Research On The Stability Of Rock Slope In The North Mining Area Of Qingshuigou Phosphate Mine Based On Energy Metho

Slope stability analysis has always been the priority among priorities in open-pit mine research.In this paper,the complex rock slope in the north stope of Qingshuigou Phosphate Mine is taken as the research object,and the main influencing factors of slope stability with reasonable mechanical parameters are determined by combining with field investigation and related rock mechanical property tests.An energy minimum energy slope stability analysis model based on energy method is proposed,and the stability analysis of slope in the north stope under normal and rainfall conditions is carried out.It provides theoretical basis for slope treatment of north stope in mining area.The main research contents and achievements of this paper are as follows:（1）Field geological survey and statistics were carried out for many times,and the stability analysis of the slope in the north stope was briefly carried out by using the pole isodensity map and the stereopar projection method.The rock mass structure characteristics,surface failure characteristics,formation lithology and the occurrence of structural plane formed by rock excavation in the north stope of mining area were investigated and analyzed.Rock samples were collected to determine the site of outdoor direct shear test and borehole in-situ shear test.The stability analysis of the slope is carried out by using the polar beam projection method.It is found that the occurrence of structural plane has little influence on the slope,and the slope is in a stable state.（2）Through the rock mechanics tests in different areas of the north stope,it is found that the mechanical properties of dolomite in different areas of slope are quite different,and the strength of rock mass in the weak area of slope toe is very low.Hoek-Brown strength criterion based on RMR rock mass quality classification was used to calculate rock mass mechanical parameters,and appropriate values were obtained by comparing with rock mechanics test results.（3）Combined with the rock mechanics test results and field investigation,the main influencing factors of the north slope were analyzed,and the stability analysis model of the slope with minimum energy was proposed.The combination of slope dip Angle and rock dip Angle is the basic influencing factor.The severe weathering damage caused by folding and the weak area located at the toe of slope also have great influence on the slope stability.From the perspective of energy work,a minimum energy slope stability analysis model based on the law of conservation of energy,kinetic energy theorem and radial strip method is proposed.From the perspective of theoretical analysis,the lower the net energy in the slope system,the more stable the slope is,which conforms to the common sense of physics and practice,and can quantify the degree of slope stability.（4）Using the proposed minimum energy slope stability analysis model,the stability analysis of north stope slope under normal conditions and rainfall conditions is carried out.Taking Beibang bedding slope as an example,comparative analysis of stability was carried out by Geo-slope limit equilibrium method and FLAC^3Dnumerical simulation method.It was found that the stability calculation results of different methods were basically consistent in the trend,which also verified the rationality of the analysis model of slope stability with minimum energy.The stability analysis of different slope types in north and south slopes shows that the model has strong applicability.Taking seismic energy as an example,the value of K parameter in other energies（△E₀）of the minimum energy model and the applicability of the model are discussed.