Abstract: A gelling agent is added to a fast setting cement slurry comprising water, cement and anti-washout retarder and the mix is injected into a void containing running water and allowed to set to form rapidly a material of high compressive strength.

Abstract: A method and apparatus for forming a subsurface zone having an increased bearing capacity in a preselected area of relatively soft soil is disclosed. A liquefaction generator is provided in the form of a plurality of interconnected perforated pipes forming a grid pattern which substantially extends over the preselected area. Air and water under pressure are supplied to the liquefaction generator while allowing it to sink within the soft soil to a subterranean layer of hard soil or rock. The air and water are continually supplied to the generator until the soil above it is in a state of liquefaction and thereafter a hardenable material and/or rock fragments are added to the liquified soft soil above the generator. Thereafter, the mixed soil and added material is allowed to solidify over a period of time. For sites containing areas of compacted material, cutters may be attached to pipes of the liquefaction generator to further break up the soil material.

Abstract: A ground hardening material injector comprises a monitor connected to the top of an injection pipe, which monitor includes an upper injection means disposed in the side wall of the monitor and a lower injection means disposed in the opposite side wall of the monitor. The upper injection means further includes an inner injection nozzle for injecting compressed liquid and an outer injection nozzle for injecting compressed gas, and the lower injection means further includes an inner injection nozzle for injecting compressed ground hardening material and an outer injection nozzle for injecting compressed gas.

Abstract: A system for filling a spatial volume below the earth's surfaces with a dry fill material by supplying the dry fill to a borehole at the surfaces, the fill falling generally vertically through the borehole so as to exit vertically at an exit thereof into the spatial volume. An ejector is positioned below the exit and provides a high velocity air stream which intercepts the dry fill as it exits from the borehole so as to direct the fill in a generally horizontal direction away from the borehole into the spatial volume.

Abstract: A method of modifying the structural integrity of material in a subterranean earth situs. The method comprises the steps of mechanically digging into the situs to break the material into pieces and, simultaneously, hydraulically admixing a modifying agent with the pieces by introducing the modifying agent into the pieces at a velocity in the range of from about 300 ft./sec. to about 2500 ft./sec. The method is particularly suitable for improving the strengh and load-bearing capacity of material in a subterranean earth situs. Also provided is a method of modifying the stuctural integrity of material in a subterranean earth situs and installing a pre-formed structural element therein.

Abstract: A method of grouting fine-grained soil mediums is presented that uses an injection process operating at low constant pressure. The process provides for deep penetration of fine sands by injecting a dilute suspension grout composition comprising water and cementatious particles. The grout composition is characterized by a water to cementatious particles ratio of at least 4:1 by weight.

Abstract: The present invention is directed to in situ structural diaphragm walls and methods for constructing such walls. The structural diaphragm walls of the present invention are comprised of a series of small and large-diameter soilcrete columns configured such that the small-diameter columns alternate with the large-diameter columns. A structural member, such as a steel I-beam, is placed within each of the small-diameter columns or within each of the large diameter columns, depending on the structural requirements of the resulting diaphragm wall.The structural diaphragm wall is capable of withstanding the lateral forces which may be imposed by soil or water. Thus, the wall is ideally suited for construction applications when ground water must be restrained or when soil adjacent an excavation site is in danger of crumbling because of the loss of the lateral support which existed prior to excavation.

Abstract: A process for attaching an injection pipe with injection valve means to the inside wall of a tubular pile section comprising: drilling holes at a plurality of points along a generatrix of the pile section said holes passing through the wall of the pile; preparing an injection pipe having substantially the same length as the section of the pile to which it is to be attached; connecting said injection pipe with injection valve to said pipe, the spacings between said valve means corresponding to those of the said holes drilled in the wall of the pipe; engaging said injection pipe in the interior of the pile while positioning the injection valve means into said holes drilled in the pile; and welding said valve means to the wall of the pile from the exterior of the pile.

