A MODEL FOR DESCRIBING THE NONLINEAR CONSOLIDATION CHARACTERISTICS OF SATURATED SOFT SOIL

Based on the nonlinear governing equation for one-dimensional primary consolidation and its dimensionless forms,an analytical consolidation theory of saturated soft soils is deduced. The relationship between void ratio and effective stress is assumed by previous studies. By using the initial and boundary conditions,the analytical expressions of normalized void ratio of normally consolidated saturated soils for uniform surcharge loading and two-way drainage are presented. The degrees of consolidation are also given in a normalized form. The consolidation deformation characteristics of saturated soft soils are analyzed;and the difference between the proposed theory and Terzaghi′s consolidation theory is pointed out. In order to express the nonlinear consolidation characteristics,a new parameter called nonlinear parameter λ is defined,and the effects of λ and thickness of soil layer h are analyzed. The comparisons between calculation results and some typical test results show that the proposed model can be well used to describe the consolidation characteristics of saturated soils. The studies show that there is an obvious difference in the characteristics of consolidation deformation with the changes of thickness of soil layer;and these differences are mainly induced by the nonlinear characteristics of soils instead of simply by secondary deformation effect among the primary consolidation process.