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| Construction method of shallow tunnel with large section downtraversing existing road |
| 1. School of Civil and Architecture Engineering, Xi′an Technological University, Xi′an， Shaanxi 710021, China; 2. China Railway First Survey and Design Institute Group Co., Ltd.， Xi′an, Shaanxi 710043， China |
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Abstract To solve the problems of easy damaging and destructing to endanger the road and traffic safety, in the blasting excavation process of large section shallow tunnel downtraversing existing road, the Guanlinzi Tunnel downtraversing the 316 National Road in the BaojiHanzhong Expressway was selected as research objective. The construction method of bridging on the pavement, advanced reinforcement, excavation by steps, monitoring and feedback information was proposed based on the project. Under normal traffic on the road, the finite element method was used to simulate the road surface settlement with and without steel frame bridge. Combined with the monitoring results of blasting vibration in the field, the safety and the feasibility of CRD method were compared and analyzed. The results show that the surface subsidence value without steel frame bridge is larger than that with steel frame bridge, and the value exceeds 2/3 permissible limits of the standard. The relative error between simulated value and measure value is 95.7%. Under the condition with steel frame bridge, the error between the simulated ground settlement and the measured value is from 2.7% to 12.4%, and the average relative error is 6.1%， and much lower than that of nonpaving steel bridges, which shows that it is very effective to put forward the construction method of laying steel bridges.
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Received: 05 June 2018
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2019, Vol. 40 
