The study of reconstructed model and mechanical properties of porous sandstone

Based on the statistic theory and image processing technology, a three-dimensional reconstructed model of pore structure for sandstone is established. On the basis of the model, the numerical simulation experiment is carried out to analyze the influence of pore structure parameters (pore size, shape and porosity) on the deformation, stress distribution and failure distribution of sandstone under the splitting load. Specific modeling process: firstly generating the spatial position of the pore with the statistical principle. Then using the finite element analysis software to establish the corresponding model and using the image processing technology in the image processing software to divide the model net. Importing the restructure 3D pore structure into the finite element analysis software and getting reconstruction of the pore model. The research results show that: the effect of void morphology on the damage of sandstone is obvious. With the change of the pore shape from the ellipsoid to the sphere, the fracture zone of the splitting disc is increased and more dispersed. With the pore shape is changed from sphere to ellipsoid, the maximum stress along the Y direction is firstly decreased and then increased. When the pore size increases, the failure mode becomes a single tensile failure from an induced-tension-shear failure, and the maximum stress along the Y direction is decreased. But the influence degree is weakened with the increase of the pore size of the model. Along with the increase of the porosity, the maximum stress along the Y direction is increased; therefore, the sandstone is easy to damage. But the degree of influence decreases with the increase of pore size. The results reveal the influence of the parameters of the pore structure on the mechanical properties of rock, which provide some reference for the study of the effect of pore structure on the rock physical mechanical properties.