| dc.description.abstract | Taiwan locates in the Circum-Pacific Seismic Belt. Frequent seismic activities lead to Taiwan’s mountainous terrain and less plains. There are many typhoons that make landfall in Taiwan and these events result in heavy rainfall. Because of these reasons, the slope becomes unstable. The slope failure may be a threat to the residents near the hills and infrastructure.
In order to discuss the failure mechanism of anti-dip slopes due to the effect of gravity, Hu (2019) performed the centrifuge tests and applied PFC3D to simulate the physical models. The results indicate that with thinner rock layer thickness and longer unsupported rock layer lengths, the anti-dip slope could deform and topple more easily. Zheng (2019) did the centrifuge tests and numerical simulation using the same model as Hu (2019) but with a second orthogonal joint set to discuss the effect of second joint set in the anti-dip slopes. The results showed that when the slenderness ratio of the layer is large, the failure mode is flexural toppling. The block toppling could occur with a smaller slenderness ratio.
In this study, we designed the rainfall system in the centrifuge model to study the effect of rainfall to the anti-dip slopes. Meanwhile, PFC3D was also performed to investigate the equivalent effect of heavier rainfall to the anti-dip slopes. In order to simulate the deteriorating strength of rock layer subject to rainfall, we adopted two-step decreasing of the micro-parameters. The simulated results indicate that the rainfall could shorten the time to slope failure, however, the rainfall intensity doesn’t have much impact on the potential failure surface pattern.
Comparing with the results of the physical tests, the numerical simulation in high gravity cannot have good result. In high gravity field of the numerical model, the potential failure surface of the model is steeper than that of the physical test in high gravity field. The potential failure surface’s position in high gravity field is the same as the physical test in 1g gravity. | en_US |