Experimental study on behavior of coefficient K_0 of Dongting Lake clay in wetting process

In order to study the effect of factors such as water content on the coefficient of lateral earth pressure at rest K0 of clay,the test apparatus taken into account wetting process of sample was designed,in which samples were vertically loaded by cylinder,and the lateral earth pressure was measured by strain gauges glued at three levels on the side ring. Undisturbed soil sample was gotten at 2 m below the ground around abutment of Cangerzong bridge in Hanshou county in Dongting Lake district.In the test,the relationship among vertical stress,vertical strain,lateral earth pressure and time were studied,and stress condition,stress path and behavior of K0 were analyzed.The results show that K0 of totally dry clay decreases from 0.40 to 0.21 with the increase of dry density of sample,and the larger the density,the lower the rate of decrease of K0.When the constant vertically load σ1 is 655 kPa,a large settlement in the sample occurs in wetting processs,and K0 finally decreases to 0.16.