Abstract: The present invention aims to provide apparatus and method for determining non-circular figure to drill boring holes having a regular N-polygonal cross sections while retaining the advantage of the turning operation. For boring a boring hole (H) with a cross-sectional shape of a regular N-polygon having vertexes of N in number, a boring tool (T) having a cross-sectional shape of a regular (N?1)-polygon which is inscribed on the regular N-polygon of the boring hole is driven to rotate at a certain rotational speed around its center (G) and revolve at a certain revolving speed along a circle (R) which is concentric to the boring hole center (0) and has a certain radius. The boring tool (T) may be replaced with a jet of fluid. A boring tool (T) with a regular (N+1)-polygonal contour may be used instead.

Abstract: An apparatus for forming a pile having a predetermined pile diameter in a cast-in-place pile includes an agitating apparatus. The agitating apparatus includes a pipe having a longitudinal axis which extends into the ground, and two nozzles are respectively disposed on and supported on the pipe. Each of the plurality of nozzles produces a directional jet flow of liquid. Additionally, an arrangement is provided for supplying liquid under pressure to the two nozzles. The two nozzles are spaced apart a predetermined distance along the longitudinal axis of the pipe, and are oriented such that fluid flow from the two nozzles intersects at a predetermined radial distance from the pipe, so that a cross jet flow is established at the predetermined radial distance to establish an outermost mixing of hardener and settable mixture. A final hardened pile diameter forms at the predetermined radial distance.

Abstract: An apparatus for forming a pile produces a predetermined pile diameter in a cast-in-place pile. The apparatus includes an agitating arrangement which includes a pipe extending longitudinally into the ground, a plurality of agitating blades supported by the pipe for agitating a settable mixture, and a plurality of nozzles respectively disposed on and supported by respective ones of the agitating blades. Each of the plurality of nozzles produces a directional jet flow of liquid. Also, an arrangement is provided for supplying liquid under pressure to each of the plurality of nozzles.

Abstract: The present invention relates to a consolidating agent injecting apparatus having a nozzle mounted at the end of a pipe. The apparatus is inserted in a guide hole formed in the ground and the nozzle injects a high pressure jet liquid in a radial direction. The injecting direction of the nozzle is downwardly inclined from the horizontal direction within a range from 15 to 45 degrees. The present invention also relates to a ground improving injecting apparatus having first and second nozzles, mounted at the end of a pipe, for injecting a high pressure liquid and a ground improving injection liquid. The first nozzle comprises a plurality of annularly-arranged nozzles. The pipe is inserted into a hole dug in the ground and the high pressure liquid and the ground improving injection liquid are injected from the first and second nozzles.

Abstract: The present invention relates to a method for improving the ground of a large area. The method comprises the steps of inserting a pipe into a hole previously dug in the ground, injecting a high pressure liquid and a ground improving injection liquid from an injecting apparatus attached to the tip of the pipe, drawing up the pipe, grouting the ground, and injecting the ground improving injection liquid to thereby form an underground columnar consolidation body for improving the ground. The drawing-up operation of the pipe is executed while applying vertical vibration to the pipe. Thus, a consolidation body of a large area for improvement of the ground is obtained without concave and convex portions.

Abstract: The present invention relates to a method for improving the ground of a large area. The method comprises the steps of inserting a pipe into a hole previously dug in the ground, injecting a high pressure liquid and a ground improving injection liquid from an injecting apparatus attached to the tip of the pipe, drawing up the pipe, grouting the ground, and injecting the ground improving injection liquid to thereby form an underground columnar consolidation body for improving the ground. The drawing-up operation of the pipe is executed while applying vertical vibration to the pipe. Thus, a consolidation body of a large area for improvement of the ground is obtained without concave and convex portions.

Abstract: A method of reusing a slurry in a ground improving method, wherein a hardening agent is injected into the ground, and wherein the muddy water (i.e., the slurry which is discharged) upon working is regenerated and again used as an injection material; namely, a hardening agent. By measuring the physical amount indicative of the permeability characteristic of the hardening agent contained in the slurry, an amount of hardening agent contained in the collected slurry (i.e., an amount of hardening agent to be collected) is calculated. Since the amount of collected hardening agent is calculated simultaneously with the collection of the slurry, the amount of hardening agent to be newly injected can be controlled in a real-time manner on the basis of the latest data (i.e., numerical value).

Abstract: The present invention relates to a multi-shaft kneading auger system having a plurality of kneading shafts or rotating shafts used to form a continuous wall in the ground. Grouting blades driven by chains, are positioned near the lower ends of the kneading shafts. A grouting edge of the blade forms a predetermined angle with the surface of the kneading shafts. Also, a scraping apparatus is formed in a part of the rotating shafts. The scraping apparatus comprises a supporting member laterally supported in the part of the rotating shafts, plain blades vertically movably supported on the supporting member and substantially located on common tangential lines of the rotational surfaces of the grouting blades, a coupling member including rollers and laterally coupling the plain blades, and cams provided in the part of the rotating shafts and adapted to engage with the rollers.

Abstract: The present invention relates to a method of improving the ground of a large section area. A double pipe, having a first nozzle directed in the lateral direction and a second nozzle surrounding the first nozzle, is inserted into a hole dug in the ground. A ground improving agent is injected at high pressure from the first nozzle through one pipe of the double pipe. A reproduced slurry, obtained by reproducing grouted slimes, is injected from the second nozzle through the other pipe of the double pipe at a lower pressure than the pressure of the ground improving agent. While rotating, the double pipe is lifted up from under ground. The ground improving agent, injected at the high pressure, is surrounded by the reproduced slurry injected at the lower pressure. The frictional resistance between the ground improving agent and the sediments is reduced, the arrival distance of the ground improving agent is increased, and the abrasive effect is obtained.