Deformation Characteristics In Wet And Dry Cycling Conditions Yunnan Laterite Strength

This paper based on the influence of comprehensively analyze drying and wetting cycles on soil properties, combining with the problem of drying and wetting cycles that drought, heavy rain led to in the area of Yunnan, the topic"study on the strength and deformation characteristics of Yunnan laterite in drying and wetting cycles" is presented. Aiming at the laterite in Kunming, the conditions of soaked, dehydration, and drying and wetting cycles are considered, and the research on strength and deformation characteristics of laterite through shear, compression tests are carried out under different influencing factors. Combing with interaction of water and soil characteristics, this paper analyze the influence on characteristics of laterite in drying and wetting cycle. It has an important theoretical significance for advanced study of the laterite problem in drying and wetting cycles caused by extreme drought.The results of soaked test show that:Laterite absorbed large amounts of water in a short period of time tend to saturation; The lower initial moisture content, or the higher initial dry density, the greater decreased in shear strength after soaked; Sharp decreased in cohesion tende to zero after soaked; Internal friction increased slightly; The compression improved after soaked. The higher initial dry density, the greater.compression factor increasedThe results of dehydration tests show that:Evaporation lost amounts of water, the laterite moisture content and saturation decreased in varying degrees. The same initial moisture content, the higher the initial dry density, the greater increased in shear strength. The same laterite initial dry density, the higher the initial moisture content, the smaller increased in shear strength. The same initial moisture content, the higher the initial dry density, the greater increased in internal friction and cohesion after dehydration. Same the initial dry density, the higher the moisture content, the greater increased in internal friction and cohesion after dehydration. Same the initial moisture content, the lower the initial dry density, the greater the compressibility coefficient, the greater decreased in compression coefficient after dehydration,the greater increased in compression modulus.The results of drying and wetting cycles test show that:Laterite shear strength decreased in a certain range. With the number of drying and wetting cycles, the laterite cohesion decreased, and the internal friction also decreased. In same initial dry density, moisture content the lower, the greater the cohesion decreased, In the same initial moisture content, the higher initial dry density, the greater decreased in cohesion. Internal friction decreased slightly. With the number of drying and wetting cycles, a slight increased in the compression factor, compression modulus slightly decreased, laterite compression are improved.In drying and wetting cycles Yunnan laterite characteristics is changed by the microscopic reaction of laterite and water that change its original structure. The laterite colloid mineral reaction with water, and migrate into the aqueous solution. Laterite lose part of the colloidal particles, so the original laterite cement particles reduce and come to new gap in the structure. The water film between the laterite colloid thickening or thinning that impact on the force between the particles. Repeated changes of drying and wetting, the formation of cracks strengthen the scope and extent of laterite react with water, resulting in the deterioration of the strength and deformation characteristics of the laterite.