JP2011032831A - Method of injecting ground improving chemical - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of injecting a ground improving chemical, by which the ground improving chemical can be stably injected in a predetermined area even when the ground is soft and sandy. <P>SOLUTION: An outer pipe packers 11, which is provided on a surface of an outer pipe 3 inserted into an insertion hole S filled with a slow-setting filling material D of water glass type having the specific gravity larger than that of the groundwater existing under the ground, are expanded. Subsequently, a flash-setting solidifying liquid C fed through an inner pipe inserted into the outer pipe 3 is injected into the ground from an injection port 3a positioned between the outer pipe packers 11 to form a packer P. Then, after the inner pipe is pulled out of the outer pipe 3, another inner pipe 5B is inserted into the outer pipe 3. The ground improving chemical G is fed from a third discharging port 5c arranged between two expanded packers 6b through the inner pipe 5B, and injected into the ground through the injection port 3a covered by a porous covering material 10 positioned separately from the packer P. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for injecting a ground improvement chemical solution, and more particularly to a method for injecting a ground improvement chemical solution that can be stably injected into a set range even in a soft sandy ground.

  Conventionally, in order to strengthen the ground, various methods for injecting a ground improvement chemical solution into a target ground using a double pipe having a packer for each of an outer pipe and an inner pipe have been proposed. In the case of soft ground, after inserting the outer tube into the drilled insertion hole, expand the packer provided on the outer tube, or remove the packer provided on the outer tube from the inner peripheral surface of the insertion hole. There has been proposed a method of carrying out construction by expanding so as to have (see Patent Document 1).

  In these methods, when the inner peripheral surface of the insertion hole in the vicinity where the packer provided in the outer pipe is located collapses, when the packer provided in the outer pipe is expanded, the inner surface of the packer and the insertion hole The gap may become too large, and the instantaneous solidifying solution may enter the gap and block the injection port of the ground improvement chemical solution, making injection impossible. Therefore, it is important not to cause a collapse of the inner peripheral surface of the insertion hole, but conventionally no countermeasure has been taken.

JP 2009-57826 A

  An object of the present invention is to provide a method for injecting a ground improvement chemical solution that can stably inject a ground improvement chemical solution into a set range even in a soft sandy ground.

  In order to achieve the above object, the ground improvement chemical solution injection method of the present invention inserts an outer tube having a plurality of injection holes provided in the peripheral wall in the axial direction into an insertion hole formed in the ground. Insert the inner tube into the tube to a predetermined position, expand the two inflatable packers spaced apart in the axial direction on the surface of the inner tube, and press the inner tube on the inner peripheral surface of the outer tube, A method of injecting a ground improvement chemical solution by supplying a ground improvement chemical solution from a discharge port provided on a peripheral wall of an inner tube located between the two inflated packers and injecting the ground improvement solution from an injection port of an outer tube. The surface of the outer tube is provided with two inflatable outer tube packers spaced apart in the axial direction across at least one injection port, and the inlet located at a position different from the position where the outer tube packer is provided Is covered with a porous coating material, which is more than the groundwater present in the ground. The outer tube packer in a contracted state is expanded by inflating the outer tube packer in a state where the outer tube is inserted into the insertion hole into which a water glass-based slow-binding filler having a specific gravity is injected. The instantaneous solidifying liquid was injected into the ground from the inlet located between the outer tube packers to form a packer made of the instantaneous solidifying liquid around the inlet, and then covered with the porous coating material. The ground improvement chemical solution is injected into the ground from the inlet.

  Here, the loose filler is injected into the casing rod after drilling the insertion hole, and after inserting the outer tube into the casing rod, the casing rod is pulled out on the ground, thereby The outer tube can also be inserted into the insertion hole into which the slow-binding filler is injected. Alternatively, the outer tube is inserted into the casing rod after drilling the insertion hole, the loose filler is injected into the gap between the casing rod and the outer tube, and then the casing rod is pulled out on the ground. Thus, the outer tube can be inserted into the insertion hole into which the loose-binding filler is injected.

  An inner tube different from the inner tube is inserted into the outer tube, and two inflatable packers that are spaced apart in the axial direction on the surface of the other inner tube are inflated to the inner peripheral surface of the outer tube. Injected into the ground from the inlet of the outer pipe by supplying the instantaneous solidification liquid from the outlet provided in the peripheral wall of the inner pipe located between the two inflated packers in a pressure contact state And after forming the packer which consists of the said instantaneous setting solidification liquid, this inner pipe | tube is pulled out and the inner pipe | tube which supplies the said ground improvement chemical | medical solution can also be inserted in an outer pipe | tube. Alternatively, the two expandable packers provided on the surface of the inner tube and spaced apart in the axial direction are inflated and pressed against the inner peripheral surface of the outer tube, and the two expanded packers are expanded. After the instantaneous solidifying liquid is supplied from the discharge port provided on the peripheral wall of the inner pipe located between the outer pipe and the ground, the packer made of the instantaneous solidifying liquid is formed. The ground improvement chemical can be supplied through the inner pipe.

  In the ground improvement chemical liquid injection method of the present invention, when the instantaneous solidifying liquid is supplied from the discharge port provided in the peripheral wall of the inner tube located between the two inflated packers, the supplied instantaneous settling is performed. The outer tube packer is expanded to fill the inner tube with the internal solid surface of the insertion hole and the supply port located between the expanded outer tube packer. It is also possible to inject an instantaneous solidifying liquid into the ground. Further, the insertion hole can be formed in the horizontal direction by changing its direction in the middle.

