NUMERICAL SIMULATION ON THE FAILURE MECHANISM OF A HIGH SLOPE AT A GRANITE MINE SITE

A slope at a granite mine site is comprised mainly fill, silty clay, muck and mucky soil, medium coarse sand with mud, cliff clay, residual sandy clay. The soils are underlain with a granitic bedrock. The maximum height of the slope is 75 m and the height of the soil part above the alluvium is about 50 m. The strength reduction based finite element method is used to study the stability of the slope. The potential mode of slope failure and the safety factor of every sliding mass are obtained. The numerical results show that there are three sliding surfaces in the slope, two of them are shallow sliding surfaces and the third is a deep one. The stability factors of two shallow sliding surfaces are 1.13 to 1.17, which is at a critical state. The stability factor of the deep sliding surface is 1.29, which is at a relatively stable state. According to the analysis results, two advices are put forward: (1) reducing the loading by cutting down the slope; (2) installing anti-slide steps under the sliding.