6th INTERNATIONAL SYMPOSIUM ON MINE SAFETY SCIENCE AND ENGINEERING

123 / 2023-06-21 08:10:00

Research on stability of high and steep slope cutting and pressure reducing in open-pit coal mine

Open pit coal mine,High and steep slope,Cutting slope to reduce pressure,stability

As a long-term research topic, the slope stability of open-pit coal mine should not only require the safety production of open-pit coal mine on the one hand, but also ensure the acquisition of sufficient economy to achieve the balance between safety production and profit maximization.Slope research in open-pit coal mine is an extremely complex problem. Different from other projects such as water conservancy and hydropower, the stability of open-pit coal mine slope does not require permanent stability, but only needs to meet the stability within the working period of the corresponding mine. For high and steep slopes with hidden safety risks, slope cutting and pressure reduction can make the slope reach a stable state.Aiming at the key problem that the stability of high steep coal slope affects the safe and efficient production of mine, this paper takes an open-pit coal mine in Heilongjiang as the engineering background, and uses Flac3D numerical simulation to explore the stress displacement change law of high steep coal slope before and after slope cutting, and calculates the safety factor before and after slope cutting based on the limit equilibrium method.According to the numerical simulation and construction status, the paper puts forward the measures to further use the measures of anchor cable hanging net to control the high steep slope, and at the same time install the real-time dynamic monitoring and warning system on the slope. The results show that: (1) the landslide mode of the high steep slope under the project background is arc landslide;(2) The safety factor of the high steep coal slope: the stability factor after slope cutting is greater than the safety reserve factor, and the safety factor is increased by about 34%, and the stability of the slope after slope cutting and pressure reducing is obviously improved;(3) The slope of the high and steep coal slope: the height of the steps after slope cutting is 10m, the width of the safety plate is 5m and 8m, the overall slope after slope cutting is reduced from the original 35° to 25°, and the local slope is reduced from the original 68° to 60°. The flat plate after slope cutting can meet the normal production and transportation of the open pit mine;(4) Displacement of high steep coal slope: the maximum displacement before slope cutting is about 0.02m, the maximum displacement is concentrated in the high steep area on the upper part of the slope, and the maximum displacement after slope cutting is about 0.009m, at this time the maximum displacement is concentrated in the lower part of the slope, and the maximum displacement after slope cutting is reduced by about 0.01m;(5) Stress aspects of high and steep coal slope:Intense stress concentration appeared in the high and steep area of the upper part of the slope before cutting. After cutting, the stress concentration phenomenon only appeared slightly at the junction between the step and the slope, and the stress concentration phenomenon was significantly improved. At the same time, the maximum stress at the slope before cutting was 9262.7KPa, and the maximum stress at the slope after cutting was 3731.1KPa.