| CHENG-LAN railway is currently the railway that passes through most complex geological in the history of railway construction, which passes through the Longmen Shan mountain area and the upper Minjiang River valley area. Along the line, terrain elevation difference reach 4000 meters, the proportion of tunnel segment accounts for 90%. Challenges of rockfall hazard is very grim between it.This thesis based on it. Firstly,6 typical tunnel entrance are investigated, which gains entrance slope data, and calculates impact speed and the extent of rockfall. Then, on the basis of field research, this thesis use dynamic finite element software LS-DYNA to simulate frame shed tunnel suffered rockfall impact, which including:1 The dynamic response of frame shed tunnel under different impact energy;2 The anti-shock performance of light soil research compared to soil.3 The light soil optimal thickness research of frame shed tunnel.After doing the above job, the thesis proposes the concept of arch shed tunnel from the structure point, and designs it. Firstly finite element software LS-DYNA is also used to calculate the mechanical variable under rockfall impact, and compared which with the frame shed tunnel, on the basis of comparative studies, it has been proved that arch shed tunnel has more anti-impact resistant property. Indoor model test about shed tunnel suffering from impacting is designed, which takes into account different conditions, focuses on monitoring various parts’strain, impact force, displacement of arch. Then obtaining the rules by analyzing the physical variables. Finally, the model is studied for failure modes, observing the worst damage zone of the shed tunnel suffered from, to provide a more reliable suggestion for the using of structure’s using in practical engineering.Finally, based on the numerical simulation and model test results, the relevant guidance are given for arch shed tunnel’s using in practical engineering. |
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