Study on the influence of mining sequence and depth on slope stability of end slope in open-pit mines
王忠鑫蔡忠超王东
WANG Zhongxin;CAI Zhongchao;WANG Dong
辽宁工程技术大学 矿业学院中煤科工集团沈阳设计研究院有限公司
端帮开采技术具有无需额外剥离、安全稳定且无需支护等优点,在露天矿端帮煤炭资源回收中具有良好的应用前景;但在开采过程中边坡岩体受采硐开挖和露天开采双重影响产生复杂应力变化,存在边坡变形及失稳风险;因此,选择合适的开采方式及参数对于端帮煤回收边坡稳定性至关重要。提出了顺序开采和跳采2种方式下的煤柱应力计算公式,采用FLAC3D软件对2种方式下的煤柱稳定性计算分析,并对开采极限状态下不同采硐深度对边坡稳定性进行了研究。结果表明:采硐跳采方式的理论煤柱应力因具有较宽的支撑压力承载区间而小于顺序开采,数值计算显示跳采煤柱整体处于稳定状态,与顺序开采相比,采硐最大压应力峰值降低16.97%,未出现明显应力集中区,沉降与底鼓量分别降低了34.16%和17.63%;采硐深度显著影响边坡变形量、变形范围及其稳定性,坡顶线投影位置与该矿端帮边坡潜在滑面重叠,边坡面向临空面位移、沉降与底鼓量在这一区间增长率显著增加,边坡稳定性也快速下降。
The end wall mining technology has the advantages of no additional stripping, safety and stability, and no support, and has a good application prospect in the recovery of coal resources in the end wall of open pit mine. During the mining process, the rock body of the slope is subjected to the double influence of mining excavation and open pit mining, which generates complex stress changes, and there is a risk of slope deformation and destabilization. Therefore, the selection of appropriate mining methods and parameters is crucial for the slope stability of end slope coal recovery. We put forward the calculation formula of coal pillar stress under sequential mining and jumping mining, and use FLAC3D software to calculate and analyze the coal pillar stability under the two methods, and study the slope stability under different mining tunnel depths in the limit state of mining. The results show that: the theoretical coal pillar stress of mining tunnel jumping is smaller than that of sequential mining due to the wider support pressure bearing interval, and the numerical calculation shows that the overall coal pillar of jumping mining is in a stable state, and compared with sequential mining, the maximum peak compressive stress of the mining tunnel is reduced by 16.97%, and there is no obvious stress concentration area, and the amount of subsidence and bottom bulge is reduced by 34.16% and 17.63%, respectively; the depth of the mining tunnel significantly affects the slope deformation amount, deformation area and its stability, and the projected position of the slope top line overlaps with the potential slip surface of the mine end slope, and the growth rate of the slope-facing displacement, settlement and floor bulge increases significantly in this interval, and the stability of the slope decreases rapidly.
边坡稳定性端帮采煤顺序开采采硐跳采数值模拟煤柱稳定性
slope stability;end slope mining;sequential mining;mining tunnel jumping mining;numerical simulation;coal pillar stability
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会