一维非线性地面沉降模型参数敏感性分析

Sensitivity of parameters in one-dimensional nonlinear model for land subsidence

以孔隙水压力和位移为基本变量的一维非线性地面沉降模型考虑了土体变形的非线性和渗透系数随土体变形的变化,它包含有km、m、k0、e0、n、kur和m′等7个参数。分析计算结果表明,计算的位移和孔隙水压力对参数km、k0和kur的变化非常敏感,而且当土层不均匀时,靠近孔隙水压力变化边界处的土层的渗透性对整个土层中孔隙水压力消散影响显著,而土层的压缩性对其自身的孔隙水压力消散影响显著。结合模型参数的获取方法,建议在有现场孔隙水压力、沉降等实测资料时,可以将km、k0和kur作为反分析参数。

Taking the pore water pressure and displacement as the basic variables, a one-dimensional nonlinear model for land subsidence is concerned with the nonlinear deformation and changeable permeability of soils. The model includes seven parameters, which are k_m, m, k_0, e_0, n, k_(ur) and m′. The calculation results show that the pore water pressure and the displacement are very sensitive to the parameters such as k_m, k_0 and k_(ur). Furthermore, for the nonhomogeneity of the soil layers, the permeability of the soil near the boundary where the pore water pressure is changing has great impact on the dissipation of pore water pressure of whole soil layers, while the compressibility of a soil layer has obvious effects on that of its own. From the view of the ways of getting those parameters, it is suggested that k_m, k_0 and k_(ur) be obtained by inverse analysis if the measured field data of pore water pressure and subsidence are available.