  According to the present invention, in the insertion hole drilled in the ground, the outer tube having a plurality of inlets provided in the peripheral wall and spaced apart in the axial direction is inserted, and then the inner tube is inserted into the outer tube to a predetermined position, Two inflatable packers that are spaced apart in the axial direction on the surface of the inner tube are inflated and pressed against the inner peripheral surface of the outer tube, and between the two inflated packers. When the ground improvement chemical solution is supplied from the discharge port provided in the peripheral wall of the inner tube and is injected into the ground from the injection port of the outer tube, the inflatable outer tube packer provided on the surface of the outer tube is used to instantly By forming the packer with the coagulating solidified liquid, the gap between the inner peripheral surface of the insertion hole and the outer peripheral surface of the outer tube can be reliably sealed. Here, since the outer tube is inserted into the insertion hole into which the water glass-based loose filler having a specific gravity larger than the groundwater existing in the ground is injected, this slow filler is inserted. As a result, the inner peripheral surface of the insertion hole is much less likely to collapse compared to the case where the loose filler is not injected.

  Therefore, when the ground improvement chemical solution is injected into the ground from the injection port located at a position different from the packer formed by the instantaneous setting solidified solution, the injection port is not blocked by the instantaneous setting solidified solution. In addition, it is possible to suppress the outflow of the ground improvement chemical solution into the gap between the inner peripheral surface of the insertion hole and the outer peripheral surface of the outer tube.

  On the other hand, since the slow-setting filler is a water glass-based material, it does not substantially impede injection of the quick setting solidified liquid and the ground improvement chemical liquid into the ground. Moreover, since the specific gravity of the slow-binding filler is larger than the groundwater existing in the ground, the movement of the groundwater trying to flow into the insertion hole can be prevented, and the inner peripheral surface of the insertion hole is difficult to collapse.

  In addition, by injecting the ground improvement chemical liquid into the ground from the injection port covered with the porous coating material, even if the injection pressure is large, the ground improvement chemical liquid is spread over a wide range while being appropriately decompressed by the porous coating material. . As a result, even if the injection pressure is increased, the ground improvement chemical solution will not enter the specific area where the ground is relatively weak so as to tear the ground. It becomes possible to inject a chemical solution.

It is explanatory drawing which illustrates the state which is pouring the slow-binding filler into the inside of the casing rod after drilling the ground. It is explanatory drawing which illustrates the state which inserted the outer tube | pipe in the casing rod of FIG. It is explanatory drawing which illustrates the state in which the outer tube is inserted in the insertion hole in which the slow-binding filler is injected. It is explanatory drawing which illustrates the state which is inject | pouring the loose-binding filler into the clearance gap between the casing rod and outer pipe after drilling the ground. It is explanatory drawing which illustrates the state which inserted the inner tube | pipe which supplies a quick setting solidification liquid to an outer tube | pipe. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is explanatory drawing which illustrates the state which the outer tube | patter packer expanded. It is explanatory drawing which illustrates the state which is inject | pouring the instantaneous setting solidification liquid into the ground. It is explanatory drawing which illustrates the state which inserted the inner tube | pipe which supplies a ground improvement chemical | medical solution to an outer tube | pipe. It is B1-B1 sectional drawing of FIG. It is explanatory drawing which illustrates the state which is inject | pouring the ground improvement chemical | medical solution into the ground. It is explanatory drawing which illustrates the formed improved ground. It is sectional drawing which illustrates the inner pipe | tube provided with the switching means. It is explanatory drawing which illustrates the state which extends the casing rod in the horizontal direction and forms the insertion hole. It is explanatory drawing which illustrates the state which has inserted the outer tube | pipe into the casing rod. It is explanatory drawing which illustrates the state which pulled out the casing rod, after expanding the anchor provided in the front-end | tip of an outer tube. It is explanatory drawing which illustrates the state which is inject | pouring the instantaneous setting solidification liquid into the ground. It is explanatory drawing which illustrates the state which is inject | pouring the ground improvement chemical | medical solution into the ground. It is explanatory drawing which illustrates the formed improved ground. It is explanatory drawing which shows another example of an outer tube | pipe. It is explanatory drawing which illustrates the state which supplies the instantaneous setting solidification liquid from the inner tube inserted in the outer tube | pipe of FIG. 21, and is expanding the outer tube | pipe packer. It is explanatory drawing which illustrates the state which is inject | pouring the instantaneous setting solidification liquid into the ground.

  Hereinafter, a method for injecting a ground improvement chemical solution of the present invention will be described based on embodiments. First, the case where the insertion hole formed by drilling the ground up and down is used will be described as an example.

  As illustrated in FIGS. 5 to 7, the injection device used for implementing the ground improvement chemical solution injection method of the present invention includes an outer tube 3 inserted into an insertion hole S formed by drilling the ground, and this The inner tube 5A is inserted into the outer tube 3 and is movable in the outer tube axial direction. The inner pipe 5A supplies the instantaneous solidifying liquid C. In addition to the inner tube 5A, as illustrated in FIGS. 10 and 11, an inner tube 5B that supplies the ground improvement chemical solution G that is inserted into the outer tube 3 and is movable in the outer tube axis direction is provided. Yes.

  In the peripheral wall of the outer tube 3, a plurality of injection ports 3 a that communicate the inner side and the outer side of the tube are formed apart from each other in the outer tube axis direction. Further, two inflatable outer tube packers 11 are provided on the surface of the outer tube 3 so as to be separated from each other in the outer tube axial direction. The two outer tube packers 11 are arranged such that at least one injection port 3a exists on the peripheral wall of the outer tube 3 between them. Examples of the outer tube packer 11 include a swelling material that absorbs moisture and expands, or a sealing material that can be expanded and contracted by a fluid pressure of gas or liquid flowing into and out of the inside.

