Optimization Of The Multi-arch Tunnel's Design And Construction

Since 1990's, along with the rapid development of our country's highway, the multi-arch tunnel as a result of its own characteristic, obtained the widespread application in our country. But, more and more problems appeared in those multi-arch tunnels which had been completed and in construction because there is less such experience of multi-arch tunnel engineering can be used either inland or overseas for reference before. In which the leakage of middle-wall is the most ubiquitous case. It affected the function and the use the tunnels. In view of present situation, this thesis studied the design and construction of the multi-arch tunnels relying on the project of Xihan highway in Shaanxi province.At the base of survey and analysis to the construction of the multi-arch tunnel projects, the thesis penetrates with the research in site of construction of Xihan highway, according to the multi-arch tunnel's own characteristic, computing to the thin-wall of the compound straight-middle-wall and getting the result that thin-middle-wall can stand the pressure when its depth is 80cm. Meantime, the depth of compound middle-wall should be the same with the depth of integral straight-middle-wall. The thesis also comes out the reason of the quality flaw of ongoing projects through the analysis to those multi-arch tunnels. It optimizes the construction plan and waterproof and drainage system, even provides the solution to reform the ongoing multi-arch tunnel projects with quality flaw. The thesis mainly discusses the following in details, providing the solution for concrete girder spouted to the coping which is hollow when pouring the middle-wall of the multi-arch tunnel; analyzing why the construction of the arcade is difficult to meet the requirement and providing the relevant solutions; suggesting that the removing of the middle-guide-hole should be later than the dig of the formal hole to play its supports and protections role sufficiently; analyzing the reason of the dilapidation of waterproof plies in paving and educing the physical performance of the rubber cushion; analyzing why it's difficult to guarantee the quality in construction of the waterproof and drainage system of the integral-middle-wall and suggesting to solve the leakage of the middle-wall through curtain-slurry pouring, etc.. Other steps to optimize the waterproof and drainage system are shared meanwhile.The thesis aims at optimizing the construction scheme of the multi-arch tunnels to solve the existing problems in projects at present, as a reference to the construction and study of multi-arch tunnels in the future.