Abstract: The present invention is directed to side cutting blades for use with multi-shaft auger machines which mix soil with a chemical hardener in situ to form soilcrete columns. The side cutting blades includes two parallel blades which cut the soil between the adjacent columns along planes approximately tangential to the periphery of adjacent columns. As the soil is cut by the cutting blades, the soil is thoroughly mixed with a chemical hardening agent. Adjacent soilcrete columns are integrally connected by substantial column overlap without physically moving the columns closer together or performing multiple borings on the soil adjacent to the columns formed by the initial boring.The side cutting blades are particularly suited for use with a multi-shaft auger machine which has minimal column overlap.

Abstract: A method of injecting a hardenable mass into cracks in a structure includes drilling a borehole into the structure traversing the cracks. Inserting a tubular member into the borehole with the tubular member having an outside diameter smaller than the diameter of the borehole. Filling the gap between the borehole surface and the tubular member with a hardenable mass forming a seal of the gap at the opening into the borehole. After the seal has hardened, injecting a hardenable mass into the tubular member so that it flows into the borehole and enters into the cracks in the structure.

Abstract: This invention relates to a multi-rods type of ground improvement apparatus to be used in ground improvement work. There are provided plural rods in parallel, excavation blades are mounted to the ends of the rods, the rods are provided with injection openings for a solidifying agent, and at least one link arm is loosely mounted to connect the rods. Between the excavating blades and lowest positioned agitating blades, a still or stationary corotating prevention wing is loosely mounted and both ends of the wing are extended so as to be aligned with ends of the excavation blades positioned at opposite sides of the plural rods.Clods dug by the excavation blades are fully crushed between the rotating excavation blades and the still or stationary corotation prevention wing and well mixed with the solidifying agent.Further, by providing screw type of pilot heads at the ends of the rods, advancing of the rods into the ground is improved when the ground is excavated.

Abstract: The invention relates to a process for the reinforcement of anchoring pilings used particularly in the oil-drilling industry, where a tubular steel piling (1) is driven into the ocean floor. Successive injections of a grout which can harden are made into the ground (7) which is contained inside the piling.

Abstract: The invention relates to the formation of ground areas consisting of a three-dimensional mixture of textile threads and a granular material. According to the invention, the portable machine provided for this purpose comprises a tube provided with a handle and ending in a head equipped with ejectors, each of which has an ejection nozzle fed with threads and receiving a supply of pressurized fluid intended to spray the threads onto the ground area, said ejectors being disposed on a distributor bar on which they are oscillatably mounted. Means may in addition be provided to control the frequency and the oscillation amplitude of the ejectors and also the ejection speed of the threads. The invention is applicable to the construction of reinforced ground structures.

Abstract: The present invention is directed to side cutting blades for use with multi-shaft auger machines which mix soil with a chemical hardener in situ to form soilcrete columns. The side cutting blades includes two parallel blades which cut the soil between the adjacent columns along planes approximately tangential to the periphery of adjacent columns. As the soil is cut by the cutting blades, the soil is thoroughly mixed with a chemical hardening agent. Adjacent soilcrete columns are integrally connected by substantial column overlap without physically moving the columns closer together to performing multiple borings on the soil adjacent to the columns formed by the initial boring.The side cutting blades are particularly suited for use with a multi-shaft auger machine which has minimal column overlap.

Abstract: In a simple method of filling a wide crack in an exposed surface of an artificial or natural structures, a rigid plate is positioned on the surface, which plate has on the surface of the plate nearer the surface of the structure three enclosures each bounded by an upstanding wall of compressible material. Two of the enclosures (vacuum enclosures) each has an outlet port passing through the plate and one of the enclosures (the injection enclosure) positioned between the vacuum enclosures has two injection nipples passing through the plate. The plate is so positioned on the surface of the structure that the injection enclosure overlies the crack. Air is evacuated through the outlet ports from the vacuum enclosures to cause the rigid plate to be sucked tightly against the surface of the structure and hardenable material in a semi-liquid state is pressure injected through the injection nipples into the injection enclosure until the crack is filled.