  The two outer tube packers 11 are configured to have a gap between the inner peripheral surface of the insertion hole S when expanded. That is, there is a gap adjusting means for adjusting so that a gap is formed between the outer tube packer 11 and the inner peripheral surface of the insertion hole S when the outer tube packer 11 is expanded. As the gap adjusting means, it can be exemplified that the specification of the outer tube packer 11 itself is set so as to have a gap with the inner peripheral surface of the insertion hole S when it is expanded to the maximum. Examples of the other gap adjusting means include a flow rate adjusting means for fluid supplied to expand the outer tube packer 11, a fluid pressure adjusting means, a check valve 12 described later, and a combination thereof.

  The lower limit of the size of the gap between the expanded outer tube packer 11 and the inner peripheral surface of the insertion hole S is only required to allow the quick setting solidified liquid C to pass, and the upper limit is 1.0 cm, preferably about 0.5 cm. Therefore, if the expanded outer tube packer 11 is in contact with the inner peripheral surface of the insertion hole S without being in pressure contact, and the instantaneous solidifying liquid C can pass through, it corresponds to the gap of the present invention.

  In the present invention, the expanded outer tube packer 11 can be set so as to contact the inner peripheral surface of the insertion hole S.

  A porous coating material 10 is provided on the surface of the outer tube 3 at a position different from the position where the outer tube packer 11 is provided. The inlet 3 a in the region where the porous coating material 10 is provided is covered with the porous coating material 10.

  In the present invention, the two-liquid type instantaneous solidification liquid C is injected into the ground through the injection port 3 a disposed between the outer tube packers 11, and the ground improvement chemical solution G is injected through the injection port 3 a covered with the porous coating material 10. Is injected into the ground. Examples of the ground improvement chemical solution G include water glass grout and cement grout, and the gelation time is, for example, about one day. The two-liquid type instantaneous solidifying liquid C is a liquid that rapidly solidifies by, for example, mixing C1 liquid and C2 liquid, and has a solidification time of about 5 to 30 seconds. Examples of the quick setting solidified liquid C include water glass grout, plastic grout and the like.

  The inlet 3a has a diameter of about 3 mm to 10 mm, for example, and the number thereof is appropriately determined. For example, the area between the outer tube packer 11 and the porous coating material 10 is three to three. About 8 are provided.

  The porous coating material 10 has a large number of through-holes having an area smaller than that of the injection port 3a, and is formed of resin, metal, or the like. Examples of the form of the porous coating material 10 include a net-like body such as a resin mesh and a metal mesh, and a porous plate. The thickness of the porous coating material 10 is set to about 0.2 mm to 1.0 mm, for example, and a specification having a large number of minute through holes is preferable.

  As the porous coating material 10, a cylindrical knitted body formed by braiding resin fibers can also be used. For example, a plurality of nylon resin fibers having a wire diameter of about 0.1 mm to 0.5 mm are juxtaposed to form a belt-like body, and the plurality of belt-like bodies are knitted at a predetermined braiding angle to form a cylinder.

  In this embodiment, a cylindrical body whose tip is sealed is used as the outer tube 3, and the injection port 3 a formed at the tip is covered with the porous coating material 10. Then, the injection port 3a located on the rear end side of the region covered with the porous coating material 10 is wound around the surface of the outer tube 3 so that the two outer tube packers 11 are sandwiched in the front-rear direction (in the outer tube axial direction). Yes. The outer diameter of the outer tube 3 is, for example, about 40 mm to 50 mm, and the thickness of the peripheral wall is about 2 mm to 5 mm.

  The inner pipe 5A has two inflatable / expandable packers 6a spaced on the surface thereof in the inner pipe axis direction, and C1 of the instantaneous solidification liquid C is formed on the peripheral wall between the two inflatable / defensible packers 6a. A first discharge port 5a for supplying a liquid and a second discharge port 5b for supplying a C2 liquid are arranged. The inside of the inner tube 5A is divided into two as illustrated in FIG. 6, and there are two flow paths, a first solidified liquid flow path 7a through which the C1 liquid flows and a second solidified liquid flow path 7b through which the C2 liquid flows. It has a formed structure. The first discharge port 5a and the second discharge port 5b are formed so that the discharge destinations are close to each other.

  Inside the inner pipe 5A, packer expansion pipes 8a are extended in the inner pipe axis direction and connected to the respective packers 6a. The packer 6a is formed of a hollow elastic body such as rubber that can be expanded and contracted, expands by inflow of fluid through the packer expansion pipe 8a, and contracts by outflow of fluid.

  As illustrated in FIGS. 10 and 11, the other inner tube 5B has two inflatable and contractible packers 6b spaced on the surface thereof in the inner tube axis direction. A third discharge port 5c for supplying the ground improvement chemical solution G is disposed on the peripheral wall. The inside of the inner pipe 5B is a chemical solution flow path 7c through which the ground improvement chemical solution G flows.

  Inside the inner pipe 5B, packer expansion pipes 8b extend in the inner pipe axis direction and are connected to the respective packers 6b. The packer 6b is formed of a hollow elastic body that can be expanded and contracted, such as rubber. The packer 6b expands by inflow of fluid through the packer expansion pipe 8b and contracts by outflow of fluid.

In this embodiment, a cylindrical body whose tip is sealed is used as the inner tubes 5A and 5B.
When the ground is improved and improved by the ground improvement chemical solution G, as shown in FIG. 1, first, the casing rod 2 is extended downward from the drilling machine, and the ground is drilled in the vertical direction to insert the insertion hole S. Form. Thereafter, a slow-binding filler D is injected into the casing rod 2.

