To shorten the construction period through the support of a simple timbering construction by arranging half precast plates having iron reinforcing bars projected on the entire surface of a concrete plate in a state of being faced toward the natural ground of the tunnel.
Half precast concrete plates 1 are ready made articles having a construction where truss iron reinforcing bars are integrally buried in the inner part of a concrete plate, and a part thereof is projected from the surface of the concrete plate. The half precast plates 1 are disposed at constant distances in a state of being faced toward the excavation surface 2 of the tunnel. A stiffening material 3 such as concrete and mortar is filled between the half precast concrete plates 1 and the tunnel excavation surface 2. The iron reinforcing bars of the precast concrete plates 3 are embedded in the stiffening material 3, so that both of them are put together firmly. The concrete is made preferably to have a designing standard strength of 210 kgf/cm2, a slump of 18-23 cm, and a maximum dimension of aggregates of 20 mm or less. Thus, conducting a timbering construction having good durability without a danger of cracks.
Kataoka, Kuniaki
Teramoto, Satoru
Sakamoto, Masanobu
Yasuki, Eiichirou
Goto, Yasuyuki
TAKAMURA KENSETSU KK
NARUTSUKUSU:KK