摘要
朝上掘进盾构法施工时开挖面压力控制不当会导致开挖面前方土体发生失稳破坏。对已有模型试验的结果进行分析,建立了朝上掘进盾构隧道开挖面上方土体破坏区的力学模型,基于极限平衡法推导出被动破坏模式下的开挖面极限支护力计算公式,研究了倒圆台体模型高度以及侧面与水平面的夹角对极限支护力的影响。研究结果表明,朝上掘进盾构开挖面上方土体的被动破坏模式呈现三维倒圆台体形态,极限支护力的大小随开挖面上覆土层的厚度增大而增加;当倒圆台体模型侧面与水平面的夹角在一定范围内变化时,极限支护力的大小随夹角的增大而减小,在实际工程中,如遇开挖面上层覆土厚度过小以及倒圆台模型侧面与水平面夹角过大的情况,土体极限支护力变小,易发生失稳。因此,为保证开挖面的稳定性,需要重点关注开挖面上层覆土厚度过小以及倒圆台模型侧面与水平面夹角过大带来的影响。
The improper control of the pressure of the excavating surface during the construction of the upward shield tunneling leads to the instability of the soil in front of the tunnel face.Based on the results of the existing mod⁃el tests,the mechanical model of the soil failure zone above the excavation surface of the shield tunnel is estab⁃lished.Based on the limit equilibrium method,the calculation formula of the limit support force of the excavation sur⁃face under the passive failure mode is derived.The influence of the height of the inverted conical frustum model and the angle between the side and the horizontal plane on the limit support force is studied.The results show that the passive failure mode of the soil above the upward tunnel face presents a three-dimensional inverted conical frustum shape,and the ultimate support force increases with the increase of the overburden.When the angle between the side of the inverted conical frustum model and the horizontal plane changes within a certain range,the limit support force decreases with the angle increase.In practical engineering projects,it is necessary to focus on the influence of the overburden and the angle between the side of the inverted conical frustum model and the horizontal plane on the tunnel face stability to ensure the stability of the tunnel face.
作者
周彦臣
魏纲
王霄
陶柏丞
李奕彤
ZHOU Yanchen;WEI Gang;WANG Xiao;TAO Baicheng;LI Yitong(Department of Civil Engineering,Hangzhou City University,Hangzhou 310015,China)
出处
《低温建筑技术》
2023年第4期63-67,共5页
Low Temperature Architecture Technology
基金
国家级大学生创新创业训练计划项目(202213021013)。
关键词
朝上掘进
盾构隧道
开挖面
被动破坏
极限支护力
upward excavation
shield tunnel
excavation face
passive destruction
ultimate supporting force
