Study On Rheological Properties Of Soft Rock With Large Deformation And Its Application In Tunnel Engineering

Rheology of rock is closely related to the long-term stability and safety of rock engineering. Rheological mechanical experiment of rock is an important means to know about the rheological properties of rock. Triaxial rheological experiment is done to study the rheological properties of soft rock which is rotten and cracked. With considering the rheology of rock, the comprehensive method of theoretical analysis and numerical simulation is adopted to study convergence-confinement method, and the method of orthogonal experimental design is used to discuss optimization of tunnel support system.In this dissertation, the main investigation work focuses on the following several aspects.(1) In order to know about the rheological properties of rock specimens in Xiamen Undersea Tunnel Project, A series of triaxial compression rheological experiments were carried out on the rock servo-controlling rheology testing machine. Based on the experimental results, the variance law of axial strain of specimens with time under different confining pressures and different deviatoric stresses is investigated. By comparing the experimental results and the results predicted from the use of power law creep model, it is shown that power creep model can be used to simulate the primary creep and the secondary creep of the rock specimens.(2) Ground Characteristic Curve (GCC) and Support Characteristic Curve (SCC) are both investigated to know about convergence-confinement method comprehensively. Methods of determining GCC are being given, which include theoretical analysis, numerical simulation, and field measurement. By 2-D and 3-D numerical simulation with different material models, the corresponding ground characteristic curves of Xiamen Undersea Tunnel are obtained and compared each other. Under the hypothesis that a support has an ideal elastic-perfectly plastic behaviour, the expressions of the stiffness of shotcrete lining, radial anchored bolts, steel sets and compound support are given. Furthermore, the stiffness of compound...