节理裂隙发育诱导的隧道围岩不稳定块体的预测

Prediction of Unstable Blocks in Tunnel Surrounding Rock Induced by Joints and Fissures

围岩中节理裂隙发育形成的不稳定结构体是诱发冒顶和塌方的原因之一,为了预测围岩中的不稳定块体,首先通过块体棱矢量与结构面法向量点乘所得到的矢量判别矩阵判断块体的运动形式,然后根据不同形式块体的受力方式,给出相应的稳定性系数计算方法,最后以江玉高速公路马章岭隧道为依托,利用块体理论预测潜在的不稳定块体.研究结果表明:在不同节理裂隙组合下,块体可分为不可动块体、脱离岩体运动块体、沿单面滑动块体、沿双面滑动块体.所提的块体理论可有效地预测出不稳定块体的存在,实现节理裂隙发育工况下的围岩稳定性分析.另外,研究结果可为类似工程冒顶塌方的预测提供借鉴.

The unstable structure formed by the development of joints and fissures in the surrounding rock is one of the reasons for roof fall and collapse. In order to predict the unstable blocks in surrounding rock, the motion form of the block is clarified firstly by the discrimination vector matrix obtained by the point multiplication between block edge vector and structural plane normal vector. Then the corresponding calculation method of the stability coefficient is given according to the force mode of different forms of the block. Finally, based on the Mazhangling tunnel of Jiangyu expressway, the potential unstable block is predicted by using the block theory. Results show that blocks can be divided into immovable blocks, moving blocks separated from rock mass, sliding blocks along one side, and sliding blocks along two sides under different joint fissure combinations. The block theory proposed in this paper can effectively predict the existence of unstable blocks, and realize the stability analysis of surrounding rock under the condition of developed joint fissure. In addition, this paper can provide references for the prediction of roof fall and collapse in similar projects.