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岩土工程稳定性潜在失效风险问题日益引起人们的重视。分析了岩土边坡极限平衡理论特征,针对其滑动模式的稳定性系数计算公式为隐式表达,逆可靠度极限状态方程偏导数不易求解等问题,以极限理论中的Bishop模式为例,结合响应面途径,导出了将边坡稳定性系数隐式表达函数近似为显式二次多项式的简化方法。然后将其与基于一次二阶矩的结构逆可靠度算法融合,构建出基于风险控制的边坡稳定逆可靠度分析设计方法。基于该设计方法得出的方案具有可靠度与稳定性系数的双重控制指标。通过对示例边坡的拓展分析,阐述了该方法的实施过程,展示了边坡稳定失效风险与稳定系数的关系及相关因素对风险影响程度的分析方法。本文为边坡工程的风险设计提供了有效的可选途径。
The potential failure risk of geotechnical engineering is paid more and more attention. The theory of limit equilibrium of rock and soil slope is analyzed. In view of the problems that the formula of stability coefficient of sliding mode is implicit expression and the partial derivative of limit state equation of inverse reliability is not easy to solve, the Bishop model of limit theory is taken as an example. Response surface approach, a simplified method of approximating the implicit expression function of slope stability coefficient as an explicit quadratic polynomial is derived. Then, it is fused with the inverse structural reliability algorithm based on the first order second moment to construct the reliability analysis method of slope stability based on risk control. The scheme based on this design method has dual control indexes of reliability and stability coefficient. Through the expansion analysis of the example slope, the implementation process of the method is expounded. The relationship between the risk of slope failure and the stability coefficient and the analysis method of the influence degree of the relevant factors on the risk are demonstrated. This paper provides an effective alternative for the risk design of slope engineering.