LIEVONEN, Tuomas (Varassaarenkatu 1 L, Nokia, FI-37120, FI)
HÄKKINEN, Sami (Viertokatu 35, Tampere, FI-33730, FI)
LIEVONEN, Tuomas (Varassaarenkatu 1 L, Nokia, FI-37120, FI)
| CLAIMS 1. A method for condensing, filling, or replacing soil and/or for lifting structures, the method comprising providing the soil or structure with a hole, arranging into the hole an injection bar and an expansion element arranged in connection therewith, and injecting into the expansion element, along the injection bar, a substance which expands as a consequence of a chemical reaction such that a force pressing the expansion element against the soil is generated mainly by said chemical reaction, characterized by opening, after the injected substance has reacted, a re-injection route and injecting more of the substance into the same expansion element and/or injecting the substance by using the same injection bar. 2. A method as claimed in claim 1, characterized by injecting, at least at two different injection instances, a different substance into the expansion element. 3. A method as claimed in claim 1 or 2, characterized by lifting a structure at an injection instance subsequent to a first injection instance. 4. A method as claimed in claim 3, characterized by injecting, at the first injection instance, a heavy substance and injecting, at an injection instance subsequent thereto, a light substance. 5. A method as claimed in any one of the preceding claims, characterized by opening a re-injection route by opening up an already used injection bar, and injecting the substance by utilizing the same, already used injection bar. 6. A method as claimed in claim 5, characterized by opening the re-injection route by drilling the already used injection bar open. |
BACKGROUND OF THE INVENTION
[0001 ] The invention relates to a method for condensing, filling, or replacing soil and/or for lifting structures, the method comprising providing the soil or structure with a hole, arranging into the hole an injection bar and an expansion element arranged in connection therewith, and injecting into the expansion element, along the injection bar, a substance which expands as a consequence of a chemical reaction such that a force pressing the expansion element against the soil is generated mainly by said chemical reaction.
[0002] US 2009/0155002 discloses a solution for improving soil and/or for lifting structures. According to the publication, the soil or structure is provided with a hole, and an injection bar having a fillable expansion element provided in connection therewith is arranged into the hole. A substance that expands as a consequence of a chemical reaction is injected into the expansion element. The expansion element filled with the reacted substance improves the soil or lifts and balances structures. A force pressing the expansion element against the soil is generated by the chemical reaction that expands the substance injected into the expansion element.
BRIEF DESCRIPTION OF THE INVENTION
[0003] An object of the present invention is to provide a novel solution for condensing, filling, or replacing soil and/or for lifting structures.
[0004] A method according to the invention is characterized by opening, after the injected substance has reacted, a re-injection route and injecting more of the substance into the same expansion element and/or injecting the substance by using the same injection bar.
[0005] In the disclosed solution, the soil or structure is provided with a hole, and into the hole is arranged an injection bar having a fillable expansion element provided in connection therewith. A substance that expands as a consequence of a chemical reaction is injected into the expansion element. A force pressing the expansion element against the soil is generated by the chemical reaction that expands the substance injected into the expansion element. The substance also solidifies quite quickly, so no valves are needed in the solution to keep the substance inside the expansion element. Owing to the expansion element, the expansive substance may be placed in a desired position in a controlled manner. Consequently, the localization of expansion pres- sure is completely controlled. It is possible also in loose soil, for instance, to provide the substance with a great compression strength. It is possible to arrange the injection bar into quite a small hole, so no extensive digging is necessary. The disclosed solution further comprises opening, after the injected substance has reacted, an injection route and injecting more of the substance into the same expansion element and/or injecting the substance by using the same injection bar. This enables also difficult targets to be treated precisely and accurately. Further, if the solution is used for lifting structures, the lifting becomes more stable and more accurate. All in all, the machines and devices used in the solution are quite small and simple and, in addition, the solution is excellent as far as occupational safety is concerned.
