基于露天地下协同开采的地表岩移控制技术研究

以某超大规模矿山露天与地下协同开采现状为工程背景,运用室内试验、理论分析与数值模拟相结合的方法,研究了急倾斜多层位矿体露天与地下协同开采条件下的地表岩移控制方法。首先,通过散体流动特性试验,得到塌陷坑内散体的临界跨径比为2.64,塌陷坑实际宽度远大于散体有效流动所需的最小宽度值,即散体流动过程中不会发生结拱现象;其次,根据临界散体柱支撑原理与数值模拟分析,塌陷坑内临界散体柱仅占整个散体堆积高度的22.98%~25.31%,裂隙主要存在于临界散体柱两侧的边壁围岩中,地表岩移程度主要由临界散体柱控制;然后,通过计算分析,得到塌陷坑散体覆盖层一次下移量的最大值约为0.27 m,证实了向塌陷坑充填废石散体的安全可行性。在上述分析的基础上,提出了沿塌陷坑边帮与走向方向的两步三向协同排岩岩移控制新方法,在示范矿山应用效果良好,取得了显著经济效益,为解决围岩及地表移动变形造成的重大地质灾害提供了理论和技术支撑。

Study on Surface Rock Movement Control Technology Based on Open-pit and Underground Synergetic Mining

Taking the status of super-large-scale open-pit and underground synergetic mining as the engineering back-ground.The laboratory experiments,theoretical analysis and numerical simulation are used to study the surface rock movementcontrol method under the conditions of open-pit and underground mining in steeply inclined multi-level orebodies.Firstly,through the experiment of bulk flow characteristics,the critical span ratio of the bulk in the collapse pit is 2.64,and the actualwidth of the collapse pit is much larger than the minimum width required for the effective flow of the bulk,that is,the archingdoes not occur during the bulk flow.Secondly,according to the principle of critical medium column support and numerical sim-ulation analysis,the critical mass column in the collapse pit only accounts for 22.98%~25.31% of the total bulk height,andthe crack mainly exists in the side wall of both sides of the critical medium column.The degree of surface rock movement ismainly controlled by the critical mass column.Thirdly,through calculation and analysis,the maximum value of the vertical dis-placement of the bulk layer of the collapse pit is about 0.27 m,which confirmed the safety feasibility of filling the collapsed pitwith waste rock.Based on the above analysis results,a new two-step and three-way coordinated rock movement control methodalong the side of the collapse pit is proposed,and good application results and remarkable economic benefits in demonstrationmines are obtained.It provides theoretical and technical support for solving major geological disasters caused by surroundingrock and surface movement deformation in mining.