Patent Application
20240093453
The present invention relates to a method and device for injecting a grout material into a longitudinal hole from which it permeates into the bulk material in which the hole is formed.
Methods and devices for grout injection into various types of bulk material via holes filled in this bulk material are known in the art. Typical bulk materials can be natural materials such as various forms of bedrock or soil or manmade objects, for instance objects made from concrete such as building structures, tunnels, pipes, dams etc. Grout injection techniques can be used to strengthen and waterproof the bulk material surrounding the injection site, for instance in permeation grouting or in compaction grouting techniques where holes and cracks in the bulk material are filled with grouting material or where grout expanding from the injection site into the bulk material is used to densify the bulk material. Other techniques such as hydrofracturing can be employed to create cracks in the bulk material and to fill those cracks with high performance material, for instance in order to compress soil.
A variety of grouting materials can be employed, for instance a pre-mixed cementious grout which is pumped via a single line hose to an injection site within a borehole. It is also known to use chemically reactive grouting compositions, which are made from two or more chemically reactive components which, upon reaction, form the final grout. For instance, chemical grouts, which require the mixing of two components are known as “binary grouts”.
When such two-component grouts (binary grouts) or multi-component grouts are employed, a pre-mixing before injection into the borehole is only possible for slowly reacting compositions which, after mixing, provide sufficient time for pumping the grouting composition into the borehole via a single-line hose and injected into the surrounding bulk material at the injection site within the borehole.
Typical single-component grouting materials have a setting time of several hours so that time is not a real issue. With two-component grouting materials, transport and injection times are more critical and compositions having setting times below approximately ten or fifteen minutes can hardly be used for sustainable grouting operations. Therefore, two-component grouting materials are typically used with manually operated hoses, often as a kind of emergency procedure when special soil characteristics indicate that the usual one-component systems are not sufficient. A disadvantage of such quickly reacting two-component systems is that the injection equipment can no longer be retrieved from the boreholes after setting of the grouting composition and is therefore lost, leading to increased overall operation costs.
JP-A 57165519 discloses a grout injection device having two points of injection, namely a first injection port formed on the base side of the injection tube, and a second injection port formed on the tip side thereof.
US 2001/0041100 A1 describes a three-component chemical grout injector, which comprises three separate hoses operated by three separate pumps to inject three fluids of a three-component chemical grout to a grout injector arranged close to the injection site within the borehole where the three-components are mixed and injected into the surrounding bulk material. In US 2001/0041100 A1, the three fluids include a resin, a catalyst and an additive, which, when combined with the resin and the catalyst, modifies at least one characteristic of the grout. It is also mentioned, that the injector is designed to create turbulence so that the injector exhibits certain self-cleaning properties. It is also indicated, that in certain embodiments, one of the hoses can be used for feeding a cleaning solution to flush out the injector after use, i.e. after injection of the grout has been accomplished.
The device of US 2001/0041100 A1 is rather complicated requiring three hoses to be operated using individual pumps and storage reels for the three hoses, which give life to considerable costs. To hold the injector in the place of the desired height within the borehole, US 2001/0041100 A1 provides for a clamping device arranged on the surface above the borehole. Typically, the device of prior art is used with a so-called Tube a-Manchette (TAM) where the borehole is aligned with a tube provided with rubber sleeves for releasing grout at the injection site into the surrounding bulk material. In longitudinal direction of the borehole, a ported pipe of the injector is provided with an upper and lower packer, respectively.
The technical problem underlying the present invention is to improve the multi-component grout injector of prior art in terms of reliability and cost effectiveness. The device of the present invention shall also allow using fast-setting grouting materials, for instance a grouting material having a setting time of less than a minute.
This technical problem is solved by the grout injection device of present claim 1. Preferred embodiments of the grout injection device are subject of the dependent claims.
Accordingly, the present invention concerns a grout injection device comprising
Accordingly, rather than using three separate hoses for the individual components as in prior art, the present invention suggests using a single hose having at least three separate lines-lumen defined in its interior, thus allowing an easier handling of the holes when it is inserted into a longitudinal hole, such as a borehole.
