The Disturbance Effect Of Double Tunnels Excavation Through Sensitive Structures And Study Of Safety Control Technology

During a tunnel excavation in the city, how to reduce disturbance and damage of sensitive structures caused by construction on surface has been one of the unresolved problems related to researchers. As a consquence of this dissertation, combined the Ministry of Railways topic "Chang ZhuTan intercity rail construction of key technologies"(2011G013-C), based on the tunnel under the Xiyuan Hotel, Pingge district, and Second West Ring Road overpass as three typical sensitive structures to start the study, the main research work as fllows:(1) The paper not only elaborated the formation mechanism as well as regularity of shallow tunnel’s law settlement disturbance, but also deduced the basic equations of the load transfer method on the basis of the principle of transferring pile load. Further more, it made use of finite difference method to infer the vertical and horizontal displacement of the pile each node equations effected by the tunnel excavation disturbence.(2) The method took advantage of FLAC3D numerical software to have numerical simulation analysis of two-hole buried tunnels through West Second Ring overpass. At the same time, it had considered cave reinforcement measures such as Tunnel ahead grouting bolt, and steel arch. What is more, the difference bewteen perturbation effect on the Second West Ring Road overpass of full-face method, three-step method, and the annular excavation reserved core indigenousm was campared and analysed.The numerical results as well as the actual monitoring data were compared.(3) When having numerical simulation for the double-tunnels through Pinge, the paper tooke consideration of tunnel pre-reinforcement measures and Inside reinforcement measures. Not only could program thought about the protective effect on the isolated pile for high-rise residential buildings in Pinge community, but campared difference counting result bewteen full-face method, three-step method and measurement results in reality. (4) Simulating two-hole tunnel excavation through Xi Yuan hotel, the dissertation took into account of the special terrain conditions of Xi Yuan hotel which was located near the slopes, and added reinforcement measures, including retaining walls, piles isolation construction of the actual construction as well as campare difference counting result bewteen full-face method, three-step method and measurement results in reality.