砂卵石地层新建通道施工对上覆既有地铁车站的变形影响研究

Study on Influence of New Transfer Channel Construction on Deformation of Overlying Existing Metro Station in Sandy Pebble Stratum

  • 摘要: 文章以成都地铁8号线换乘通道密贴下穿既有地铁车站工程为依托,采用现场监测与数值模拟相结合的方法分析暗挖施工对既有地铁车站的轨道沉降、影响范围、横断面变形等的影响。研究表明:暗挖施工完成后,既有地铁车站右线轨道沉降大于左线轨道沉降,数值模拟最大沉降为4.82 mm,与实测值误差为1.8%;随着导洞的开挖,在影响范围内既有地铁车站底板纵梁呈现下缘受拉,上缘受压的状态,暗挖施工对既有地铁车站的影响边界到开挖边界的距离约为16 m,对既有地铁车站的影响范围为55.5 m;在暗挖施工过程中,既有地铁车站横断面变形存在“扭转”现象,既有地铁车站横断面沉降最终表现为出口侧略大于进口侧,总体沉降均匀。

     

    Abstract: Based on the transfer channel project of Chengdu Metro Line 8, which is closely passes under the exist? ing metro station, the influence of mined excavation of the transfer channel on the track settlement, influence range and cross-section deformation of the existing metro station is analyzed by combining on-site monitoring and numerical simulation methods. It is concluded that: the settlement of the right track of the existing metro station is greater than that of the left track after completion of the mined excavation, the maximum settlement obtained by the numerical simulation is 4.82 mm and the error between the numerical simulation result and the measured value is 1.8%;along with the excavation of the pilot tunnel, the longitudinal beam of the existing metro station bottom slab is in a state of tension at the lower edge and compression at the upper edge within the influence range, the distance from the influence boundary of the existing metro station affected by the mined excavation to the excavation boundary is about 16 m and the influence range of the existing metro station is 55.5 m; in the process of mined excavation, a "tor? sion" phenomenon would occur in the cross-section deformation of the existing metro station, while the final crosssection settlement of the existing metro station at the exit side is slightly greater than that at the entrance side, with uniformity of the overall settlement.

     

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