CONNECTION STRUCTURE FOR ADJACENT TUNNELS, LINING PIECE, AND CONNECTION METHOD FOR TUNNEL

PROBLEM TO BE SOLVED: To provide a connection structure between linings capable of easily connecting mutual linings of adjacent tunnels in a sufficient strength, and using it as an earth retaining support structure in common when excavating the tunnel to widen the width between linings. SOLUTION: The natural ground between a plurality of tunnel linings 22 adjacently formed with a specified distance in the underground is excavated and nutual tunnel linings 22 are connected to each other to form a connection structure, in which a plurality of lining pieces 32, 34 having main girders 36, 38 are assembled to form a ring. An anchorage part 66 fixed to the main girder 36 is provided in the lining piece 32 arranged in an estimated connection position of the lining 22 of the tunnel formed to have the ring-shape. Mutual linings 22 are anchored in the anchorage part 66 between the tunnels and connected so as to transmit stresses by connection members 64 between the tunnels constructed astride between the lining pieces 32.