Stability Analysis Of Open-pit Slope Of The Second Phase Project Of A Mine In The Qinghai-Tibet Plateau

China is one of the countries with more open-pit mining,the most important problem encountered in open-pit mining is the stability of the stope slope,the stability of the stope slope is especially important for safe production.This paper mainly studies the stability of single step slope and the influence of material parameters on safety factor;combines Geo-Slope and FLAC3 D to analyze the stability of two-dimensional section slope under natural and seismic conditions;uses Midas to carry out three-dimensional geological modeling of mine slope,to analyze the stability of three-dimensional integral slope under natural and freeze-thaw conditions,at the same time,summarizes the influence strength of different factors on stability.The main results are as follows:1.Using FLAC3D's built-in strength reduction method,the influence of different parameters of the same rock mass on the safety factor is analyzed,The calculation results show that the internal friction angle has the greatest influence on the safety factor,followed by the cohesion force,and the least affected parameter is the elastic modulus;Slope angle,fault and rock mass strength can affect the displacement of the slope after deformation,and the influencing strength is in turn fault,slope angle and rock mass strength.2.The limit equilibrium method in Geo-Slope and the strength reduction method in FLAC3 D are used to calculate the safety factor of two-dimensional slope profile,The results show that the two-dimensional slope profile is stable in natural state;the two-dimensional slope can also maintain stability under gravity+seismic condition,but the safety factor is significantly reduced,so the earthquake can be determined as the main external factor affecting the stability of the slope.By establishing a three-dimensional geological model,the calculated safety factor is also greater than the slope safety reserve factor,which indicates that the open-pit slope can maintain stable state under the action of self-weight stress.The calculated safety factor of mine slope is smaller than that of natural state under freeze-thaw condition,but the slope does not destabilize.The main mechanism of the influence of freeze-thaw on slope stability is to reduce the strength of rock mass by lowering temperature,thus reducing the stability of slope.3.The calculation results of safety factor of single step slope,two-dimensional typical section slope and three-dimensional integral slope are basically the same.The simulation analysis shows that the safety factor of open-pit slope is reliable,and the comprehensive evaluation shows that the overall stability of open-pit slope is higher.