RESUMO
Reasonable design of the slopes of mining field is an important prerequisite for optimizing open-pit mine boundary, ensuring safe production and improving economic benefits of open-pit mines. This study took the open-pit coal mine coal mine in Block I of Thar coal field in Pakistan as the research background, based on the section morphology effect of slope stability and the occurrence characteristics of coal seam and weak layer, the section morphology of slope was optimized step by step from two-dimensional angle by using the rigid body limit equilibrium method. The three-dimensional numerical simulation method is used to analyze the three-dimensional spatial effect of slope stability and reveal the influence of the spatial geometry of the slope stability. The spatial morphology of the slope was optimized and the evolutionary mechanism of slope instability was revealed. By comparing the optimized slope morphology with the preliminary design and the slope morphology of the straight slope with equal flat plate, the economic benefits were further analyzed. The results showed that under the premise of meeting the safety reserve coefficient, compared with the preliminary design and the design of equal plate. The slope angle of the optimized section morphology was increased by 1° and 3° respectively, and the coal resource recovery was increased by 332 m2 and 1790 m2 respectively, and the economic benefits were $ 18,065,859 and $ 54,408,251 respectively. And the slope angle of the optimized spatial morphology was increased by 3° and 5° respectively, and the coal resource recovery was increased by 1188 m2 and 2726 m2 respectively, and the economic benefits were $ 72,082,808 and $ 108,417,368 respectively.
RESUMO
It is of great practical significance to carry out quantitative risk assessment of landslide disaster to protect people's lives and property safety and maintain the sustainable development of social economy. The delineation of landslide disaster range is the key link of landslide risk evaluation in open-pit mine. This study took the open-pit coal mine coal mine in Block I of Thar coal field in Pakistan as the research background, and constructed a framework for landslide risk evaluation in open-pit mines. Based on the numerical simulation method of large deformation of landslide, the disaster range of landslide in open-pit mine was delineated. The stability of stope slope was analyzed based on rigid body limit equilibrium method. The probability of landslide instability was calculated based on Monte Carlo method. And the comprehensive fuzzy evaluation model was established to calculate the total risk value of landslide. The results showed that: through numerical simulation and empirical formula calculation, the landslide disaster range was accurately delineated, and the comprehensive vulnerability of the disaster bearing body was determined to be medium vulnerability; the annual probability of landslide instability under natural conditions was 0.003, which belongs to moderate risk. The annual probability of landslide instability under rainstorm conditions was 0.024, which was highly dangerous; the annual probability of landslide instability under seismic conditions was 0.018, which was highly dangerous. Under natural conditions, the total risk value of landslide was 114,686.4 rmb, and the annual mortality rate of population was 0.0255 people/year. The total risk value of landslide under rainstorm condition was 11,707,570 rmb, and the annual mortality rate of population was 0.18375 people/year. The total risk value of landslide under earthquake condition was 43,007,400 rmb, and the annual mortality rate of population was 0.135 person/year, which was an unacceptable risk. The economic loss was a small geological disaster risk under natural conditions, and it was a medium-sized geological disaster risk under both rainstorm and earthquake conditions. Therefore, landslide prevention and control and management measures such as slope deformation monitoring were proposed to ensure the safety of personnel and property in open-pit mines.
