应力分析,将每次计算得到的塑性破坏区内的岩土体强度用劣化后的强度进行替换,逐次劣化,直至塑性破坏区在坡体内贯通,模拟滑移面的渐进发展过程,最终确定边坡的劣化滑移面,并以该滑移面为临界滑移面计算边坡的安全系数。选取匀质和非匀质两类边坡算例,运用该方法确定边坡的临界滑移面,并将其与传统的强度折减法进行比较;同时采用矢量分析法分别计算两种滑移面的安全系数。分析结果表明,劣化滑移面由最初的塑性区逐渐扩展形成,劣化滑移面的确定方法适用于确定匀质和非匀质两类边坡的临界滑移面,其适用条件比传统的强度折减法更广;与强度折减法确定的滑移面相比,劣化滑移面更接近边坡实际的临界滑移面。

Critical Slip Surface Based on Deterioration and Failure of Slope Rock and Soil

A new method for determination of the critical slip surface in slope is proposed based on the deterioration and failure mechanism of  slop rock and soil. With this method, the elastic-plastic calculation and stress analysis were conducted several times for slope rock and soil with finite element simulation. And the strength of the rock mass in the plastic failure zones obtained from each calculation was replaced by the  strength after further deterioration, until the plastic failure zone extended through the slope. Based on the simulation of progressive development of the slip surface, the slope slip surface with deteriorated rocks was finally determined, which was taken as the critical slip surface for calculating the safety factor for the slope. With homogeneous and inhomogeneous slopes as examples for calculation by this method, the critical slip surface of the slope was determined and compared with the result from the calculation by the traditional strength reduction method. Meanwhile, the vector analysis method was used to calculate the safety factors for two kinds of slip surfaces. The analysis shows that, the slip surface with deteriorated rocks is gradually formed by the extension of the initial plastic zone, and the method for determination such surface is applicable for both homogeneous and inhomogeneous slopes, with  application wider than the traditional strength reduction method. Furthermore, such slip surface with deteriorated rocks is closer to the real critical slip surface of the slope.