Abstract:

Suppose the constitutive relation of soil to satisfy the hyperbola model. By assuming that the decrease of the hydraulic conductivity is proportional to the decrease of the compression conductivity and the distribution of initial effective pressure doesn’t vary with depth, the one-dimensional nonlinear partial differential consolidation equation which is under random time-depending loading is deduced. According to the idiographic initial conditions and the boundary conditions, the equation is solved using the variable separation method. The general solution of the effective stress is achieved; and then the general solution of the excess pore pressure, the general solution of the average consolidation degree defined according to the settlement and the general solution of the average consolidation degree defined according to the excess pore pressure are achieved. Finally, the solutions under trapezium low-frequency cyclic loading are achieved using the general solutions; and the factors which influence the consolidation characters are found. Based on the solutions under low-frequency cyclic loading, the relevant computer program is developed using FORTRAN language. Using this program, the consolidation characters and the influences of the parameters E and n which reflect the constitutive relation on the consolidation characters are analyzed. The computing results show that the average consolidation degree defined according to the settlement is a little bigger than the average consolidation degree defined according to the excess pore pressure; the closer to the drainage plane, the more obviously the mode of the loading influence the additional effective stress; the influences of E and n on the average consolidation degree defined according to the settlement are so small that can be ignored; however, the influences of E and n on the average consolidation degree defined according to the excess pore pressure and the additional effective stress are bigger, so that they can not be ignored.

Key words: cyclic loading, one-dimensional consolidation, hyperbola model, settlement