Jia Lan, Wang Jiaqi, Fang Linhao, Cui Yuedi, Chen Jianbing, Cao Lanzhu
Ordos Institute of Liaoning Technical University, Ordos, 017004, Inner Mongolia, China.
Liaoning Institute of Technology and Equipment for Mineral Resources Development and Utilisation in Higher Educational Institutions, Liaoning Technical University, Fuxin, 123000, Liaoning, China.
Sci Rep. 2024 Dec 28;14(1):31088. doi: 10.1038/s41598-024-82234-9.
Water is one of the most important influences on slope stability in open pit mines. In order to solve the problem of slope stability analysis in multi-aquifer open pit mines, the open pit mine in Block I of Thar Coalfield in Pakistan with multiple aquifers was taken as the research background. The groundwater flow field at different excavation phases was analyzed by numerical simulation method. Based on the seepage theory of groundwater, the distribution law of hydrostatic pressure in phreatic aquifer and confined aquifer was analyzed. Based on the rigid body limit equilibrium method, the slope stability analysis method under the action of hydrostatic pressure of multiple aquifers was proposed. Based on the water level distribution within the slope body obtained by numerical simulation, the slope stability at different excavation phases was calculated, and the influence of aquifers on slope stability was analysed. The research results show that: With the excavation and drainage of the mine pit, the groundwater flow field in the open pit mining area changes significantly, and a descending funnel was formed at the mine pit. When mining reached the pit bottom boundary, the water level dropped by about 155-163 m in the mining area. The hydrostatic pressure action of aquifer on slope is related to water level, quantity and location of aquifer. Under the condition of considering hydrostatic pressure of aquifer, the slope stability coefficients are all reduced. And the slope stability coefficients of the three different mining phases were reduced by 6.74%, 11.87%, and 5%, respectively. The more aquifers the sliding surface crosses, the greater the effect of hydrostatic pressure on slope stability. When mining to the boundary, the combined sliding surface passed through two aquifers, and the slope stability coefficient decreased by 5% under the hydrostatic pressure condition, and the arc sliding surface passed through three aquifers, and the slope stability coefficient decreased by 8.74% under the hydrostatic pressure condition. The stability of slope with arc sliding mode is more affected by aquifer hydrostatic pressure than that with combined sliding mode. When mining to the floor of the coal seam roof confined aquifer, the stability coefficient of slope with combined sliding surface decreased by 11.87%, while that with arc sliding mode decreased by 16.32%.
水是影响露天矿边坡稳定性的最重要因素之一。为解决多含水层露天矿边坡稳定性分析问题，以巴基斯坦塔尔煤田I区具有多个含水层的露天矿为研究背景。采用数值模拟方法分析了不同开挖阶段的地下水流场。基于地下水渗流理论，分析了潜水含水层和承压含水层中静水压力的分布规律。基于刚体极限平衡法，提出了多含水层静水压力作用下的边坡稳定性分析方法。根据数值模拟得到的坡体内水位分布，计算了不同开挖阶段的边坡稳定性，分析了含水层对边坡稳定性的影响。研究结果表明：随着矿坑的开挖与排水，露天采区地下水流场变化显著，矿坑形成降落漏斗。开采至坑底边界时，采区水位下降约155 - 163m。含水层对边坡的静水压力作用与含水层的水位、水量及位置有关。考虑含水层静水压力条件下，边坡稳定系数均降低。三个不同开采阶段的边坡稳定系数分别降低了6.74%、11.87%和5%。滑动面穿过的含水层越多，静水压力对边坡稳定性的影响越大。开采至边界时，组合滑动面穿过两个含水层，静水压力条件下边坡稳定系数降低5%，圆弧滑动面穿过三个含水层，静水压力条件下边坡稳定系数降低8.74%。圆弧滑动模式边坡的稳定性比组合滑动模式边坡受含水层静水压力的影响更大。开采至煤层顶板承压含水层底板时，组合滑动面边坡稳定系数降低11.87%，圆弧滑动模式边坡稳定系数降低16.32%。