In a preferred embodiment, the hose is made from an extruded plastic material with said at least three separate lines defined by smooth interior walls of that plastic material. Extrusion allows for a cost effective production of the hose of the invention, which can have several ten or even hundred meters in length. The smooth interior walls obtained from the extrusion process provide internal lines within the hose, which exhibit a low resistance to fluid flow, thus reducing power and injection pressure requirements of an associated pump for pumping fluids through those lines.
The plastic material for the hose can be chosen from a vast variety of suitable, extrudable plastic materials. The hose should have a certain flexibility to allow, for instance, storage of the hose on a reel, but also a certain rigidity to allow easy introduction into a longitudinal hole such as a borehole arranged in soil or bedrock. The rigidity of the hose should also allow the packer system arranged at the free end of the hose to be moved within the hole or within a hole lined with a tube, where a steering system is provided between an outer wall of the packer system and an interior wall of the borehole or of a tube lining the borehole.
Accordingly, the hose used in the present invention has a stiffness to a degree that it can transmit a pushing force to the packer system and move it forward, not just pull or retract. The degree of stiffness or the stiffness value depends on the geometry of the hose having at least three separate internal lines.
The hose of the present invention is typically made of a material selected from the group consisting of polypropylene (PP), polyethylene (PE) and polyurethane (PU), preferably is made from polypropylene (PP), polyethylene (PE) or polyurethane (PU), more preferably is made exclusively from polypropylene (PP), polyethylene (PE) or polyurethane (PU), and most preferably is made from a single body, layer or sheath consisting exclusively of polypropylene (PP), polyethylene (PE) or polyurethane (PU). Polyethylene (PE) is particularly preferred for the injection of grout containing isocyanate or an isocyanate component.
In certain embodiments, the plastic material of the hose is selected from polyurethane, polyethylene or polyvinyl chloride.
These materials help to achieve the level of rigidity/stiffness needed to transmit a pushing force to the packer system and to drive the packer system to a desired or pre-determined position or depth of insertion/injection in the TAM pipe and injection site, are sufficiently chemically inert, and also give a high value of bursting pressure that allows their use for applications deep inside the ground, particularly at depths of insertion exceeding 10 m and/or at depths of insertion of up to 200 m, preferably at depths of insertion from 25 m to 200 m, more preferably from 50 m to 100 m.
The depths of insertion can be understood to be for an insertion in any direction, for instance selected from a substantially horizontal, vertical and slanting direction, preferably selected from a substantially horizontal direction, a substantially vertical direction pointing upwards, a substantially vertical direction pointing downwards, a slanting direction pointing upwards and a slanting direction pointing downwards. The slanting direction is depending on the application. Typical uses can be: forepoling in underground construction, compensation grouting, permeation grouting under foundation, slope stabilization. Depending on the application the angle could range from 0 degree to 90 degrees.
The present invention is particularly advantageous for applications deep inside the ground at injection sites exposed to a relatively high ground and/or water pressure and/or at which elevated pressures for grout injections are necessary, due to the viscosity of the grout and the loss of pressure with distance from the grouting equipment, particularly at pressures exceeding 10 bar, particularly being from 20 bar to 100 bar, particularly from 50 bar to 80 bar.
In certain embodiments, the hose used in the grout injection device of the present invention is a x-way hose having x separate internal lines, x being an integer and x 3, preferably x being an integer from 3 to 10, more preferably from 3 to 5, yet more preferably being 3 or 4, and most preferably being 3 with the 3-way-hose having three separate lines. The separate internal lines are defined in the interior of the hose. The separate internal lines run in parallel to each other and parallel to the longitudinal axis of extension of the hose.
A preferred hose of the present invention features the x separate lines defined in the interior of said hose to be arranged in a symmetric fashion relative to each other. For instance, in a hose having three, four, five, six or seven internal lines, said lines are arranged in a triangular, square, pentagonal, hexagonal or heptagonal fashion, respectively.
