Study On Slope Stability Of Complex Rock Mass Structure In Diantan Iron Mine,Tengchong,Yunnan Province

Open-pit mining projects have formed many high and steep slopes,which seriously threaten the safety of human lives and property and the normal operation of mine production.In the process of coordinating with nature,the research of slope stability has made remarkable achievements,and the methods of slope stability research have become more and more mature.However,rock mass parameters are the basis of slope stability research and directly affect the calculation results of slope stability.At present,although there are various methods for obtaining rock mass parameters,there are few studies on the suitability of methods for obtaining rock mass parameters of different types of slopes.In the slope stability study,the randomness of the method of selecting rock mass parameters resulted in large differences in the results.This paper takes the stability of the complex rock mass structure of the Diantan Iron Mine in western Yunnan as the research object.Through data collection,field geological mapping and joint and fissure investigation,the geological conditions and engineering geological problems of the study area have been identified.At the same time,the study area has been drilled and recorded,on-site direct shear test in the hole,point load test and sample indoor test.On this basis,the rock mass quality classification and parameter inversion are used to obtain the slope rock mass and fault in the study area.The physical and mechanical parameters of the fragmentation zone.Use borehole data,slope structural surface characteristics and stereographic projection to comprehensively determine the potential sliding surface(zone)in the study area,and establish a realistic landslide and slope geological model,and compare the reliability of the parameter value method through the simulation of the model.Three typical sections in the study area are selected,and different limit equilibrium methods are used to check the stability of the slopes in the study area.The check results are compared with the simulation results to obtain a more suitable calculation method.Based on the above research content,the knowledge obtained is as follows:1.Obtained a large amount of fracture data through actual field measurement,combined with the iso-density map of the fracture to obtain the development of dominant fractures,obtained the unstable wedges cut by the dominant joint fractures in the study area through the slope stereographic projection,and on this basis,combined with drilling The revealed fracture zone and the development of weak structural planes comprehensively determine the potential slip planes(zones)of the slopes in the study area.2.On the basis of investigations such as indoor test,point load test,direct shear test in hole and field joint and fissure investigation,combined with rock mass quality classification and parameter inversion methods,three rock mass mechanical parameters are obtained.By comparing the parameters,the size of different rock mass parameters can be expressed as: rock mass quality classification>in-hole direct shear test>parameter inversion.3.Select the H1 landslide(weathered layer)that has occurred in the study area to establish a three-dimensional geological model,and use two parameters to fit the threedimensional model.Direct shear parameters,it is concluded that parameter inversion is suitable for weathered layer slopes to obtain rock mass parameters,and the feasibility of using the three-dimensional simulation method to simulate the slopes of this study area is also proved.4.Establish a three-dimensional geological model for the slope(rock quality)of the study area,and use three parameters for numerical simulation.The results show that the simulation effect of the rock mass parameters obtained by the in-hole direct shear test method is more in line with the actual situation.It can be obtained that the in-hole direct shear test is an effective method for rock slopes with more complex rock masses.The method of obtaining the mechanical parameters of the rock mass.5.The Morgenstern price method,Bishop method and Janbu method are used to calculate the two-dimensional stability of three sections under rainfall condition and rainfall plus earthquake condition respectively.The results of rainfall condition calculation and three-dimensional simulation are compared and analyzed.It is concluded that Morgenstern price method is more accurate for complex rock slope calculation,By analyzing the calculation results under the condition of rainfall and earthquake,it is concluded that the slope is in an unstable state under this condition.