Effect of Traffic Load on Permeability of Remolded Kaolin

Abstract

Soil anisotropic strength and strain behavior under principal stress rotation, caused by traffic loading, have been widely studied, while anisotropic permeability is of little concern. Large settlement will be induced by consolidation or secondary consolidation of soft clay, particularly for reclaimed clay. Permeability behavior is thus very important. Since current experimental setups do not take into account the influence of dynamic loading on the permeability of soil, hollow cylinder apparatus (HCA) was modified so that it can be utilized to determine the hydraulic conductivity of clay. HCA is usually used to simulate complex stress paths and to determine anisotropic strength and stiffness of soil under different directions of major principal stress. As no permeation experiment has been conducted by HCA before, firstly this paper proposes the test procedure for measuring the hydraulic conductivity of samples. Then, a series of permeation experiments under different K0 consolidations were conducted. Horizontal and vertical permeabilities were measured before and after traffic loading. Experimental results show that under K0 consolidation condition, the anisotropic permeability of remolded kaolin increases with the applied axial stress in spite of the same K0 value. Hydraulic conductivity decreases in both vertical and horizontal directions after traffic loading. Dynamic load has a greater impact on permeability behavior in its main consolidation direction, which leads to an increase in the anisotropy ratio of permeability. Findings in this paper will help understand the settlement and uneven settlement of embankments in soft ground, where permeability is normally regarded as a constant.KeywordsAnisotropyPermeabilityTraffic loadSettlement