| Most of the soil in slope engineering is unsaturated.Under the effects of natural conditions,long-term drying evaporation,rainfall infiltration or other factors,deformation,strength and other physio-mechanical property of soil is usually changed.Landslides or other natural disasters would be induced,which greatly threaten life and property security.So a thorough study of the mechanism of sliding instability,as well as stability analysis on the high rock slope,has importantly theoretical and practical significance to ensure safe mine production.The engineering background of this thesis is based on the western slope of the Sijiaying Iron Mine,in order to grasp the mechanism of flooding weakening on the western slope and soil slope stability to evaluate slope stability of Quaternary alluvium,an in-depth analysis and research to changes in the characteristics soil strength under repeated wetting-drying cycles was carried out based on experiments and field test.Through on-site sampling,the variation law of shear strength was studied under the condition that the internal structure and characteristics of the soil is the same as direct shear test.Finally,the limit equilibrium analysis method was applied to evaluate the slope stability and ultimately make reasonable suggestions.Combined withfield exploration,geological exploration,slope geotechnical sampling and experimental analysis,slope stability evaluation,blasting vibration test and so on,control measures on the western slope of the quaternary slope stability are put forward.The western slope in the upper soil layer is composed of the silty clay and sandy soils.Due to the thickness of the quaternary system is larger,the N8-N16 prospecting line soil thickness is about 30m to 70m,the soil aquifer water is strong,the slope angle is larger,the soil under the condition of bottom water seepage erosion,instability and failure of approximate circular arc is easy to occur.Through the soil mechanics test and back analysis of the thick soil slope,confirmed the sand and silty clay mechanics index,revealed the attenuation law of flooding weakening that groundwater seepage are the main reasons for the landslides.The N9-N13 area of western slope is in limit equilibrium state,according to the original design,the N8-N13 prospecting line area final state of slope safety factor cannot reach the safety reserve of 1.20.To make the western quaternary slope can meet the safety requirements and to consider the stability of weathered zone,according to current situation of different regions of the slope and the final state,under the premise of not moving pole and belt corridor,the comprehensive measures combining cutting local slope with slope reinforcement is proposed. |
