错缝拼装盾构管片的收敛变形研究

地铁隧道的收敛变形是影响地铁正常运营的重要因素,地铁保护区内工程施工造成的堆载、卸载、基坑降水等工况会导致地铁隧道收敛变形发生极大变化。为分析错缝拼装盾构管片的收敛变形规律,首先,设计和实施了三环足尺试验,发现管片在试验工况下呈"横鸭蛋"式变形,中环横向收敛变形存在进入塑性阶段的关键点,原因是纵缝螺栓屈服;然后,利用通用有限元软件ABAQUS建立三维有限元模型,经试验数据对比验证后,用该模型探究拼装方式对管片收敛变形的影响规律,发现在试验前后环拼装方式下,封顶块位于底部时横向收敛变形较小;环间错缝效应越强,收敛变形越小。

Research on Convergence Deformation of Staggered Assembly Segmental Lining in Shield Tunnel

The convergence deformation of metro tunnel is an important factor affecting the normal operation of the metro.The conditions of loading,unloading and foundation pit dewatering caused by the construction in the metro protection area will cause great changes in the convergence deformation of the metro tunnel.To study convergence deformation law of staggered assembly segmental lining in shield tunnel,a three-ring full-scale test was designed and implemented f irstly .The test indicates that segmental lining deforms like a “transverse duck egg”,and there is a key point to enter into the plastic phase in lateral convergence deformation of middle ring due to the yield of longitudinal seam bolts.Then a three-dimensional f inite element model was established with ABA Q US.After the test data were compared and verif ied ,this model was used to explore the inf luence of assembly method on the convergence deformation of segmental lining.The results indicate that under the front ring and rear ring assembly mode,when the capping block is at the bottom,the lateral convergence deformation is small,and the stronger the inter-ring staggering effect,the smaller the convergence deformation.