黄河中下游超深盾构工作井基坑变形警情分析  

Deformation Alarm Analysis of Ultra-deep Shield Working Shaft Foundation Pit in Yellow River Middle-lower Reaches

作　　者：闫文博 刘燕[2,3] 刘俊岩 皇甫帅帅[2] 邵玉婷 YAN Wenbo;LIU Yan;LIU Junyan;HUANGFU Shuaishuai;SHAO Yuting(Yellow River Engineering Consulting Co.,Ltd.,250003,Zhengzhou,China;不详)

机构地区：[1]黄河勘测规划设计研究院有限公司,郑州250003 [2]济南大学土木建筑学院,济南250022 [3]山东省城市地下工程支护及风险监控工程技术研究中心,济南250022 [4]山东省土木建筑学会,济南250002

出　　处：《城市轨道交通研究》2023年第12期97-102,共6页Urban Mass Transit

基　　金：国家自然科学基金项目(51979122);山东省自然科学基金面上项目(ZR2022ME042);黄河勘测规划设计有限公司二类科研课题(2018-ky20(2))。

摘　　要：目的:为了充分把握黄河中下游超深工作井基坑的变形控制,应充分关注施工流程与支护结构的关系,安排合理的施工工序,以丰富沿岸地区特殊地层结构基坑的施工经验。方法:基于济南市某穿黄河隧道工程超深盾构工作井基坑,从开挖期监控测量出现的几次预警信息入手,结合基坑围护结构设计和复杂的施工流程安排,分析基坑施工过程中出现的围护墙深层水平位移和内力报警原因,并提出了可采取的应对措施。结果及结论:施工流程的安排应统筹端头加固、坑深变化及支护刚度变化位置,应重视施工引起的坑顶荷载等工况及相互间组合因素的影响,合理安排施工工序。支撑架设、端头加固与基坑开挖工况叠合及坑边超载等是造成基坑变形和支撑轴力报警的主要原因;支护刚度变化处的支撑轴力报警的主要原因是支撑受端头井开挖工况和开挖进度的影响较大,而不取决于标准段的施工工况。因此,应重视端头段与标准段的支护结构转换处支护刚度加强的必要性。Objective:To comprehensively control the deformation of ultra-deep working shaft foundation pits in Yellow River middle-lower reaches,it is crucial to focus on the relationship between construction process and support structures,which involves arranging rational construction sequences to enrich the construction experience in foundation pits in river bank areas with special geological structures.Method:Based on the ultra-deep shield working shaft excavation pit of a tunnel project crossing Yellow River in Ji’nan,starting with the several early-warning messages detected during the excavation period,combining the foundation pit retaining structure design and the complex construction process arrangement,an analysis is conducted on the causes of diaphragm wall deep-seated horizontal displacement and internal force alarms during the foundation pit construction process,and corresponding countermeasures are provided.Result&Conclusion:The construction process should coordinate the reinforcement of tunnel face,changes in pit depth and changes in support stiffness.Attention should be given to the influence of working conditions such as excavation-induced pit-top loads and the combination of factors between working conditions,so that construction procedures are reasonably sorted.Support installment,tunnel face reinforcement,the overlay of excavation working conditions,and edge overload are the main causes of foundation pit deformation and supporting axial force alarms.The main reason for axial force alarms at locations with changing supporting stiffness is the significant impact of tunnel face shaft excavation working conditions and progress,independent of the construction conditions of the standard section.Therefore,the necessity of reinforcing the supporting stiffness at the transition between the tunnel face section and the standard section should be emphasized.

关 键 词：超大深基坑 警情分析 现场监测 应对措施 

分 类 号：TU492[建筑科学—土工工程]