The symmetric geometries of arrangement of the internal lines impart an enhanced stiffness to the hose. The stiffness value, however, also depends on the material used for the hose and is preferably characterized by the following values:
The use of a single hose comprising three separate lines according to a preferred embodiment of the present invention instead of using two or more separate hoses not only allows to keep the chemically reactive components of a two-component grout composition separate in order to prevent their premature reaction with each other before they actually reach the desired site of injection, but also permits the use of a significantly longer hose. This is because the single hose comprising three separate lines is stiffer or more rigid than a conventional arrangement of three separate hoses. Accordingly, while three separate hoses can be inserted simultaneously into a TAM pipe only if the hoses do not exceed a length of 10 m each, or, in other words, can be inserted up to a depth of 10 m only into the TAM pipe, the single rigid hose according to the present invention can be used in lengths of up to 200 m, typically in lengths of from 25 m to 200 m, preferably from 50 m to 100 m, and inserted as deep as the aforementioned lengths.
At one end which will remain outside of the hole, the hose is preferably provided with suitable connections, for instance steel connections, connecting the tube to the pump system, for instance to a high pressure pump. The hose may also be arranged on a hose reel. In this case, rather than connecting the hose directly to the pump, an intermediate hose can be provided connecting the reeled main hose with the pump. On its opposite end, i.e. the free end, which is inserted into the hole, the hose is provided with a connector connecting the holes with the packer system. The connector can be provided with non-return valves for the lines. The non-return valves can be inserted directly into the openings of internal lines at the free end of the hose. Preferably, a threaded connection between hose connector and packer system is employed.
The packer system is arranged at the free end of said hose such that the at least three lines lead into a chamber of the packer system where mixing of fluids discharged from these lines occurs. In a three-line hose, two of these three lines are operated simultaneously or intermittently to discharge the two components of a binary grouting system into the chamber, while the third line is only used after and/or before grout injection for cleaning purposes.
In one embodiment, the chamber of the packer system comprises at least four circumferentially arranged discharge openings from which the grouting mixture is injected into the hole surrounding the chamber.
The chamber of the packer system can be made from plastic material or from metallic material such as steel.
The packer system can be employed with a variety of sealing configurations. In one embodiment, the packer system comprises an upper seal above said discharge openings of said chamber and a lower seal below said discharge openings of said chamber. The upper and lower seals can be configured as a V-ring sealing system. Such a double packer configuration allows grout injection via a selected single valve in a hole lined with a sleeved pipe. The sealing solution is able to work with sleeved types made from a variety of materials, especially steel or plastic materials, and with different valve types, such as TAM or button valves. In one embodiment, the upper and lower seals are each composed of at least two, preferably three gaskets having different rigidities. The more rigid gaskets have a dual function, namely sealing and cleaning the inner part of the sleeved type, while the softer gaskets improve the sealing by adapting to irregularities on the inner wall of the sleeve type. The V-shape of the sealing gaskets allow a better steering during grout injection using pressurized fluids.
In contrast to US 2001/0041100 A1 which uses spider clamps activated by pulling a cable, the mechanical packer of the present invention offers particular advantages. In the present invention, the sealing is provided by the gaskets and does not need a mechanical system to get activated. This is an advantage in terms of reliability and durability of the system: Once the sealing effect decreases or is compromised the worn-out gaskets can be replaced by new gaskets.
Another part of the packer system can be composed of a rigid plastic part that guarantees a perfect alignment of the packer, which in turn improves the sealing capabilities of the gaskets.
In another embodiment, the packer system uses a single inflatable packer which allows injection down-top in a borehole without casing, for instance in rock or in cohesive soils. One of the lines of the holes can then be used to inflate the single packer by injecting a suitable fluid, for instance oil, water or pressurized air.
In a further embodiment, the packer system may be configured as a multi-packer system for simultaneous injection. In this embodiment, the different lines of the holes can be used to inject a single-component grout in different valves of a sleeve pipe simultaneously. The sealing devices is then composed by a series of packers, one for each line in the hose. The distance between the packers can be adapted to the distance between the valves in a sleeved pipe.
In one embodiment, the hose is provided with three lines where two lines are used for the two components of a binary grouting material and one line for injecting a cleaning solution into the chamber of the packer system.
