砂层隧道开挖面失稳对侧邻既有框架结构的影响  

Influence of Instability of Tunnel Excavation Surface in Sand Stratum on Adjacent Existing Frame Structure

作　　者：吕金彪 张旺 沈宇鹏[3] LYU Jinbiao;ZHANG Wang;SHEN Yupeng(Beijing Municipal Construction Group Co.Ltd.,Beijing 100045,China;CCCC Highway Consultants Co.Ltd.,Beijing 100010,China;School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京市政建设集团有限责任公司,北京100045 [2]中交公路规划设计院有限公司,北京100010 [3]北京交通大学土木建筑工程学院,北京100044

出　　处：《铁道建筑》2023年第3期108-112,共5页Railway Engineering

摘　　要：通过设计小尺寸模型试验,探究在不同埋深、不同施工方法下砂层中新建隧道开挖面失稳对侧邻既有框架结构的影响。结果表明:隧道开挖面发生失稳时,在开挖面前方地层中产生的松动区先呈半个心形,然后沿竖向和横向扩展,逐渐呈上宽下窄的喇叭形,此时地表产生沉降;不同埋深、不同施工方法下开挖面前方土压力均先迅速减小,然后小幅上下波动,最后趋于稳定;隧道埋深和施工方法对地表最大沉降影响很大,地表沉降随隧道埋深增加而减少,采用中隔壁法施工时地表沉降仅为全断面法的17.7%;隧道开挖面失稳会导致既有框架结构产生纵向弯矩,随隧道埋深增加,结构中更多位置出现纵向弯矩;既有结构内力随失稳程度增加而增大,靠隧道侧既有框架结构受影响更大。Through the design of small-scale model tests,the influence of instability of the excavation surface of a new tunnel in sand stratum on the existing frame structure under different cover depths and construction methods was explored.The results show that when the excavation surface of tunnel is unstable,the loose area in the stratum in front of the excavation surface is half heart-shaped at first,then expands vertically and laterally,and gradually becomes an upward width and low narrow trumpet shape.At this time,the surface subsidence occurs.Under different cover depths and different construction methods,the soil pressure in front of the excavation face decreased rapidly at first,then fluctuated slightly,and finally stabilized.The cover depth of the tunnel and the construction method have a great influence on the maximum surface settlement.The surface settlement decreases with the increase of the tunnel cover depth.When the center diaphragm method is used for construction,the surface settlement is only 17.7%of that with the full-section method.The instability of the excavation surface of the tunnel will cause the longitudinal bending moment of the existing frame structure.As the cover depth of the tunnel increases,the longitudinal bending moment will appear in more places in the structure.The internal force of the existing structure increases with the increase of the instability degree,and the existing frame structure on the side of the tunnel suffers more.

关 键 词：地铁 模型试验 隧道开挖面失稳 既有结构 地表沉降 砂层隧道 

分 类 号：U455.4[建筑科学—桥梁与隧道工程]