Construction method for new underground structure

Abstract

[Problem] An object of the present invention is to provide a construction method for a new underground structure, the method achieving reduction in the load imposition of a new underground framework on an existing underground concrete framework, and reduction in construction cost for constructing the new underground structure. [Solving Means] A new underground structure 100 having a basement available as a residential space, and an underground pit which is an underground facility for housing piping equipment, etc., is constructed with a fluidized soil wall 300 held between an existing underground concrete framework 200 and a new underground concrete framework 400.

1 . A construction method for a new underground structure by which a new underground concrete framework is constructed without entirely dismantling and removing an existing underground concrete framework, wherein:
 a fluidized soil wall is constructed by filling an inner circumferential face of the existing underground concrete framework with fluidized soil, and the new underground concrete framework is constructed on an inner circumferential face of the fluidized soil wall.   
     
     
         2 . A construction method for a new underground structure by which an existing underground concrete framework is partially utilized to construct a new underground concrete framework without entirely dismantling and removing the existing underground concrete framework, the method comprising:
 vertically providing a first formwork body on the side of an inner circumferential face of the existing underground concrete framework at a predetermined distance from the existing underground concrete framework;   filling a space between the existing underground concrete framework and the first formwork body with fluidized soil to construct a fluidized soil wall;   vertically providing a second formwork body on the side of an inner circumferential face of the fluidized soil wall at a predetermined distance from the fluidized soil wall; and   casting concrete in between the fluidized soil wall and the second formwork body to construct the new underground concrete framework.   
     
     
         3 . The construction method for a new underground structure according to  claim 2 , wherein the first formwork body and the second formwork body are kept upright by separators. 
     
     
         4 . The construction method for a new underground structure according to  claim 2 , wherein the first formwork body and the second formwork body are formwork panels formed by bending and cutting a plate-like steel material into a substantially rectangular front shape and a substantially angular-wave-like cross-sectional shape. 
     
     
         5 . The construction method for a new underground structure according to  claim 3 , wherein the first formwork body and the second formwork body are formwork panels formed by bending and cutting a plate-like steel material into a substantially rectangular front shape and a substantially angular-wave-like cross-sectional shape.