In one embodiment, the chamber of the packer system is provided with a suitable mixing equipment, for instance with static mixers. Accordingly, when, for instance, a binary or multi-component grouting material is used, the components of the grouting material are injected into the chamber via separate lines of the hose so that mixing occurs only in the chamber and the mixed grout is injected into the surrounding of the packer system immediately after mixing. Consequently, fast reacting grouting materials can be employed because mixing and injection occurs at the injection site only. Accordingly, the grout injection device according to the present invention can be used for a large variety of chemical grouting systems ranging from single-component grouting systems to multi-component grouting systems having a large variety of setting times ranging from hours to minutes and even time scales below one minute.
The term “fast reacting” means that the chemically reactive components of a composition polymerize or cure and thereby the entire composition hardens to a degree of at least about 90%, preferably from 90% to 100% and within a period of time from about 1 to 30 minutes, preferably from 1 to 10 minutes, more preferably from 1 to 3 minutes. A two-component grout composition, particularly a fast reacting two-component grout composition consists of one component which comprises at least one organic compound which undergoes a polymerization reaction upon contact with the second component, which comprises at least one further organic compound. If need be, i.e. if the reaction between the first and second component is too slow to be useful in practice for underground stabilization by the injection of grout, and/or to obtain a fast reacting two-component grout composition, the first or second component may additionally contain a catalyst which accelerates the polymerization reaction. One of the components of a two-component grout composition may additionally comprise cementitious material; such a two-component grout composition may also be called a “mixed grout (system)” or a “two-component cementitious grout (system)”.
Preferably, the grout injection device according to the present invention is equipped with a single pump system, thus offering a cost and complexity benefit over the device described in US 2001/0041100 A1. In one embodiment, the pump system comprises a multi-piston pump having each of the at least three lines of the hose associated with an associated piston of the multi-piston pump.
For instance, for a binary grouting material, a three-component electro-hydraulic piston pump having two pistons for the components of the binary grouting material that inject simultaneously the first and second part of the grouting material into the chamber and a cleaning pump is employed. The cleaning pump is preferably provided with a suitable suction system that is capable of pumping highly viscous and/or thixotropic cleaning fluids like grease or oil, offering an improved cleaning of the packer system with reduced cleaning fluid consumption, thus providing an environmental friendly solution. For certain chemical grouting compositions, e.g. acrylic resins, water can be used as cleaning fluid as well.
Alternatively, dedicated electro-hydraulic pumps can be employed for each component of the binary or multi-component grouting material, as well as a dedicated pump for the cleaning fluid.
It is important to maintain a desired ratio of the components of the grouting material during injection. Moreover, the main grouting parameters for designing and controlling the grouting process are the flow rate and pressure of the grouting mixture injected at the grouting site. In order to control flow rate and pressure and, especially if dedicated pumps are employed, it is important to control flow rate and pressure of each component in the respective lines of the hose. Therefore, according to a preferred embodiment, a Programmable Logic Controller (PLC) is used to control the separate pumps or the single, multi-piston pump via suitable flow and pressure control devices that are synchronized through the PLC with the engine of the pump(s) to check and control the grouting process. With such an equipment, it is possible to set a flow rate limit or a pressure limit and the pump automatically adjusts the power of the engine in order to maintain the design-values set by the engineers, especially as far as injection pressure and flow rate are concerned. It is also possible to record those parameters for controlling and post-processing of data.
In one embodiment, the pump system is connectable to at least three different fluid sources. In one embodiment, the at least three different fluid sources comprise at least two components of a multi-component (at least binary) grouting material and at least one cleaning solution.
The hose of the grouting injection device according to the present invention can be operated manually. However, a particular advantage of having a single hose comprising at least three lines for the components of the grouting mixture and the cleaning solution, respectively, resides in offering the possibility to employ a motorized transporting system. Thus, according to one embodiment, the grout injection device comprises a motorized hose-transporting system, which can, for instance, comprise a rotatable hose reel for storing the multi-line hose, a motorized puller-roller for winding and unwinding the hose from the reel and suitable control equipment for operating the motorized hose-transporting system. Accordingly, it is possible to push down or pull up the hose with attached packer system within a sleeved pipe for directly within the borehole. The puller-roller is preferably configured to push or pull the hose according to a pre-selected length in order to automatically place the packer system inside the sleeved pipe at the desired injection site, i.e. at the height of the valves of the sleeved pipe.
