深部采场构造可动块体失稳风险分析与预测

Risk analysis and forecast of the instability of the movable structure blocks in the deep stope

为了分析采场构造块体稳定性,以金川二矿区深部采场构造和矿体下盘采空后形成的临空面构成的可动块体为例,采用赤平解析法判断块体的可动性,采用Risenblueth方法计算可动块体失稳破坏概率。结果表明:对F16、Fb、Fc断层和采场临空面构成的赤平投影图分析得到裂隙块体JP(001)为潜在的滑动楔体;根据各结构面的向上单位法量及各运动方向的坐标,确定出可动块体的运动方向是沿结构面P2(Fb)和P3(Fc)滑动;采用Risenblueth方法获得滑动楔体失稳风险概率为12.96%。

The paper intends to analyze the stability of the geological structure blocks of the stope by taking the Jinchuan Mine No.2 as a case study of the movable block built up on the free surface due to the mined ore configuration and the stope＇s particular geo-structure.For our research purpose,we have adopted the stereo-graphic analytical method to judge the bulk mobility and worked out the instability and failure probability of the movable block with the Risen-blueth method.The research results we have gained demonstrate that： the fractured block body JP（001） we have discovered with the stereo-analytical method is a potentially sliding wedge with free surfaces as F16 fault,Fb fault and Fc fault.By using the unit normal vector and motion direction of the structural surface,we have succeeded in locating the movement direction of the sliding movable block,which is sliding along the structural surface（Fb fault） and（Fc fault）.Moreover,by means of Risen-blueth method analysis,we have worked out the instability risk rate of the sliding wedge is 12.96%.In identifying the depth of the sliding wedge which is composed of faults and stope free faces,a conclusion is made that the calculation of instability risk rate of probable sliding wedge should not include the role of the filling body.This is because,if the role of the filling body were to be taken into account for the key block,the geological structure of the stope would become more stabilized.Therefore,each fault should be a continuous smooth space structure when determining the key block,though the actual fault turns to be intermittent and curved,which seems to be favorable for the stability of the block.Besides,since the surrounding rock of the stope is subject to the geological structure action caused by the varying degrees of fracture,cleavage,faults,etc.,we prefer to believe that it is the factors that may have internal and external influence on the entire block system that determine the key block.Hence,our research results can serve as a practical reference to other similar analyses on the stope stability.