[0006] An idea of an embodiment is that the injection route is opened by opening up, e.g. by drilling, an injection bar that has already been used, and injecting the substance by utilizing the same, already used injection bar. In such a case, the re-injection of the substance into the same expansion element is reasonably quick as well as simple and easy.
[0007] An idea of an embodiment is that at an instance of injection subsequent to a first instance of injection, a structure is lifted. Thus, when lifting the structure, the soil has already been improved, so the structure to be lifted has a strong support and the lifting can be carried out in a controlled manner.
BRIEF DESCRIPTION OF THE FIGURES
[0008] The invention is described in closer detail in the accompanying drawings, in which
Figures 1 , 2, 3, and 4 show different stages of lifting a structure.
[0009] For the sake of clarity, the figures show some embodiments of the invention in a simplified manner. Like reference numerals identify like elements.
DETAILED DESCRIPTION OF THE INVENTION
[0010] In Figure 1 , reference numeral 1 designates a structure that has subsided downwards into soil 2. The structure 1 may be e.g. the foundations of a house or another building, a road surface or a road structure.
[0011] In order to lift the structure, a hole 3 is made through the structure 1 and in to the soil 2, and through the hole 3 an injection bar 4 and an expansion element 5 external to the injection bar 4 are arranged in place. The structure 1 may have subsided on account of a cavity 6 in the soil 2, for instance. However, no cavity necessarily exists in the soil 2 but the structure of the soil may be too loose or soft such that the structure 1 subsides or has subsided downwards. After the injection bar 4 and the expansion element 5 have been arranged in a desired position, a substance 8 which expands as a consequence of a chemical reaction is injected into the expansion element 5 through the injection bar 4. The expansion element 5 filled with the reacted substance fills the cavity 6. In addition, the expansion element 5 may condense and/or replace the surrounding soil as illustrated in Figure 2.
[0012] As illustrated in Figures 1 and 2, at the beginning of an injection procedure the injection bar 4 is inserted into a lower part of the expansion element 5 and, during injection, the injection bar 4 is pulled outwards, out of the expansion element 5. At a first injection stage, an amount of the injectable substance 8 that is smaller than the maximum volume of the expansion element 5 is injected. By inserting the injection bar 4 into the lower part of the expansion element 5, the injectable substance 8 is arranged to be located in the lower part of the expansion element 5 and the expansion element 5 is made to fill up towards its upper part during injection when the injection bar 4 is pulled out of the expansion element 5.
[0013] Furthermore, a structure to enable the expansion element 5 to expand only after a sufficiently high expansive power is provided inside the expansion element may be arranged outside the expansion element 5. This structure may be e.g. a plastic film with a perforation line allowing the structure to be torn in a controlled manner therealong when the injectable substance expands. This enables the expansion element 5 to be filled from bottom to top.
[0014] Further, the injection bar 4 and the expansion element 5 are sealed to the hole 3 e.g. by a sleeve 7 to prevent the injectable substance from penetrating through the hole 3.
[0015] After the injectable substance has reacted and solidified and/or hardened, a re-injection route 9 is opened inside the injection bar. At this stage, the substance may have reached more than 50%, preferably more than 70%, and particularly preferably more than 80% of its final hardness. The re-injection route 9 may be opened e.g. by drilling. The re-injection route 9 is made slightly longer than the injection bar 4, i.e. the re-injection route 9 extends to the area of the substance 8 as illustrated in Figure 3. In such a case, the re-injectable substance can be made to spread inside the already reacted substance. When the injectable substance 8 is a substance that expands as a consequence of a chemical reaction, it is possible to inject more of a substance inside the injectable substance 8, and when this substance expands, it penetrates through the pores of the already reacted substance. The re- injectable substance, i.e. additional substance, breaks the structure of the already reacted substance. Further, upon expanding, the additional substance condenses into connection with the already reacted substance.
