The objective of this research is to study the design and construction technology for constructing large-scale underground spaces in a shallow overburden underground (overburden: 2m to less than 10m) using tunneling methods. In this method, the roof formation is carried out by non-open cut using combined technologies such as shield or NATM and is supported by the arch action as a structure without expecting the ground arch effect. Though this is the interim report, the following conclusions have been obtained. 1) According to the overseas case investigation, the application of both small sections combined system and the column-type support system to Japan is practicable. 2) Regarding the arch effect as a structure, following knowledge has been obtained. (a) It is important to restrict the horizontal displacement of the arch leg as much as possible. (b) The ground reaction is almost independent of arch effect when member stiffness is large. (c) When considering the unbalanced earth pressure, the small arch-rise is favorable. 3) The result from the actual case study on the underground parking lot shows that the composite method that constructs the roof structure by using NATM, shields, jacking method, etc. has been found to be effective.
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