Abstract: Method of treating subsurface layers of the earth for controlling movement of subsurface water and building strength of the subsurface layers characterized by injecting at a plurality of predetermined depths and at a plurality of predetermined spaced-apart locations a lime-fly ash slurry consisting essentially of water, particulate hydrated lime and particulate fly ash; the particulate lime and fly ash being present as particulate solids and a proportion of from twenty-five percent by weight of the water to as much as two hundred percent by weight of the water when employed along. The particulate solids comprise lime and fly ash in proportions ranging from three parts lime to one part fly ash to one part lime to ten parts fly ash. The injection is carried out by pumping the slurry of one of the particulate solids and water through a jet slurry mixing apparatus for aspirating in the other dry particulate solid. Preferably the fly ash will be aspirated into a slurry of the lime in water.

Abstract: A grouting rod is formed with a first channel, a second channel (or channels) surrounding the first channel and a third channel which is normally in communication with the first channel. A piston valve is vertically movably received in an upper portion of the third channel. When the piston valve is raised, upper lateral communication holes and upper discharge holes which are formed in the upper peripheral wall of the third channel are closed by the piston valve and concurrently the second channels are permitted to communicate with a lower portion of the third channel through lower lateral communication holes also formed in the upper peripheral wall of the third channel. When the piston valve is lowered, the upper lateral communication holes and upper discharge holes are opened and concurrently the second channel(or channels) is prevented from communicating with the lower portion of the third channel through the lower lateral communication holes.

Abstract: Hazardous wastes are identified and treated in situ by forming a downwardly extending zone of particles in the waste. Toxic components in the waste are identified by injection of a pressurized fluid into the zone and capturing a sample of gases rising to the surface of the waste. At least one treatment agent is injected into the zone as appropriate until sampling indicates the particles of waste have been treated to a desired degree.

Abstract: A system for preparing a ground impregnating material which comprises a line for feeding a base liquid component of the ground impregnating material, such as an aqueous sodium silicate solution, and a high pressure carbon dioxide gas bomb connected via a carbon dioxide gas delivery line to the base liquid component feed line. The carbon dioxide gas delivery line has a carbon dioxide blowing nozzle provided therein. The carbon dioxide gas blowing nozzle comprises a disk centrally perforated with a nozzle bore. A plurality of the carbon dioxide gas blowing nozzles having different opening diameters may be switchably provided in parallel in the carbon dioxide gas delivery line.

Abstract: In a chemical liquid injector mainly for use in filling with a chemical liquid cracks developed in a wall of a concrete building and a gap between the wall and the underlying concrete body, an air-escape groove is provided in the interior surface of the injector casing. While in use a mouthpiece is attached to a nozzle of the injector.

Abstract: The invention involves the selective emplacement of an impermeable polymeric barrier in the semi-permeable substructure, faulted or fractured geologic barriers which underlie leaking waste disposal sites. The emplacement of the barrier requires the creation of a horizontal fracture below the waste disposal site and the injection of a gellable solution containing a synthetic or biologically produced polymer into the fracture. The solution is then allowed or caused to gel in situ within the subterranean formation.A proppant may be dispersed in the gellable solution. The proppant may be a waste active material.

Abstract: Process and apparatus for consolidating, sealing and stabilizing a predeterminable area in the ground, particularly for making foundations, underpinnings or seals in a building site, by injecting at least one hardening liquid material in a high energy liquid jet into the ground, accompanied by the simultaneous injection of a gaseous material, characterized in that for the injection of the gaseous material, at least one discrete gas jet is formed and injected separately from the liquid jet and is located in the vicinity of the exit port of the liquid jet and guided at a distance from the liquid jet.

