某矿分段采场上盘围岩稳定性分析及工程应用

为了保证某倾斜矿体分段采场的安全生产,采用理论分析和FLAC^3D相结合的方法对不同条件的采场上盘围岩的稳定性进行研究;分析各参数条件下上盘围岩的当量暴露面积、应力、位移、塑性区分布等指标与采场长度、高度之间的关系;结合岩石强度理论、拉应力区分布面积及位移极限判据提出安全经济的结构参数,并通过工程应用对分析结果进行论证。结果表明:当量暴露面积随采场长度的增长率大于随高度的增长率,当采场长度大于40 m时,采场高度对当量暴露面积的影响权重逐渐增大;当采场长度和高度均为40 m时,其上盘围岩沿采场左右边缘及底部分布拉应力破坏区,最大位移量为41.77 mm,局部逐渐产生了塑性区,但各塑性区未发生贯通,可保持自身稳定。工程应用结果表明,开采过程中上盘围岩在出矿期间未出现剥离和掉渣现象,整体稳定。因此,为了有效保证采场安全和生产效率,建议矿山采场高度选择40 m,长度选择40 m。

Stability Analysis of Hanging Wall Rock at Sublevel Stope and Its Engineering Application in a Mine

In order to ensure sublevel mining safety of inclined orebody, theoretical calculation method and numerical simulation method were combined to analyze the stability of the hanging wall rock at sublevel-step stope with different structure parameters. The relationship between equivalent exposed area, stress variation, displacement and plastic zone distribution of surrounding rock on the hanging wall and the length, height of the stope was analyzed under different parameter conditions. Based on the theory of rock strength, the distribution area of tensile stress zone and the limit criterion of displacement, the parameters of stope structure which can guarantee the stability of the upper plate were put forward and demonstrated by the engineering application. The results show that the increase rate of equivalent exposed area with the stope length is greater than that with the height. When the stope length is greater than 40 m, the influencing weight of stope height on equivalent exposed area increases gradually. When stope length and height are both 40 m, the maximum displacement of surrounding rock on the upper wall along the left and right edges and the bottom of stope is 41.77 mm, and the plastic zone gradually generates in local. However, each plastic zone does not penetrate with each other, so it can maintain its own stability. The engineering application results show that there is no peeling and slag dropping of the surrounding rock on the hanging wall during the mining process, with good stability. Therefore, in order to effectively ensure the safety and production efficiency of the stope, it is suggested that the height of the stope should be 40 m and the length should be 40 m.