Classifications

• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
  • E02D3/12—Consolidating by placing solidifying or pore-filling substances in the soil
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
  • E02D5/18—Bulkheads or similar walls made solely of concrete in situ
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
  • E02D5/22—Piles
  • E02D5/34—Concrete or concrete-like piles cast in position ; Apparatus for making same
  • E02D5/46—Concrete or concrete-like piles cast in position ; Apparatus for making same making in situ by forcing bonding agents into gravel fillings or the soil

Definitions

• the present invention relates to a method for control and
• the invention furthermore, relates to an arrangement of the 15 above mentioned jet injection head for carrying out said method, and as stated in the introductory part of the follow ⁇ ing dependent claim 4.
• Jet injection is a method for sealing off and strengthening
• This method involves loosening the soil structure by the aid of a high pressure water beam sur ⁇ rounded by air (jet beam), at the same time as a binder, commonly cement grout, is injected. Said binder will displace the loosened material (slurry) flowing up to the surface.
• a binder commonly cement grout
• Jet injecting can be carried out in all soils the grain
• jet injection finds a large range of application and utilization of this method may be listed in three main areas:
• Strengthening of the soil Injection is carried out beneath existing or new foundations, commonly in the shape of piles.
• Stabilization of soil Temporarily or permanently, often in conenction with building and construction work.
• This method will be especially advantageous in connection with necessary foundation work on older buildings since such work may be carried out in a precise and considerate manner and with a minimum of space needed.
• rapidly curing cement may be used.
• cement may be mixed with bentonite.
• Panels with a thickness from 5 ti 10 cm in cohesive soils, and from 15 to 30 cm in frictional soils.
• ⁇ T to be very irregular and rugged. This is due to local variations of homogeneity and of the compactness of the soil.
• the homogeneity of the injection zone depends on how well the injected agent will mix with the original soil. In frictional soils where there is no adherence between grains, the grainy structure is readily broken down by jet washing, and intimate mixing with the injected agent is achieved. In such material the homogeneity will, thus, normally be good. Pebbles not being thrown up through the pilot hole during jet injection will stay in the injection zone. Larger rocks will not in ⁇ fluence the quality of the injection zone if homogeneity is otherwise satisfactory.
• the homogeneity of the injection zone will be more variable. Especially in soils having a high clay content. Previously, it was not possible to break down the structure of the soil completely by the aid of the jet, and portions of clay would stay intact in the shape of large and small lumps. The lumps not driven up to the surface via the pilot hole will become embedded in the injection zone. * The content of such lumps of clay will reduce the quality of the injection zone, i.e. the final hardened body of binder and broken dowm components from the soil.
• Coring comprises removal of core samples from the injection zone.
• a common diameter is 50 mm and the samples are, as a matter of routine, taken from the centre of the piles and 80 cm outwards from the centre, in all three core samples from each test pile.
• the advantage of this method is that samples are taken from the injection zone for control and further examination. Coring is obviously a complicated and expensive method and, additionally, it is doubtful whether core samples are representative of the quality of the injection zone. Examinations of the strength of jet injected soil should, in fact, be made with the largest possible samples.
• the present invention also provides an arrangement in connect ⁇ ion with a jet injection head for use when the above method is carried out, and said arrangement is achieved by the features appearing from the characterizing part of the following arrangement claim 4 and the following claims.
• Control of the extend of an injection zone across its longi ⁇ tudinal direction is, thus, achieved by the aid of ultrasonic waves.
• an emitter, a re-ordinatever, a digital indicator, a printer, and an electro- acoustic converter provided in said injection head with the water nozzle, and the cement nozzle the extent of the inject ⁇ ion zone may be determined.
• Said electroacoustic converter a so called oscillator
• Said electroacoustic converter will emit ultrasonic signals which are reflected from the wall of said injection zone, and are received by the receiver.
• the velocity of reflection depends on the solidity of the medium in the wall of said injection zone.
• Said signals are process- ed to form a continuous graphic representation of the shape and extent of the pile simultaneously with the running injection operations.
• Jet injection parameters e.g. pressure, water/ cement ratio and lifting velocity of said jet injection head may be adjusted during operations to provide for the prescrib ⁇ ed pile diameter and to avoid variations of homogeneity, e.g. "lenses", lumps, etc. in the produced jet pile.
• Figure 1 shows a jet injection head with a rod having three passages and a swivel joint with connections for said passages and a display conencted with said injection head
• Figure 2 shows a collar/container surrounding said rod with three passages of said jet injection head, with a mump and a flowmeter
• Figures 3a, b, c show an example of production of jet piles
• Figures 4a,b,c show an example of production of panels (shields) .
• a jet injection head A comp ⁇ rises an uupper nozzle 11 for a jet of water surrounded by air, and a lower nozzle 13 for injection of a curable binder.
• Jet injector head A is provided at the end of a rod 16 having three passages for supply of highpressure water, compressed air, and a curable binder under pressure to said nozzles 11 and 13, respectively.
