考虑空间变异性的加筋路堤力学响应敏感性分析

Sensitivity analysis of foundation soil's mechanical parameters to mechanical response of geogrid reinforced embankment considering spatial variability

基于K-L级数分解法,结合有限元方法和蒙特卡罗策略,针对地基土体弹性模量、内摩擦角、黏聚力和泊松比的空间变异性对路堤在不同位置(地基土、格栅层、结构层上表面、结构层下表面)、不同时间点的位移和应力影响进行了深入系统的不确定性分析,并利用敏感性综合评价方法,开展参数敏感性分析.结果表明:土工格栅加筋路堤对地基土参数敏感性由高到低的排序为弹性模量、内摩擦角、泊松比、黏聚力.加筋路堤不同位置的挠度和应力对参数空间变异性的敏感程度不同,竖直方向越靠近地基土的区域,其挠度对参数空间变异性的敏感程度越高,路堤内应力敏感程度最高的区域为土工格栅层,其次是结构层下表面.

Based on the K-L level decomposition method,combined with the finite element method and Monte-Carlo strategy,an indepth systematic uncertainty analysis was conducted for the effects of spatial variability of elastic modulus,internal friction angle,cohesion and Poisson's ratio of foundation soil on the displacement and stress of embankment at different locations(foundation soil,grating layer,upper surface of structural layer and lower surface of structural layer)and different time points.By using the comprehensive sensitivity evaluation method,the parameter sensitivity analysis was carried out.The results show that the sensitivity of the geogrid reinforced embankment to the foundation soil parameters is ranked from high to low:modulus of elasticity,internal friction angle,Poisson's ratio,cohesion.The sensitivity of the deflection and stress to the spatial variability of the parameters varies in different locations of the reinforced embankment,the closer the vertical direction is to the foundation soil,the higher the sensitivity of the deflection to the spatial variability of the parameters.The area with the highest stress sensitivity within the embankment is the geogrid layer,followed by the lower surface of the structural layer.