GB2587631A - An injection lance - Google Patents
An injection lance Download PDFInfo
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- GB2587631A GB2587631A GB1914188.6A GB201914188A GB2587631A GB 2587631 A GB2587631 A GB 2587631A GB 201914188 A GB201914188 A GB 201914188A GB 2587631 A GB2587631 A GB 2587631A
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- sleeve
- tube
- injection lance
- apertures
- lance according
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- 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
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- 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
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- Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Agronomy & Crop Science (AREA)
- Environmental & Geological Engineering (AREA)
- Soil Sciences (AREA)
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
Abstract
An injection lance 100 for permeation grouting, the injection lance comprising one or more stages 150 with each stage comprising: a tube 160 defining a longitudinal conduit 162; a plurality of first apertures 165 through the tube, a resiliently deformable sleeve 170 fitted onto the exterior of the tube, and a plurality of second apertures 175 (e.g. slits) through the sleeve. Preferably the sleeve is tight around the tube when no internal pressure is applied to the sleeve and preferably the second apertures are closed when the pressure within the sleeve is below a threshold pressure. Preferably the second apertures expand as pressure inside the sleeve increases.
Description
An Iniection Lance
Field of the Invention
The present invention relates to an injection lance for permeation grouting. Background to the Invention Permeation grouting is a process in which setting fluid, known as a grout, is injected into ground material such as soil or rock such that the grout spreads into gaps in the ground material before setting therein to bind the ground material together. Permeation grouting is commonly used to solidify, strengthen and reduce the permeability of loose soil or rock material during construction, excavation, or underpinning operations.
Grouts used in permeation grouting may be resins or cements which set after being injected into ground material. Grouts are typically low viscosity fluids before setting and are preferably colloids or Newtonian fluids. Such grouts are effectively free or particulates, allowing them to more easily permeate ground material and fill the gaps therein. Grouts may react with water, which may cause them to set and/or to expand to further permeate ground material. Hydro-reactive polyurethanes and colloidal silicates are particularly effective grouts.
Grouts should typically be injected into ground material at low pressures to avoid fissuring ground material such as soil, which could lead to the disposition of grout within veins, leaving layers of unbound soil between layers of pure set grout. Such an arrangement would not enhance the load bearing capacity of the soil.
Such grouts are typically injected into the ground using an injection lance. Injection lances are elongate pipes that are inserted into the ground so that fluid grout can be pumped therethrough. Grout is typically pumped into (the proximal) an end of the injection lance protruding out of the ground and typically exits the lance through its (distal) opposite end or through one or more lateral openings along its length.
In open-end-tube grouting, or open case grouting, the injection lance is an elongate tube with openings only at its ends. The injection lance is inserted into the ground to be stabilised and grout is pumped into a first end of the lance protruding from the 30 ground and enters the ground out of an open distal second end of the lance embedded therein. In such grouting methods, separate volumes of grout may be injected into the ground at different depths, with the tube being lifted or otherwise displaced to different depths between the injection of each volume.
In some instances, a drill string is used as an open-end-tube grouting injection lance to deliver grouting down a hole drilled using the drill rig.
Open-end-tube grouting works well in open ground at depth and is primarily used for compaction grouting deeper than four meters below ground level or to infill deep solution ground features. This method is of limited use in small scale operations, wherein lifting and withdrawing the lance may loosen it within the ground. This may cause injected grout to leak to the surface through gaps created between the lance and the border of the hole through which it was inserted and cause a decrease in the pressure of the grout preventing it from adequately permeating the ground. In some instances a packer may be inflated between the injection lance and the bored hole into which it has been inserted to prevent grout escaping therethrough.
Additionally, some effective grout types based on hydro-reactive polyurethane resin react quickly and may bind the lance into the soil where such vertical permeation back along the outside of the lance has occurred. This will prevent the lance from being lifted and the grouting operation from being completed.
Multiple tube grouting is a method of inserting multiple injection lances into the 20 ground to different depths so as to avoid the above-mentioned problems. However, this method is only effective over limited ranges of depths as clusters of multiple lances can become very bulky.
Fully perforated injection lances comprise a plurality of regularly spaced lateral openings along their lengths, through which grout can escape into the ground when pumped into the lance. However, such systems offer a user no control of the volumes of grout displaced into the soil at different depths. This is disadvantageous because ground permeation may vary with depth and soil permeability and fully perforated injection lances will typically only deliver grout to the depths where the ground offers the least resistance, frequently close to the surface. Injecting grout in this way lacks the required degree of control and is therefore unreliable.
