Study On Form Of Shed-Tunnel To Prevent Rockfall From The High And Steep Slope For Mountain Tunnel

In recent years, our country has providing more and more investment’in the western region, results in a rapid development within this region. But the poor traffic conditions has gradually restricted its further increase. To solve this problem, it’s nessesary to build more and more traffic routes, like railway and highway. And then, the natural disasters which the newly builded roads would encounted should be considered in western region as there lots of mountain and heavy hill terrain in it. One of them is rock-fall form unstable rocks in high and steep terrain. As a effective measures to defense disasters caused by rock-fall, shed-tunnel is playing an increasingly important role, and its application is in constant expansion. Under a condition of the complex terrain, how to choose the most suitable form of shed-tunnel for the actual project is a focus of current research.Referencing to the existing research focused in rock-fall and shed-tunnel, this thesis review the definition and causes of rock-fall, and the theoretical formula about the trajectory of rock-fall after being produced. The displacement of the rock-fall could be figured out using those formulas, and coupled with the five existing methods to calculate the impacting force of rock-fall, we can get the theoretically size of shed-tunnel and its strength to resist impact.Considering the background of actual engineering, this thesis analyzes the response of shed-tunnel those have different forms under different load conditions by theoretical calculation and numerical simulation. After comparing the structural displacement and stress distribution during the rationality analysis of the structure, the result show that the arch-wall shed-tunnel has the best loading effect. At last, when considering the ventilation and lighting, there are some further optimization of arch-wall shed-tunnel. Judging from the results of numerical simulation, under a certain load, the shed-tunnel loading capacity just has a little distinction when using porous or imporous arch-wall. The conclusion is that we should choose the porous arch-wall shed-tunnel to completely replace the traditional ones, which has good loading capacity and better economical efficiency at the same time.In addition, this paper also have analysis the safety of shed-tunnel when it is in the earthquake. The results show that this shed-tunnel could keep a safe condition in Wen chuan earthquake.