Analysis of complex behavior characteristics under multi-pressed steel pipes in non-open cut method

The box structure construction method under the ground can be divided into the open cut method and the non-open cut method. Generally, the non-open cut method is applied when non-avoidable vehicles or trains are in service on the ground. This method is usually applied in urban areas. Since the ground depth above the non-open cut method applied is usually low in urban areas, loads on the upper ground are likely to occur as brittle failure on the surface. In order to minimize the displacement of the upper ground, each non-open cut method using steel pipe reinforcement is applied. However, this can bring many problems when steel pipes are press-fitted and reinforced before the excavation. This research tried to compare the displacement by complex behavior for multi-press fitted steel pipe condition with single press-fitted condition. Laboratory tests were conducted to investigate complex behavior under horizontal and vertical multi-press fitted steel pipe conditions. Field tests were also performed in a test construction site by measuring surface settlement during press-fitting of small diameter pipes. The research results show that the influence zone under multi-press fitted steel pipes can be defined when no-open cut methods are applied.