A tube-a-manchette, or sleeve port pipe, is an injection lance in the form of an elongate tube with sets of lateral openings at different points along its length, each set of lateral openings being covered by a short rubber sleeve. In use a chamber is defined within the tube by inflating two annular packers above and below a set of lateral openings located at a given point along the length of the tube. An inner grout carrying tube then delivers grout to the chamber under pressure causing it to escape through the lateral openings and to force the rubber sleeve surrounding them to expand, allowing the grout to enter the ground surrounding the lance. After a volume of grout has been injected in this way, the pressure is removed and the sleeves contract, preventing grout from re-entering the tube. The packers are then deflated, the inner tube and packers are displaced within the injection lance to a different point along the length with another set of lateral openings, and the process is repeated.
In some such injection lances the rubber sleeves are protected from damage by rings formed on the outside of the injection lance above and below the rubber sleeves, or by arranging the rubber sleeves in recessed portions of the tube where the sets of lateral openings are located.
In use, tube-a-manchette injections lances are typically inserted into drilled holes and sealed therein, such as with a bentonite clay fill.
Tube-a-manchette injection lances are effective and widely used especially for 20 compensation grouting in clay. However, in loose soils, it can be difficult, cumbersome and expensive to maintain a drilled open hole for insertion of the injection lance.
International patent application W02014013215 (GEOINNOVATIONS LTD) discloses an injection lance in the form of an elongate tube with lateral openings along its length. The interior of the tube is separated into a plurality of chambers separated by bulkheads with valves therethrough. In use an inner grout carrying tube is inserted through one or more of the bulkhead valves to reach and deliver grout to one of the chambers at a time. A measured quantity of grout is then delivered through the inner tube and is only able to escape through the lateral openings of the chamber to which it is delivered, entering the ground at a desired depth. The injection lance is advantageously able to be driven into loose soil allowing it be used to inject grout into weak, collapsing or saturated soil.
However, leakage of injected grout between the exterior of this injection lance and the ground into which it is driven may still occur in some circumstances. Additionally, when multiple such lances are used simultaneously to permeate a large area of ground (for example, when forming a curtain wall of bound soil), grout injected by one lance may permeate to, surround, and set around a neighbouring lance, causing the neighbouring lance to become clogged or bound within the ground so preventing its effective function. This will also prevent additional lances being driven into the ground due to the presence of solidified masses of grout and soil.
In some circumstances soil may be variable in composition, making an even dispersion of grout unachievable, due to the above systems only being usable once with resinous grouts.
An aim of the present invention is to provide an improved injection lance for permeation grouting which overcomes the problems described above.
Statement of the Invention
According to a first aspect of the present invention, there is provided an injection lance for permeation grouting, the injection lance comprising one or more stages, and each stage comprising: a tube defining a longitudinal conduit; a plurality of first apertures through the tube between the conduit and the exterior of the tube; a resiliently deformable sleeve fitted onto the exterior of the tube; and a plurality of second apertures through the sleeve.
In use, the injection lance, which may comprise a single stage, or a plurality of stages connected end to end, may be inserted or driven into ground material, such as non-cohesive soil. Fluid grout may then be pumped into and along the lance through the one or more conduits defined by the one or more tubes and may exit the conduits through the first apertures. The grout escaping through the first apertures may force the resiliently deformable sleeves to expand and inflate around the tubes and may then escape from the sleeves into the ground material through the second apertures.
The resiliently deformable sleeves may advantageously act as one way valves in a manner similar to the rubber sleeves of a tube-a-manchette injection lance, ensuring grout is unable to return into the injection lance. Additionally, expansion of the deformable sleeve under pressure act as packers by expanding to fill any gaps between the injection lance and the ground material into which it inserted, thereby preventing grout from escaping along the length of a hole into which the injection lance is inserted.
The use of the resiliently deformable sleeve resists the transfer of grout from inside the lance to the outside until sufficient pressure is obtained to inflate the deformable sleeve so as to form a seal against the surrounding ground. In addition the high resistance of the small pores creates a high pressure gradient which permits an even flow of grout through the pores in the deformable sleeve and therefore allows the even delivery of grout throughout the length of the lance. The closure of ports reduces the pressure and so hermetically seals the lance allowing for subsequent injections.
One, some, or all, of the stages may have any of the features described below.
In preferred embodiments, the ends of the sleeve are secured around the tube is without a gap between the sleeve and the tube. The ends of the sleeve are preferably secured tightly to the tube such that fluids (such as grout) are unable to pass between the tube and the sleeve through the ends of the sleeve and are preferably secured to the tube such that they cannot expand to provide a gap between the tube and the sleeve through which material could exit the tube through its ends.
The ends of the sleeve being secured snugly around the tube may advantageously ensure that fluids (such as grout) which have been pumped out of the tube through the first apertures, are only able to escape the space between the tube and the sleeve through the second apertures. This may also advantageously allow the resiliently deformable sleeve to expand around the tube, for example, when the rate at which fluid is passing through the first apertures exceeds the rate at which it is passing through the second apertures. This may enable the sleeve to act as packer to fill space between the exterior of the injection lance and the ground into which it is inserted, thereby preventing injected grout from travelling along the length of the injection lance through a hole created by or for the insertion of the injection lance.
