司家营厚大矿体矿房分步式开采结构工程分析

Analysis of the Distributed Mining Structural Engineering of Large and Thick Orebody in Sijiaying

针对司家营铁矿井下大规模开采围岩的潜在失稳性,运用UDEC软件进行数值计算,分析不同开采阶段地压变化,应力云图揭示了采场顶板岩体内应力场向有利于维护围岩稳定的拱形承载结构演化,该结构的拱失f和拱跨L近似相等。同时在拱脚矿体上下盘边界和拱顶风化带岩层共显现出3个高压应力区,其中上下盘处应力集中,表明该部位矿房应快速组织充填。基于数值分析结果,建立了拱形桁架结构工程体系,并对该体系力学模型进行了分析,得出一、二步矿房宽度比值,并设计了厚大矿体的矿房宽度为20 m,安全系数达1.96。通过数值计算预警及理论分析优化设计,可有效保证地下规模化开采的安全性和连续性。

In view of the potential instability of surrounding rock in large-scale underground mining in Sijiaying,UDEC software is used to carry out numerical calculation to analyze the variation of ground pressure in different mining stages. Stress nephogram reveals the evolution of arch bearing structure in roof rock mass of stope,which is beneficial to maintaining the stability of surrounding rock. The arch rise f and arch span L in this structure are approximately equal. At the same time,there are three high pressure stress zones in the upper and lower boundaries of orebody at the arch foot and the rock strata of the arch roof weathering zone. The stress concentration in the upper and lower wall suggests that the ore room in this area should be filled quickly. In addition,based on the results of numerical analysis,the arch truss structure engineering system is established. The mechanical model of the system is analyzed by the force method,and the width ratio of one-step room to two-step room is obtained. The width of the room with thick and large orebody is designed to be 20 m,with the safety factor of 1.96.The safety and continuity of large-scale underground mining can be effectively guaranteed by early warning of numerical calculation,and optimization design based on theoretical analysis.