复杂出入口通道近接施工对既有车站隧道及地表影响研究  

Study on the Impact of Adjacent Construction of Complex Entrance and Exit Passageways on Existing Station Tunnels and Ground Surface

作　　者：缪振畴[1] 赵东平[2,3] 朱龙 刘晓贺 MIAO Zhenchou;ZHAO Dongping;ZHU Long;LIU Xiaohe

机构地区：[1]中国水利水电第五工程局有限公司,四川成都610066 [2]西南交通大学土木工程学院,四川成都610031 [3]西南交通大学交通隧道工程教育部重点实验室,四川成都610031

出　　处：《重庆建筑》2024年第11期36-42,共7页Chongqing Architecture

摘　　要：地铁出入口小净距上跨施工会对既有车站隧道产生不利影响,合理的开挖方法可以有效控制或减小这种不利影响程度。以重庆轨道交通4号线西延伸段玉带山站7号出入口通道工程为依托,采用三维数值模拟方法,研究了全断面法和两台阶法两种工法条件下出入口通道开挖对既有车站及地表沉降的影响。研究结果表明:(1)出入口通道近接施工会导致车站隧道支护结构安全性降低,断面A处关键步序为L4~L7段开挖,断面B处关键步序是L3~L5段开挖,而断面C处关键步序为L1、L2段开挖;(2)出入口通道近接施工会引起地表沉降的增大与沉降槽的最低点由车站隧道正中向出入口通道一侧偏移,偏移量的值约在2.0~4.6 m;(3)出入口通道的开挖会引起围岩塑性区的发展,特别在通道第L2~L6段开挖过程中围岩塑性区拓展较为明显,车站隧道拱部靠近出入口侧的围岩塑性区发展约有18 m,7号出入口周围径向的塑性区约有26 m;(4)两种工法条件下,既有车站隧道结构安全性均满足规范要求,推荐入口通道采用全断面法施工,在保障安全的前提下兼顾施工效率。The construction of small clear-distance overhead entrances and exits for subway stations can adversely affect existing station tunnels,and reasonable excavation methods can effectively control or reduce the degree of such adverse effects.Based on the Entrance and Exit No.7 passage project at Yudaishan Station of the West Extension of Chongqing Rail Transit Line 4,a three-dimensional numerical simulation method was used to study the impact of excavation using two methods,namely the full-face method and the two-bench method,on the settlement of existing station tunnels and the ground surface.The research results indicate that:(1)Adjacent construction of the entrance and exit passages can reduce the safety of the support structure of the station tunnel.The critical steps at Section A are the excavation of segments L4 to L7,at Section B are the excavation of segments L3 to L5,and at Section C are the excavation of segments L1 and L2;(2)Adjacent construction of the entrance and exit passages can increase ground surface settlement and shift the lowest point of the settlement trough from the center of the station tunnel towards the side of the entrance and exit passage,with a shift value ranging from approximately 2.0 to 4.6 m;(3)Excavation of the entrance and exit passage can cause the development of plastic zones in the surrounding rock,particularly during the excavation of segments L2 to L6 of the passage,where the expansion of plastic zones in the surrounding rock is more pronounced.The development of plastic zones in the surrounding rock near the entrance side of the station tunnel arch extends about 18 m,and the radial plastic zone around Entrance and Exit No.7 extends about 26 m;(4)Under both construction methods,the structural safety of the existing station tunnel meets the regulatory requirements.The full-face method is recommended for the construction of the entrance and exit passage,balancing construction efficiency while ensuring safety.

关 键 词：出入口通道 近接施工 车站隧道 地表沉降 

分 类 号：U231[交通运输工程—道路与铁道工程]