ELEMENT INSERTION METHOD, UNDERGROUND STRUCTURE CONSTRUCTION METHOD, AUXILIARY COVER, TAPER ELEMENT, AND UNDERGROUND STRUCTURE

摘要

PROBLEM TO BE SOLVED: To provide an element insertion method, underground structure construction method, auxiliary cover, taper element, and underground structure, capable of efficiently and safely constructing an underground structure whose structure section varies gradually in the axial direction.;SOLUTION: An element insertion method for inserting connection joints 11 into natural ground 400 while connecting the connection joints in a connection direction X includes: constitution using a taper element 10a having its element width 10W gradually varying in the connection direction X from an end on the insertion direction tip side La (element tip width 10Wa) to an end on the insertion direction base end side Lb (element base end width 10Wb); arrangement, on the tip in the insertion direction L, of the taper element 10a to which an auxiliary cover 30 is detachably attached on the connection direction front side Xa, the auxiliary cover having a cover width 30W corresponding to a difference from the wider element tip width 10Wa; and insertion while drilling the natural ground 400 using a cutting edge 20 having a width corresponding to the wider element tip width 10Wa.;SELECTED DRAWING: Figure 6;COPYRIGHT: (C)2018,JPO&INPIT