• emitter/ receiver equipment 12 is provided and is connected with signal processing equipment, and a display 14 via a line 14a.
• Jet injection head A has excavating claws 17 provided in a ring at the lower portion of said head, and having an ex ⁇ ternal ring diameter which is larger than that of the jet injection head A.
• Jet injection head A with rod 16 is placed in a pilot hole P indicated with dotted lines. The lower portion of said hole is enlarged to an injection zone I by jets of water and air from top nozzle 11 during rotation and lifting of said jet injection head A.
• FIG 2 a combined collar and container 4 is shown. It is intended for surrounding rod 16 of jet injection head A at the upper end of pilot hole P for collection of liquid matter flowing up to and out of pilot hole p during- production of injection zone I by jet treatment and simultaneous injection of binder.
• a pump 2 is pro ⁇ vided and is connected with the interior space of container 4 by the aid of a diver 3.
• Pump 2 is, furthermore, provided with a flow meter 1 for measuring the liquid matter conveyed by said pump.
• the liquid matter flowing out of the upper end of pilot hole P can, thus, be measured as regards volume and, if desired, as regards composition as well, for controlling the composit ⁇ ion and volume of material of the carrying or supporting structure K.
• Figure 3a shows drilling of a pilot hole P by the aid of excavating blades 17 of jet injection head A, rod 16 of jet injection head A, which rod may be compared to a drill pipe, being attached to a drill tool feeder 18 on a vehicle 19.
• Said pilot hole e.g. having a diameter of approximately 150 mm is drilled down to the desired level of the bottom of a pile.
• the bore hole walls may, if desired, be stabilized by a casing or a heavy liquid.
• Figure 3b Injection head A is then slowly lifted upwards being simultaneously rotated, and with top nozzle 11 working the wall of pilot hole P with a jet of water surrounded by air to extend said pilot hole so as to form an injection zone with a larger diameter, and with simultaneous injection of an agent, e.g. in the form of cement and water, through lower nozzle 13 to fill up injection zone I.
• an agent e.g. in the form of cement and water
• water and air will, thus, under high pressure break down the grainy structure and loosen the soil to a distance fron the centre of pilot hole P simultaneously with said injection agent being injected into the broken down volume of soil which is, thus urged upwards through pilot hole P.
• Figure 3c shows continued lifting and rotation of jet inject ⁇ ion head A with simultaneous jet washing with water and air under high pressure, as well as injection of binder.
• Liquid matter will continue to flow up through pilot hole P to the surface.
• This liquid flowing matter consists of soil, water, and some cement. It may be collected in a sedimentation basin, or it may be collected in containers to be removed.
• the liquid matter is removed via collar/container 4, shown in Figure 2, a portion 7 of said collar depending from container 4 extending into pilot hole P or a casing inside said hole for collecting the -liquid matter flowing upwards.
• Said liquid matter may be conveyed by pump 2 provided on container 4 with simultaneous measuring by the aid of flow meter 1.
• piles having a diameter of approximately 0.8 -4 m may be produced, depending on the kind of soil and the process, and this may be carried out during continuous monitoring via said graphic representation on display 14 showing the width of injection zone I in relation to the centre of pilot hole P.
• FIGs 4a, b, and c the procedure of building panels (shields) is shown.
• Said procedure has several features in common with the procedure of building piles, as shown in Figure 3.
• This procedure can also be divided into three phases, i.e. A: Drilling of several pilot holes P, e.g. with a dia ⁇ meter of 150 mm along a desired direction of the panel to be produced in the soil. The distance between pilot holes is adapted to the conditions of the soil, and may vary between 0.5 and 3 m. After drilling said pilot holes by the aid of a special drill steel and drill ring, if desired,by the aid of jet injection head A with excavation blades 17, said jet injection head A is lowered in a first pilot hole P.
• pilot holes P e.g. with a dia ⁇ meter of 150 mm along a desired direction of the panel to be produced in the soil.
• the distance between pilot holes is adapted to the conditions of the soil, and may vary between 0.5 and 3 m.
• Jet injection head A is oriented with nozzle 11 for water/air jet towards adjacent pilot hole P. While jet injection head A is slowly pulled up the soil between said two adjacent pilot holes P is washed off with simultaneous injection of binder into the formed injection zone I.
• the formed liquid matter or slugde consisting of water and washed out soil matter, and some binder will rise through adjacent pilot hole P to the surface and may be collected as mentioned above.
• Said sludge may, if desired, be collected in a collar/container 4 which is provided in the mouth of said pilot hole P, to be measured and removed. In this case the through collar portion 7 must be closed at its upper opening provided with a gasket 6.
• B Thus, a panel or a shield is erected between said two adjacent pilot holes P.
• Such jet panels 20 will have a thickness in an order of 5-30 cm and a width varying from 0.5 m to 3 m. Their height is adapted to the requirements, depending on the soil and the design. Such panels need not be completed up to the sur ⁇ face of the site but may, if desired, be limited between two levels below the surface.

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• 1985
  • 1985-11-25 NO NO854710A patent/NO854710L/no unknown
• 1986
  • 1986-11-25 EP EP86906965A patent/EP0247135A1/en active Pending
  • 1986-11-25 WO PCT/NO1986/000078 patent/WO1987003319A1/en unknown

Non-Patent Citations (1)

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