Papers by Author: Wei Shen Zhu

Abstract: Based on a shear test for jointed rock sample conducted by former study, a numerical improved method DDARF is carried out to simulate the shear test. The simulation result of shear fracture phenomenon show high compatibility with the model test. Different fracture phenomenon and peak strength value of shear testing are explored in the condition of different colinnear and ladder echelon arrangement of cracks.

Abstract: The discontinuous deformation analysis for rock failure (DDARF) method is adopted to simulate the biaxial compression test under different lateral pressure conditions. Then this paper analyzes the impact of the lateral pressure on the specimen failure rules. The simulation results show that the lateral pressure has obvious inhibiting effect on the expansion of wing cracks, crack initiation stress, and specimen peak strength.Keywords: Multi-joint specimen; DDARF method; Lateral pressure; Biaxial compression test simulation

Abstract: In this paper, we have developed a seepage-damage coupling analytical procedure based on FLAC-3D, which can simulate and analyze the crack initiation, propagation and coalescence process of jointed rock under coupling effect. It simulates the failure process of inhomogeneous specimen with two existing fractures under pore water pressure and biaxial loading. Meanwhile compare the results with corresponding non-seepage working condition. By showing the dynamic damage state and analyzing the stress-strain relationship, the mass damage and progressive failure process of jointed rock under the influence of seepage were studied.

Abstract: According to test exploration and research, the authors developed a multiaxial compression testing machine and water injection pressure device. Using the device, the authors carried out a multiaxial compression testing of transparent rock-like material successfully under water pressure condition. It has important meanings to the study on the engineering characteristic of fractured rock under pressurized water conditions.

Abstract: Referring to the previous shearing model tests on intermittence jointed rock mass, DDARF method was adopted to conduct the corresponding numerical simulation. It could be concluded from the cracking failure phenomena that the results of the numerical simulation and the tests were in good agreement. Then the intermittence joints were arranged as en echelon and different cracking failure phenomena, peak shear strengths and strain-stress relationships were also obtained.

Abstract: Based on joint statistics from the in-situ survey, using numerical simulation technique of joint network (Monte-Carlo method), the calculation model of fractured rock mass is generated. Underground seepage discharge filed in fractured rock mass surrounding storage caverns is analyzed by using distinct element method. The result of simulation has shown good agreement with surveying data. Two cases have been simulated that is water curtains is installed and is not installed. Water pressure distributions in joints are investigated in these two cases. It is shown that in the case without water curtain the groundwater in joints which locate the upper of underground caverns is drained out and water sealed conditions is completely unrealized. When water curtain pressure is set at 0.3MPa, can underground water seal the storage caverns.

Abstract: The distribution of hydraulic pressure in fractured rock mass surrounding caverns after excavation and technique of stochastic generation of joint network are investigated based on discrete element method. In order to seal the oil in underground caverns with water in the actual engineering, a water curtain with water pressure is installed, and the changes of hydraulic pressure are simulated with a series of curtain pressures. It is shown that some joints that have been drained out during excavation can not be saturated if the water curtain pressure is less than a certain value. Water curtain pressure with a certain value gives a strong safe guarantee of saving oil in the underground petroleum storage caverns.

Abstract: Based on the engineering background of -350m level roadway in Beizao Coal Mine ,three schemes about the excavation and support of the roadway were simulated via the coupled fluid-solid theorem in the the finite difference software FLAC^3D. The stability of the soft rock roadway and the effect of bolt-grouting support were analysed according to the obtained numerical results of displacement,principal stress and plastic zone.It is concluded that the seepage has an influence on the stability of the soft rock roadway,besides,it is proved that the bolt-grouting support is rational and effective in the design of support concerning the soft rock roadway.The study has important guiding significance to other similar engineering.

Abstract: Underground seepage discharge field in fractured rock mass surrounding storage caverns is analyzed by using discrete element method and stochastic joint-generation method. Meanwhile water pressure distributions in joints are investigated with a series of curtain pressures and compared with no water curtain. In the case without water curtain the groundwater in joints which locate the upper of underground caverns is drained out and water-seal conditions are completely unrealized. When the water curtain pressure is less than a certain value, the joints that have been drained out can not be saturated, and only the water curtain pressure exceeds this certain value, can groundwater seal the storage caverns.

Abstract: Using DDARF method, the uniaxial and biaxial compression experiments of double-fractured rock samples are numerically investigated. Influences of different fracture angles and confining pressures on behaviour of rock samples are studied. Moreover, the fracture process, the crack initiation stress, and the peak strength of the fractured rock under both uniaxial and biaxial compression tests are obtained. The results are used to obtain the strength envelope and to analyze the rock stability of an underground project as a case study.