Abstract

Uncertain climatic factors like rainfall can induce the complex hydro-chemo mechanical processes within the rock mass, and thus substantially increase the failure probability of rock slope. This paper presents a numerical investigation into the rainfall-induced instability mechanism of jointed rock slope with two joint inclinations of dipping 45° and 60° and the corresponded safety factor using the two-dimensional Distinct Element Method (DEM), where the non-uniform strength reduction approach is employed. For this purpose, some crucial aspects were mainly discussed, i.e. the quantifications of water softening and chemical weathering effects in the micro bond contact model, the necessary fitted functional relationships used in the safety factor, and determinations on the intensities of water softening and chemical weathering. The results show that the proposed DEM strength reduction provides a feasible approach to analyze the rainfall-triggered instability of jointed rock slope. The significant rise of bond breakage and the accompanied large displacement of sliding block indicate the achieved critical infiltration depth of rainfall and the consequent destabilization of jointed rock slope. The jointed rock slope with steeper dipping joints has lower safety factor, and thus is more prone to instability under the same rainfall effect.

摘要

降雨等不确定的气候因素会诱发岩体内部复杂的水化学力学过程，从而大大增加岩体边坡的破坏概率。本文采用二维离散元法（DEM）对具有 45°和 60°两种节理倾角的节理岩质边坡降雨失稳机理及相应的安全系数进行数值研究，其中非均匀采用强度降低方法。为此，主要讨论了一些关键方面，即微键接触模型中水软化和化学风化效应的量化，安全系数中使用的必要拟合函数关系，以及水软化和化学风化强度的确定。 . 结果表明，所提出的 DEM 强度折减法为分析节理岩质边坡的降雨触发失稳提供了一种可行的方法。断键显着增加，滑块位移大，表明降雨达到临界入渗深度，节理岩质边坡失稳。倾斜节理较陡的节理岩质边坡安全系数较低，在相同降雨作用下更易失稳。断键显着增加，滑块位移大，表明降雨达到临界入渗深度，节理岩质边坡失稳。倾斜节理较陡的节理岩质边坡安全系数较低，在相同降雨作用下更易失稳。断键显着增加，滑块位移大，表明降雨达到临界入渗深度，节理岩质边坡失稳。倾斜节理较陡的节理岩质边坡安全系数较低，在相同降雨作用下更易失稳。