基于采场结构参数优化后的充填体强度数值模拟

Numerical Simulation of Backfill Strength Based on Optimization Results of Stope Structural Parameters

合理的采场结构参数能够有效控制岩体位移,改善围岩应力分布状态,提高采场稳定性。为确定高尔奇铅锌矿采场最优结构参数,根据矿山地质条件和矿体赋存状态,建立5种采场结构模型,通过有限元软件ANSYS进行数值模拟,综合考虑顶板、间柱和充填体柱的拉应力、压应力及位移变化,引入安全系数对各模拟方案进行对比分析。结果表明:拉应力在模型边界发生应力集中现象;压应力侧帮靠近采场两端处发生压应力集中现象;随着空区跨度的增大,位移量呈逐步增大趋势;综合安全、经济和技术等因素,最终优选出的采场结构参数为75.0 m×6.0 m×1.8 m。但由于矿山自身条件制约,矿山过渡阶段拟采用的采场结构参数:矿房为75.0 m×3.5 m×1.8 m,矿柱为75.0 m×6.0 m×1.8 m。为确定与之匹配的充填体强度,再次进行数值模拟,确定最佳充填体强度范围为1.2~1.4 MPa。矿山过渡阶段的实践表明,该方案提供了安全的作业条件,取得了良好的经济效益,对于类似矿山开采具有一定的借鉴意义。

With the construction of exploration and mining engineering and mining preparation engineering,the industrial orebody is gradually exposed.Compared with the exploration report,the shape of the orebody has changed greatly:(1)The thickness of the orebody becomes thinner and the grade is improved;(2)The stability of the orebody is poor,especially the soft and weak fault gouge exists in the hanging wall of most sections of the orebody.Based on the deterioration of ore occurrence conditions,if the open stope method recommended by the original preliminary design continues to be used,it will lead to low recovery rate,high dilution rate,poor safety and high safety production pressure.In order to adapt to the changed orebody occurrence conditions and solve the above-mentioned safety and economic problems existing in the preliminary design recommended open stope method,the open stope method is changed into a filling method with better safety,higher recovery rate and more environment-friendly.At the same time,reasonable stope structure parameters can effectively control the displacement of rock mass,improve the stress distribution of surrounding rock,and improve the stability of stope.In order to determine the optimal structural parameters of the stope in Gaoerqi lead zinc mine,five stope structure models were established according to the mine geological conditions and orebody occurrence state.The numerical simulation was carried out by the finite element software ANSYS.Comprehensive consideration of the tensile stress,compressive stress and displacement changes of the roof,inter-column,and filling body column,the safety factor is introduced to compare and analyze the simulation schemes.The results show that:Tensile stress occurs stress concentration at the boundary of the model;Compressive stress concentration occurs near the two ends of the stope;Displacement increases gradually with the increase of goaf span;The final optimized stope structure parameter is 75.0 m×6.0 m×1.8 m according to the factors of safety,economy and technology.However,due to the fact that the filling station has not been built,the goaf of one-step stoping can not be filled in time,the exposure time of roof is long,and the risk of roof collapse increases.It is proposed to adopt the one-step 3.5 m-wide strip tight mining method.Due to the increase of stope width in one step,the requirements for the strength of filling body have changed.The stope structure parameters to be adopted in the transition stage of the mine are:Room 75.0 m×3.5 m×1.8 m,pillar 75.0 m×6.0 m×1.8 m.In order to determine the matching strength of filling body,the numerical simulation was carried out again,and the optimal strength range of filling body was determined to be 1.2~1.4 MPa.The practice in the transition stage of the mine shows that the scheme provides safe operation conditions and achieves good economic benefits,which has reference significance for similar mines.