砂土路基湿化变形和稳定性的可靠度分析

Reliability Analysis for Wetting Deformation and Stability of Sand Soil Roadbed

针对某高速公路砂土路基浸水湿化的情况,在现场钻取土样进行试验得到土性非线性参数统计结果的基础上,将参数变异性较大的土性参数K、Kb模拟为宽平稳高斯随机场;应用二维随机场局部平均理论和Duncan-Chang模型,建立二阶非线性摄动随机有限元分析模型,对该高速公路砂土路基的湿化变形和稳定性进行可靠度分析。结果表明:砂土湿化后将发生附加沉降变形,土性参数的变异引起路基沉降的变异性较小;虽然砂土湿化后其土性参数将降低,但路基稳定性的可靠度指标仍然较大,发生破坏的可能性较小。

Aimed at the problem of sand soil roadbed of a freeway impregnated in water, soil was cored for the statistical result of nonlinear parameters by 3-axial experiment. The parameters of soil properties, such as K and KB which had more variability than the others were simulated as stationary Gaussian processes. The local average theory of 2-D random field was applied for the processes. The Duncan Chang nonlinear constitutive law was also applied for the second order nonlinear perturbation stochastic finite element method and the algorithm was also put forward. The reliability of wetting deformation and stability of the sand soil roadbed was analyzed. As a result, the roadbed will evolve additional deformation when the sand soil is impregnated, while the variability of soil mechanical parameters shows less influence on the deformation of roadbed and pavement. Even though the mechanical parameters of soil will decrease when it is impregnated, the reliability index of the roadbed stability is still so high that there is less possibility that the roadbed will slide failingly.