  Next, as illustrated in FIG. 2, the outer tube 3 is inserted into the casing rod 2 in which the slow-binding filler D is injected. Thereafter, the casing rod 2 is pulled out on the ground. Thereby, as illustrated in FIG. 3, the outer tube 3 is inserted into the insertion hole S into which the loose filler D is injected.

  Alternatively, as illustrated in FIG. 4, the outer tube 3 is inserted into the casing rod 2 after the insertion hole S has been drilled, and the loosely packed filler D is injected into the gap between the casing rod 2 and the outer tube 3. To do. Thereafter, the casing rod 2 is pulled out on the ground. Thereby, as illustrated in FIG. 3, the outer tube 3 is inserted into the insertion hole S into which the loose filler D is injected.

  Thus, in this invention, before pulling out the casing rod 2 on the ground, the slow-binding filler D is injected into the inside of the casing rod 2. Thereafter, the casing rod 2 is pulled out on the ground, so that the outer tube 3 is inserted into the insertion hole S into which the slow-binding filler D is injected.

  In order to smoothly pull out the casing rod 2 on the ground while the outer tube 3 is inserted into the insertion hole S, an expandable anchor may be provided at the lower end of the outer tube 3. When such an outer tube 3 is used, the outer tube 3 is fixed to the ground by expanding the anchor larger than the inner diameter of the casing rod 2 at a position where the anchor protrudes from the lower end of the casing rod 2, and thereafter Pull out the casing rod 2.

  Here, when the ground is very soft, if the ground water flows into the insertion hole S after the casing rod 2 is pulled out on the ground, the inner peripheral surface of the insertion hole S is likely to collapse. Therefore, in the present invention, a slow-binding filler D that functions so as not to allow groundwater to flow into the insertion hole S is injected into the insertion hole S. Thereby, even if the sandy geology is soft and easily collapsed, the occurrence of collapse of the inner peripheral surface of the insertion hole S can be suppressed.

  As the slow-binding filler D, a water-glass-based solidifying solidification liquid having a specific gravity larger than that of groundwater present in the target ground on which the ground improvement work is performed is used. The solidification time (gelation time) until the slow-setting filler D is solidified (gelled) from a liquid is, for example, about one week to one month. Specific examples of the slow-setting filler D include water glass grout.

  As will be described later, the instantaneous setting solidified liquid C and the ground improvement chemical liquid G are injected from the insertion hole S toward the ground on the outer periphery of the insertion hole S in a later step. For this reason, when a filler containing a large number of clay particles such as bentonite is used, injection of the instantaneous solidifying liquid C and ground improvement chemical liquid G into the ground is obstructed by the filler. In order to avoid such a problem, a water glass-based slow-setting solidified liquid is used as the slow-setting filler D.

  In the case of sandy soil, unless the groundwater moves into the insertion hole S, the inner peripheral surface of the insertion hole S does not collapse. Therefore, the specific gravity of the slow-setting filler D is set larger than that of the groundwater existing in the ground. For example, if the groundwater existing in the ground is fresh water, the specific gravity of the loose filler D is set to more than 1.0, and if the groundwater present in the ground is seawater (specific gravity is about 1.03), the looseness The specific gravity of the filler D is set to exceed 1.03. The upper limit of the specific gravity of the slow-binding filler D is, for example, about 1.20, and the range of the specific gravity of the slow-binding filler D is approximately 1.01 to 1.20.

  After the outer tube 3 is inserted into the insertion hole S into which the slow-binding filler D is injected, the inner tube 5A is inserted into the outer tube 3 as illustrated in FIG. The outer tube packer 11 in the contracted state is in an expanded state so as to have a gap with the inner peripheral surface of the insertion hole S as illustrated in FIG.

  Next, the first discharge port 5a and the second discharge port 5b of the inner tube 5A inserted in the outer tube 3 are aligned with the position of the injection port 3a between the two expanded outer tube packers 11. Position it. During this positioning, the packer 6a is kept in a contracted state.

  After positioning, as illustrated in FIG. 9, the packer 6 a is inflated and brought into pressure contact with the inner peripheral surface of the outer tube 3. In this state, the C1 liquid is supplied from the first discharge port 5a, and the C2 liquid is supplied from the second discharge port 5b. Thereby, C1 liquid and C2 liquid are mixed and it becomes the quick setting solidification liquid C. Since the first discharge port 5a and the second discharge port 5b are sandwiched between the two expanded packers 6a, the C1 liquid and the C2 liquid are separated from the inner peripheral surface of the outer tube 3 and the outer peripheral surface of the inner tube 5A. There is no leakage in the gap.

  Immediately before being injected into the ground in this manner, the instantaneous solidifying liquid C obtained by mixing the C1 liquid and the C2 liquid is injected into the ground through the inlet 3a located between the two expanded packers 6a. Since the injection port 3a for injecting the instantaneous solidifying liquid C is sandwiched between the two outer tube packers 11, the instantaneous solidifying liquid C is guided between the two outer tube packers 11 to the ground. Injected.

  The slow-setting filler D filled in the outer periphery of the injection port 3a for injecting the instantaneous solidifying liquid C is pushed into the ground by the injected instantaneous solidifying liquid C. Since it is a water glass-based slow-setting filler D, it does not contain clay particles, and since it is not solidified at this point, injection of the instant-setting solidified liquid C into the ground is not substantially hindered.