The ends of the sleeve may be secured to the tube by collars or other annular connectors which preferably fit around the ends of the sleeve and the portions of the tube which the ends surround and clamp them together. The ends of the sleeves may be crimped onto the tube by the collars or annular connectors.
The sleeve preferably fits over the plurality of first apertures, which are preferably located intermediate the ends of the sleeve (which are preferably secured around the tube as described above). The plurality of first apertures may be intermediate the collars or other annular connectors which secure the ends of the sleeve to the tube. This may advantageously ensure that all of any fluid (such as grout) which exits the tube through the first apertures enters the space between the exterior of the tube and the interior of the sleeve.
The sleeve is preferably of generally equal length to the tube, substantially equal length to the tube, or of equal length to the tube. The ends of the sleeve are preferably secured around the ends of the tube, the sleeve will therefore be maintained at a substantially equal length to the tube even as it expands and inflates or retracts and deflates.
In preferred embodiments, the sleeve is tight around the tube with no gap between the interior of the sleeve and the exterior of the tube when no internal pressure, or an internal pressure below a threshold level is applied to the sleeve. For example, the sleeve may have a radius less than the outer radius of the tube when it is fully relaxed.
In preferred embodiments the second apertures through the sleeve expand as the sleeve expands and/or stretches and/or as pressure inside the sleeve increases. For example, the second apertures may be holes cut or otherwise formed in the resiliently deformable material forming the sleeve such that they expand and stretch with the sleeve and/or when the pressure of fluid within the sleeve increases.
In such embodiments, when additional fluid is pumped into the injection lance, such that the rate at which fluid enters the lance exceeds the rate at which fluid exits the one or more sleeves through the second apertures, the resiliently deformable sleeves may inflate, and/or the pressure within the sleeves may increase, thereby expanding and stretching the second apertures. This may advantageously cause the rate at which fluid exits the sleeves through the second apertures to increase until this rate equals the rate at which fluid is delivered to the lance.
In further preferred embodiments, when the resiliently deformable sleeve is tight around the tube with no gap between the interior of the sleeve and the exterior of the tube, the combined area of the second apertures is smaller than the combined area of the first apertures.
In such a configuration, if fluid is pumped into the tube at a given pressure, the rate at which fluid is able to exit the tube through the first apertures will be greater than the rate at which fluid is able to exit the sleeve through the second apertures, the sleeve may therefore expand as fluid exits the tube into the space between the exterior of the tube and the interior of the sleeve.
In further preferred embodiments, when the resiliently deformable sleeve is tight around the tube with no gap between the interior of the sleeve and the exterior of the tube, the second apertures are closed or substantially closed.
For example, the second apertures may be piercings, cross slit valves, or other openings cut in or formed through the resiliently deformable material of the sleeve without removing material such that when the sleeve is substantially unexpanded, the edges of the second apertures are in contact with each other and the second apertures are substantially closed.
In further preferred embodiments, the second apertures are closed when the pressure within the sleeve is below a threshold pressure. The threshold pressure is preferably greater than a pressure at which the resiliently deformable sleeve is expanded and/or inflated away from the tube.
In such embodiments, when the one or more resiliently deformable sleeves are tight around the one or more tubes with no gaps between the interior of the sleeves and the exteriors of the tubes and when fluid is pumped into the injection lance, the resiliently deformable sleeve will initially be stretched and expanded as the fluid is unable to escape through the closed apertures. As the sleeve is expanded and stretched the second apertures may open, allowing the fluid to exit the injection lance. When fluid ceases to be pumped into the lance and the internal pressure is removed, the resiliently deformable sleeve may relax and retract back onto the exterior of the tube, removing any gap between the sleeve and the tube and the second apertures may close, thereby sealing the injection lance.
The threshold pressure for opening the second apertures is preferably sufficient to provide a significant fluid pressure gradient between the interior of the sleeve and ground material into which the lance is inserted.
In particularly preferred embodiments, the second apertures are formed by piercing the sleeve and/or the resiliently deformable material thereof without removing material.
In some embodiments, when the resiliently deformable sleeve is tight around the tube with no gap between the interior of the sleeve and the exterior of the tube, none of the first apertures overlap any of the second apertures. In such an arrangement, each first aperture will open onto an unpierced interior surface of the sleeve and each second aperture will open onto an unpierced exterior surface of the tube. Therefore, fluid will be unable to pass from the conduit inside the tube out through one of the first apertures and then out of the sleeve through one of the second apertures without the sleeve being expanded and/or stretched to define a gap between the exterior of the tube and the interior of the sleeve such that the fluid is able to travel from one of the first apertures to one of the second apertures.
The tube is preferably substantially straight, which may allow the injection lance to be inserted into straight bored or drilled holes in ground material or may facilitate in driving the injection lance lengthwise into ground material. In preferred embodiments, the tube is substantially cylindrical and preferably defines a central cylindrical conduit along the full length of its longitudinal axis.
