考虑主应力偏转和土拱效应的干砂盾构隧道掌子面极限支护力计算方法研究  

Method for calculating limit support pressure of face of shield tunnels considering principal stress axis rotation and soil arching effects in dry sand

作　　者：张宇 陶连金[2] 刘军 赵旭[2] 郭飞 边金 ZHANG Yu;TAO Lianjin;LIU Jun;ZHAO Xu;GUO Fei;BIAN Jin(School of Civil and Transportation Engineering,Beijing University of Civil Engineering and Architecture,Beijing 102627,China;Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China;Beijing Municipal Construction Co.,Ltd.,Beijing 100048,China;College of Ocean Engineering,Guangdong Ocean University,Zhanjiang 524000,China)

机构地区：[1]北京建筑大学土木与交通工程学院,北京102627 [2]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124 [3]北京市政建设集团有限责任公司,北京100048 [4]广东海洋大学海洋工程学院,广州湛江524094

出　　处：《岩土工程学报》2023年第3期530-540,共11页Chinese Journal of Geotechnical Engineering

基　　金：北京未来城市设计高精尖创新中心项目(UDC2019032824);国家重点研发计划项目(2017YFC0805403,2019YFC1509704);国家自然科学基金项目(41877218,42072308)。

摘　　要：深埋干砂盾构隧道在施工过程中存在显著的土拱效应,如何确定考虑土拱效应的隧道掌子面极限支护力至关重要。基于极限平衡法和楔形体理论,提出了一种多层抛物线承载拱模型。根据隧道不同埋深下掌子面失稳破坏的特征和土拱类别,将隧道状态划分为浅埋隧道、过渡隧道和深埋隧道。考虑多层抛物线承载拱区域主应力偏转角和侧向土压力系数的连续性,并假定抛物线承载拱为满足合理拱轴线三铰拱结构,推导了过渡区和深埋区多层抛物线承载拱荷载传递的计算公式,进而通过极限平衡法计算得到掌子面极限支护力。将本模型计算结果与已有理论模型、模型试验和数值结果进行对比,验证了本模型计算得到的掌子面极限支护力和失稳破坏区的合理性。最后,通过参数分析讨论了土体内摩擦角对隧道浅埋和深埋分界线以及极限支护力的影响。该研究成果可为深埋干砂盾构隧道极限支护力的预测提供理论依据。For the deep-buried shield tunnels in dry cohesionless soils, it is critical to determine the support pressure acting on the tunnel face due to the significant soil arching effects. Based on the limit equilibrium method and the wedge theory, a multi-layer parabolic bearing arch model is proposed. According to the characteristics of failure zone of the tunnel face and the category of soil arch under different buried depths, the tunnel state is divided into shallow buried tunnel, transition tunnel and deep buried tunnel, respectively. By considering the continuity of the principal stress deflection angle and lateral earth pressure coefficient in the multi-layer parabolic bearing arch and assuming the parabolic bearing arch as a three-hinged structural arch with reasonable arch axis, the load transfer expression for the multi-layer parabolic bearing arch is derived in transition zone and deep buried zone respectively, and then the limit support pressure is calculated. By comparing the proposed model with the existing model, model tests and numerical model, the rationality of the limit support pressure and failure zone of the tunnel face obtained by the proposed model is verified. Finally, the influences of the internal friction angle on the boundary between shallow and deep burials and the limit support pressure are discussed through parameter analysis. This study may provide a theoretical basis for predicting the limit support pressure acting on the tunnel face in dry sand.

关 键 词：盾构隧道 极限平衡 极限支护力 理论解析 土拱效应 

分 类 号：U45[建筑科学—桥梁与隧道工程]