Influence Of Construction Deficiencies On Surrounding Rocks And Structures Of Liujiawan Large-span Multi-arch Tunnel

Because of its large span,complex construction technology , also with repeated disturbance to surrounding rocks, Large-span multi-arch tunnel appears construction deficiencies(such as serious excavation,incompact grout-injection in the top of middle wall) easily in the process of construction. If construction deficiencies could't be treated effectively in time, it would become holes in the top of middle wall and the first lining. Also, the bolts of many tunnels can't be drived up to the standard of requirements in the process of construction(such as the lack of quality and length).The influences of surrounding rocks and structures on construction deficiencies existing in large-span tunnels had been researched in this paper. with the means of in site testing and numerical simulation analysis, the influences of stability about surrounding rocks and structures were evaluated. At the same time, some treatments of construction deficiencies in large-span multi-arch tunnels were put forward.The main contents of this paper are as follows:1. Full investigation on construction deficiencies were carried out in Liujiwan tunnel. Besides, the displacement convergence and the second lining forces of the representative section were monitored; the influences of the displacement convergence on construction deficiencies existing in the tunnel were analyzed. Also, the change regularity on the second lining forces of the representative section before and after landslide were given.2. A finite element code, ABAQUS, was employed to simulate Liujiawan tunnel. The influences on typical construction deficiencies and the assembled construction deficiencies existing in the tunnel were discussed; Also, the degrees of influences were disclosed. The calculation results explained the displacement convergence results and the phenomena of landslide and collapse on the tunnel3. Some treatments of typical construction deficiencies, which could give references to the design and construction, were put forward in this paper. .