The tube is preferably formed from a metal such as steel or from some other rigid material strong enough to allow the injection lance to driven into ground materials without bending or otherwise being damaged.
In some embodiments the stage comprises a plurality of sets of first apertures through the tube, each set comprising a plurality of first apertures at substantially the same distance along the length of the tube. The sets of first apertures are preferably regularly spaced along the length of the tube. The plurality of first apertures of each set may be distributed, preferably regularly, around the circumference or perimeter of the tube. A regular arrangement of first apertures may advantageously ensure fluid such as grout pumped into the tube exits the tube in an even pattern and that the sleeve is expanded and inflated in an even manner.
The sleeve is preferably formed from an elastomer or synthetic rubber or from some other elastic or resiliently deformable material.
In some embodiments the stage comprises a plurality of sets of second apertures through the sleeve, each set comprising a plurality of second apertures at substantially the same distance along the length of the sleeve. The sets of second apertures are preferably regularly spaced along the length of the sleeve. The plurality of second apertures of each set may be distributed, preferably regularly, around the circumference or perimeter of the sleeve. For example, the sleeve may comprise a plurality of sets of three second apertures, each of the apertures of each set being at approximately 120 degrees around the circumference of the sleeve from the other two and the plurality of sets of second apertures being spaced apart along the length of the sleeve with approximately 10 cm gaps between them.
Regularly spaced second apertures through the sleeve may advantageously ensure fluid such as grout is released into ground material surrounding the injection lance in an even distribution pattern.
The elasticity of the sleeve is preferably such that the sleeve does not expand and/or inflate at internal pressures less than 15psi (0.1mPa), less than 45psi (3.1 mPa), less than 75psi (0.52 mPa), less than 100psi (6.9 mPa), less than 125psi (8.5 mPa), less than 150psi (1.03 mPa), or less than 185psi (1.28 mPa).
The elasticity of the sleeve and/or the size of the second apertures is/are preferably such that the second apertures remain substantially closed at internal pressures less than 100psi (6.9 mPa), less than 125psi (8.5 mPa), less than 150psi (1.03 mPa), less than 175psi (1.2 mPa), or less than 200psi (1.38 mPa).
In preferred embodiments, when the sleeve is tight around the tube with no gap between the interior of the sleeve and the exterior of the tube, the sleeve is flush with collars or other annular connectors which secure the ends of the sleeve to the tube. The injection lance may therefore have a substantially constant radius when the sleeve is not inflated or expanded, this may facilitate the insertion or driving of the injection lance into ground material.
In preferred embodiments, in addition to the one or more stages, the injection lance comprises an end seal for sealing an end of the conduit of one of the one or more stages. In use, the end of the conduit defined by the tube a single-stage injection lance, or by a plurality of interconnected tubes of a multi-stage injection lance may be sealed by the end seal, such that fluid (such as grout) pumped into the conduit through the proximal end of the injection lance is only able to escape through the first apertures through the one or more tubes of the one or more stages.
The end seal may be in the form of, or may comprise a plug, which fits into an end of the conduit of one of the one or more tubes to seal it. In some embodiments, the end seal may be secured using adhesive.
In preferred embodiments, the end seal comprises a pointed tip and when sealing and end of the conduit of the tube of a stage defines a pointed tip for that stage. The end seal may therefore define a pointed tip for the injection lance, facilitating driving the injection lance into ground material and allowing it to be used as a ram injection lance (an injection lance which is driven into ground material without a hole being drilled or bored for it beforehand).
In preferred embodiments, the one or more stages are a plurality of stages. One, some, or each of the plurality of stages may comprise any of the optional features of the tube, sleeve, and/or first and second apertures as described above. In preferred embodiments, each of the plurality of stages comprises the same features and may be substantially identical.
The plurality of stages are preferably connectable or connected to each other, preferably releasably.
In preferred embodiments the plurality of stages are connected or connectable to each other end-to-end. In embodiments where the plurality of stages are releasably connectable end-to-end, the length of the injection lance to be adjusted by attaching stages thereto and/or detaching stages therefrom. This may allow the injection lance to be adjusted for permeation grouting at different depths.
In use, stages may be connected to the injection lance one by one as the injection lance is driven into the ground. For example, a single stage (preferably tipped with a pointed end seal) may be driven partially into the ground, an additional stage may then be attached to the end of the partially embedded stage which protrudes from the ground and the remainder of the partially embedded stage and a first part of the additional stage may then be driven into the ground. This may be repeated, with additional stages being added to the injection lance and driven into the ground until the injection lance has been driven to a desired depth.
In preferred embodiments the plurality of stages are connected or connectable to each other such that the conduit defined by the tube of each interconnected stage is interconnected with the conduits defined by the tube of each other stage to which its stage is connected.
