地铁叠线隧道小净距盾构施工工序研究

Study on the construction procedure of small clear distance shield tunneling in subway overlapping line

结合工程实例,采用“叠线隧道夹土体加固+洞内移动台车支撑”技术方案,通过三维有限元方法分析考虑“先上后下”和“先下后上”两种施工工序,并现场监控量测。指出采用先下后上施工工序,对地表沉降和已建盾构隧道影响范围更小;加固后叠线隧道施工各项监测指标均满足城市轨道交通监测规范要求,保证了盾构施工安全,验证了有限元计算的准确性和加固方案的可靠性。

Combining with engineering example,using“fold line tunnel soil consolidation and in mobile trolley supporting hole”technical solutions,through three-dimensional finite element method(fem)analysis considering“building the above tunnel first”and“building the down tunnel first”two kinds of construction process,combined with field monitoring measurement.The following conclusions are drawn:the construction procedure of first down and then up has less influence on the surface settlement and the shield tunnel built.The monitoring indexes during the construction of the reinforced post-stack tunnel,all of them meet the requirements of urban rail transit monitoring specifications,ensure the safety of shield construction,and verify the accuracy of finite element calculation and the reliability of reinforcement scheme.