三山岛金矿软破介质下残柱开采的稳定性分析

Stability Analysis of Remnant Pillars Recovery under Weak Rock in Sanshandao Gold Mine

为确保三山岛金矿顶底残柱安全高效回采,采用理论力学与数值模拟对散体下顶底残柱开采过程进行了稳定性分析。建立了理论力学模型,应用修正普氏拱理论计算了进路顶部荷载,采用数学力学解析法对不同规格的进路在开挖过程中的承载层进行了内力分析,得出了进路开采半宽和承载层厚度之间的拟合函数,进而得出了不同跨度进路顶板需预留原岩的最小安全厚度。应用ABAQUS软件对不同规格进路的开挖过程进行了塑性变形和顶板应力分析,得出了进路的合适采高及预留原岩的安全厚度,以及不同跨度的进路顶板冒落规模,从而得到采场进路宽和高分别为1.5 m和1.6 m。将理论力学分析和数值模拟分析的结果应用于三山岛金矿残柱的开采中,并对采场沿脉巷道进行位移监测,能确保试验采场安全生产。

For effectively stopping remnant roof and bottom pillars in Sanshandao Gold Mine, the stability analysis was conducted for the recovery process of remnant pillars under weak rock by using theoretical mechanics and numerical simulation methods. After the computation model was established based on the theoretical mechanics, the modified natural arch theory was applied to calculate load on the top of the access and the internal pressure of the loaded layer in the course of mining was analyzed for the different access with mathematical analytical method. A fitting function between the half width of the mining access and the thickness of the loaded layer was established, obtaining the minimum safe thickness of the reserved original rock required on the roof of the access with different span. The plastic deformation and roof stress were analyzed with ABAQUS software for different accesses during the excavation process, the proper mining height for the access and the safe thickness of the reserved original rock, and possible roof caving for the access with different span were all consequently calculated. It was concluded that the width and height of access to the stope are 1.5 m and 1.6 m, respectively. Results from theoretical mechanics analysis and numerical simulation analysis were applied into the remnant pillars recovery in Sanshandao Gold Mine with displacement monitored in the along-vein workings, showing safe production in the tested stooe can be ensured.