Moon Kyum Kim, Seok Ho Cho, Jeong Soo Kim, Jong Hwa Won
Excavating construction below the river section is exposed to the risk of groundwater leakage, so additional time and cost are required to prevent the occurrence of that leakage. A shield TBM (tunnel boring machine) method is widely used in construction site below the river section because of its advantages that it causes minimal disturbance of surrounding soil and is easy to block the groundwater. This study analyzed the stress distribution on segments of tunnel lining from the field data measured at construction site. The site where the data measured was the construction section of subway extension of Seoul city, Korea. The shield TBM method was adopted in the part below the Han River for the first time in Korea. In TBM method, excavation is achieved by driving of a TBM and existing lining segments are used as supporting structures. So, the stress caused by thrust force besides earth pressure, water pressure makes an effect on the stress distribution of lining segments. Accordingly, an analysis considering construction steps is required for analyzing more accurate behavior of a TBM tunnel. Thus, the field data was measured in each construction step. Analyses are performed from these field data and numerical method considering construction steps. As a result, axial stress of segments tends to reduce and converge finally as the distance between segment and shield jack becomes farther. The tendency of stress distribution with respect to construction steps agrees well in both data from field measurement and numerical analysis but the stress values have differences"