关键词: 地表变形; 盾构隧道; 盾构掘进; 有限元分析;

Abstract: To establish a theoretical analysis model of surface deformation caused by shield tunneling, based on the statistical analysis of the measured data of longitudinal surface deformation of the Beiheng super large diameter shield tunnel in Shanghai City, the finite element software is used to simulate the construction of shield tunnel, and the relationship between the surface deformation in front of cutter head and construction parameters is mainly studied.The results show that when the soil reaches the passive limit state, the maximum uplift value in front of the cutter head is about 10 mm, the uplift form is approximately quadratic parabola; under the same buried depth ratio, the maximum uplift value in front of cutter head is directly proportional to the support ratio; under the same support ratio, with the increase of buried depth ratio, the uplift range gradually moves away from the cutter head and moves forward, and the change relationship between them is proportional.This indicates that the degree and range of surface uplift in front of cutter head are related to support pressure and overburden thickness.Based on the analysis of the results of finite element simulation and mathematical derivation, a theoretical model for predicting the surface longitudinal deformation caused by shield tunneling is proposed.The engineering example shows that the prediction results of the theoretical model are in good agreement with the field measured data of the Beiheng cross passage.The theoretical model has important reference value for other similar projects.

Key words: ground surface deformation; shield tunnel; shield excavation; finite elementanalysis;