基于物质点强度折减法的二维均质c-φ边坡稳定性分析图表

TWO-DIMENSIONAL HOMOGENEOUS c-φSLOPE STABILITY ANALYSIS CHARTS BASED ON MATERIAL POINT STRENGTH REDUCTION METHOD

安全系数是判断边坡稳定性最常用的指标。应用传统极限平衡法求解边坡安全系数时,没有考虑土体内部的应力-应变关系,不能准确、真实地描述边坡土体破坏时的应力场、位移场及塑性区的发展情况。而应用有限元法虽然可以解决上述问题,但在计算过程中,会因网格畸变导致计算不收敛,造成求解困难。为此,本文基于物质点强度折减法,建立了安全系数无量纲参数F/tanφ与土体无量纲参数λ之间的关系,并绘制了求解均质边坡安全系数的稳定性图表。该方法无需任何迭代过程即可快速、方便地确定边坡安全系数。以文献中常见的4个典型边坡算例为例,将本文计算结果与文献中其他边坡稳定性图表进行对比,验证本文方法的准确性。结果表明,用本文研制的边坡安全系数分析图表计算获得的边坡安全系数与其他方法获得的安全系数计算结果相接近,吻合较好,证明该方法是一种有效且保守的估计边坡安全系数的计算方法,为快速评估边坡安全系数提供了一种新的途径。

Factor of safety(FOS)is an important parameter to evaluate slope stability.Two common methods used for evaluating FOS are the limit equilibrium method(LEM)and the finite element method(FEM).Since the stress-strain relationship is not considered,the LEM cannot truly reflect the development of stress field,displacement field and plastic zone during soil failure.On the other hand,although the constitute model is considered in FEM,it may suffer from nonconvergence problem due to grid distortion in the calculation process.To solve this problem,the strength reduction material point method(SRMPM)is proposed to evaluate the slope stability.The relationship between dimensionless soil parameters and FOS is subsequently constructed and plotted by different curves to obtain the stability analysis chart.This method can quickly and conveniently determine the FOS of slope without any iterative process.The reliability of the method is verified by four typical examples.The results show that the FOS calculated by the proposed chart is close to that calculated by other methods.The proposed method is conservative and effective.