无底柱分段崩落法采场稳定性分析

Stability analysis of stope in pillarless sublevel caving

无底柱分段崩落法是国内外地下矿山广泛采用的采矿方法。长期以来由于受凿岩、装药以及出矿设备的制约,国内矿山大多采用小结构参数的无底柱分段崩落法,所产生的地压问题十分严重,开采效率低。近年来无底柱分段崩落法朝着增大采场结构参数的方向发展,不但有利于改善采场稳定性,同时还降低了生产成本。因此,开展采场稳定性分析有利于实现安全、高效开采。采用三维有限元方法对10 m×10 m、15 m×15 m、15 m×20 m共3种不同结构参数的崩落法采场进行了数值模拟,对进路开挖与矿石回采两个不同过程的巷道顶板竖直位移、主应力进行分析。数值计算结果表明:进路开挖时15 m×20 m与10 m×10 m的结构参数相比较,巷道顶板的竖直位移降低了20.1%,最小主应力下降了约18.8%;开采过程中顶板的竖直位移、主应力值都比进路开挖时小,采场地压得到改善;进路开挖与矿石回采过程巷道顶板的竖直位移和主应力值都随着结构参数的增大而降低。因此,大结构参数能更好地改善采场地压,增强采场稳定性,采用大结构参数的无底柱分段崩落法是安全可行的。

The pillarless sublevel caving is one of major mining methods in underground mine at home and abroad.As for the equipment constraint of rock drilling and blasting,the sublevel caving with small structural parameters has been applied for a long time processing with dynamite,and ore removal,which caused some problems such as serious ground pressure and low mining efficiency.In recent years,enlarging structural parameters is gradually used in pillarless sublevel caving,which improves both the mining stability and economic efficiency.Therefore,the analysis of underground pressure in pillarless sublevel caving favors the realistic safety,and the high effective mining.Three different structural parameters models（10 m×10 m,15 m×15 m,15 m×20 m） have been simulated.By adopting three-dimensional finite element method,and analysis has been done on the displacement and stress on the different processes of excavation and ore mining.The results are as follows： Firstly,compared 15 m×20 m with 10 m×10 m,the displacement of admission passage roof is reduced by 20.1% and the minor principal stress is also lowered by 18.8%.Secondly,the roof displacement and the stress in mining process is smaller than excavation process;the problems of underground pressure has been improved.Thirdly,the vertical displacement and principal stress is lowered with the increase of the structural parameters both in excavation and ore mining process.The results show the higher structural parameters possess better stability,and can improve the underground pressure.Therefore,using the large-spacing pillarless sublevel caving is safe and feasible.