Study On Surface Subsidence Law And Control Technology Caused By Subway Tunnel Crossing Ground Fissure

The ground fissure is the main problem that the Xi'an subway tunnel will face in the construction process. How to deal with the ground crack correctly and solve the problem of the stability and stability of the subway tunnel will be the key problem of Xi'an subway construction. Therefore, the subway tunnel The surface subsidence law and control technology has very important significance.. In this paper, it uses the method that combines with the theoretical analysis,in-situ monitoring and, numerical simulation followed the background of interval tunnels between Banpo and Fangzhi-cheng . The main jobs are as follows:(1) Ground failure manifestations is manifested as cyclical, limited, directional, slow and progressive, non-equilibrium and asymmetry, and irresistible resistance to ground fissures.Subway tunnels, both in terms of load and deformation, show a large difference from groundless cracks, mainly in two respects: 1) the load acting on the tunnel changes; 2)the bottom of the tunnel has a void phenomenon.(2)Based on the theoretical analysis of the tunnel load, the calculation model of the tunnel through ground fissure is established,and the process of the tunnel under the action of ground fissures is divided into three stages, which are the initial stage of settling, the development stage and the complete voiding stage.(3) The results showed that the vertical and surface subsidence values of the tunnel vault are far more than the allowable values of the tunnel, and the foundation of the building in the building above the tunnel is very large and easy to cause wall tilt or overturning, which must take reasonable and effective control measures.(4) Combined with project features of Xi'an Metro Line 1 between Banpo and Fangzhi-cheng between the dark excavation, This paper puts forward the technical measures of surface subsidence control caused by tunneling through tunnel fissures from three aspects:tunnel structure design, stratum reinforcement design and excavation step.(5) The site monitoring program design was given and completed the field measurement.The results of the analysis and monitoring showed that after taking the control measures proposed in this paper, the whole tunnel will be able to ensure that the deformation of the road above the tunnel is within the allowable range, and the deformation of the building is small,thus ensuring the normal road Transport and adjacent to the building's security and stability,which indicated that the proposed control measures are reasonable and effective.