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

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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.