A Simulation Study On The Strength Of Unsaturated Soils Affected By The Hysteretic Of Soil-water Characteristic Curve

unsaturated soils are widely distributed on land, the root cause difference between unsaturated soils and saturated soils is the existence of suction in unsaturated soils. Suction of unsaturated changes with water content, and soil-water characteristic curve for a soil is defined as the relationship between water content and suction for the soil. In many research areas of unsaturated soils, such as the strength theory,seepage theory,consolidation theory and constitutive theory, all involved the application of soil-water characteristic curve. But it is usually very expansive and time-consuming to obtain soil-water characteristic curve, the experimental data is discrete, and the processing and analysis of test data are far more complex than that of the saturated soil. This a certain extent leads that the practice and application of unsaturated soils is still far behind theoretical research. In order to the theory of unsaturated soil can be easily applied in engineering practice, This paper focuses on soil water characteristic curve, carried out some related research.The main work consists of:1,The paper systematically expounds the status of unsaturated soils,the concept of suction,the development of effective stress and shear strength of unsaturated soils, describes in detail the characteristics of soil-water characteristic curve,the relevant factors that affect soil-water characteristic curve,the reasons and research status of hydraulic hysteresis and the model of soil-water characteristic curve.2,Taking the fundamental theory of traditional domain model as the starting point, a simple model is proposed ,which is able to simulate the hysteretic characteristic of a soil-water characteristic curve under arbitrary drying and wetting paths. Through the existing experimental data, the rationality of the model was verified. By using this method, the amount of the experiment data necessary for calculating the hysteresis models can be reduced, So that some of the existing soil-water characteristic curve hysteresis models can be easily applied to engineering practice.3,Through stress analysis of the capillary cross section, pointed out that the mechanism of the negative pressure caused by suction to increase the pressure between the soil particles, introduced volumetric water content in the strength formulation, proposed a strength model formulation of unsaturated soils based on the effect of suction ,and verified its effectiveness.