摘要
沿海地区往往地层起伏较大且软硬不均,由于地层抗力的差异导致盾构隧道结构承载状态存在较大区别,为此,通过1∶5精细化模型试验,结合数值模拟研究了不同地层条件下错缝拼装盾构隧道结构承载状态的差异和结构承载状态定量判定方法。研究结果表明:①竖向荷载作用下结构在试验加载过程中依次发生拱顶管片开裂、拱腰纵缝外侧明显张开、拱顶纵缝外侧混凝土挤压开裂、拱腰外侧和拱顶内侧钢筋屈服、拱底螺栓屈服;②淤泥层、黏土层和填砂层的管片结构承载演化过程均存在6个关键节点,但不同地层在管片裂缝、接缝张开、钢筋受力、螺栓受力等方面存在差异;③根据管片损伤程度将结构承载状态分为4个等级,确定了各等级对应的竖向收敛和剩余承载力控制值。以粉质黏土层为例,各等级的竖向收敛控制值为2.0‰D,3.9‰D,15.3‰D,剩余承载力比例控制值为88.0%,76.9%,19.7%。研究结论可为沿海城市地铁服役状态的评估提供参考。
In coastal areas,the soil strata often fluctuate greatly and are uneven in softness and hardness.Due to the difference in the resistance of the soil strata,the bearing state of shield tunnel structure varies greatly.The 1∶5 fine model tests and numerical simulations are carried out to study the difference of structural bearing state of a staggered jointed shield tunnel under different stratum conditions,and a quantitative determination method for structural bearing state is proposed.The results show that:(1)The obvious cracking of the arch and the lateral opening of the longitudinal seam are obvious at the arch waist position,and the extrusion cracking of the joint outside the arch waist and inside the arch and the yield of the bolt at the bottom of the arch occur successively during the test loading process.(2)There are six critical bearing states in the segment bearing evolution process of silt layer,clay layer and sand-filled layer,but there are differences in the segment cracks,joint openings,reinforcement forces and bolt forces.(3)According to the damage degree of segment,the bearing state is divided into four grades,and the corresponding control values of vertical convergence and residual bearing capacity of each grade are determined.Taking the silty clay layer as an example,the control values of vertical convergence of each grade are 2.0‰D,3.9‰D,15.3‰D,and the proportion control values of residual bearing capacity are 88.0%,76.9%,and 19.7%.The conclusion of this study may provide reference for the evaluation of the service status of metros in coastal cities.
作者
刘学增
李振
赖浩然
桑运龙
杨学良
LIU Xuezeng;LI Zhen;LAI Haoran;SANG Yunlong;YANG Xueliang(College of Civil Engineering,Tongji University,Shanghai 200092,China;Shanghai Engineering Research Center of Underground Infrastructure Detection and Maintenance Equipment,Shanghai 200092,China;Tongyan Civil Engineering Technology Co.,Ltd.,Shanghai 200092,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2023年第7期1357-1364,共8页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(51878497)。
关键词
盾构隧道
承载状态
模型试验
数值模拟
定量判定方法
shield tunnel
bearing state
model test
numerical simulation
quantitative determination method
作者简介
刘学增(1971—),男,教授级高级工程师,博士生导师,主要从事隧道加固设计、安全风险评估、健康诊断等方面的研究工作。E-mail:liuxuezeng@tongji.edu.cn。;通信作者:李振(E-mail:lz12201314@tongji.edu.cn)。
