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Mountain tunnels built near faults often suffer from significant permanent deformation and structural dislocation during seismic activity. In this paper, we present a rock-fault-tunnel geological model with a transition area between the hanging wall and the foot wall which allows the free slippery growth inside the area. A time-sequenced load based on design code and fault activity is conducted in this model to simulate dynamic seismic input after fault dislocation. In our case, a reverse fault with a tunnel cross has been created with this method. A 30cm fault dislocation is simulated by putting the displacement boundary of the hanging wall with a compression vector and the seismic wave is input from the bottom boundary as acceleration waveform adjusted to 0.4g. The model simulates the uplift of the hanging wall and the growth of the slip surface, and reveals the extension mechanism of the triangular shear zone of shear rupture of the surrounding rock due to the extrusion of the reverse fault during the propagation of the reverse fault. The seismic wave with a three-way acceleration was input after the dislocation process. The simulation indicates that with the gradual uplift of the hanging wall, the rock body of the fracture zone shows a more significant large deformation flow trend and a more significant horizontal slip flow. Under reverse fault thrust, the width of the shear effect influence zone is around 300m. A decreasing trend of accumulated strain can be found at the interface due to acceleration input. Dislocation-seismic time-sequence loading may underestimate its damage effects.

期刊论文 2025-04-01 DOI: 10.1142/S0219876223420161 ISSN: 0219-8762

A fault is a geological structure characterized by significant displacement of rock masses along a fault plane within the Earth's crust. The Yunnan Tabaiyi Tunnel intersects multiple fault zones, making tunnel construction in fault-prone areas particularly vulnerable to the effects of fault activity due to the complexities of the surrounding geological environment. To investigate the dynamic response characteristics of tunnel structures under varying surrounding rock conditions, a three-dimensional large-scale shaking table physical model test was conducted. This study also aimed to explore the damage mechanisms associated with the Tabaiyi Tunnel under seismic loading. The results demonstrate that poor quality surrounding rock enhances the seismic response of the tunnel. This effect is primarily attributed to the distribution characteristics of acceleration, dynamic strain, and dynamic soil pressure. A comparison between unidirectional and multi-directional (including vertical) seismic motions reveals that vertical seismic motion has a more significant impact on specific tunnel locations. Specifically, the maximum tensile stress is observed at the arch shoulder, with values ranging from 60 to 100 kPa. Moreover, NPR (Non-Prestressed Reinforced) anchor cables exhibit a substantial constant resistance effect under low-amplitude seismic waves. However, when the input earthquake amplitude reaches 0.8g, local sliding occurs at the arch shoulder region of the NPR anchor cable. These findings underscore the importance of focusing on seismic mitigation measures in fault zones and reinforcing critical areas, such as the arch shoulders, in practical engineering applications.

期刊论文 2025-01-01 DOI: 10.1007/s11629-024-9240-5 ISSN: 1672-6316
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