In preferred embodiments the plurality of stages are connected or connectable to each other such that the conduits defined by their tubes are interconnected to define a combined conduit along the injection lance. This may allow fluid such as grout to be injected into the combined conduit so as to reach the first apertures of each of the plurality of stages. The combined conduit preferably extends along substantially the entire length of the injection lance and/or substantially between opposite ends of the injection lance (one of which may be sealed by an end seal and one of which may be fitted with a valve).
The plurality of stages and the conduits comprised by the tubes of the plurality of stages may be interconnected by connecting tubes which preferably fit into ends of the interconnected conduits of the tubes of the interconnected stages. The injection lance preferably comprising one or more such connecting tubes.
In preferred such embodiments, the connecting tubes are fitted into and held within annular seals within the ends of the interconnected conduits of the tubes of the interconnected stages. The annular seals are preferably resiliently deformable material and preferably comprise a central aperture which is preferably smaller than the cross-sectional area of the connecting tubes. The friction between the connecting tube and the two annular seals preferably holds the two stages together.
In use a first end of a connecting tube may be forced into the annular seal in an end of the conduit defined by the tube of a first stage and a second end of the connecting tube may then be forced into the annular seal in an end of the conduit defined by the tube of a second stage. If necessary, the connecting tube may then be forced through the annular seals into which it is fitted until the ends of the first and second stages are in contact with each other.
In some embodiments, each of the stages comprises such an annular seal in and at or proximate to each of the ends of the conduit defined by its tube. In preferred embodiments, one stage comprises such an annular seal in and at or proximate to a first end of the conduit defined by its tube and the second distal end of the conduit defined by its tube is sealed by an end seal as described above, in such a preferred embodiment, each additional stage of the one or more stages comprises annular seals in and at or proximate to each of the ends of the conduit defined by its tube.
In some embodiments, the injection lance comprises an end valve. The end valve is preferably for fitting into an end of a conduit defined by the tube of one of the stages and may be for fitting into an annular seal as described above. The valve is preferably a one-way valve. The valve is preferably for connecting the injection lance to a pump or other means for delivering fluid into the injection lance.
In use, the valve may be fitted into the end of the conduit defined by the tube of a stage at a first end of the injection lance preferably distal to an end seal at a second end of the injection lance. Fluid such as grout may be pumped into the injection lance through the valve and the valve preferably prevents fluid exiting the injection lance through the first end thereof. The end seal preferably prevents fluid exiting the injection lance through the second end thereof, such the fluid is only able to exit the injection lance through the first and second apertures.
The present invention may advantageously provide an injection lance which can be driven into the ground, instead of only being inserted into pre-drilled or pre-bored holes, allowing use with weak or collapsing soils and in saturated ground. The lance may also advantageously be capable of evenly delivering grout along the length of the lance irrespective of resistance created by the depth of insertion or differences in soil permeability. The lance may advantageously be reusable and unaffected by local impingement, allowing an embedded lance to be reused for additional injections of grout if required. The lance may advantageously comprise inflating sleeves which prevent injected grout from spreading along the length of the lance between it and the ground material. The lance is advantageously provided in a plurality of interconnectable stages facilitating its transport and storage and allowing it to be used in permeation grouting operations at a variety of different depths.
The invention will now be described by way of examples only and with reference to the Figures in which:
Brief Description of the Figures
Figure 1 shows a cross-sectional view of a first injection lance according to the present invention and a detailed exploded view of the driving stage thereof; Figure 2a shows partially disassembled and fully assembled cross-sectional views of an injection lance according to the present invention; Figure 2b shows a detailed cross-sectional view of the joint between two stages of the injection lance of Figure 2a; Figures 3a and 3b show cross-sectional views of the sleeve expanded with grout passing through the first apertures but not the second apertures; Figure 4 shows cross-sectional views left to right of an illustration of stages of installation and of gradual egression of grout from a lance into a the ground during a placement; Figure 5 shows in cross-section an arrangement of lances which might typically be used to inject a solidifying grout into soil to form piles beneath a structure such as a house; and Figure 6 shows in cross-section an arrangement of lances which might typically be used to inject a solidifying grout into soil to form a curtain wall where multiple injections may be required.
Detailed Description of the Figures
Referring to the figures generally, there are shown injection lances 100 according to the first aspect of the present invention. The injection lances 100 are each constructed from one or more stages 150 which are connectable end-to-end to define injection lances 100 of various lengths.
In addition to the one or more stages 150, each injection lance 100 further comprises a driving tip 110 with a plug 115 for sealing a lower end of the injection lance 100. The injection lances 100 optionally further comprise a one-way end valve 130 for fitting into an upper end of the injection lance 100.
Injection lances 100 comprising multiple stages 150 further comprise one or more connection tubes 120 for connecting multiple stages 150 and the conduits 162 thereof to each other.
