基于变位分配法地铁车站变形规律研究  

STUDY OF METRO STATION DEFORMATION REGULARITY BASED ON DEFLECTION DISTRIBUTION CONTROL METHOD

作　　者：扈世民[1] 王梦恕[2] 张丽[1] 张小伟[1] 郭婷[1] 

机构地区：[1]北京城建设计研究总院有限责任公司,北京100037 [2]北京交通大学隧道及地下工程试验研究中心,北京100044

出　　处：《岩石力学与工程学报》2013年第2期266-272,共7页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点基础研究发展计划(973)项目(2010CB732102)

摘　　要：以北京地铁某车站工程为背景,基于变位分配法原理对PBA施工引起地层变形进行分阶段研究,提出相应控制措施以减小对周围环境的不利影响,可得出以下结论:(1)PBA工法地层与车站结构的力学响应可分为4个"卸载-加载"的过程,其中"小导洞开挖"和"拱部土体开挖与扣拱"为控制地层变形的关键步序;(2)小导洞开挖前,应及时超前注浆加固周边地层。采用错距开挖、短进尺减少对洞周围岩的扰动;(3)在扣拱阶段,传力途径的转换使洞周地层应力重分布,车站结构产生相应的协调位移;建议采用短进尺,设置横向钢支撑等措施;(4)随着施工步序的推进,洞周地层塑性区范围逐渐增加,最终形成剪切楔破坏;大量张拉性微裂纹伴随剪切性微裂纹构成宏观上的剪切带;(5)对比4个施工阶段地表沉降的比例,数值计算和现场监测分别为4.5∶1∶6∶1和4.3∶1.6∶5∶1,二者基本吻合。Taking the metro station in Beijing as the project background, the study of stratum displacement has been performed based on the deflection distribution control method. The effective control measures are proposed to reduce the impact on the surrounding environment. The results show： （1） Mechanical response of the pile-beam- arch（PBA） method between strata and station structure can be divided into four processes of unloading-loading, the pilot excavation and support and supporting arch are the key points which caused surface subsidence. （2） Beibre pilot excavation, the surrounding strata is reinforced timely by advanced grouting. The measures are performed such as malposition excavation, short footage and tough supporting to reduce the adverse impact on the surrounding environment. （3） The stress adjustment is performed between formation and station structure in the supporting arch stage. The structure would produce a certain coordination deformation and long stress adjustment process. Due to larger settlement rate, the measures are suggested such as setting the horizontal steel support, short footage and reinforcement strata. （4） The range of plastic zone around station increases gradually with the construction development, especially pilot excavation and supporting arch stage. （5） Comparison of surface settlement rate of four construction stages, the numerical calculation rate is 4.5 ： 1 ： 6 ： 1 and the in-situ monitoring rate is 4.3 ： 1.6 ： 5： 1, the results show they are consistent.

关 键 词：隧道工程 地铁车站 地表沉降 PBA工法 变位分配 扣拱 

分 类 号：U45[建筑科学—桥梁与隧道工程]