| Summary: | 碩士 === 國立臺灣大學 === 土木工程學研究所 === 107 === Toppling failure is one major failure types of slate slope, and the strength of the weak planes of slate dominate the safety of the overall rock slope. To determine the strength and the failure envelope of slate foliation, this study include a series of pull-off test and direct shear tests, which results are used to establish a nonlinear foliation failure criterion. Furthermore, the proposed failure criterion is implemented in UDEC to simulate toppling failure of slate slopes. It explores the difference between the nonlinear foliation failure criterion and other criteria. The results of this study are summarized as follows. First, the experiment results show that the failure criteria of foliation is highly nonlinear under low normal stress. In addition, the friction angle under low normal stress is significantly higher than that under high normal stress. Second, comparing with the results from dry and wet condition, the slate exhibits wet-weakening effect. Third, the results which are exhibited by the simulation based on the proposed failure criterion could be more reasonable and conservative than those based on the linear failure criterion. Finally, the constant term α and the exponential term β of the nonlinear foliation failure criterion positively correlate with the material strength. By decreasing α or β, the slope is prone to occur toppling failure and the decrease of the angle of failure. In fact, the latter leads to expansion of the failure zone.
|
|---|
