【作者】 杨会军； 王志刚； 周晓敏； 刘虹阳；

【Author】 YangHui-jun~1 Wang Zhi-gang~1 Zhou Xiao-min~2 Liu Hong-yang~1 1.China Railway Tunnel Group Co.,Ltd.,Luoyang 471009 2.University of Science & Technology Beijing,Beijing 100083

【机构】 中铁隧道集团有限公司； 北京科技大学；

【摘要】 浅埋小净距群洞暗挖施工中,由于应力集中、塑性区域叠加、地层的反复扰动等现象,对地表沉降的影响增大,严重的还可能危及周边建筑物、地中管线等设施的破坏。本文结合宣武门车站小净距群洞暗挖施工,通过数值模拟优化确定群洞开挖顺序,以减小群洞施工的影响。并通过实测数据分析了地表沉降的变化规律:(1)导洞施I阶段地表累计沉降为-35.8～23.5mm,其中:下排导洞施工引起的地表下沉为-8mm,上排导洞施工引起的地表下沉为-26mm;(2)导洞施工阶段,其地表沉降约占总沉降48%,因此控制导洞施工阶段对地表沉降的影响非常关键;(3)导洞开挖支护完成后,有2.13～4736%监测数据超过-30mm,因此,应该对地表沉降的限值进行修正。达到施工对周边环境影响最小,同时,降低工程成本。更多还原

【Abstract】 During the course of the construction of a little space between tunnels,safe state of the soil mass between two tunnels and construction of the subsequent tunnel are influenced because of stress concentration, plastic zone overlaying,ground motion,and so on;and safety of the subsequent tunnel is also influenced. Moreover,peripheral buildings and underground utilities can be destroyed severely,which is mainly contributed by the stress concentration.In the paper,by linking with the undercutting construction of the little space between tunnels of Xuanwumen station,optimizing and determining excavation sequence among tunnels by numerical simulation;analysis is made on the pattern of the surface settlement on basis of monitoring and measurement: (l)total surface settlement is -35.8—23.5mm at the stage of pilot construction,including -8mm imposed by the construction of the lower row pilots and -26mm imposed by the construction of the lower row pilots;(2)at the stage of pilot construction,the ratio of the surface settlement accounts for 48%of the total surface settlement, therefore it is very important to control the impact on the surface settlement by the pilot construction;(3)after finishing pilot excavation and reinforcement,2.13~47.36%of the monitoring data excess -30mm,therefore,limit value of the surface settlement ought to be amended in order to achieve least impact caused by construction and to lower engineering cost.更多还原