UNSATURATED STRENGTH CHARACTERISTICS OF GLACIOFLUVIAL DEPOSITS OF TAOPING AREA IN LI COUNTY, SICHUAN PROVINCE

This paper investigates the influence of water content on shear strength of glaciofluvial deposits in Taoping area. Unconsolidated undrained triaxial shear tests were conducted on original samples with six different water content conditions. The unsaturated strength characteristics of this special soil are discussed by combining the soil water characteristic curve. Water content has a significant effect on the shear strength of the breccia soil in Taoping deposit. When the soil is saturated, its cohesion and internal friction angle are 40.0% and 29.5%lower than that in the case of natural water content. The increase of water content causes the matrix suction of glaciofluvial deposits to decrease rapidly, and the ability to suppress the plastic sliding of soil particles is greatly reduced. The fine cracks in the soil are continuously developed and expanded, resulting in the destruction of macro-microstructure and the attenuation of shear strength. Aiming at the shallow landslides which are widespread on the slope, it is necessary to carry out dynamic monitoring of rainfall in the accumulation area, to optimize the irrigation method and to strengthen the construction of the drainage system.