[0016] Figure 4 shows how a substance has been re-injected into the expansion element 5. This re-injected substance lifts up the structure 1 as illustrated in Figure 4. When the amount of the injectable substance 8 injected at the first injection stage is smaller than the amount the expansion element 5 could hold, it is also possible to fit this substance injected during the re- injection inside the expansion element 5. The expansion element 5 is thus provided with a wall portion that is loosely arranged around the injection bar 4 and allowed to slide from outside the injection bar 4 to below the structure 1 , thus enabling a controlled lifting procedure.
[0017] An outer diameter of the injection bar 4 may vary e.g. between 3 and 200 mm. A length of the injection bar 4 may vary e.g. between 0.5 and 25 m. The injection bar 4 may be made e.g. from metal, such as steel.
[0018] The injection bar 4 may also be made from another material, such as plastic, e.g. polyethylene PE. Further, the injection bar 4 does not necessarily have to be rigid. Thus, the injection bar 4 may be a flexible tube or a pipe made from plastic. Furthermore, if the injection bar 4 is a flexible tube, its wall may be provided with textile reinforcement fabrics or metal or other corresponding reinforcements.
[0019] The expansion element 5 may be made from a material that is impermeable to air and substantially non-stretchable. Further, the wall of the expansion element may also let a material seep therethrough, and the wall of the expansion element may even be made from a stretchable material. An example of the material for the expansion element 5 is a geotextile. Further, another flexible and strong material may also be used.
[0020] The material of the expansion element may be a plastic, such as polyester or polypropylene, or artificial fibre or natural fibre. The material may also be rubber or another elastomer. The wall of the expansion element may be permeable to air or it may be impermeable to air. The wall of the expansion element may also be flexible or inflexible. The wall of the expansion element may be provided with a metal reinforcement material or fibreglass or another suitable reinforcement material, as discussed above in connection with the injection bar made from a flexible tube. The expansion element may be either seamless or it may have seams. A seam may be provided e.g. by sewing, gluing, using a fastening element, stapling, welding, soldering, melting, or by another mechanical, chemical, thermal, or electrotechnical method or a combination thereof.
[0021] A thickness of the wall of the expansion element may vary e.g. between 0.02 and 5 mm, depending on the material, size of the expansion element, expansion pressure, etc.
[0022] Before the injection bar 4 is arranged into the soil, the expansion element 5 is wound or folded against the injection bar 4. When the expansion element 5 is full of a solid substance, its outer diameter may vary e.g. between 20 cm and 2 m. Similarly, a length of the expansion element 5 may vary e.g. between 20 cm and 20 m.
[0023] The expansion element 5 may be e.g. cylindrical in shape. Further, the expansion element may have narrower upper and lower ends while a middle section has a larger diameter. Before the substance is injected into the expansion element, the external form or shape of the expansion element is irrelevant. Once the substance has reacted inside the expansion element, the expansion element reaches its final external appearance.
[0024] The injectable substance may be e.g. a polymer, an expansive resin, or an organically incrystallizable, chemically expansive multicompo- nent substance.
[0025] The injectable substance may be e.g. a mixture mainly of two components. In such a case, a first component may mainly contain e.g. a poly- ether polyol and/or a polyester polyol. A second component may contain e.g. an isocyanate. The volumetric ratios of the first component to the second component may vary e.g. within a range of 0.8 to 1 .2 : 0.8 to 1 .8. The expansive injectable substance may further contain catalysts and water and, when desirable, also other components, such as silica, rock dust, fibre reinforcements, and other possible additional and/or auxiliary agents.
[0026] The injectable substance is preferably such that it starts reacting by expanding within 0.5 to 3600 s after being injected into the expansion element. In an embodiment, the substance starts reacting within more than 20 or more than 25 s after being injected. In still another embodiment, the substance starts reacting within less than 50 s after being injected.
