Test Study On The SWCC And Application In The Analysis Of Soil-slope Stability

Landslides are one kind of significant geological hazards, which have caused many casualties and much damage to property. Water conservancy, transportation and mine construction are playing a role part in the economic development of our country, and steep slopes are common geotechnical problems in these civil engineering projects, in which landslides often occur. Slope failures are caused by many factors, among which rainfall is the most significant one. The infiltration of precipitation will cause reduction in the soil shear strength which can be divided into two aspects: the change of the characteristics of the soil and the reduction of the soil cohesion due to increase in water content. So the research on the relationship between water content and reduction of the soil strength is of value to prevent disaster caused by landslides. This paper has focused on the following aspects to discuss the slope stability/water content relationship and to develop a new method.1, The properties of the saturated and unsaturated soil strength were measured through the tri-axial test with undisturbed soil samples, from which some rules of the relationship between soil strength and water content are analyzed.2, Present SWCC research results have been generalized, and a fitting curve is presented from a practical SWCC model through measured data. A reasonable unsaturated soil shear strength equation and the water content/shear strength relationship is developed from back-analysis results of the unsaturated soil characteristics, from which a further relationship between water content and slope stability has been achieved. An application of the SWCC on the soil slope stability analysis is discussed3, The analysis results by means of different theories (saturated and unsaturated soil mechanics theory) were discussed based on the laboratory tests and on the new shear resistance equation developed in this paper, which indicated that the water content in unsaturated soil is an important parameter for slope stability analysis and the unsaturated theory is of great value for the slope engineering. A new simple and reasonable numerical method avoiding some limitations of traditional ones is presented in this paper, which will provide a reliable theory reference for the soil slope construction, safety assessment and management.