非均匀边坡稳定的光滑有限元极限分析

Limit Analysis of Smoothed Finite Element of the Stability of Inhomogeneous Slope

非均匀层状边坡稳定是岩土工程中的重要问题之一。基于理想塑性上限和下限的极限分析方法是分析此类问题的常用方法之一。近期提出的基于混合常应力–光滑应变单元的极限分析方法(MCSE-LA)在克服体积锁定和计算性能(精度、效率以及收敛性)方面已被证明比传统有限元极限分析方法具有一定的优势,并且可以同时获得极限状态下的应力场和速度场。基于此,首先通过与经典有限元极限分析对比分析,验证MCSE-LA在非均匀边坡稳定分析中的可行性;其次,针对含软弱层边坡进行参数分析,发现软弱层的黏聚力对安全系数的影响更显著,而软弱层的摩擦角则对破坏机构特征的影响更明显;同时说明自适应的MCSE-LA可以较好地分析实际边坡的稳定性,为边坡工程的稳定性评价提供了一种有效的方法。

The stability of inhomogeneous layered slopes is one of the crucial issues in geotechnical engineering. Among the commonly used methods for analyzing such problems is the limit analysis approach based on the upper and lower bounds of plasticity. Recently, a novel limit analysis method (MCSE-LA) based on the mixed constant stress-smoothed strain element has been proposed. It has been demonstrated to have certain advantages over traditional finite element limit analysis methods in overcoming volume locking and computational performance (accuracy, efficiency, and convergence), and can simultaneously provide stress and velocity fields at the limit state. Firstly, by comparing with classical finite element limit analysis, the feasibility of MCSE-LA in analyzing the stability of inhomogeneous slopes is verified. Secondly, parameter analysis is conducted for slopes containing weak layers, revealing that the cohesion of weak layers has a more significant impact on the safety factor, while the friction angle of weak layers has a more noticeable effect on the characteristics of failure mechanisms. It is also noted that the adaptive nature of MCSE-LA can effectively analyze the stability of actual slopes, providing an efficient method for evaluating slope stability in slope engineering.