龙泉隧洞出口浅埋段开挖支护方案及临近建筑物影响分析  

Analysis of Excavation Support Scheme and Influence of Adjacent Buildings in Shallow Buried Section of Longquan Tunnel Exit

作　　者：闫尚龙 苏恒 黄青富 YAN Shanglong;SU Heng;HUANG Qingfu(Power China Kunming Engineering Corporation Limited,Kunming 650051,China)

机构地区：[1]中国电建集团昆明勘测设计研究院有限公司,云南昆明650051

出　　处：《云南水力发电》2025年第2期112-117,共6页Yunnan Water Power

基　　金：云南省重大科技专项计划项目(202102AF08001)。

摘　　要：针对龙泉隧洞出口浅埋段在开挖过程中存在的隧洞围岩稳定性和临近建筑物的地表沉降等问题,提出了“SMW隔离桩+地表注浆”隔离预加固后再进行开挖支护的方案。首先对处于城区区域的隧洞开挖前利用SMW隔离桩+桩间地表注浆进行预加固,以此降低对临近建筑物影响;其次对隧洞洞周及掌子面进行超前灌浆和超前大管棚+超前小导管加固措施;然后分3台阶进行隧洞开挖,并在开挖完成后及时施作衬砌和衬后灌浆;最后对隧洞出口段500 m洞段进行整体三维有限元分析研究。经过对龙泉隧洞出口浅埋段开挖支护方案进行数值模拟分析,得到以下结论:(1) SMW隔离桩+桩间地表注浆进行预加固能有效控制保护侧的地表建筑物变形;(2)隧洞施工对地表的影响主要集中在以隧洞断面中心线为基准的30 m范围内;(3)地表周边建筑物区最大沉降值出现在距隧洞中心测点17.7 m处,为1.06 mm;(4)以“反弯变化点”为基点,沉降曲线左侧最大斜率为0.000 14(0.93 mm/6.5 m),右侧最大斜率为0.000 035(0.13 mm/3.7 m)。Aiming at the problems of tunnel surrounding rock stability and surface settlement of adjacent buildings in the excavation process of shallow buried section of Longquan tunnel exit,this paper proposes a scheme of 'SMW isolation pile + surface grouting ' isolation pre-reinforcement before excavation and support.Firstly,the SMW isolation pile + surface grouting between piles is used to pre-reinforce the tunnel in the urban area before excavation,so as to reduce the impact on adjacent buildings.Secondly,advanced grouting and advanced large pipe roof + advanced small pipe reinforcement measures are carried out around the tunnel and the tunnel face.Then,the tunnel excavation is carried out in three steps,and the lining and post-lining grouting are carried out in time after the excavation is completed.Finally,the overall three-dimensional finite element analysis of the 500 m tunnel section of the tunnel outlet section is carried out.Through the numerical simulation analysis of the excavation and support scheme of the shallow buried section at the exit of Longquan tunnel,the following conclusions are obtained:(1) SMW isolation pile + surface grouting between piles for pre-reinforcement can effectively control the deformation of surface buildings on the protection side;(2) The influence of tunnel construction on the surface is mainly concentrated in the range of 30 m based on the center line of the tunnel section.(3) The maximum settlement value of the building area around the surface appears at 17.7 m from the center of the tunnel,which is1.06 mm;(4) Based on the ' inflection point ',the maximum slope of the settlement curve on the left side is 0.00014(0.93mm/6.5m),and the maximum slope on the right side is 0.000035(0.13mm/3.7m).

关 键 词：隧洞浅埋段 开挖支护 SMW隔离桩 地表沉降 

分 类 号：TV64[水利工程—水利水电工程] TV223