摘要
针对大跨PBA法施工中出现的梁柱等结构尺寸偏差、初支裂缝和表观缺陷等问题,采用随机介质理论,建立群洞开挖时空效应的理论分析模型,分析了PBA工法左右不对称施工导致扣拱偏差的原因。以PBA典型车站实际工程中8导洞非对称开挖为例,研究了大跨断面隧道中多个导洞分步施工引起地层空间不均匀变化的机理。对扣拱偏差现象产生的本质成因进行分析,再现了地表沉降槽空间形态随导洞开挖而左右摆动的变形规律。根据以上研究,确定了分别成拱封闭成环、快速同步作业、侧洞分跨扣拱及施工优化来实现对称同步是消除或减小扣拱偏差现象的主要对策。
Aiming at the problems of structural dimension deviation,initial cracks and apparent defects in beam-column and other structures that occurred during the construction by Pile-Beam-Arch(PBA)approach,Based on the stochastic medium theory,a theoretical analysis model of the space-time effect of group tunnels excavation is established.The causes for the deviation of the building arches caused by the asymmetric construction are analyzed.Taking asymmetric excavation of 8 pilot tunnels in a typical PBA station as an example,the mechanism of uneven changes in stratum space caused by multi-step construction of pilot tunnels in large-span cross-section tunnels is researched.The essential cause of the deviation of the building arches is analyzed,and the deformation law of the surface settlement trough spatial shape swinging left and right with the excavation of the guide tunnel is reconstruced.According to the above research,it is pointed out that the arching being closed and looped,the rapid synchronization operation,the side hole divided into span building arches and construction optimization to achieve symmetric synchronization are the main countermeasures to eliminate or reduce the deviation of building arches.
作者
刘波
付春青
李东阳
杨航
Liu Bo;Fu Chunqing;Li Dongyang;Yang Hang(School of Mechanics and Civil Engineering,China University of Mining&Technology-Beijing,Beijing 100083,China;General Contract Department of Rail Transit and Municipal Engineering,Beijing Uni-Construction Group Co.,Ltd.,Beijing 100027,China)
出处
《矿业科学学报》
CSCD
2021年第1期9-20,共12页
Journal of Mining Science and Technology
基金
国家自然科学基金(41771083)
中国矿业大学(北京)越崎青年基金(800015Z1200)。
关键词
地铁车站
群洞开挖
PBA法
随机介质理论
subway station
group tunnels excavation
Pile-Beam-Arch(PBA)approach
stochastic medium theory