  Here, since there is a predetermined gap between each outer tube packer 11 and the inner circumferential surface of the insertion hole S, the outer tube packer 11 does not press the inner circumferential surface of the insertion hole S. Therefore, even when the strength of the inner peripheral surface of the insertion hole S is low (weak sandy ground) or the like, the inner peripheral surface of the insertion hole S is not broken by the expanding outer tube packer 11. In addition, even in the sandy ground, when the construction is performed on the ground where the inner peripheral surface of the insertion hole S is less likely to collapse even when the expanded outer pipe packer 11 contacts, the outer pipe packer 11 is inserted into the insertion hole S. It can also be inflated so as to contact the inner peripheral surface.

  Moreover, since the instantaneous setting solidified liquid C also circulates outside the outer tube packer 11 through this gap, the instantaneous setting solidified liquid C can be injected into a wider area of the ground. On the other hand, since the clearance between the inner peripheral surface of the insertion hole S and the outer peripheral surface of the outer tube 3 is smaller than when the outer tube packer 11 is not expanded, the outer tube packer 11 and the inner peripheral surface of the insertion hole S The instantaneous solidifying liquid C does not flow out excessively through the gap (about 1.0 cm at the maximum). Therefore, the instantaneous setting solidified liquid C can be reliably injected into the ground and rapidly solidified to form a strong packer P around the injection port 3a.

  Thereby, the gap between the inner peripheral surface of the insertion hole S and the outer peripheral surface of the outer tube 3 can be reliably sealed by the packer P formed of the instantaneous setting solidified liquid C. In particular, when the first discharge port 5a and the second discharge port 5b formed so that the discharge destinations are close as illustrated in FIG. 6 are mixed so that the C1 liquid and the C2 liquid collide, It becomes easy to mix each other uniformly.

  Next, the packer 6a is contracted, the inner tube 5A is pulled out from the outer tube 3, and another inner tube 5B is inserted into the outer tube 3 as illustrated in FIG. And it positions so that the 3rd discharge port 5c may be united with the position of the injection port 3a covered with the porous coating material 10. FIG. During this positioning, the packer 6b is kept in a contracted state.

  After the positioning, the packer 6b is expanded by the fluid supplied through the packer expansion pipe 8b illustrated in FIG. 11 and is brought into pressure contact with the inner peripheral surface of the outer tube 3. In this state, as illustrated in FIG. 12, the ground improvement chemical solution G is supplied from the third discharge port 5c. Since the third discharge port 5c is sandwiched between the two expanded packers 6b, the ground improvement chemical G does not flow out between the inner peripheral surface of the outer tube 3 and the outer peripheral surface of the inner tube 5B. .

  The supplied ground improvement chemical solution G is injected into the ground through the injection port 3a. Even if the ground improvement chemical solution G to be injected flows out between the inner peripheral surface of the insertion hole S and the outer peripheral surface of the outer tube 3, The outflow is blocked by the packer P.

  The slow-setting filler D filled in the outer periphery of the injection port 3a for injecting the ground improvement chemical solution G is pushed into the ground by the injected ground improvement chemical solution G. Since it is a water glass-based slow-filling filler D, it does not contain clay particles, and since it is not solidified at this point, injection of the ground improvement chemical G to the ground is not substantially hindered.

  Moreover, when the ground improvement chemical | medical solution G is inject | poured into a ground, it passes the porous coating | covering material 10 which covers the injection port 3a. Therefore, even if the injection pressure is large, the pressure is reduced moderately by the porous coating material 10 so that the ground improvement chemical solution G does not simply go straight from the injection port 3a in the direction orthogonal to the outer tube axis (horizontal direction) but spread over a wide range. Become.

  In this way, even when the injection pressure is increased, the ground improvement chemical solution G does not enter the specific area of the relatively weak ground so as to tear the ground, as illustrated in FIG. Thus, it becomes possible to stably inject the ground improvement chemical solution G within the set predetermined range.

  When the ground improvement chemical solution G is injected into the ground at another height position, the outer tube packer 11 and the porous coating material 10 described above are also provided at another height position of the outer tube 3. Then, the inner pipes 5A and 5B inserted into the outer pipe 3 are sequentially moved to appropriate positions, and the same procedure as described above is performed.

  The slow-setting filler D may be injected and filled up to the upper end of the insertion hole S, but at least up to a height position covering the injection port 3a for injecting the instantaneous setting solidified liquid C at the highest position. ,inject.

  When a cylindrical knitted body made of resin fibers is used as the porous coating material 10, the ground improvement chemical solution G passes through the gaps between the resin fibers and is injected into the ground. In this case, the resin fibers are knitted so as to cross each other up and down, and since the ground improvement chemical solution G also passes through the gaps between the resin fibers that are overlapped with each other, the injection pressure is easily equalized and stably spread over a wide range. It is further advantageous to spread the ground improvement chemical solution G.

  In the above-described embodiment, the instantaneous setting solidified liquid C and the ground improvement chemical liquid G are supplied using different inner pipes 5A and 5B. However, as illustrated in FIG. Moreover, the instantaneous setting solidified liquid C and the ground improvement chemical | medical solution G can also be supplied. The inner tube 5C is provided with a switching means 9 for switching and supplying the ground improvement chemical solution G and the instantaneous solidifying solution C to the inner tube 5A shown in FIG. The switching means 9 is installed on the ground, and a pipe extending from the switching means 9 is connected to the rear end portion of the inner pipe 5C.

