| Arch tunnel is a Large-span tunnel type which proposed with the rapid development of China’s highway construction. It has the feature that smooth linear, occupies less and high space utilization. Avoiding the entrance bridge roadbed or framing make it easy to connect with the lines outside the cave. So,it’s benefit to the linear planning and optimization of highway. At the same time, arch tunnel is better on adapting to terrain conditions, environmental protection and reducing engineering. Arch tunnel has the incomparable advantage, but the shortcomings that long duration, high cost and difficult to control quality restricts its development. At home and abroad, especially in China’s urbanization process,it is an urgent task to solve the problem that how to design and construct the large shaped arch tunnel in complex urban environment. The object of study is a new double-arch tunnel structure in horizontal bedded rocky in Chongqing,which wall is sprayed steel reinforced concrete. In this paper, the main research method is theoretical derivation and simulation analysis. The main research work is as follows:1. According to the tunnel load calculation formula in Specification and the mechanical characteristics and failure modes of the horizontally layered rock,it can deduce the load calculation formula of arch tunnel under conditions of horizontally layered rock. Then calculating the arch tunnel suffered loads bases on the revised formula. The load of different depths under horizontally layered rocks and continuous media conditions were analyzed.2. According to the force characteristics of SRC and the structural characteristics of arch tunnel wall,the limit state design which bases on probability theory were introduced to calculate arch tunnel wall SRC members that in the case of axial compression and eccentric compression. Steel reinforced concrete walls which on the construction process and construction completed were calculated by the formula. Also, beam arrangement was optimized analysis using the above method.3. The mechanical characteristics and critical control parts of the new double-arch tunnel structure which under the conditions of horizontally layered rock were analyzed. Engineering measures that involving the wall structure optimization, the rock reinforcement technology top of the wall, the reinforcement technology of the temporary support and Rock Pillar in the wall were used for the construction,and the optimization results were analyzed.4. Various construction method and process of the new structure was analyzed,also the safe and efficient construction method and the Reasonable construction process were found. The key step in the construction sequence is determined.5. When the rock off the block and the overall damage,the ultimate displacement value was calculated and recorded.And according to the value, control reference were established to guide the construction. |
PDF Full Text Request