Three-D Mechanical Effect Analysis Of Heavy Load Over Shallow Buried Large Span Multi-arch Tunnel In Construction Process

The multi-arch tunnel is always applied to the high-grade road construction in the mountain area where is suffered from multi-influences of terrain, geological conditions, industry city condition, and road guidelines of even, vertical, and horizontal both in a respective and an interactive way. With the merits of streamline, high space utilization ratio, low room taking, convenient connection with lines outside of hole, and environmental protection, the multi-arch tunnel has been used widely in the road construction.To avoid large working of applying roadcut, removing of factory, mine and residents, polluting environment when we need to cross road buildings in such a complex geographic condition in the crossing, we apply shallow buried large span multi-arch tunnel, which has the effect of guaranteeing the use of original road, reducing the construction cost, assuring project quality, and protecting environment, and it's good efficiency and applicability is well tested. Based on road and building standards and summarized finite element analysis methods in shallow buried large span multi-arch tunnel construction, the paper analyzed the design, construction scheme and working procedure of shallow buried large span multi-arch tunnel, which settle a good foundation for appropriate designing, monitoring, early warning, appreciating and emergency treating.Meanwhile, the paper undergo some stability analyses on cut or cover tunnel structure, slope, and roadcut slope at tunnel gate, carry on the analyses of 3D mechanical effect of large span multi-arch tunnel construction under over heavy load and building, 3D mechanical effect influenced by the weakening rock mass quantity to the large span multi-arch tunnel construction under over loading and buildings. The result indicates the moving rule of surrounding rock, mid-board stress, displacement and strain field of large span multi-arch tunnel in the dynamic construction process under over heavy load and building. This rule well proved the monitoring data of type A and B, so we can protect the original road and buildings efficiently. Moreover, getting familiar with the significances of appropriated construction process in the aspects of space and time, we can optimize construction plan and guide the construction of support project efficiently. In conclusion, the rationality of shallow buried large span multi-arch tunnel construction plan plays a guiding role to the security, efficiency, and reliability of construction process. And the paper riches the design, construction and appraisement system of shallow buried large span multi-arch tunnel under road and building.