Experimental Study on Nonlinear Characteristics of Permeability and Compressibility of Soft Clay

Abstract

Consolidation and permeability tests were conducted on soft clays with different liquid limit by GDS consolidation apparatus. Some fitting parameters were studied for 4 common nonlinear permeability models based on the test data. But different soil samples have different parameters for the same model. In order to find the universal law of permeability coefficient and compressibility with the soil property and void ratio, the void ratio was normalized by the liquid void ratio eL, and the relationship of e/eL with logkv and logp were established based on the test data. The Chapman-Richard curve fitting model was adopted to best fit the obtained time-compression data. The relationship between e/eL with logkv was further verified using 30 groups of test data of permeability collected from China and abroad. The relationship between e/eL with logp was also discussed in this paper, and the fitted curves and nonlinear equations was further simplified into two linear equations at the point of e/eL=0.9 so as to consistent with the well-known theory. The nonlinear equations can be used to calculate the permeability and compressibility according to the void ratio and liquid limit.