Space Characterization Of Structural Plane In Joint Rock Mass And Its Model Optimization

Rock mass is made up of rock and structural plane separating and cutting rock. Rock mass structural planes have the characteristic of different sizes, different attitude, different forms, etc, so rock mass present the mechanical properties of discontinuity, heterogeneity and anisotropy. A large number of engineering practices shows that the geometry and physical properties of rock mass play a key role on control deformation and failure of rock mass and have important influence on the stability of engineering rock mass in the process of tunnel cavern excavation. Analysis of stability of engineering rock mass is a very important practical problem, such as the excavation of underground caverns, tunnels, canals, building roads bridges, high dam, ravines libraries and open-pit mining etc in the mountains. These engineering all need to analyze the stability of rock mass. Along with the development of computer, numerical simulation method has a unique advantage on the analysis of the stability of rock mass. How to establish the analysis model of rock mass structure, conduct a comprehensive characterization and simulation on the basis of plenty of structural plane information, and take into consideration of the influence of the physical parameters of structure, build a more accurate three dimensional rock mass tunnel structural plane space model, and analyse the interaction between the excavation surface and structural plane reasonably, search key blocks which influence the stability of rock mass, finally display the results calculated on three dimensional, is the key issues of stability research in the process of tunnel excavation.On the basis of reading vast amount of literature, and summarizing research methods of structural plane and rock mass stability analysis, this paper has carried on the three dimensional grid reconstruction using delaunay triangle subdivision method on the surface of the structural plane based on digital photography measurement method, and conducts aperture simulation of structural plane by using the surface triangular mesh model, optimizes the structure of the disc model, puts forward a new method to characterize the three dimensional roughness-SAR. Finally this paper carries on the experience estimation of mechanical parameters on structural plane based on verification of roughness coefficient, mainly carry out the following work:Firstly, Structure informarion is collected by applying digital photogrammetric system, the whole three-dimensional space morphology form of structure is reflected though exposed part. The point of data is captured through shapeMetriX3D system. Delaunay triangular subdivision method is applied to the reconstruction of the structural plane surface, achieving the result that reflects the structure of the surface morphology through the three-dimensional triangular mesh.Secondly, considering the shortage of two-dimensional roughness in the characterization of structure surface roughness, the specific surface area ratio method (SAR) is put on the basis of structural plane surface three-dimensional reconstruction. The roughness is reflected through the ratio between the structure plane grid area and fitting area. According to the locale measurement of structure surface, roughness coefficient is calculated by using method of fixed straight edge, and the correlation between JRC and SAR is analysed.Thirdly, the average of aperture is calculated according to the reconstruction of the surface structure, and conducts a computer simulation with the equivalent aperture as the aperture of asingle structure. The mechanical parameters of structural plane are empirically estimated by using Barton formula.Finally, combined with specific engineering example, the scene structure information is collected by the ShapeMetriX3D system. The real information of structural plane is simulated by structural plane network simulation method, and the three-dimensional structural plane space model of rock mass tunnel is built. Using the system to search key block, and the stability of the rock mass is analyzed. Compared with the actual engineering, this paper compares and analyzes the effectiveness of the procedures, and the results are displayed.