JPH06173243A - Chemical grouting method and device therefor - Google Patents

Abstract

PURPOSE:To make possible step-down system chemical grouting and simplify the constitution of equipment used for chemical grouting. CONSTITUTION:The ground G to be improved is drilled, and a packer 16 is expanded so as to be brought into contact with the inner wall surface 10i of a drilled hole 10 for sealing. Chemicals A, B are injected from below the expanded packer 16. After the hardening of the injected chemicals A+B, the packer 16 is contracted and reset to the original state. These processes are repeated every specified drilling distance, and the ground improvement work is performed continuously from the upper part toward the lower part on the respective specified blocks 1, 2, 3, 4, 5,....

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical solution injecting method used for improving soft ground and a chemical solution injecting apparatus preferably used in the method.

[0002]

2. Description of the Related Art A conventional chemical injection method and apparatus are shown in FIG.
Will be described with reference to. FIG. 10 shows a system of a so-called multi-phase double-pipe strainer construction method. In the conventional chemical liquid injecting apparatus indicated by reference numeral 1, a triple pipe 3 is provided in a boring machine 2 and 50% silicic acid is provided in the triple pipe 3. A soda agitation tank 4, an instant setting type hardening material stirring tank 5, and a medium-long setting type hardening material stirring tank 6 are connected to each other. Reference numeral 7 indicates a grout pump, reference numeral 8 indicates a pressure flow meter, and reference numeral 9 indicates a grout monitor.

At the time of injecting a chemical solution, the soft ground G requiring ground improvement is excavated by the boring machine 2 to form the boring hole 10. After drilling up to a predetermined depth, the excavation part of the boring machine 2 is pulled up while injecting the medium-and-long binding material 6S. Here, in order to prevent the hardening material 6S from flowing out, it is necessary to seal the inside of the boring hole 10. At that time, it was conventionally said that a pucker (mechanical pucker) could not be applied to soft ground. This is because if the packer is expanded radially outward (diameter expansion) during sealing, the ground will be correspondingly deformed.
On the other hand, in the conventional technique, the outflow of the hardening material is prevented by injecting the instantaneous hardening material 5S and momentarily hardening the vicinity of the boring hole 10.

[0004]

Here, in the above-mentioned conventional technique, the chemical liquid injection is performed so as to move from the lower side to the upper side (so-called "step-up"). However, the chemical injection method is preferably a so-called “step-down” in which the chemical injection method moves from the upper side to the lower side. Therefore, the conventional chemical injection method or ground improvement method has a problem in working efficiency.

Further, when the instantaneous setting type curing material and the long-centering type curing material are mixed, they are instantly solidified. Therefore, after the instantaneous setting type curing material and the long-centering type curing material are respectively injected, a boring machine is used. In order to prevent the two from mixing inside, the structure of the chemical injection mechanism becomes very complicated, which causes an increase in the chemical injection cost.

The present invention has been proposed in view of the above-mentioned problems of the prior art, and enables the so-called "step-down" type chemical injection, and simplifies the structure of the equipment used for chemical injection. The purpose of the present invention is to provide a chemical solution injection method and device that can be used.

[0007]

According to the chemical solution injecting method of the present invention, in the chemical solution injecting method of injecting a chemical solution to improve the ground, a boring step of excavating and boring the ground to be improved, and expanding the packer. Then, the pucker expansion step of abutting against the inner wall surface of the punched hole to seal it, the chemical solution injection step of injecting the chemical solution from below the expanded pucker, and the pucker shrinking after the injected chemical solution hardens. The pucker contracting step of returning to the state of, and the perforation step, the packer expanding step, the chemical solution injecting step, the packer contracting step are repeated for each predetermined excavation distance, and the ground improvement processing is performed from the upper part to the lower part in a predetermined section. It goes continuously every time.

The chemical solution injection device of the present invention for carrying out such a chemical solution injection method is perforated with a perforation means for excavating and perforating the ground to be improved, a chemical solution injection means for injecting a chemical solution for ground improvement. A packer for preventing the injectable liquid from flowing out between the inner wall of the hole and the perforating means, the packer being formed of a flexible member which is expandable by a fluid pressure, and It is connected to the supply means and the fluid pressure discharge means.

Here, the packer has an inner peripheral surface having a circular sectional shape and an outer peripheral surface having a polygonal sectional shape, and the outer peripheral surface is formed with ridges and valleys at equal intervals. The pucker is preferably divided into two or more sections by the valley.

