复杂条件下不规则空区围岩冒落时空演化特征研究

复杂条件下不规则空区围岩冒落一直是裂隙岩体冒落研究领域的难点之一，岩性、断层、节理、空区形态及周边空区等条件越复杂，空区围岩冒落特性越难表征。石人沟铁矿开采M2矿体期间因下部民采空区突然冒透-210 m水平，形成埋深大、规模大、不规则且位于主要生产区域的M2主空区，同时该空区北侧还分布4个非法盗采诱发的隐伏空区，严重威胁了矿山安全生产。为此，提出了集三维探测、三维建模与三维数值模拟于一体的不规则空区围岩冒落范围预测方法。利用三维激光扫描技术探测空区形态与位置分布，在Rhino软件中利用复杂地层条件和空区最大不规则断面建立三维数值模型，基于3DEC研究周边空区开挖形成的采动应力影响下的M2主空区围岩时空演化特征，得到空区围岩最大冒落范围，并以空区水平截面半径和横向最大冒落范围之和确定安全隔离区半径，用以保障空区安全治理与周边矿体安全生产。研究表明：M2主空区围岩冒落活动在向上扩展的同时，也在沿矿体走向方向发展，且北侧围岩冒落范围远大于南侧。此外，通过开采安全隔离区外部南侧矿体，可有效利用已有采准巷道和中深孔穿孔工程，使该矿产能得到有效衔接。

Study on the Temporal and Spatial Evolution Characteristics of Surrounding Rock Caving in Irregular Goaf under Complex Conditions

Caving of irregular caving surrounding rock under complex conditions is always the difficulties in the research field of caving of fractured rock mass.The more complex the conditions such as lithology,fault,joint,cavity morphology and surrounding goaf,the more difficult it is to characterize the caving characteristics of surrounding rocks in the goaf.During the mining of the M2 orebody in Shirengou Iron Mine,the lower civilian goaf suddenly penetrated to the -210 m level,forming the M2 main goaf with large buried depth,large scale,irregularity and located in the main production.Meanwhile,four concealed empty areas induced by illegal mining are distributed in the north of the M2 main goaf,which seriously threatens the safety of mine production.Therefore,a method combined 3D detection,3D modeling and 3D numerical simulation is proposed to predict the caving range of surrounding rock in the irregular goaf.Three dimensional laser scanning technology is used to detect the morphology and location distribution of the goaf.Then,a 3D numerical model with the complex formation conditions and the maximum irregular section of the goaf is established by the Rhino.The 3DEC is used to study the spatial and temporal evolution characteristics of surrounding rock of M2 main goaf under the influence of mining stress formed by surrounding goaf excavation,and the maximum caving range of surrounding rock is obtained.Moreover,the sum of the horizontal cross sectional radius of the goaf and the maximum horizontal caving range is identified as the radius of the safety isolation zone,which can ensure the safety management of the goaf and the safe production of surrounding orebodies.The results show that while the surrounding rock caving activity in the M2 main goaf is expanding upward,it is also developing along the direction of the orebody strike,and the range of surrounding rock caving on the north side is much larger than that on the south side.In addition,the existing mining roadway and the medium and deep hole perforation project can be effectively used by mining the orebody on the south side of the safety isolation zone,so that the production capacity of the mine can be effectively connected.