Analytical Study on the Transverse Internal Forces of Shield Tunnel Segments due to Adjacent Excavations in Soft Clays

• Published in: KSCE journal of civil engineering Vol. 25; no. 12; pp. 4842 - 4855
• Main Authors: Zhang, Bing-qiang, Huang, Wei, Chen, Fu-quan, Wang, Qi-yun
• Format: Journal Article
• Language: English
• Published: Seoul Korean Society of Civil Engineers 01.12.2021; Springer Nature B.V; 대한토목학회
• Subjects: Civil Engineering; Construction; Deformation; Depth perception; Diaphragm wall; Distance; Dredging; Empirical analysis; Engineering; Excavation; Geotechnical Engineering & Applied Earth Sciences; Industrial Pollution Prevention; Internal forces; Load; Load distribution; Segments; Stability analysis; Tunnel Engineering; Tunneling shields; Tunnels; 토목공학; Adjacent excavation; Transverse internal forces; Elastic equation method; Tunnel segments; Source-sink imaging method
• ISSN: 1226-7988; 1976-3808
• DOI: 10.1007/s12205-021-1794-y

Deep excavations unavoidably cause the changes in stress and displacement of surrounding soils, which further generate additional internal forces on the adjacent existing tunnel segments, and compromise the performance and stability of the tunnels. In this study, two-stage analysis method is used to theoretically calculate the additional internal forces in the tunnel segments due to laterally adjacent excavation. Based on an empirical deformation curve of diaphragm walls, the excavation-induced stress in a linear elastic soil is formulated using source-sink imaging method. A distribution model of additional external load acting on the tunnel segments due to adjacent excavation is further established, and the additional internal forces in the tunnel segments under the corresponding additional loads are estimated using elastic equation method. Parametric studies are then conducted to investigate the effects of excavation procedure, buried depth of shield tunnel, and excavation-tunnel horizontal distance on the additional internal forces in the tunnel segments. The results show that the studied parameters have significant effect on the additional internal forces in the tunnel segments due to laterally adjacent excavation. When the excavation-tunnel horizontal distance is less than the excavation depth, the accompanied effect on the additional internal forces in the tunnel segments is highly sensitive. This study can provide theoretical insights into the estimation of tunnel segment responses due to laterally adjacent excavation.