Research On The Deformation And Strength Property Of Chlorine Saline Soil

The composition of saline soil, with crystalline salt in solid phase and salt liquor in liquid phase differs from that of ordinary soils, which makes its own character of deformation and strength property. With the development of our country's economy, some large and medium scale projects have to be built across saline soil area, so research on the deformation and mechanical property of saline soil is very practical. This paper explores systematically its deformation and mechanical property, using chlorine soil of Louyang loess disposed indoors as an object of study.The basic physical, chemical and compaction characters of chlorine saline soil have been studied and it is realized that the proportion and salt content of clorine saline soil have better linear relations. The plastic limit and liquid limit have a linear decreasing as salt content increases, CEC of grains and exchange Na+ increase with salt content whose ration is most obvious when salt content is between 3% and 8%, the optimum water ratio decreases with salt content increasing and the maximum dry density of 8% saline soil is the biggest value.The curve of soil and water of saline soil with different salt content and dry density is determined by using the pressure plate apparatus, and the effect of dry density and salt content on matrix suction of such soil is been analyzed.A shrinkage testing apparatus is used to test the dehydration deformation of chlorine saline at normal temperate (25oC), and when the water ratio is the same, dry density and salt content have been changed, the effect of dry density and salt content on linear deformation ration has been analyzed. Three main deformation types of chlorine saline soil exist: shrinkage, swelling shrinkage, expansion. The initial swelling water ratio and the take-off point of salt content from shrinkage to expansion are put forward.A consolidometer is used to test the compression and karst collapse deformation of saline soil with the same dry density and different initial water ratio and salt content, and the affacting factors are analyzed. Furthermore, the initial karst collapse pressure with different salt content and initial water ratio has been put forward, and the effect of salt content and initial water ratio on initial karst collapse pressure is also analyzed. The stretching resistance of chlorine saline soil with different salt and water ratio is tested with the single axis stretching resistance apparatus. The changing rule of tensile strength and the maximum stretching strain with different salt content and water ratio are analyzed and it is concluded that there is logarithmic relation between tensile strength and water ratio under the same salt content and dry density.The shear strength of saturated and unsaturated soil with the same dry density and initial water ratio is studied respectively by using normal and unsaturated soil apparatus. The linear relation increased between the effective index and index of total shear strength of saline soil and salt content. The failure net normal stress of unsaturated soil under the same confining pressure becomes small first, and then increases as salt content is increasing, and its value is minimum when salt content is 8%. The effective cohesion value calculated with linear regression is different from the determination value in the CU test on saturated soil and increases with salt content. The shear strength indexφ~b,χof unsaturated soil decreases first, then increases as salt content rises, and it is minimum when salt content is 8%.