Experimental Study On Unsaturated Dynamic Deformation Characteristics For Chuanxi Gravel Mixed Soil

In a complex geological environment of the southwest mountains in China, there exist widely a kind of mixed soil, which features many origins, various compositions, multiple gradations, complex particle morphology and environmental sensitivity. In the engineering practice, on the ChuanXi slopes including the natural slope and artificial excavation high steep slope that is made of this kind of mixed soil, there is always deformation and slide as a result of the change of water content, which will lead to a huge loss of economy. A lot of practices show that the talus mixed soil belongs to unsaturated soil under natural conditions.Therefore, carrying out experimental study on the unsaturated mechanical characteristics is of great theoretical and practical significance.The main purpuse of this paper is to study the deformation characteristics and its impact factor of this kind of mixed soil under dynamic load which will provide a theory for the geotechnical stability evaluation and disaster prevention projects composed of this mixed soil.The research strategy is to carry out a series of soil tests on ChuanXi unsaturated mixed soil to study the relationship and influence between the matric suction and the dynamic deformation of the soil based on the matric suction.The main contents and conclusions as follows:1. By carrying out experiments on the identification of mineral composition and analying the grain composition and moisture content test of the two types of undisturbed mixed soil taken back in two different places, we found that these two mixed soil differ in physical forms.For example the large particles content of No.2soil is bigger than No.1obviously.And the difference in the mineral composition and grain composition leads to the difference in the hydrophilia between the two types of soil, so dose the void ratio.2. By perfoming soil-water characteristic experiment on the remolded mixed soil with filter paper method, the relationship between the matric suction and the water content would be determined.The test shows that the SWCC of the two kind of soil differs from each other because of the difference in mineral composition and grain composition.3. According to the former test, perform undrained triaxial experiment and undrained dynamic triaxial test on the remolded mixed soil in the way of controlling of moisture to indirectly control the matric suction, and analyze analyze the influence to the constitutive relation of the two kind of soil by the matric suction. The test shows that the dynamic elastic modulus is bigger than the static of the same soil.The matric suction has an influence on the constitutive relation.