Abstract: An apparatus (U) is shown in FIGS. 11-13 that includes a power operated vehicle (V) that supports a vertically movable frame (W) that has a confined space defining shroud (X) on the lower end thereof that may be placed in sealing contact with the upper surface of a hazardous waste impoundment (Y) at a first station to permit the insitu detoxification of a desired portion of the impoundment. At least one power driven blade (Z) is rotated downwardly from within the shroud (X) into the impoundment to form a vertically extending zone (A-1) of particled material that is treated with a detoxifying agent that may be chemical, biological or heat from one or more plasma torches. Gases emitted during the formation of the particled zone (A-1) are subjected to scrub action by a liquid within shroud (X) and the liquid returned to zone (A-1). After the detoxification of a zone has been completed the apparatus (U) is moved to a succession of overlapping second stations where the above described method is repeated.

Abstract: A rock bolt system (10) including a mechanical rock bolt (12) having an interior channel (24) therein and a feeder attachment (14). An anchor may be affixed to the distal end of the rock bolt (12). An aperture (22) extends from the rock bolt (12). The feeder attachment (14), capable of being demountably affixed to the proximal end of the rock bolt (12), supplies hardenable material to the interior channel (24) where it courses through the interior of the rock bolt (12) and exits into the bore hole (16) through the aperture (22). A breather tube (38) extending from the feeder apparatus and into the interior channel (24) permits entrapped air to escape.

Abstract: A method of feeding concrete into a drill hole in the concrete bolting of a rock, in which method a feeding hose is pushed into the hole and concrete is pumped into the hole through the feeding hose at the same time as the hose is drawn outwards within the hole. In order to ensure that the hole is filled properly, the amount of concrete pumped into the feeding hose for the distance the feeding hose is withdrawn, is greater than the concrete amount theoretically sufficient for filling an unbroken hole with concrete when the hose is withdrawn that distance. A device designed for the realization of the method comprises a primary pump which pumps concrete into a piston-type metering pump which in turn pumps the metered amount of concrete into the feeding hose in proportion as the feeding hose is withdrawn.

Abstract: Process using a ground anchor (1) with a longitudinal hole (7), on which is fitted an interface device (12) comprising a cylinder containing a chamber connected to the said hole (7); a grout is pumped under pressure to the tip (6) of the hole in the ground; the cylinder is struck mechanically, and transmits the mechanical shock wave to the ground anchor. The grout injected is a liquid mix (L); the grout is injected by means of a pump (21) at a pressure greater than 20 MPa; the grouting pressure is sufficient to fragment the ground by means of the injected grout, and the cylinder is struck by a percussion/vibration hammer (2) at a frequency greater than 10 Hz.

Abstract: An improved grout impregnation method which uses an injection tube for contacting and mixing different kinds of materials supplied thereinto separately to prepare a grout and impregnates the grout into the earth through an injecting opening provided at a tip end of the tube.

Abstract: A non-return valve for bore hole sleeves, which are intended for injection of a sealing and/or reinforcing compound into rock cracks and similar cracks and which comprise a rigid case (10), one end (10A) of which is provided with means for detachable connection to the case of a pump hose (12) for the compound to be injected, as well as an expandable device (15) for securing the rigid case in the bore hole (21), comprises an elastic sleeve (22) which is adapted at the other end (10B) of the rigid case (10) in such a way that the rigid case (10) runs into the elastic sleeve (22). The elastic sleeve is adapted for automatical contraction, when no compound is being injected through the elastic sleeve, so that already injected compound can not flow backwards into the rigid case (10). The sleeve (22) is preferably provided with diametrically positioned clamp means (23-26) at its free ends, so that the free end of the sleeve has a flat shape, when no compound is being injected through the elastic sleeve.

Abstract: A device for storing a concrete feeding hose in a rock bolting device, comprising a reel for a hose, which reel is mounted rotatably on a supporter, and that end of the hose which is attached to the reel is connected to concrete feeding means. In order that the coiling device could be used for passing the hose into a drill hole and for drawing it out of the hole, the reel is surrounded by a ring-shaped supporting wall against which the hose is positioned when the reel is rotated in the uncoiling direction. An unrotative guiding means is provided beside the supporting wall so as to guide the hose out of the reel by the action of an axial expulsive force exerted on the hose due to the rotary movement of the reel.

