Abstract: The purpose of the present invention is to provide a determining device and a determining method to determine whether an inspected jet nozzle is defective by inspecting the jet nozzle for injecting a jet stream with long ground penetrating distance at a stage before installing in a construction site where a large diameter jet grouting method is used. To achieve this purpose, with this invention, in which a nozzle to be inspected is mounted onto an outlet port, a jet stream is ejected from a jet stream generating device, and measurement data measured by a pressure sensing unit when the jet stream impacts the pressure sensing unit is processed with a controlling device (for example, a computer), a nozzle to be inspected is determined to be a non-defective product if a first ratio is no less than a first prescribed value, a second ratio is no less than a second prescribed value, and a third ratio is no less than a third prescribed value.

Abstract: The purpose of the present invention is to provide an artificial ground freezing method having good coolant thermal efficiency without a gas-phase coolant being released into the ground or into the air.

Abstract: The purpose of the present invention is to provide an artificial ground freezing method having good coolant thermal efficiency without a gas-phase coolant being released into the ground or into the air.

Abstract: The purpose of the present invention is to provide a determining device and a determining method to determine whether an inspected jet nozzle is defective by inspecting the jet nozzle for injecting a jet stream with long ground penetrating distance at a stage before installing in a construction site where a large diameter jet grouting method is used. To achieve this purpose, with this invention, in which a nozzle to be inspected is mounted onto an outlet port, a jet stream is ejected from a jet stream generating device, and measurement data measured by a pressure sensing unit when the jet stream impacts the pressure sensing unit is processed with a controlling device (for example, a computer), a nozzle to be inspected is determined to be a non-defective product if a first ratio is no less than a first prescribed value, a second ratio is no less than a second prescribed value, and a third ratio is no less than a third prescribed value.

Abstract: A contaminated soil remediation method activates a microorganism in soil contaminated with a toxic chemical substance. The contaminant is decomposed by a biodegradation reaction of the microorganism. The method involves forming a boring hole reaching into contaminated soil. A rod whose end is provided with a jet device is inserted into the boring hole. The contaminated soil is cut in a manner forming a flat-plate area in which the soil is intermittently cut by a microorganism activator, and the soil and the microorganism activator are mixed, by jetting water and/or the microorganism activator from the jet device.

Abstract: Sludge which is supplied from an untreated sludge tank 3 and diluting water from a diluting water supply facility 14 is charged into a continuous kneading mixer 12 for diluting the sludge to make the specific weight of the sludge 1.15 to 1.35. The diluted sludge is supplied to a dehydrating machine 25 in accordance with the capacity of the used dehydrating machine 25. The diluted sludge is firstly added with an inorganic flocculating agent G and is mixed in a first blender 24A and is then added with a high molecular flocculating agent G2 and is mixed in a second blender 24B. Thereafter, the sludge is supplied to a belt press dehydrating machine 25 in which it is subjected to a dehydrating treatment.

Abstract: Sludge which is supplied from an untreated sludge tank 3 and diluting water from a diluting water supply facility 14 is charged into a continuous kneading mixer 12 for diluting the sludge to make the specific weight of the sludge 1.15 to 1.35. The diluted sludge is supplied to a dehydrating machine 25 in accordance with the capacity of the used dehydrating machine 25. The diluted sludge is firstly added with an inorganic flocculating agent G and is mixed in a first blender 24A and is then added with a high molecular flocculating agent G2 and is mixed in a second blender 24B. Thereafter, the sludge is supplied to a belt press dehydrating machine 25 in which it is subjected to a dehydrating treatment.

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: 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.