Each stage 150 comprises an elongate cylindrical metal tube 160 which defines an elongate cylindrical conduit 162 along its length; an elastic resiliently deformable sleeve 170 fitted onto the exterior of the tube; a pair or annular collars 180 clamping the ends of the sleeve 170 onto the tube 160; and at least one annular seal 190 in an end of the conduit 165.
Each tube 160 comprises a plurality of first apertures 165 formed through the wall between its interior conduit 162 and its exterior, around which the sleeve 170 is fitted. The first apertures 165 are arranged in three sets, which are spaced apart along the length of the tube 160 with regular separations between them. The first apertures 165 of each set are regularly spaced around the circumference of the tube 160.
Each sleeve 170 is substantially cylindrical and is formed of an elastic resiliently deformable material such as an artificial elastomer. The sleeves 170 are each dimensioned to fit tightly around the full length of one of the tubes 160 and as such have an internal radius substantially equal to or less than the external radius of the tubes 160 when fully relaxed. Therefore, unless a sleeve 170 is stretched outwards by an internal pressure it fits tightly around the tube 160 without a gap between the exterior of the tube 160 and the interior of the sleeve 170.
Each sleeve 170 is of substantially equal length to the tube 160 around which it is fitted, such that it covers the entire outer surface of the tube 160. The ends of each sleeve 170 are clamped onto and around the ends of the tube 160 around which it is fitted by a pair of annular collars 180. The collars 180 compress end portions of the sleeve 170 against end portions of the tube 160 such that there is no gap therebetween and such that the exterior of the collars 180 are substantially flush with the outer surfaces of the sleeve 170 when unexpanded.
Each sleeve 170 comprises a plurality of second apertures 175 formed therethrough.
The apertures are pores formed by piercing the resiliently deformable material of the sleeve 170 without removing material. The second apertures 175 are therefore closed and do not permit the passage of fluid therethrough when the sleeve 170 is unexpanded. The second apertures 175 open and expand as the sleeve 170 is expanded and inflated.
In the illustrated embodiment, the sleeve 170 is configured to inflate and expand at interior pressures between 15psi (1.03 mPa) and 180psi (1.24 mPa) and the second apertures 175 are configured to be opened at interior pressures greater than 100psi (0.69 mPa).
The number of second apertures 175 through the sleeve 170 of each stage 150 is greater than the number of first apertures 165 through the tube 160. The second apertures 175 are arranged in sets, which are spaced apart along the length of the sleeve 170 with regular separations between them. The second apertures 175 of each set are regularly spaced around the circumference of the sleeve 170.
The second apertures 175 are offset from the first apertures 165 such that when the sleeve 170 is unexpanded and uninflated, the first apertures 165 are covered by unpierced portions of the sleeve 170.
The sleeve 170 is formed from a tough elastic material which is strong enough to resist damage from being driven into ground material which may contain brick or stone rubble, or fragments of metal, ceramics, slate or glass. For example, the sleeve 170 may be a reinforced vulcanised rubber tube, a thick walled reinforced silicon tube or industrial unreinforced PVC tube.
Each injection lance 100 comprises an initial stage 150 to which the driving tip 110 of the lance 100 is fitted. The driving tip 110 comprises a point tapering from a wider circular end of the same radius as the annular collars 180 to a narrow end point. The driving tip further comprises a cylindrical tang of substantially the same radius as the conduit 162 defined by the inside of the tube 160. In use the tang is inserted into a first end of the conduit 162 of the lowermost stage 150 such that the wider end of the point abuts the end of the tube stage 150 and defines a pointed end for the lance 100. In the illustrated embodiment, the tang is secured within the first end of the conduit 162 using adhesive 182. A plug 115 is also inserted into the open end of the conduit 162 before the tang of the driving tip 110. The plug 115 seals the end of the conduit and prevents fluid from escaping therethrough.
The initial stage 150 further comprises a single annular seal 190. The annular seal 190 is a cylindrical resiliently deformable body with a central cylindrical aperture extending therethrough. The exterior radius of the annular seal is substantially equal to the radius of the conduit 162 of the tube 160 and the annular seal is fitted into a second end of conduit distal from the first end and the driving tip 110. The annular seal 190 is secured within the conduit 162 by adhesive 192 proximate to the first end and intermediate the first end and the first apertures 165 closest to the first end.
In injection lances 100 comprising a plurality of stages 150 each additional stage 150 other than the initial stage 150 comprises two annular seals 190 as described above.
The two annular seals are fitted into and secured within the two opposite open ends of the conduit 162 using adhesive 192 proximate to those ends and intermediate those two ends and the first apertures 165 closest thereto.
In use, the annular seals 190 may be used into interconnect adjacent stages 150 and the conduits 162 thereof using connecting tubes 120 so as to define joints 125 15 between the stages 150.
