| dc.description.abstract | The properties of rock mass such as mechanical behavior and hydraulic conductivity are controlled by the direction because of the orientation of discontinuities. The relationship between the orientation of the foundation configuration and the anisotropic rock mass will also significantly affect the bearing behavior. Therefore, how to evaluate the orientation of discontinuity is favorable or unfavorable playing an important role in rock engineering.
PFC3D is adopted in this study to simulate uniaxial compressive tests, triaxial compressive tests and bearing capacity tests on transversely isotropic rock mass. The simulation of the rock test is used to check the macroscopic rock mechanical behavior by the microscopic parameters of the particles. Through the simulations, we obtain a series of elastic constants to establish the constitutive law of transversely isotropic synthetic rock mass, and verify with the previous theories. In addition, this study carries out a series of simulation tests on the ultimate bearing capacity. By adjusting different fracture orientation (dip angles and strike) and fracture condition (fracture intensity and Fisher constant) respectively, we can discuss the influences of the discontinuity on the bearing capacity, settlement, and crack development.
Based on the numerical simulation results：(1) The mechanical behavior of rock mass which involves the single direction of DFN is regarded as transversely isotropy, and the deformability conforms to the prediction of anisotropic elastic mechanics. (2) The experimental results of Asan gneiss can be fitting by using SRM, it illustrates that SRM can simulate the mechanical behavior of real rock mass. (3) The bearing capacity of the intact rock is close to the theoretical strength calculated by Bell solution (1915), and the development of cracks can be compared with the footing test results observed by Goodman (1989). (4) In a transversely isotropic rock, the relationship between ultimate bearing capacity and joint dip angles shows U-type. In addition, the crack number and settlement with different joint dip angles reveal the analogous shape of ultimate bearing capacity. (5) Observing the development of cracks in rock masses with different joint dip angles from bearing capacity tests. It shows that the cracks will be generated along the direction of the inherent fractures, which is consistent with the equivalent stress direction calculated by Bray solution (1977). (6) With the fracture condition (P32、κ) increases, the anisotropy of bearing capacity will be increased, and the direction of crack development will become more obvious. (7) The influence of the α (dip angle) on the bearing capacity is greater than the γ (the angle between the strike and the long axis of the foundation). When γ at the larger angle, the bearing capacity is generally higher than the γ at the smaller angle. (8) The configuration direction of the foundation also has the significant influence on the bearing capacity. When the foundation vertical to the strike, the bearing capacity will be better than it parallel to the strike. | en_US |