Abstract: The invention relates to a method and a device for guiding a concrete feeding hose in connection with the grout feedin rock bolting. The concrete feeding hose is therein passed by means of a feeder froma reel into a guide head supported on a feeding beam of a drilling equipment and further through the guide head into a hole drilled in the rock, and is passed back on to the reel in proportion as the hole is filled. In order to protect the feeder of the concrete feeding hose against dirt and mechanical damage, the concrete feeding hose is pushed into the guide head through a flexible guiding means.

Abstract: The nozzle structure for a root feeding device includes a ground inserting tube or pipe having a nozzle unit at the end thereof formed with an axially extended bore and radially extended fluid discharge passages intermediate the ends thereof. The nozzle unit is generally comprised of a pair of coaxially aligned cone sections with the outer cone section of a reduced size and the outlets of the radial passages positioned between the adjacent ends of the cone sections. The fluid discharged from the outer end of the axial bore acts to pre-soften or lubricate the soil for hard ground penetration; and the fluid from the radial passages assists penetration and is discharged into a receiving chamber formed about the nozzle unit, when in the soil, for ground dispersion annularly about the nozzle unit.

Abstract: A method and apparatus for anchoring rock bolts and cables in drill holes is disclosed. The method of the invention comprises mixing a dry aggregate-cement mixture with a limited, predetermined amount of water in a water fitting and blowing the wetted cementitious mixture through a delivery tube into a drill hole, in which an anchor cable or rock bolt has been inserted, resulting in the cable or bolt becoming permanently anchored in the drill hole. The use of a wetted dry cementitious mixture eliminates leakage of mixture from the drill hole and obviates the use of a plug, cover or collar plate.The equipement includes a pressurized, dry mix delivery vessel, a source of pressurized air, a water fitting for wetting dry mix with water and a delivery tube for delivery of the wetted dry mix into the drill hole.

Abstract: Rotatable fill pipe for use in blind-filling underground voids has a collapsible backfill elbow on the lower end thereof, including an upper elbow part rigidly connected to the lower end of the fill pipe and a lower elbow part pivotally connected to the upper elbow part for pivotal movement between a lower position in coaxial alignment with the fill pipe to facilitate passage of the backfill elbow and lower end of the fill pipe through a fill hole into an underground void, and a raised position extending at an angle relative to the fill pipe to facilitate distribution of fill material introduced into the underground void through the fill pipe in a circular pile within the underground void as the fill pipe and backfill elbow are rotated about the longitudinal axis of the fill pipe. A cable may be connected to the lower elbow part for remotely actuating the lower elbow part for pivotal movement between the lower and raised positions.

Abstract: The invention relates to civil engineering works.In particular, it relates to a device suitable for forming a primary column of stabilized and compacted soil, which comprises at least two parallel shafts driving in opposite directions, two parallel augers with opposite pitch, each auger being provided at the opposite end to the drive shaft with a loosening drillhead and the distance between the axes of the augers being less than the diameter of an auger, the shafts and the shanks of the augers comprising a bore connected to a source of material to be added, and at least one orifice which communicates with the said bore being provided on the shank of each auger so as to discharge the material to be added and allow it to be mixed with the loosened soil.Applicable in particular for the compaction of railroad territory.

Abstract: A method and device for properly mixing stabilizing chemicals into earthen formations. A helical blade of one or more convolutions is attached to a hollow torque tube and rotated down into the soil. As the device is rotated through the soil to be stabilized, chemicals are pumped down the torque tube, out the device, and then mixed into a soil column by the rotating action of the device.

Abstract: A solidification apparatus in the form of a rack and prongs rake structure, the prongs of which are a multiplicity of hollow tubes, each tube containing a serrated augar for providing augar assisted feeding of a gaseous suspension of cementing solids through the hollow tubes into the liquid, the rack supporting each hollow tube tine being pivotally attached to the arm of a backhoe so that the backhoe operator can generate lateral, pivotal and longitudinal movement of the tubes in the liquid while the gaseous suspension is being added to the liquid, a guard ring being provided at the open end of each tube for preventing submersion of the tube ends into the bed underlying the liquid of the encatchment.

