局部安全系数引入下岩质边坡稳定性分析极限平衡滑面应力法  

Limit equilibrium method based on stresses of slip surface for stability analysis of rock slope with introduction of local factor of safety

作　　者：邓东平[1] 彭一航 陈浩宇 王翊民 DENG Dongping;PENG Yihang;CHEN Haoyu;WANG Yimin(College of Civil Engineering,Central South University,Changsha,Hunan 400075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙400075

出　　处：《岩石力学与工程学报》2024年第4期964-985,共22页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(52278380);湖南省自然科学基金项目(2023JJ30670);湖南省交通运输厅科技项目(202008)。

摘　　要：由于广义非线性Hoek-Brown(H-B)强度准则可展现出岩体的复杂剪切破坏行为,因此,其被广泛地应用于岩质边坡稳定性分析。然而,以条块划分与条间力假设模式而建立的传统极限平衡方法不易于直接引入非线性强度准则,使得极限平衡方法在分析岩质边坡稳定性方面存在些许不足。此外,边坡稳定性分析时,以往常将滑面局部安全系数假定为与位置无关的单一变量。事实上,边坡在未达到临界失效状态前,滑面局部安全系数分布存在差异性。为此,应用Taylor级数展开式构建滑面正应力函数,并考虑滑面局部安全系数差异性,建立滑面局部安全系数倒数线性分布特征下滑面剪应力函数。进而,实现滑面应力计算模式与滑面局部安全系数差异分布特征下广义非线性H-B强度准则的融入。随后,引入滑面端部应力约束条件,并依据边坡滑体所满足的整体力学平衡方程,推导出岩质边坡稳定性极限平衡解答。通过算例对比分析,可知本文方法不仅可准确地评估出非线性强度准则下岩质边坡稳定性,而且能够合理地模拟出近坡顶处滑面拉剪应力区、客观地描述出应力集中效应下近坡脚处滑面压剪现象以及有效地判别出滑面局部安全系数差异分布特征。进一步,为了便于指导工程岩质边坡设计与加固,绘制了均质岩石边坡最小安全系数等值曲线图与临界滑面局部安全系数差异分布特征分区图。Because the generalized nonlinear Hoek-Brown(H-B)strength criterion can exhibit the complex shear failure behavior of rock mass,it is widely used in the stability analysis of rock slope.However,the traditional limit equilibrium(LE)methods based on the slice division and assumption of inter-slice forces is not easy to directly introduce the nonlinear strength criterion,which makes the LE methods have some shortcomings in analyzing the stability of rock slopes.In addition,the local factor of safety(FOS)of slip surface is usually assumed as a single variable independent of its position in the analysis of slope stability.In fact,before the slope reaches the critical failure state,the distribution of the local FOS of the slip surface is different.Here,the Taylor series expansion is applied to construct the function of the normal stress on the slip surface,and the function of the shear stress on the slip surface under the linear distribution characteristics of the reciprocal of the local FOS of the slip surface is established to consider the difference of the local FOS of the slip surface.Thereby,the generalized nonlinear H-B strength criterion is integrated with the calculation mode of the stresses on the slip surface and the difference distribution characteristics of the local FOS of slip surface.Thereafter,the stress constraint conditions at both ends of the slip surface is introduced,and then the LE solution of rock slope stability is derived according to the mechanical equilibrium conditions of the sliding body.Through the comparison and analysis of examples,it can be verified that the proposed method can not only accurately evaluate the stability of rock slope under the generalized nonlinear H-B strength criterion,but also reasonably simulate the tension-shear stress zone of the slip surface near the slope top,objectively describe the compression-shear phenomenon of slip surface near slope toe under the stress concentration effect,and effectively distinguish the difference distribution characteristics of the loca

关 键 词：边坡工程 广义非线性H-B强度准则 岩质边坡稳定性 极限平衡 滑面应力 滑面局部安全系数 滑面端部应力约束条件 

分 类 号：TU457[建筑科学—岩土工程]