  When this inner tube 5C is used, until the packer P is formed by the instantaneous solidifying liquid C, the instantaneous solidifying liquid C (C1 liquid, C2 liquid) is supplied to the inner pipe 5C by the setting of the switching means 9. The same procedure as in the above embodiment is performed. Thereafter, when the ground improvement chemical solution G is injected into the ground, the setting of the switching means 9 is switched to supply the ground improvement chemical solution G to the inner pipe 5C. That is, the first solidified liquid flow path 7a and the second solidified liquid flow path 7b are switched to the chemical liquid flow path 7c, and the inner tube 5C is moved in the outer tube axis direction to be positioned at a predetermined position. And the 1st discharge port 5a and the 2nd discharge port 5b are functioned as the 3rd discharge port 5c, the ground improvement chemical | medical solution G is supplied, and the ground improvement chemical | medical solution G is grounded from the injection port 3a covered with the porous coating | covering material 10. inject.

  The present invention uses not only the insertion hole S formed in the vertical direction as in the above embodiment, but also the insertion hole S inclined in the oblique direction or the insertion hole S bent in the middle and formed in the horizontal direction. It can also be applied to cases. When the ground on which the structure is erected is improved and strengthened, the insertion hole S is bent in the middle and formed in the horizontal direction. In this case, as illustrated in FIG. 15, the casing rod 2 is obliquely extended from the drilling machine 1 to drill the ground, and the drilling direction is changed in the middle to insert the hole into the ground below the structure 13. S is formed.

  Next, the outer tube 3 having the anchor 4 at the tip is inserted into the casing rod 2 inscribed in the insertion hole S as illustrated in FIG. The anchor 4 is formed of a hollow elastic body such as rubber, for example. In this embodiment, since the insertion hole S is bent, it is preferable to use the outer tube 3 and the inner tubes 5A and 5B excellent in flexibility.

  Next, as illustrated in FIG. 17, a fluid is supplied to the inside of the anchor 4 that protrudes from the tip of the casing rod 2, and is expanded to be larger than the inner diameter of the casing rod 2 to fix the outer tube 3 to the ground. Thereafter, the casing rod 2 is pulled out to the ground. Thereby, a gap is formed between the inner peripheral surface of the insertion hole S from which the casing rod 2 has been pulled out and the outer peripheral surface of the outer tube 3.

  Also in this embodiment, after the loose filler D is injected into the inside of the casing rod 2, the outer tube 3 is inserted into the casing rod 2, and then the casing rod 2 is pulled out on the ground, thereby loosening. The outer tube 3 is inserted into the insertion hole S into which the conductive filler D is injected. Alternatively, after the outer tube 3 is inserted into the casing rod 2 after the insertion hole S has been drilled, the loose filler D is injected into the gap between the casing rod 2 and the outer tube 3. Next, the casing rod 2 is pulled out on the ground, so that the outer tube 3 is inserted into the insertion hole S into which the slow-binding filler D is injected.

  Next, as in the previous embodiment, the inner tube 5A is inserted into the outer tube 3, the first discharge port 5a and the second discharge port 5b are positioned at predetermined positions, and are expanded as illustrated in FIG. Then, the instantaneous setting solidified liquid C is injected into the ground from the inlet 3a located between the outer tube packers 11, and the packer P made of the instantaneous setting solidified liquid C is formed around the inlet 3a. Next, the inner tube 5A is moved in the outer tube axis direction, the first discharge port 5a and the second discharge port 5b are positioned at different predetermined positions, and the packer P is formed at another position by the same procedure. In this way, the packer P is formed so as to sandwich the inlet 3a covered with the porous coating material 10 in the outer tube axis direction.

  Next, as in the previous embodiment, the inner tube 5 </ b> A is pulled out from the outer tube 3, and another inner tube 5 </ b> B is inserted into the outer tube 3. Then, as illustrated in FIG. 19, the third discharge port 5c of the inner tube 5B is positioned at the position of the injection port 3a covered with the porous coating material 10, and is located between the expanded packer 6b. The ground improvement chemical | medical solution G is supplied from the discharge outlet 5c, and is inject | poured into the ground through the injection inlet 3a.

  Also in this embodiment, the same effect as the previous embodiment can be obtained. That is, while the inner peripheral surface of the insertion hole S is not easily collapsed by the slow-setting filler D, the slow-setting filler D substantially injects the instantaneous setting solidified liquid C and the ground improvement chemical liquid G into the ground. Will not be disturbed.

  In addition, even when the injection pressure is increased, the ground improvement chemical solution G does not invade so as to tear the ground only in specific areas where the ground is relatively weak. It becomes possible to inject the improved chemical solution G. Then, as illustrated in FIG. 20, the ground on which the structure 13 is erected can be an improved ground reinforced with the ground improving chemical solution G.

  Also in this embodiment, the instantaneous solidifying liquid C and the ground improvement chemical | medical solution G can also be supplied with the same one inner pipe | tube 5C. In the present invention, the number of installation locations of the outer tube packer 11 and the porous coating material 11 provided on the outer tube 3 is not particularly limited.

  In the present invention, the outer tube packer 11 is expanded so as to have a gap with the inner peripheral surface of the insertion hole S, as in the above-described embodiment, by filling the inside with the instantaneous solidifying liquid C. It can also be made. In this case, as illustrated in FIG. 21, injection ports 3 b and 3 c that communicate between the inside of the tube and the outside of the tube are provided on the surface of the outer tube 3 at the position where the two inflatable outer tube packers 11 are provided. In other words, the expandable outer tube packer 11 is disposed at each position where the injection ports 3b and 3c are formed. Then, the instantaneous solidifying liquid C is filled inside the two outer tube packers 11 through the inlets 3b and 3c to be expanded.

