Research And Application On Structure Plane Characteristics Of Granite In The Preselected Area For High-level Radioactive Waste Geological Disposal

Structural plane is a fracture structure and extensive development in the crust.It damages rock mass continuity and integrity and influences on the mechanics and seepage characteristics of rock mass.In siting and design of High-level radioactive waste repository,granite as the disposal surrounding rock has good compactness,low porosity and low moisture which is the favorable conditions for disposa repository.But structural plane in the rock mass become the main channel of nuclide migration is the adverse factors for the security and stability of disposal repository.In the paper,structural plane geometric features for the pre-selected site of rock mass make a detailed and accurate statistics and analysi through remote sensing image interpretation and field investigation,gain rock mass structural plane distribution characteristics,evaluate development degree of rock mass structural plane and rock mass quality,carry out joint three-dimensional network simulation and permeability properties of fractured rock mass.A lot of different scale structure surface raw data is acquired through different investigation methods to surface fault and joint and borehole fissure for the pre-selected site granite rock mass.Rose diagram and circular window method is used to statistical analysis of joint geometric parameters such as occurrence,density and trace length.The fault size and extension direction can be determined through deciphering surface structure surface in the satellite traffictraffic and tracking GPS.At the same time,the scope of fault zone can be obtained based on geometric feature of fault surrounding joints.According to combination configuration of joint to joint divided period and coordination and investigation of fault and mechanics analysis principle,the genetic relationship of between fault and joint is determined.Geometrical parametersof aperture are recorded and described in detail and space distribution features of aperture are figured out by Borehole TV and drilling geological record.It was studied the influence of structure in the face of rock mechanics properties.Based on the geometry parameters of surface structural plane,JSR is put forward to evaluate joint development degree on surface rock mass and FJSR is put forward to evaluate rock mass quality and is contrasted with FRMR and FQ which is corrected from traditional rock mass quality evaluation index.At the same time,it is used to select High-level radioactive waste geological disposal candidate site to combine with FJSR and drilling rock mass integrity index Q’ and drilling rock mass quality evaluation index QR HLW.Through field joint investigation and indoor analysis,probability and statistics model of joint geometry parameters is established and joint three-dimensional network model is drawn in the computer based on Monte Carlo method random number generation principle.It an be verified through comparing between statistical model and measured values of joint geometry parameters whether the model is reasonable or not.In view of the problem about the fractured rock mass permeability characteristics,this paper puts forward to combine density zoning laws and occurrence quantitative homogeneous area partition method with based on the structure of the mechanical causes of qualitative homogeneous area division method,then determines the final drilling rock mass structure homogeneous area through the mathematical principles.After obtaining homogeneous borehole rock area,permeability tensor calculation program is compiled according to the principle of permeability tensor calculation and rock mass permeability tensor and penetration principal value and the main direction of penetration can be calculated through inputing the geometric parameters of borehole fissure to the program.The results can provide a basis for drilling rock mass permeability analysis.