Abstract: An impulse injector apparatus operates to produce pulsed delivery of injected material, with the material moving during a delivery pulse at high velocity and under the urging of a compressed captured gas supply which is permitted to rapidly expand. The device includes an elongate cylinder and an actuating piston mounted for reciprocal movement within the cylinder. A captured compressible gas supply is located within a chamber which is defined between one end of the piston and one extremity of the cylinder. Another chamber is defined between the opposite end of the piston and the opposite extremity of the cylinder. A pressurized fluid is controllably admitted into the other chamber, thereby causing movement of the actuating cylinder towards the one extremity of the cylinder and resulting in compression of the captured gas supply.

Abstract: A foundation improvement process comprising providing a first nozzle, a third nozzle, and a second nozzle opened up encircling the first nozzle at the side wall of a lower portion of an injection rod, at the same time providing a diffusion nozzle at an intermediate portion between the first and third nozzles, forming a curtain with a high pressure water jetting from this diffusion nozzle, providing a partition wall between hardening agent jetting from the third nozzle and an air lift portion by means of a fresh water and air jetting from the first and second nozzles by using this water curtain, thereby preventing the raising of the injected hardening agent for performing a sure improvement of a foundation, and at the same time preventing waste of the hardening agent.

Abstract: Soft soil stratum is stabilized by jetting powdery agent into the ground and mixing and agitating the same with the soil, wherein a rotary shaft is inserted into the ground and a powdery stabilized agent carried by air is pneumatically transported by way of a transportation tube positioned within the rotary shaft and is jetted out from a nozzle disposed in communication with a blade which is integrally attached to and extended from the bottom end of the shaft, is mixed and is agitated for solidification with the soil by the rotation of the mixing blade, while the carrier air jetted into the ground is induced and discharged to the outside of the ground after separation and filtration. The state of the supply of the powdery stabilized agent is continuously optimally controlled in accordance with a predetermined set condition. The powdery stabilized agent can be transported smoothly and mixed with the soil uniformly to provide satisfactory soil stabilization, without repair and maintenance problems.

Abstract: A rockbolt for installation in a bore in the roof of an underground excavation, such as a tunnel or mine, to support the roof, comprises a sleeve having a closed top and ports in its upper end, a plunger slideably mounted in the sleeve, and hardenable binder material encapsulated in burstable cartridges in the sleeve above the plunger. The rockbolt is inserted into the bore and the plunger is operated either mechanically or by the application of pressurized fluid to the plunger, to extrude the binder material to secure the rockbolt in the bore. A mechanical anchor can be provided on the top of the sleeve so the rockbolt can be tensioned before the binder sets. Alternatively, faster setting binder can be provided in the sleeve below the balance of the binder so that it is the last to be extruded and remains near the top to secure the top to the surrounding rock before the balance of the binder sets so that the rockbolt can be tensioned before the balance of the binder sets.

Abstract: A method of filling voids underneath the lower surface of a structure placed upon the ocean floor, using a sandjet stinger conduit inserted through the structure to carry a water and sand suspension to the base of the structure.

Abstract: A method of lifting and stabilizing a concrete slab having an opening therein in which a plate is attached to the top surface of the slab, the plate having an opening coinciding with the opening in the slab, a hydraulic jack having a downwardly extending piston is removeably secured to the plate and a series of tubular shafts are forced downwardly through the opening in the plate and the slab to penetrate the earth beneath the slab and apply lifting force. When the slab has been lifted to the desired elevation, grout, such as a concrete slurry, can be injected below the slab so that the slab is stabilized in the selected elevational position. After the plate is removed the hole in the slab is filled.