The present invention also concerns a method for injecting grout into a longitudinal hole comprising the steps of
With the method of the present invention, using a hose having at least three separate lines, it is possible to employ fast setting grouting materials without risking to lose the grout injection equipment even in emergency cases, because cleaning solution can be immediately injected into the chamber of the packer system in step (f) after injecting the grout at the injection site. Consequently, there is no risk of blocking the packer system and the hose can easily be withdrawn partially or completely in step (g).
While injection of a cleaning solution in step (b) is not always required, it is generally preferred to have at least a minor amount of cleaning solution injected before conducting the injection of grouting material, thus ensuring that only fresh grouting material is injected at a desired injection site. Also, injection of cleaning solution can be performed when the packer is inserted into a TAM pipe to enable an easier movement of the packer system in the pipe.
The method of the present invention can be conducted directly in a borehole, but preferably the borehole is equipped with a suitable liner in which the hose is inserted, for instance with a TAM (Tube a Manchette) pipe, which essentially consists of a plastic tube provided with rubber gasket. Alternatively, multiple port sleeved pipes (MPSP) can be employed. The ports can, for instance, have gaskets or single opening valves such as button valves.
TAM pipes are typically provided with multiple injection sites defined by suitable valves in the TAM pipe, which are spaced apart from each other in a longitudinal direction of the pipe. Accordingly, in order to inject grouting material at multiple injection sites, the method of the present invention is performed by feeding the multi-line hose into the TAM pipe in step (a) until the injection site farthest from the pipe entrance is reached. Then, as desired, optional step (b), i.e. injecting a cleaning solution, can be performed or not. Subsequently, steps (c) to (f) of the method of the invention are performed and in step (d), the hose is only partially withdrawn until a nearer injection site to the pipe entrance is reached and, optional step (d) and steps (c) to (g) are repeated one or more times. If injection at additional injection sites is desired, the hose is only partially withdrawn in step (g) until an even nearer injection site to the pipe entrance is reached. Only after completing the desired injections, the hose is completely withdrawn from the TAM pipe.
The present invention is suitable to work with a TAM pipe having injection sites which are spaced apart. Typically, the injection sites are spaced apart, seen in the longitudinal direction along the TAM pipe, by 30 to 150 cm, preferably 50 to 150 cm, more preferably 50 to 100 cm.
In certain embodiments of the present invention, the TAM pipe comprises 20 or more injection sites, preferably 20 to 600, more preferably 50 to 500, in particular 50 to 250, in particular 50 to 200.
Typically, the number of injection sites will depend on the length of the TAM pipe. For instance, 1 to 3 injection sites per each 1 m of length of the TAM pipe can be provided, preferably 1 injection site per each 1 m of length of the TAM pipe.
A particular advantage of the present invention is the provision of a compact arrangement of hose and packer. For, instance, for a 27 mm-internal diameter TAM pipe, a hose with three internal lines having an external diameter of 21 mm and a suitable packer system can be employed. For a 40 mm TAM pipe, a 27 mm hose or a 33 mm hose can be employed. In contrast, inflatable packers or the packer system described in the above mentioned US 2001/0041100 A1 can usually not be used with TAM pipes smaller than 40 mm internal diameter.
The present invention will now be described in more detail with reference to a preferred embodiment, which is schematically depicted in the appended drawings. In the drawings,
The grout injection device 10 comprises a hose 11 made from an extruded plastic material which, in the depicted embodiment, has three separate lines 12, 13, 14 defined in the solid interior of the hose. A cross-sectional view of the hose 11 showing a typical arrangement of three separate lines 12, 13 and 14 is shown in
As can be taken from
At its outer circumference, the chamber 17 is provided with discharge openings 22, 23, 24 for releasing fluid, especially the grout mixture obtained in the chamber 17 or cleaning fluid pumped fed via line 14, into the surrounding of the packer system, i.e. into a space 107 defined between the exterior of the packer system 16 and the interior of the TAM pipe 103. In the depicted example, four discharge openings are equally spaced around the circumference of the chamber 17 but in the view of
Before grout injection, the packer system 16 is arranged at such a height within TAM pipe 103 that the discharge openings 22, 23, 24 of chamber 17 are located at the same height as the valve plates of the selected injection site, i.e. in the example of
As can be taken from
The upper and lower seals 26, 27 can be chosen from a variety of packer seals known in the art, for instance from inflatable seals. In the depicted embodiment, however, the upper and lower seals are chosen from mechanical seals. Specifically, each seal 26, 27 is provided with three elastic V-rings 26a, 26b, 26b and 27a, 27b, 27b, respectively, which are arranged adjacent to each other (c.f.
