Influence of Remoulding Water Content on Resilient Modulus of Subgrade Clay Soils
Clay soils were always used in the construction of road subgrade.During in-situ compaction,under the effects of the factors such as rainfal and evaporation,clay subgrade soils were usually compacted under a wide range of remoulding water content(optimum water content as well as its wet and dry sides).Thus,the microstructure of the compacted clay soils could change,leading to variations in stiffness property under cyclic loadings.The dynamic behavior and microstructure of compacted subgrade clay soils at various remoulding water contents were investigated.Results showed that:when compacted at wopt and its dry side,soil fabric was characterized by aggregate-aggregate contact structure with pore size distribution(PSD)exhibiting a bi-modal feature,while at wet side of wopt,soil fabric was characterized by particle-particle contact structure with an uni-modal PSD.The variations of resilient deformation ε1r and resilient modulus Mr with remoulding water content were similar,which varied rapidly at the initial loading stage and then tended to stabilize.The variations of ε1r and Mr with remoulding water content exhibited"inverted bell"and"bell"shapes,respectively.A characteristic remoulding water content was defined at the turning point of the curve,defining two stages of the variations of ε1r and Mr:when w<wcha,w increment led to a decrease in ε1r and an increase in Mr,while when w≥wcha,w increment led to an increase in ε1r and a decrease in Mr.This phenomena could be attributed to the variations in aggregate and matric suction.The soil stiffness at wet and dry sides of the wcha was smaller than the value at wcha.Thus,the too wet or too dry case should be handled to guarantee the dynamic performance of the road subgrade.
unsaturated soilsremoulding water contentdynamic loadingresilient modulusmicro-structure
万方数据
维普
