Effects of Surface Subsidence in Excavation of Metro Crossing Passage Tunnel by Shield Machine

The excavation of the metro crossing passage tunnel by the shield method is turned into reality at the Ningbo metro subway tunnel,that is the world first metro crossing passage.However,for the effects of the excavation by the shield machine on the surface subsidence,rare studies can be found and the deep understanding of the mechanism is needed.Taking the excavation of the metro crossing passage tunnel in a certain section of the Ningbo Metro Line 3 as an example,this paper conducts the field test and CAE(Computer Aided Engineering)simulation on the construction process of the shield method.The calibration analysis between test data and CAE results of the surface subsidence during the construction process is performed.The variation law of the subsidence amplitude under various working conditions is obtained,and the dangerous conditions that need to be paid attention to during the construction of the metro crossing passage tunnel by the shield machine are pointed out.Consequently,an authentic,reliable and advanced simulation process is established,and thus the surface subsidence caused by the metro crossing passage tunnel and other similar constructions can be well monitored and predicted.