Outside of the borehole 102, the opposite end 28 of hose 11 of grout injection device 10 is attached to a pump system 30, which comprises a piston pump 31, which is connects three fluid reservoirs 32, 33, 34 to the three separate lines 12, 13, 14 of hose 11, respectively. Reservoirs 32, 33 contain two components of the binary grouting mixture of the present example. Piston pump 31 will pump the two components at a pre-selected ratio through the first and second lines 12, 13, respectively, to the chamber 17 of packer system 16, where the two components are mixed and the mixture is injected from the internal chamber through the valve plates of TAM pipe 103 into the injection site. Reservoir 34 contains a cleaning fluid, for instance an oil or grease or a mixture thereof which can be pumped via third line 14 to chamber 27 of packer system 16. The piston pump 31 can be operated such that the fluid flow through each of the lines 12, 13 and 14 can be adjusted separately, i.e. independent from each other. To this effect, pump system 30 also includes a PLC controller 35, which allows to control pressure and flow rate of the fluid injected into lines 12, 13 and 14 of hose 11. The pump system also comprises a suitable connector, where three lines coming from piston pump 31 are attached and which has a connecting piece with three openings, to which the three line hose 11 is attached in a manner that each fluid can be fed into one of the three lines of the hose.
The grout injection device can further include a hose-transporting system 40, which includes a motorized puller-roller 41 for transporting the hose to and from a hose reel 42 into the borehole 102. A motor 43 of the puller-roller 41 is provided with a motor-controller 44, which allows to control the puller-roller in such a manner that a pre-determined length of the holes can be lowered into or pulled from a borehole 102, so that the packer system 16 can be arranged at a desired height at a free-selected injection site. If the main hose 11 is stored on a reel, it is usually preferred to have an intermediate three-line hose 36 connecting the hose 11 with the pump system, rather than connecting hose 11 directly with the pump system.
In the following, the operation of the grout injection device of the present invention will be described with reference to a binary chemical grouting composition:
Typically, operation begins with drilling a borehole at the desired site into the ground and installing a TAM pipe inside the borehole.
Then, a three-line hose having a double-seal-packer at its free end is connected with its' opposite end to a pumping system fed by grouting components (for instance of a binary chemical grout system) and a cleaning fluid.
The three-line hose is lowered via a motorized puller-roller into the borehole and placed at the lowest valve plate system of the TAM pipe, which constitutes the first grout injection site.
The two components of the binary grout system are pumped separately through two lines of the three-line hose and the components are mixed in a chamber of the packer. Accordingly, the reaction can start immediately at the injection site before permeation of the grout mixture into the ground, thus allowing to use very fast reacting resins. The grout components are continuously pumped through the two lines of the three-line hose, mixed in the packer and injected into the surrounding of the injection site of the TAM pipe through appropriate valve plates of the TAM pipe until the pre-defined injection design parameters are achieved.
Once the injection is finished, the third line of the three-line hose is used to flush the packer system and the sealed space surrounding the packer system with a cleaning fluid such as grease and/or oil. As the third line is already pre-filled with cleaning fluid, cleaning can start immediately after termination of grout injection, so that even fast working resins will not damage the injection equipment. Further, only a low amount of cleaning fluid is required, thus presenting an environmental friendly solution. Finally, as only non-reacting components are transported to the lines of the hose, it is not necessary to clean the two lines for the grout components themselves.
After cleaning, the hose and packer system are lifted upwards towards the next injection site/TAM-type valve and the injection procedure is repeated.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20210302.4 | Nov 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/083433 | 11/29/2021 | WO |
