Analysis On Nonlinear Consolidation Of Clayed Soil By Considering Non-Darcian Flow And Stress History

The deviation of water flow from Darcy’s flow law and the influence of stress history on the settlement of soil have been recognized by many researchers, but the theory of consolidation with the considerations of non-Darcian flow and stress history is rarely reported. Based on Terzaghi’s theory of consolidation and Hansbo’s flow model, a nonlinear model of consolidation is developed by considering different characteristic of settlement of soil with different stress states and time-dependent load in practical engineering. Due to the established mathematical model is difficult to obtain its analytical solution, therefore, the finite difference method is adopted to obtain numerical solutions for this model. Based on the reliability of numerical solutions, the one-dimensional nonlinear consolidation behavior of saturate soft soil considering non-Darcian flow under different stress state was investigated. The studies of this paper consist of the following parts:(1) Considering non-Darcian flow in soft clay, the governing equation of one-dimensional nonlinear consolidation of normally consolidated soil was developed, and numerical solutions were obtained by finite difference method. The reliability of numerical solutions was verified by comparing the numerical solutions with the corresponding analytical solutions and semi-analytical solutions. Furthermore, on this basis, the influences of the non-Darcian flow, the external load, the compression index, the permeability index, the distribution of self-weight stress, the loading rate on one-dimensional nonlinear consolidation behavior of normally consolidated soil was analyzed in detail.(2) In engineering practice, abundant foundation soil are in over-consolidated condition. In order to guide the engineering practice better, it is necessary to further improve the consolidation theory more correspond to actual fact. At first, the governing equation of one-dimensional nonlinear consolidation of over consolidated soil under non-Darcian flow was developed, and numerical solutions were obtained by finite difference method. The reliability of numerical solutions was verified by comparing the numerical solutions in the condition of ce=cc with the corresponding numerical solutions of normally consolidated soil. Finally, the influences of the non-Darcian flow, the preconsolidation pressure, the index of recompression, the compression index, the permeability index, the loading rate on one-dimensional nonlinear consolidation behavior of over consolidated soil was analyzed in detail.(3) In addition to the state of normal consolidation and over consolidation, the state of the soil is under consolidation. Similarly, the soil in under-consolidated condition also has a significant influence on the consolidation behavior. At first, the governing equation of one-dimensional nonlinear consolidation of under consolidated soil under non-Darcian flow was developed, and numerical solutions were obtained by finite difference method. Finally, the influences of the non-Darcian flow, the compression index, the permeability index, the difference between self-weight stress and preconsolidation pressure, the loading rate on one-dimensional nonlinear consolidation behavior of over consolidated soil was analyzed in detail.(4) One-dimensional nonlinear consolidation behavior of different stress states with non-Darcian flow was analyzed, and similarities and differences of consolidation behavior are compared.