A study of applying stochastic poroelastic theory to the problem of subsidence

In this paper, the first-order second-moment (FOSM) stochastic approach is utilized to estimate the uncertainties of the pore pressure and the deformation of a soil body. The hydraulic conductivity is treated as the only random variable, due to its large variation in natural environment, to investigate the mean and the variance behaviors of the excess pore water pressure and the displacement in the poroelastic theory. The mean solution of the FOSM is closer to the analytical solution than the Monte Carlo simulations. However, the covariance solutions of both stochastic approaches have similar pattern but with different magnitudes. The results show that the compaction of the soil body is large for positions close to the drained boundary and the uncertainties of the variables increase with distance away from the fixed boundary. When both loading and drainage are applied to the boundary, the mean value of settlement is larger and the covariance values are smaller than the case with drainage boundary only. The results demonstrate that loading is an important factor and should be considered in the subsidence problems.