METHOD FOR FORMING OPENING IN CONCRETE BODY

PROBLEM TO BE SOLVED: To economically form an opening by cutting and forming right and left side face cutting lines of an opening forming scheduled position by a wire saw, forming lateral and longitudinal core boring holes there, inserting and comminuting a cylinder head of a hydraulic comminutor in the hole, and dividing a concrete body. SOLUTION: Right and left longitudinal sectional surfaces of an opening 12 forming scheduled position are cut by a wire saw, and side face cutting lines 16 for partitioning both the side faces of the opening 12 are formed. Then, core boring holes 20 made of first to eighth lateral core boring holes 20H1 to 20H8 and first to tenth core boring holes 20V1 to 20V10 are formed. Cylinder heads of a hydraulic comminutor are respectively installed in the holes 20H1, 20H2, and operated to form a first crossing cutting line H1. Then, the head is installed in the hole 20V1 to form a first longitudinal cutting line V1. A block is then divided and removed. Similarly, the above operations are executed.