基于有限元强度折减法的抗滑桩滑坡推力及抗滑桩内力可靠性分析

Reliability analysis of landslide-thrust and internal forces of anti-slide pile based on strength reduction finite element method

现行的抗滑桩滑坡推力以及抗滑桩内力计算方法本质上属于定值方法,由于该方法未考虑边坡岩土体材料参数的变异性等不确定性因素,存在着抗滑桩支护不足或过度支护等问题,因此提出基于有限元强度折减法(SRFEM)的抗滑桩滑坡推力及抗滑桩内力可靠性分析方法。将极限分析法、有限元方法和可靠性分析法三者耦合,用2结点梁单元模拟抗滑桩受力状态,采用拉丁超立方抽样法(LHS)进行可靠度计算,分析求解边坡抗滑桩可靠性问题,并将该过程在数值计算程序中得以实现。对抗滑桩滑坡推力以及抗滑桩内力进行概率统计,得出函数分布关系,并根据已给定的失效概率控制值,反算出滑坡推力以及抗滑桩内力设计值。结合典型算例分析结果表明该法显著区别于一般方法,能较全面地反映出边坡整体现状特征和岩土体材料强度参数的变异性,相对更加合理,且更符合工程实际。

Currently,the calculation method of landslide-thrust and internal forces of anti-slide pile in essence belongs to the fixed value method.However,for the lack of considering geotechnical uncertainties,inadequate and excessive support problems for the anti-slide piles cannot be ignored.Thus,based on strength reduction of finite element method,the reliability analysis method of landslide-thrust and internal forces of anti-slide pile is proposed.In this method,the limit analysis,finite element analysis as well as reliability analysis are included.In the calculation process,2-node beam element is used to simulate the stress condition of anti-slide pile;and the Latin hypercube sampling(LHS) method is used for reliability calculation;and above process is realized in the numerical calculation program.Landslide-thrust and internal forces of anti-slide pile are statistically analyzed;and function distributions can be achieved.With the control values of a given failure probability,the design values of landslide-thrust and internal forces can be accurately determined.Typical example analysis shows that the proposed method is significantly different from the general methods;it can reflect the slope present situation,overall characteristics and the variability of material parameters;and the results are closer to the reality.