Semi open cut type tunnel construction method at low overburden

摘要

According to the present invention, in the tunnel by the semi-opening construction of the low toffee section, the bottom surface 10B of the upper excavation line 10 is cut to the stable ground layer, and the bottom surface 10B of the upper excavation line 10 On both sides of the first step of forming a plurality of a plurality of perforations (20) facing the center line in the longitudinal direction of the tunnel; The support portion 32a of the first reinforcement member 30a, which is formed in a semi-arch shape, is inserted into the perforation 20; 20a on one side formed in the bottom surface 10B of the upper excavation line 10 and partially perforated 20 A second step supported against; The support portion 32b of the second reinforcement member 30b, which is formed in a semi-arch shape, is inserted into the other side of the perforation 20; 20b formed on the bottom surface 10B of the upper excavation line 10 and partially perforated 20 A third step supported against; And a first flange portion 34a formed at the half-arch end of the first reinforcement member 30a and a second flange portion 34b formed at the half-arch end of the second reinforcement member 30b facing each other to fasten the member. Provided is a low-top semi-open tunnel construction method with improved construction and work safety, including a fourth step coupled by.