In order to interconnect a pair of stages 150, a connecting tube 120 is inserted into the central cylindrical aperture of the annular seal 190 in the end of the conduit 162 of a first stage 150, such that the connecting tube extends out of the end of the conduit 162. The extending end of the connecting tube 120 is then inserted into the central cylindrical aperture of the annular seal 190 in the end of the conduit 162 of a second stage 150 and the first and second stages 150 are pressed together to define a joint 125 between the two stages 150. The connecting tubes 120 have central longitudinal conduits which interconnect the tube conduits 162 of the two stages which they form a joint 125 between.
In some of the injection lances 150 a one-way valve 130 is inserted into the central cylindrical aperture of the annular seal 190 in the end of the conduit 162 at the end of the lance 100 distal (proximal to the injection) from the driving point 110. This is the end of the lance 100 which will protrude from the ground in use. The one-way valve 130 may be used to connect the injection lance 100 to a pump or other means for providing fluid (such as grout) to the injection lance 100 under pressure.
The one-way valve 130 prevents the pressure inside the injection lance 100 from falling below a minimum pressure (such as 150psi). When fluid ceases to be pumped into the lance, the second apertures 175 of the sleeve may seal as the pressure decreases, causing the pressure within the injection lance 100 to be maintained. Once the lance 100 is sealed, impingement from other grout sources will not have negative impacts on the lance 100. Additionally, this may allow multiple injections to be performed using the lance 100, allowing the treatment of variable ground using
suitable grouts.
Figure 1 shows a cross-sectional view of an injection lance 100 comprising a pair of stages 150 interconnected by a single connection tube 120 with driving tip 110 at one end, as well an exploded view of one of the driving stage 150 of the lance, along with the driving tip 110 and the connection tube 120.
Figure 2A shows partially disassembled and fully assembled cross-sectional views of an injection lance 100 comprising a pair of stages 150, a driving tip 110, a single connecting tube 120 and a one-way valve. Figure 2b shows a detailed cross-sectional assembled view of the joint 125 between the two stages 150.
In use, after a lance 100 as described above is driven into the ground or inserted into a hole drilled or bored into the ground, pressurised fluid grout 200 is injected into the lance through the end of the lance distal from the driving tip 110, into the end of a conduit 162 of a stage 150 of the lance. This end may be open or may be fitted with a one-way valve 130 in an annular seal 190 thereof.
The fluid grout 200 fills the conduits 162 of each of the stages 150 of the injection lance and causes the sleeves 170 to inflate away from the tubes 160 as fluid passes through the first apertures 165. This allows the sleeves 170 to expand and press against the ground into which the lance 100 has inserted filling any gaps along the length of the exterior of the lance 100. The second apertures 175 initially remain closed during this expansion.
The internal pressure increases and is controlled by the volume of grout passing from the pump into the lances. The pump must be able to deliver sufficient volume of grout to ensure sufficient pressure is obtained to inflate sleeve 170 given the number of secondary apertures 165.
The invention has been described by way of example only and it will be appreciate that variation may be to the invention and without departing from the scope of protection as defined by the claims appended hereto.
Claims (25)
- Claims 1 An injection lance for permeation grouting, the injection lance comprising one or more stages, and each of the one or more stages stage comprising: a tube defining a longitudinal conduit; a plurality of first apertures through the tube between the conduit and the exterior of the tube; a resiliently deformable sleeve fitted onto the exterior of the tube. and a plurality of apertures through the sleeve.
- 2 An injection lance according to claim 1 wherein the ends of the sleeve are secured around the tube without a gap between the sleeve and the tube.
- 3 An injection lance according to claim 2 wherein the ends of the sleeve are secured to the tube by collars which fit around the ends of the sleeve and portions of the tube and clamp them together.
- 4 An injection lance according to any preceding claim wherein the plurality of first apertures are located intermediate the ends of the sleeve and the sleeve fits over the plurality of first apertures.
- An injection lance according to any preceding claim wherein the sleeve is of substantially equal length to the tube.
- 6 An injection lance according to any preceding claim wherein the sleeve is tight around the tube with no gap between the interior of the sleeve and the exterior of the tube when no internal pressure is applied to the sleeve.
- 7 An injection lance according to any preceding claim wherein the second apertures expand as the sleeve expands and stretches
- 8 An injection lance according to claim 7 wherein when the resiliently deformable sleeve is tight around the tube with no gap between the interior of the sleeve and the exterior of the tube the second apertures are substantially closed.
- 9. An injection lance according to any preceding claim wherein the second apertures expand as the pressure inside the sleeve increases.
- 10.An injection lance according to claim 9 wherein the second apertures are closed when the pressure within the sleeve is below a threshold pressure.
- 11 An injection lance according to claim 10 wherein the threshold pressure is greater than a pressure at which the sleeve is inflated around the tube.
- 12 An injection lance according to any preceding claim wherein the second apertures are formed by piercing the sleeve without removing material.
