基于非线性化衡重式挡土墙稳定性分析

Stability Analysis of Balance-weight Retaining Wall Based on Nonlinear Model

为了准确判断衡重式挡土墙的稳定性,基于挡土墙的滑移失稳和倾覆失稳2种主要的失效模式,并考虑到浆砌块石挡土墙边坡的土工材料物理特性和力学特性的非线性以及可能出现第2破裂面时的非线性情况,运用一次二阶矩法的基本原理,建立涉及到挡土墙高度h、填料的内摩擦角φ、墙后边坡土的重度γ、土对挡土墙基底的摩擦系数μ、土对挡土墙墙背的摩擦角δ等挡土墙稳定性影响因素的非线性功能函数,计算出其可靠度指标。研究结果表明:改进的功能函数式考虑到挡土墙出现第2破裂面的情况,并计算出其抗滑移稳定性与抗倾覆稳定性的可靠度大小,解决了挡土墙背受到非线性土压力影响的问题;将基于非线性挡土墙稳定性分析的方法与线性分析方法计算的结果进行对比,可知非线性分析方法计算得出的可靠度偏小,更加安全,且符合实际情况,值得在工程中进行推广使用。

In line with the basic principle of First Order Second Moment method,a nonlinear function involving many influencing factors,including the height of retaining wall,the internal friction angle of filling material,the unit weight soil behind the retaining wall,the coefficient of friction between soil and wall base,the friction angle between soil and wall back,is established to calculate the reliability of balance-weight retaining wall,hence judging the stability accurately. Two failure modes,sliding failure and overturn failure,are considered. The nonlinearity of physical and mechanical properties of geomaterials and the possible second fracture surface are also taken into account. Results suggest that the present function could solve the problem caused by nonlinear earth pressure on the back of retaining wall by calculating the reliability of anti-sliding stability and anti-overturn stability in consideration of the possible second fracture surface. Compared with linear model,the present nonlinear model is worth promotion in engineering as the calculated reliability is smaller,hence is safer and more suitable for practice.