Abstract: A rock bolt to be inserted into a bore formed in the ground from the inner periphery of a tunnel and anchored to the ground with grout filled in the space in the bore around the bolt to reinforce the ground. The rock bolt has two grooves extending axially thereof and an elastic tubular member fixedly fitting around the bolt close to one end thereof. A tube having an opening close to the other end of the bolt is provided within one of the grooves. Another tube provided in the other groove has an opening close to one end of the tubular member remote from the above-mentioned one end of the bolt. Before the injection of the grout, the rock bolt can be fixed to the ground easily and reliably by pressing the elastic tubular member into the bore. The grout is filled into the space through one of the tubes while displacing air through the other tube.

Abstract: Structure for supporting the excavated wall of a tunnel comprises a plurality of unit pipe support members connected in end-to-end relation by pipe couplings with lap joints, or by flanges on the ends of the support members, to form a plurality of sub-assemblies which are then connected by a closure member to form a pipe support having a periphery substantially conforming to the periphery of the tunnel wall, and having ports through which the pipe support can be filled with mortar or concrete. The unit pipe support members are substantially the same size and shape for mass production from ductile cast iron or cast steel and are provided with integral reinforcing ribs.

Abstract: Slag on the surface of a molten metal is drawn into the inlet end of a suction pipe which is provided with a water cooling jacket having orifices permitting the flow of water to the inlet end of the pipe for pelletizing the entering slag. The suction pipe is connected to a separator hopper, which is evacuated by an exhaust pump to create the suction, and which includes a slag discharge port closed by an openable valve. A sealed auxiliary hopper receives slag from the discharge port of the separator hopper when the valve thereof is opened, and also includes a slag discharge port closed by an openable valve. The hopper discharge valves are operated alternately by suitable control means so that when one valve is open the other is closed, thereby enabling slag to be continuously sucked, separated, and intermittently discharged from the auxiliary hopper.