[0027] The substance expands to a volume that is e.g. 1 to 120 times the original volume. The expansion coefficient of the substance, i.e. the volume of the substance at the end of the reaction as compared with the volume of the substance at the beginning of the reaction, may be e.g. in the order of 1 .1 to 120. Preferably, the substance is arranged to expand to a volume that is 1 .5 to 20 times the original volume.
[0028] A different substance may be injected into the expansion element at different injection instances. For example, at the first injection instance a heavy substance may be injected to condense, fill and/or replace the surrounding soil, depending on the type and density of the surrounding soil. The replacement takes place by pushing the existing soil to the side. The soil may be compactable or non-compactable. At an instance of injection subsequent to the first instance of injection, e.g. while lifting a structure, a light substance, which thus has a high expansive power, may be injected into the same expansion element. In this context, the lightness and heaviness of a substance are determined as a free expansion density, i.e. as a level of density of the substance when freely foamed at a temperature of 20°C. A heavy substance may have a free expansion density e.g. of 300 kg/m 3 while a light substance may correspondingly have a free expansion density of 30 kg/m 3 . The free expansion density of a heavy substance may vary e.g. between 50 and 500 kg/m 3 and, in turn, the free expansion density of a light substance may vary e.g. between 5 and 50 kg/m 3 .
[0029] At some stage, an exclusively hardenable but not expandable substance may also be injected into the expansion element.
[0030] The re-injection route may be opened e.g. by drilling an already used injection bar open or by opening an already used injection bar in another mechanical manner, such as by pressing, vibrating, milling, or in some other suitable mechanical manner. Further, the opening up of an injection bar that has already been used may be carried out by chemically cleaning or dissolving the reacted substance, in which case the substance either becomes structurally destroyed or liquefied. Further, a thermodynamic method comprising melting the substance may be used. In addition, at the end of the injection procedure, the injection bar may be blown empty e.g. by pressurized air, or the reacting substance may be replaced by a non-reacting substance, such as a polyol or castor oil exclusively. After this, re-injection may be carried out by sucking or blowing the injection bar containing a non-reacting substance empty and, subsequently, performing re-injection. Further, the injection bar containing a non-reacting substance may be emptied when carrying out re-injection with an expandable substance.
[0031] It is also possible to provide the opened injection route with one or more new injection bars to be placed either inside or outside the already used injection bar.
[0032] It is not necessary to re-use the same, already used injection bar. Alternatively, it is thus possible to provide an already injected element with a new injection bar in a desired position such that the substance may be injected into the already injected element. Therefore, the already injected element is provided with a route for a new bar.
[0033] It is also possible to inject a substance into several different elements through the same injection route. The elements may be fastened to one another or they may be separate ones.
[0034] Injection may be carried out in different stages, in which case a desired amount of a substance is fed to a desired position of an element. In the injection, it is possible to use either the same substance or a different substance. This enables the element to be structurally developed at desired points and e.g. its structural properties, such as strength or size, to be modified. In such a case, the structure is thus not necessarily lifted at all.
[0035] The injectable substance may be fed into the injection element at an end of the injection bar, as shown in the accompanying drawings. Further, the injection bar may be manufactured such that its sides are provided with channels, openings or holes which enable a substance to be fed into the element also elsewhere than from an end of a pipe, i.e. through the wall of the injection bar.
[0036] If the lifting brings about any generation of an empty space e.g. underneath a structure, the empty space may be filled e.g. with another element or by injecting the substance freely in order to fill and compress the empty space. Furthermore, the substance may be injected freely also in order to achieve a uniform structure between several different elements. If several elements are fastened to one another, it is advantageous that the fastening points form a strong structure so as to enable lifting forces and a necessary structural strength to be achieved. [0037] In some cases, the features disclosed in this application may be used as such, irrespective of other features. On the other hand, when necessary, the features disclosed in the present application may be combined in order to provide different combinations.
[0038] The drawings and the related description are only intended to illustrate the idea of the invention. The details of the invention may vary within the scope of the claims.