Papers by Author: Jian Guo Zhang

Abstract: The center hole deformation test of rigid bearing plate is an important method for understanding deformation properties of deep weak rock mass. According to the center hole deformation test of rigid bearing plate in dam zone of Dagangshan hydropower station, this paper detailedly recommends test method of this experiment, and the settlement deformation formula of deep rock mass under circular rigid bearing plate is deduced, which could be used to calculate deformation modulus and equivalence deformation modulus of different deep rock mass at test points. According to curves of depth-deformation under different pressures at test points in dam zone, we have analyzed deformation characteristics of deep weak rock mass. By the center hole deformation test of rigid bearing plate, stratum properties in dam zone of Dagangshan hydropower station could be understood further, and it provides important references for the study of creep speciality of weak rock mass in dam zone.

Abstract: Due to lots of hypothesis, the theoretical analytical solution of the creep parameters inversion can not reflect the in-situ conditions actually. In order to simulate the process of the compressive creep tests of the in-situ bearing plate, the affection of the stratum distribution and the influence of the geological status in site actually, FLAC3D is used and numerical back analysis method of the creep parameters at dam site is set up. Based on the in-situ compressive creep tests’ data of the diabase rock masses at Dagangshan dam site, creep parameters are got with this method. Results indicate that the numerical calculated displacements of the compressive creep are similar to the in-situ monitoring displacements. It reveals that with this numerical method creep parameters can be backing analyzed logically. This supplies technical assurances to stability estimate and analysis of rock masses in slope projects.

Abstract: As the implementations of the western development in China, more and more tunnels will get through the western mountains in China. In order to economize the construction costs, a new type of underground structural form called branching-out tunnel must be applied. The failure process of the branching-out tunnel under lateral overload action is also greatly complicated, which is related with the depth of the mountains, the branching-out angle, the in-situ stress field, the thickness of the middle wall and so on. This paper uses the 3D-physical model of geo-mechanical model tests to study the stability and failure process of this complicated structure, especially the part of the middle wall. The physical model is built up in a new kind of analogy material. In the process of the whole experiments, different lateral pressures imposed on both of the lateral planes of the physical model. According to different lateral pressures, we have attained the change of the stress and displacement field and looked into the failure process of the pivotal positions in the branching-out tunnel. We also use finite element method analysis software RFPA (Realistic Failure Process Analysis) to simulate the whole failure process of the branching-out tunnel. Finally, we have got the load-bearing safety reliability of this complicated structure through comparative analysis of physical modeling and numerical simulation.