基于极限平衡法和强度折减法的边坡稳定性分析

Slope Stability Analysis Based on Limit Equilibrium and Strength Reduction Method

考虑传统的极限平衡法和FLAC二维非线性数值分析方法的优缺点,将边坡稳定性分析的Slide极限平衡法和FLAC2D强度折减法相结合,以某排土场为工程实际,进行了边坡在天然、天然地震、降雨和降雨地震四种不同工况下的稳定性验算比较;鉴于影响边坡稳定因素的不确定性,采用基于Spencer法的Mont-Carlo法进行了边坡可靠度指标的计算,并对强度参数C、φ和容重γ对边坡稳定的影响进行了分析,得出边坡稳定对内摩擦角φ的敏感性高于内聚力C的敏感性,而容重γ的影响较C、φ可忽略不计。该方法通过两者的相互校核,不仅给出边坡非线性应力-应变关系和安全系数来共同评价边坡的稳定性,而且结合排土场边坡安全系数的概率分析提供边坡潜在的失效概率使边坡稳定性评价更加科学、精确。

Considering the advantages and disadvantages of conventional limit equilibrium method and two-dimensional nonlinear numerical analysis method of FLAC,a method combining the limit equilibrium method of Slide with the strength reduction method of FLAC2D was used to analyze and calculate the slope stability of a soil dump under natural condition,natural earthquake condition,rain condition and rainy earthquake condition,In consideration of the uncertainty of the factors influencing the slope stability,Spencer method with Mont-Carlo simulation was explored for computation of the reliability of slope.Meanwhile,soil parameters C （cohesion）,（φ） （friction angle） and γ （unit weight） effecting on the slope stability was analyzed,the result shows that the stability of slope is more sensitive to （φ） than to C,while the influence of γ comparing to C and （φ） can be ignored.The proposed method can not only provide the nonlinear stress-strain relationship and safety factor of slope together to evaluate slope stability by mutual verification,but also offer potential failure probability of slope combining with probability distribution of dump slope safety factors which makes the estimation of stability more scientific and precise.