Study On One-dimensional Nonlinear Consolidation Behavior Of Soft Soils

Although the studies on the theory of one-dimensional nonlinear consolidation of soil have been made over 40 years, nonlinear consolidation behavior of soft soil is still not very clear. In this thesis, one-dimensional nonlinear consolidation behavior of saturated soft soil is studied in detail through a great mount of typical numerical examples and many consolidation curves are prepared, from which, the behavior of one-dimensional nonlinear consolidation of soft soil is illustrated.The study shows that besides boundary conditions, the factors influencing the nonlinear consolidation behavior of soils are the compression index cc, the permeability index ck, the level and the rate of loading, and the thickness of soil, etc.In nonlinear consolidation, especially for layered soils, the average consolidation degree defined by settlement, Us is greater than the one defined by effective stress, Up, i.e., the rate of the development of settlement is greater than that of the dissipation of excess pore water pressure.If self-weight stress is assumed to be uniform, the settlement will increase with the increase of the value of ratio cc/ck, or the level of loading, or the thickness of soil. When the level of loading is increased, the excess pore water pressure will be increased too as cc/ck≥ 1, but it will be decreased at later stage of consolidation as cc/ck<1 The increase of either the value of ratio Cc/Ck or the thickness of soil will result in the increase of excess pore water pressure.The influence of the level of loading on Us and on Up are different for different value of the ratio Cc/Ck The influence on Us is greater than on Up when Cc/ckl.