Abstract: A method for performing rock bolting, according to which a cementing agent is fed into a hole drilled into the rock, whereupon a bolt is fitted into the drill hole for supporting the rock. In order to permit use of a rapidly hardening cementing agent and mechanization of the bolting, a number of capsules (16) are fed to the bottom of the drill hole, which capsules contain a preferably two-component cementing agent which hardens rapidly when the components are mixed together, and a conventional cementing agent (12) hardening slowly and/or protecting the bolt against corrosion is fed into the remaining portion of the drill hole by means of a feeding pipe (5).

Abstract: An automatic ground softening apparatus for crushing underground earth layer into pieces by blowing out compressed air from tips of air nozzle pipes driven deep into the ground at several positions at a time, is mounted on the load-carrying platform of a truck. The automatic ground softening apparatus includes a plurality of piston-cylinder assemblies mounted on the truck's load-carrying platform at different positions thereof. The air nozzle pipes each depend from the lower end of the piston rod of each of the piston-cylinder assemblies. Some or all of the piston-cylinder assemblies are operable through centralized control by operating an operating panel provided aside a driver's seat in the truck. The depth of driving of each air nozzle pipe driven by each piston-cylinder assembly into the ground and the pressure of compressed air jet from the tip nozzle of the air nozzle pipe into the earth can be set to desired values by operating the operating panel.

Abstract: An automotive aerator includes a tractor or the like and an aerator carried movable vertically by the tractor or the like. A landing sensor for the detection of the spike pipe of the aerator, a device for driving the spike pipe into soil, and a depth sensor for detecting that the spike pipe has been driven to a predetermined depth in soil are provided so that actuation of the spike pipe driving device is preferably started when the spike pipe engages the surface of the ground and is stopped when the spike pipe reaches the predetermined depth.

Abstract: The present invention provides a method of improving soft ground.In this method, slurry formed by a mixture of cement-based hardener and water is supplied to the soft ground under pressure and is mixed with soft soil thereby to harden the same. Then, at least when a ground improvement machine having mixing propellers is penetrated into the above-mentioned soft soil, the cement-based hardening slurry is discharged from the mixing propellers.Further, in another method of improving soft ground according to the present invention, slurry formed by a mixture of cement-based hardener and water is supplied to the soft ground under pressure and is mixed with soft soil. Then, when deep and short walls, both consisting of mixed layer of the cement-based hardening slurry and the soft soil are formed one after the other, a plurality of deep walls are formed at a distance therebetween and then the short walls are jointly formed between a plurality of these deep walls.

Abstract: A compacting apparatus is provided and includes a material supply line having an upright inlet portion and a transversely disposed lower outlet portion provided with a discharge opening at its discharge end. The lower outlet portion is supplied with high pressure air from an air supply line which includes an outlet end portion disposed coaxially within the lower outlet portion of the material supply line and is provided with a nozzle assembly for directing pressurized jets of air toward the discharge opening.

Abstract: A boring-injection device comprises a fluid supplying hollow rod, a fluid discharge portion at the lower end of the rod, and a packer element inflatable from the rod to seal a space between the rod and a borehole wall at a desired depth position. The rod is surrounded by a sheath so that the packer element and fluid discharge portion can be protruded out of and retracted within the sheath in a body. They are retracted during the boring operation and protruded during injecting or investigating operation. The device can be used for practising a method of ground improvement or a method of ground investigation.

Abstract: A method for improving the ground or foundation by injecting a grouting agent from the tip end of a hollow injection rod inserted into a boring hole formed in the ground at site so as to infiltrate it into the ground to be solidified. The injection is carried out by varying an injection pressure or injection rate depending on the intensity, particularly, the tensile strength, of the ground so that no vein-like coagulation can be formed around the injection rod, and a columnar or spherical coagulation can be formed.

Abstract: A high-pressure packing device for injecting hardenable synthetic resin into cracks in concrete includes a sleeve of plastics to be wedged into a hole drilled in concrete in the region of the crack and an injection needle attached to the sleeve. The outer surface of the sleeve is formed with grooves starting from the front end face of the sleeve and extended axially of the sleeve to permit the synthetic resin injected into the base of the hole through the sleeve to rise along the grooves towards the crack in concrete to seal the crack.