  Specifically, the injection ports 3b and 3c are arranged in the front and rear of the tube axis direction with the injection port 3a for injecting the instantaneous solidifying liquid C into the ground, and a check valve 12 is provided in the injection port 3a. The check valve 12 is formed, for example, by winding a belt-like body made of an elastic body such as rubber around the surface of the outer tube 3 so as to cover the injection port 3a. The check valve 12 abuts two belt-like bodies at a position on the injection port 3a.

  When the outer tube packer 11 is expanded, as illustrated in FIG. 22, two expansions of the inner tube 5 </ b> A inserted into the outer tube 3 are possible within the range where the outer tube packers 11, 11 are provided. Positioning is performed so that the first discharge port 5a and the second discharge port 5b are aligned with each other so that the ranges between the packers 6a overlap. After positioning, each packer 6a is expanded and brought into pressure contact with the inner peripheral surface of the outer tube 3, and the C1 liquid is supplied from the first discharge port 5a and the C2 liquid is supplied from the second discharge port 5b. .

  As a result, the instantaneous solidifying liquid C in which the C1 liquid and the C2 liquid are mixed enters the outer tube packer 11 through the inlets 3b and 3c. By filling the inside of the outer tube packer 11 with the entered instantaneous solidifying liquid C, the outer tube packer 11 is in an expanded state with a predetermined gap with the inner peripheral surface of the insertion hole S. .

  At the same time, as illustrated in FIG. 23, the instantaneous solidifying liquid C supplied through the inner pipe 5A is extruded and injected into the ground through the injection port 3a so as to leak from the butting surface of the check valve 12. . Since the injection port 3 a for injecting the instantaneous solidifying liquid C is sandwiched between the two expanded outer tube packers 11, the instantaneous solidifying liquid C is guided between the two outer tube packers 11. And injected into the ground.

  In addition, since a predetermined gap (for example, 1.0 cm or less) is provided between each outer tube packer 11 and the inner peripheral surface of the insertion hole S, the strength of the inner peripheral surface of the insertion hole S is low ( Even in the case of weak sandy ground) or the like, the inner peripheral surface of the insertion hole S is not collapsed by the expanding outer tube packer 11. And the instantaneous setting solidified liquid C can also go outside the outer tube | pipe packer 11 through this gap, and the instantaneous setting solidified liquid C can be inject | poured into the wider range of the ground.

  Therefore, the instantaneous setting solidified liquid C is surely injected into the ground and rapidly solidified to form a strong packer P around the injection port 3a. Thereby, the gap between the inner peripheral surface of the insertion hole S and the outer peripheral surface of the outer tube 3 can be reliably sealed by the packer P formed of the instantaneous setting solidified liquid C.

  Here, before the instantaneous solidifying liquid C is supplied from the inlet 3a to the ground, in order to reliably fill the outer tube packer 11 with the instantaneous solidifying liquid C and inflate it, rather than through the inlet 3a. The structure is such that the quick-setting solidified liquid C can be easily supplied to the outside through the respective inlets 3b and 3c. Therefore, for example, the area of the inlet 3a for supplying the instantaneous solidifying liquid C to the ground (in the case of a plurality of inlets 3a, the total area obtained by adding them) is set as the instantaneous solidifying liquid C in the outer tube packer 11. Is smaller than the area of each of the inlets 3b and 3c (in the case of a plurality of inlets 3b and 3c, the total area obtained by adding them). Or, the rigidity of the check valve 12 is increased to make it more difficult to be elastically deformed. Alternatively, the area of each of the injection ports 3b and 3c is made larger than the area of the injection port 3a, and the rigidity of the check valve 12 is increased to make it less elastically deformed, so that the injection ports 3b and 3c are more resistant than the injection port 3a. The structure is such that the instantaneous solidifying liquid C can be easily supplied to the outside.

  Note that the check valve 12 can function as a gap adjusting means as described above because the expansion degree of the outer tube packer 11 can be adjusted by changing its specification (rigidity and the like).

  Further, of the inlets 3b and 3c, the inlet 3c on the distal end side of the outer tube 3 located far from the supply source of the instantaneous solidifying liquid C is less likely to supply the instantaneous solidifying liquid C to the outside. . When the outer tube 3 extends vertically, the lower injection port 3c located far from the supply source of the instantaneous solidifying liquid C has an instantaneous setting property compared to the upper injection port 3b. It becomes difficult to supply the solidified liquid C to the outside.

  Therefore, for example, the area of the inlet 3c (the total area obtained by adding them in the case of a plurality of inlets 3c) is calculated from the area of the inlet 3b (the total area obtained by adding them up in the case of the plurality of inlets 3b). Also make it bigger.

  When the outer tube packer 11 is inflated with the instantaneous setting solidified liquid C as described above, it is not necessary to provide a special pipe for circulating the fluid for expanding the outer tube packer 11. The method and structure for expanding the outer tube packer 11 with the quick setting solidified liquid C can also be used in the embodiment in which the quick setting solidified liquid C and the ground improvement chemical solution G are supplied by the same inner pipe 5C described above. it can.

  The supply speed (that is, the discharge speed) and the gelation time (the time required for solidification) of the quick setting solidification liquid C and the ground improvement chemical liquid G are appropriately set depending on conditions such as the geology of the ground at the construction site. For example, when attention is paid to the gelation time tc of the instantaneous setting solidified liquid C and the time (filling time t) for filling the instantaneous setting solidified liquid C having a correlation with the supply speed of the instantaneous setting solidifying liquid C, It becomes like this. The solidification of the instantaneous solidification liquid C starts immediately after it stops flowing.

