Constitutive modeling of jointed rock mass and development of measurement system with bore hole television

节理的滑动和张开被认为是大型开挖过程中岩体行为的控制机制。基于该控制机制进行本构建模。采用基于细观力学的连续介质方法对节理岩体进行建模。提出了岩石结构的一般分析方法。地质调查报告的优势节理方位及其平均间距作为输入参数直接反映在分析中。数值分析不仅提供了各主节理的位移、应力和应变分布，还提供了各主节理的开口位移和滑动位移分布。分析了电站洞室开挖中存在的问题，并将数值计算结果与施工现场实测数据进行了比较。结果表明，所建立的分析方法具有较好的一致性和有效性。该模型的特点是能够预测沿节点的张开和滑动位移。为了进一步将测量结果与分析结果进行比较，研制了一种新的钻孔电视测量系统。利用图像分析技术对开挖前后的钻孔壁图像进行了对比，得到了沿钻孔方向的位移分布。将该方法应用于施工现场，并与嵌入式位移传感器的数据进行了比较。结果表明，该方法具有较好的一致性，可用于岩体跨节理位移跳变的测量。

The sliding and opening of joints are considerd to be the governing mechanism of behaviors of rock mass during large scale excavation.Constitutive modeling is carried out based on this governing mechanism.Micromechanics-based continuum approach is adopted for the modeling of jointed rock mass.A general analysis method for rock structures is developed.Orientation of dominant joints and their average spacing reported from geological survey are reflected in the analysis directly as input parameters.Numerical analysis provides not only displacement, stress and strain distributions but also distribution of opening and sliding displacements along each set of dominant joints.Problems of excavation of power station cavern are analyzed and numerical results are compared with measurement data obtained at the construction site.Reasonable agreement is observed and validity of the developed analysis method is confirmed.The characteristics of the proposed model is its ability to predict opening and sliding displacement along the joints.To carry out further comparison between measurement and analysis results, a new measurement system with bore hole television is developed.The images of the bore hole wall before and after excavation are compared with image analysis technique and displacement distribution along the bore hole is obtained.The method is applied in the construction site and results are compared with data by embedded displacement transducers.They show good agreement, and the proposed method is expected to be used for the measurement of displacement in rock mass displacement jump across a joint.