基于响应面法和强度折减法的边坡可靠性计算研究

针对边坡安全系数是隐式函数的特点,提出将有限差分强度折减法和响应面法(RSM)相结合,分析边坡可靠性的方法。采用安全系数、破坏概率及对应的临界滑动面等,作为综合评价边坡稳定性的指标。算例验证表明,笔者提出的计算方法所得结果与其他方法比较接近,且更能反映边坡真实的工作状态。对某钢铁基地工程的昔格达组地层边坡,采用新的计算方法进行可靠度分析,对比研究确定性破坏模式和概率破坏模式中剪应变增量和破坏区的分布。研究结果表明,均值强度较高的边坡岩土体,如果变异系数较大,便仍处于较高风险水平,虽然边坡整体的安全系数满足工程要求;均值安全系数和最小可靠度指标对应的破坏模式也是有差别的。

Analysis of Slope Reliability Based on Response Surface Method and Strength Reduction Method

As implicit expression is used in calculation of safety factor,a new method for slope reliability analysis which combined strength reduction method and RSM was presented.Factor of safety,failure probability and corresponding critical slip surface were taken as evaluation indexes in slope stability analysis.An example was given for demonstrating the validity of the present method.The results obtained by the present study were similar to those by other researchers.And the failure mechanism of the slope can be truly reflected by the present method.Aiming at Xigeda slope engineering project in a certain steel production base,the new method was adopted.A comparative analysis of the deterministic failure mode and the probabilistic failure mode,which involved contour of shear strain increment and failure zone,was carried out.Analytical results show that a slope with fairly great variability in parameters faces a fairly high risk,even if it has fairly high mean strength,and its overall safety factor meets the engineering requirements.