Pile foundation and method of contructing pile foundation

Abstract

The present invention relates to a pile foundation includes: a pile that extends in a vertical direction and that supports a tower structure, a pile head protruding above the ground, and a lower end of the pile being open; and a ground improving body that, in a state in which the pile has been driven into the ground, is provided inside the pile, and at least a part of the ground improving body being in close contact with an inner peripheral surface of the pile.

1 . A pile foundation comprising:
 a pile that extends in a vertical direction and that supports a tower structure, a pile head protruding above the ground, and a lower end of the pile being open; and   a ground improving body that, in a state in which the pile has been driven into the ground, is provided inside the pile, and at least a part of the ground improving body being in close contact with an inner peripheral surface of the pile.   
     
     
         2 . The pile foundation according to  claim 1 , wherein:
 sediment has entered inside the pile; and   the ground improving body is provided between the inner peripheral surface of the pile and the sediment.   
     
     
         3 . The pile foundation according to  claim 2 , wherein the ground improving body is provided in a plurality of locations, with spaces therebetween, along the inner peripheral surface of the pile in a cross-sectional view of the pile as viewed from an axial direction of the pile. 
     
     
         4 . The pile foundation according to  claim 2 , wherein the ground improving body is formed only in a part, in an axial direction of the pile, of the sediment that has entered inside the pile. 
     
     
         5 . The pile foundation according to  claim 1 , wherein the ground improving body is provided in an entire area inside the pile in a cross-sectional view of the pile as viewed from an axial direction of the pile. 
     
     
         6 . The pile foundation according to  claim 1 , wherein a support member is provided at the inner peripheral surface of the pile, in a vicinity of the pile head, the support member supporting the ground improving body from above. 
     
     
         7 . A pile foundation comprising:
 a pile that extends in a vertical direction and that supports a tower structure, a pile head protruding above the ground, and a lower end of the pile being open; and   a support member that is provided at an inner peripheral surface of the pile, in a vicinity of the pile head, the support member supporting, from above, at least a part of sediment that has entered inside the pile.   
     
     
         8 . The pile foundation according to  claim 7 , wherein the support member is a ring-shaped flange that extends toward a radial direction inner side from the inner peripheral surface of the pile. 
     
     
         9 . The pile foundation according to  claim 7 , wherein the support member is a disk-shaped member that blocks a lower end portion of the pile head. 
     
     
         10 . The pile foundation according to  claim 7 , wherein a filler is filled between the support member and the sediment that has entered inside the pile. 
     
     
         11 . The pile foundation according to  claim 1 , wherein a floor slab is provided at the ground, and the floor slab is fixed to the pile head and transmits a force acting on the pile to the ground. 
     
     
         12 . The pile foundation according to  claim 1 , wherein the tower structure constitutes a leg portion of a wind power generating device. 
     
     
         13 . A method of constructing a pile foundation, the method comprising:
 a process of driving a pile into the ground, a lower end of the pile being open, such that a pile head protrudes above the ground; and   a process of ground improving, of sediment that has entered inside the pile, at least a part of sediment that is in a vicinity of an inner peripheral surface of the pile.