  When filling the outer tube packer 11 with the instantaneous solidifying liquid C, the outer tube packer 11 starts to expand and the instantaneous solidifying liquid C is injected into the ground from the butting surface of the check valve 12 through the injection port 3a. Begin to be. When the filling time t is equal to or longer than the gelation time tc, the instantaneous solidifying liquid C is solidified inside the outer tube packer 11, so that the outer tube packer 11 is maintained in an expanded state.

  And between the outer peripheral surface of the outer tube 3 and the inner peripheral surface of the insertion hole S, the outer tube packer 11 maintaining this expanded state, and the instantaneous solidification solidified supplied to the periphery of the expanded outer tube packer 11. The packer P is formed by the liquid C and the instantaneous solidifying liquid C injected into the ground.

  On the other hand, when the filling time t is shorter than the gelation time tc, the instantaneous solidifying liquid C inside the outer tube packer 11 is not solidified, and therefore the outer tube packer 11 in which the instantaneous solidifying liquid C has expanded. After being injected into the periphery and the ground, the outer tube packer 11 contracts. Between the outer peripheral surface of the outer tube 3 and the inner peripheral surface of the insertion hole S, the instantaneous solidifying liquid C supplied to the periphery of the outer tube packer 11 and the instantaneous solidifying liquid C injected into the ground. As a result, the packer P is formed.

  Thus, regardless of the magnitude relationship between the gelation time tc and the filling time t, the packer P can be reliably formed by the instantaneous setting solidified liquid C.

DESCRIPTION OF SYMBOLS 1 Drilling machine 2 Casing rod 3 Outer tube 3a, 3b, 3c Inlet 4 Anchor 5A, 5B, 5C Inner tube 5a 1st discharge port 5b 2nd discharge port 5c 3rd discharge port 6a, 6b Expandable / shrinkable packer 7a 1st solidified liquid flow path 7b 2nd solidified liquid flow path 7c Chemical liquid flow path 8a, 8b Packer expansion pipe 9 Switching means 10 Porous coating material 11 Outer tube packer 12 Check valve 13 Structure S Insertion hole G Ground improvement chemical liquid P Packer C Instantaneous solidifying liquid D Slow-setting filler

Claims (7)

  Insert an outer tube with a plurality of injection holes provided in the peripheral wall into the insertion hole drilled in the ground, and then insert the inner tube into the outer tube to a predetermined position. Two inflatable packers spaced apart in the axial direction are inflated and pressed against the inner peripheral surface of the outer tube, and the inner wall of the inner tube located between the two inflated packers A ground improvement chemical solution is supplied from a discharge port provided in the ground and injected into the ground from an injection port of the outer tube, and the axial direction is sandwiched by at least one injection port on the surface of the outer tube Two inflatable outer tube packers are provided apart from each other, and the inlet located at a position different from the position where the outer tube packers are provided is covered with a porous coating material, so that the groundwater existing in the ground is more Water glass-based loose filler with large specific gravity is injected In the state where the outer tube is inserted into the insertion hole, the contracted outer tube packer is expanded, and the instantaneous solidifying liquid is injected into the ground from the inlet located between the expanded outer tube packers. A ground improvement chemical solution injection method in which a packer made of an instantaneous setting solidified solution is formed around the injection port, and then the ground improvement chemical solution is injected into the ground from the injection port covered with the porous coating material.   By injecting the loose filler into the inside of the casing rod after drilling the insertion hole, inserting the outer tube into the casing rod, and then pulling out the casing rod on the ground, the loose binding property is obtained. The method for injecting a ground improvement chemical solution according to claim 1, wherein the outer tube is inserted into the insertion hole into which the filler is injected.   By inserting the outer tube into the casing rod after drilling the insertion hole, injecting the loose filler between the casing rod and the outer tube, and then pulling out the casing rod on the ground, The method for injecting a ground improvement chemical solution according to claim 1, wherein an outer tube is inserted into an insertion hole into which the loose filler is injected.   An inner tube different from the inner tube is inserted into the outer tube, and two inflatable packers that are spaced apart in the axial direction on the surface of the other inner tube are inflated to the inner peripheral surface of the outer tube. By supplying the instantaneous setting solidified liquid from the discharge port provided in the peripheral wall of the inner tube located between the two expanded packers in a pressure contact state, the expanded outer tube packer After injecting into the ground from the injection port located between them and forming a packer made of the instantaneous solidifying liquid, the inner pipe is pulled out and the inner pipe for supplying the ground improvement chemical is inserted into the outer pipe The injection method of the ground improvement chemical | medical solution in any one of claim | item 1-3.   Two expandable and contractible packers provided on the surface of the inner tube in the axial direction are inflated so as to be in pressure contact with the inner peripheral surface of the outer tube, and between the two inflated packers. By supplying the instantaneous solidification liquid from the discharge port provided in the peripheral wall of the inner pipe positioned, the instantaneous solidification is injected into the ground from the injection port located between the expanded outer pipe packers. The method for injecting a ground improvement chemical solution according to any one of claims 1 to 3, wherein a ground improvement chemical solution is supplied from the inner tube after forming a packer made of the solution.   When the instantaneous solidifying liquid is supplied from the discharge port provided on the peripheral wall of the inner pipe located between the two expanded packers, the supplied instantaneous solidifying liquid is put into the outer pipe packer. By filling, the outer tube packer is expanded so as to have a gap with the inner peripheral surface of the insertion hole, and the instantaneous solidification liquid is injected into the ground from the injection port located between the expanded outer tube packer. The method for injecting a ground improvement chemical solution according to claim 4 or 5.   The injection method of the ground improvement chemical | medical solution in any one of Claims 1-6 which changed the direction in the middle and formed the said insertion hole in the horizontal direction.

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