- 13 An injection lance according to any preceding claim wherein when the resiliently deformable sleeve is tight around the tube with no gap between the interior of the sleeve and the exterior of the tube none of the first apertures overlap any of the second apertures.
- 14 An injection lance according to any preceding claim comprising a plurality of sets of second apertures, each set of second apertures comprising a plurality of second apertures at substantially the same distance along the length of the sleeve and the plurality of sets of second apertures being regularly spaced along the length of the sleeve.
- An injection lance according to any preceding claim comprising an end seal for sealing an end of the conduit of one of the one or more stages.
- 16 An injection lance according to claim 15 wherein the end seal comprises a pointed tip.
- 17 An injection lance according to any preceding claim wherein the one or more stages are a plurality of stages.
- 18 An injection lance according to claim 17 wherein the plurality of stages are releasably connectable to each other end-to-end.
- 19 An injection lance according to claim 18 wherein the plurality of stages are releasably connectable to each other end-to-end such that the conduits defined by their tubes are interconnected to define a combined conduit along the injection lance.
- An injection lance according to claim 19 wherein the combined conduit extends substantially between opposite ends of the injection lance.
- 21 An injection lance according to claim 19 or claim 20 wherein the plurality of stages and the conduits are interconnected by connecting tubes which fit into ends of the interconnected conduits of the tubes of the interconnected stages
- 22.An injection lance according to claim 21 wherein the connecting tubes are fitted into and held within annular seals within the ends of the interconnected conduits of the tubes of the interconnected stages
- 23.An injection lance according to claim 22 wherein the annular seals are resiliently deformable.
- 24. An injection lance according to any preceding claim comprising an end valve for fitting into an end of a conduit defined by the tube of one of the stages.
- 25. An injection lance according to claim 24 wherein the end valve is a one-way valve.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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GB1914188.6A GB2587631B (en) | 2019-10-02 | 2019-10-02 | An injection lance |
PCT/IB2020/059187 WO2021064620A1 (en) | 2019-10-02 | 2020-10-01 | An injection lance |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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GB1914188.6A GB2587631B (en) | 2019-10-02 | 2019-10-02 | An injection lance |
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GB201914188D0 GB201914188D0 (en) | 2019-11-13 |
GB2587631A true GB2587631A (en) | 2021-04-07 |
GB2587631B GB2587631B (en) | 2022-11-16 |
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GB1914188.6A Active GB2587631B (en) | 2019-10-02 | 2019-10-02 | An injection lance |
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GB (1) | GB2587631B (en) |
WO (1) | WO2021064620A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2024117903A1 (en) * | 2022-12-01 | 2024-06-06 | R. Schram Consultancy B.V. | Alternative method for moving organic plant material to an underground location with an anaerobic environment and injection lance head for use in the method |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2415767A (en) * | 1968-05-16 | 1969-11-20 | Apparatus for grouting subterranean formations | |
JP2013241812A (en) * | 2012-05-23 | 2013-12-05 | Nittoc Constr Co Ltd | Grouting device and grouting method |
JP2016156142A (en) * | 2015-02-23 | 2016-09-01 | 強化土株式会社 | Ground injection method and ground injection device |
JP2017040079A (en) * | 2015-08-19 | 2017-02-23 | 強化土株式会社 | Ground injection method and ground injection device |
JP2018012987A (en) * | 2016-07-21 | 2018-01-25 | 強化土株式会社 | Ground injection device and ground injection method |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB201213003D0 (en) | 2012-07-20 | 2012-09-05 | Collis Simon P | A ground stabilisation system and related method |
-
2019
- 2019-10-02 GB GB1914188.6A patent/GB2587631B/en active Active
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2020
- 2020-10-01 WO PCT/IB2020/059187 patent/WO2021064620A1/en active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2415767A (en) * | 1968-05-16 | 1969-11-20 | Apparatus for grouting subterranean formations | |
JP2013241812A (en) * | 2012-05-23 | 2013-12-05 | Nittoc Constr Co Ltd | Grouting device and grouting method |
JP2016156142A (en) * | 2015-02-23 | 2016-09-01 | 強化土株式会社 | Ground injection method and ground injection device |
JP2017040079A (en) * | 2015-08-19 | 2017-02-23 | 強化土株式会社 | Ground injection method and ground injection device |
JP2018012987A (en) * | 2016-07-21 | 2018-01-25 | 強化土株式会社 | Ground injection device and ground injection method |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2024117903A1 (en) * | 2022-12-01 | 2024-06-06 | R. Schram Consultancy B.V. | Alternative method for moving organic plant material to an underground location with an anaerobic environment and injection lance head for use in the method |
Also Published As
Publication number | Publication date |
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GB201914188D0 (en) | 2019-11-13 |
GB2587631B (en) | 2022-11-16 |
WO2021064620A1 (en) | 2021-04-08 |
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