Abstract: A hydraulic excavator having first and second booms pivoted end to end, plus an arm pivotally connected to a swinging end of the second boom. A bucket is pivotally mounted at the leading end of the arm. A boom operating linkage mechanism including a lever and hydraulic cylinders is mounted on a full-revolving base for swinging the first boom with respect to the base. The arm is adapted to rotate with respect to the second boom and therefore the bucket is capable of providing both back hoe and front loading operations.

Abstract: A paving material extrusion molding apparatus for continuously laying or molding a paving material wherein the paving material supplied into hoppers is conveyed into a molding element by a plurality of screw conveyors, the paving material is compacted or consolidated by screw thrusts equal to the frictional force produced by the dead weight of the extrusion molding apparatus, a reaction force created by the compaction or consolidation is utilized to float off the entire extrusion molding apparatus, and a reaction force created by the conveyance of the paving material being continuously fed serves to move the extrusion molding apparatus along the predetermined path.

Abstract: The paving material supplied into a hopper is conveyed by screw conveyors into a mold provided in the lower part of the apparatus thereby molding and laying the material. The paving material is densely compacted or consolidated in the mold, and when the paving material is conveyed under pressure further, the mold can be pushed up, and the reaction force of the conveying pressure acts to move the entire apparatus horizontally. Thus, structure having the same sectional shape as that of the mold can be formed and laid continuously on the ground.

Abstract: A method of forming a plurality of horizontal barriers in situ at a preselected depth beneath the soil surface and in a plane substantially parallel to the soil surface so as to be coextensive with a desired area, the barriers being made of a thermoplastic material such as asphalt for example, and forming further barriers joined to the horizontal barriers and extending vertically or obliquely toward the soil surface in order to surround the above-mentioned area, thereby improving soil having a poor water retention property. The method further comprises the steps of filling up chambers in a plow moving in the soil with the barrier forming material in the liquid form, leaking the material out of the chambers through passages of a given gap, and spreading the formed film laterally uniform by an ironing portion connected with the plow near the passages so as to render the formed water barrier uniform in thickness and free from apertures.