Abstract: An excavator for constructing an underground continuous wall includes an extensible guide post, an endless chain extending around a chain driving wheel provided at the upper portion of the guide post and a chain sprocket at the lower portion of the guide post, and a number of cutter bits and a number of agitator bars alternately arranged on the chain to form an endless chain cutter and a jet pipe provided in the guide post to be connectable to a fluid supply source and having a number of nozzles branched from the jet pipe. The endless chain cutter is detachably fixed to the end of the boom extending from a vehicle traveling on the ground. The endless chain cutter may be vertically movably mounted on the boom so as to be vertically driven by a driving device. The cutter bits are changeable with harder cutter bits according to obstacles in the ground.

Abstract: An excavator for constructing an underground continuous wall includes a traveling trolley movable on rails and having a sprocket in mesh with a rack extended parallelly to the rails and a hydraulic motor for driving the sprocket. The trolley further includes an upper frame arranged thereon and having a tiltable frame tiltable relative to the upper frame and a saddle provided on the tiltable frame slidable on the tiltable frame in directions substantially perpendicular to the rails. An extensible guide post is provided upward and downward movably relative to the tiltable frame. An endless chain extends around a chain driving wheel provided on the saddle and a chain sprocket provided at the lower end of the guide post, and a number of cutter bits and a number of agitator bars are alternately arranged on the endless chain to form an endless chain cutter. A chain driving device is provided for driving the endless chain.