Weld Strength Analysis of T-Joint Segments of the Metro Crossing Passage by the Shield Method Based Sub-Model

Abstract

The weld of T-joint segments is the weakest link during the excavation of a metro crossing passage tunnel with the shield method. The stress on the weld is one of the key factors and should be given special attention. This paper aims to monitor the stress and strain of the weld of the T-joint segments during the construction process of the metro crossing passage tunnel of Ningbo Metro Line 3, the world first metro crossing passage tunnel by the shield method. A finite element model of the metro crossing passage tunnel is established. The CAE (Computer Aided Engineering) simulation is conducted by the sub-model approach. The calibration analysis between test data and CAE results for the strain of the weld under several key cases is performed. Based on this, the vary regulation of the stress and strain of the weld seam at various positions of the steel tube sheet under critical working conditions is obtained. Consequently, an authentic, reliable and advanced simulation process is established, and the weld strength of the T-joint segments of such kind constructions can be well assessed and predicted.