Construction method of large section underground space, outer shell start base

摘要

Provided is a large cross-section underground space constructing method comprising: a step for constructing, in a surrounding area of a main shield tunnel (11) and a ramp shield tunnel (12), two circumferential shield tunnels (10A), (10B) each having a circular cross section along a circumferential direction E such that the circumferential shield tunnels (10A), (10B) are in parallel with each other with a gap interposed therebetween; a step for constructing a plurality of connecting galleries (102) along the circumferential direction E with a gap interposed therebetween, the connecting galleries (102) connecting the adjacent circumferential shield tunnels (10A), (10B) to each other; and a step for drilling a plurality of outer shell shield tunnels (13) by using, as an underground starting base (15), the plurality of circumferential shield tunnels (10A), (10B) and the plurality of connecting galleries (102).