In practicing the present invention, a single packer may be used, but a plurality, preferably three, may be provided. And when using multiple packers,
It is preferable to arrange the so-called "folded" state in which peaks and valleys alternate.

Here, the injected liquid chemical has a curing time of 20.
It is preferably about a minute.

The fluid pressure acting on the packer is gas,
It is particularly preferably obtained by nitrogen.

[0013]

When injecting a chemical liquid to improve the ground according to the present invention having the above-mentioned structure, first, the ground to be improved is excavated by a predetermined distance (excavation distance) to form a boring hole. To do. This excavation distance is set corresponding to the level of the area where the ground improvement should be performed by one chemical injection. After punching, the boring hole is sealed by supplying a fluid pressure to a packer made of an inflatable flexible member to expand the packer, and a chemical solution is injected from below the packer. Here, if the packer made of a flexible member is inflated by fluid pressure, the ground will not be deformed unlike the conventional mechanical packer, and it will surely come into contact with the inner wall of the boring hole to perform a sealing action. is there.

In this state, even if the ground improving chemical solution (medium-long curing type hardening material) is injected, the chemical solution does not flow out above the packer and penetrates into the ground of the section at that level. There is no need to inject the instantaneous hardening material unlike the conventional multi-phase double pipe strainer method. After injecting the chemical liquid, it waits for a predetermined curing time.

After the curing time has elapsed, the packer is contracted by discharging the fluid pressure to restore the original state, and the punching is performed again for a predetermined excavation distance. Hereinafter, the above-mentioned work may be repeated.

Here, in the case of injecting the chemical liquid of the present invention, there is no need to move it from the lower side to the upper side unlike the prior art. Therefore, each time the ground improvement of one section is completed, the head is moved from the upper side to the lower side. It is possible to repeat the above work. That is, the chemical solution can be injected by the so-called step-down method, so that the working efficiency is greatly improved.

Further, since it is not necessary to use the instant setting type curing material, the number of types of chemical liquid to be injected is reduced, and the structure of the chemical liquid injection equipment can be simplified accordingly. Further, since the inconvenience due to the mixing of the instant-curing type curing material and the long-medium-curing type curing material is completely prevented, the burden on the operator is reduced and the working cost is reduced.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. The same members as those in FIG. 10 are designated by the same reference numerals. The embodiment illustrated here is shown in FIG.
-4 is different from the prior art shown in FIG. 10 in that it has a packer as shown in FIG.

FIG. 1 and FIG. 2 show the structure near the hopper, which is the most different part between the prior art and the present invention, and a boring hole 10 having a diameter of 45 mm excavated in the soft ground G, The tip portion 12 of the boring machine 2 (Fig. 10) is shown. A ring bit 14 for excavation is provided at the tip (lower end) of the tip portion 12, and the opposite side of the ring bit 14 is connected to a hard rubber mechanical packer 16 and the triple pipe 3. . The packer 16 is not expanded in the state shown in FIG. 1, and is shown in the expanded state in FIG. Further, the tip portion 12 is provided with a mixing chamber 17 for mixing the constituents of the chemical liquid, and an ejection hole 19 is formed in the lower portion of the mixing chamber 17.

The triple pipe 3 has three passages formed therein, and the outermost passage 18 in the radial direction is compressed air which is a pressure fluid supplied to the packer 16 (see FIG. 2).
The arrow N) indicated by the dotted line in FIG.
0 is so-called "A liquid" which is the composition of the drilling water (arrow W) for hydraulic boring or the chemical liquid injected for ground improvement.
(Arrow A) flows through the flow path 22 near the center line of the triple pipe 3.
The drilling water W for hydraulic boring or the so-called "B liquid" (arrow B), which is the composition of the injected chemical liquid, flows through. here,
In the state of FIG. 1, the drilling water W flows through the flow paths 20 and 22,
In the state of, the chemical composition flows.

Next, the flow of the compressed air N, the drilling water W, and the components A and B of the injected chemical liquid will be described with reference to FIGS.

During the excavation or drilling process shown in FIG.
Since the packer 16 does not expand, the compressed air N does not flow through the flow path 18. On the other hand, the drilling water W for hydraulic boring is used in the flow path 2
0, 22 is flowed, and is injected from the radial inside of the ring bit 14 through the mixing chamber 17 and the ejection holes 19 to excavate the ground G. After the excavation, the drilling water W is directed from the space L between the tip portion 12, the packer 16, the outer peripheral surface of the triple pipe 3 and the inner wall surface 10i of the boring hole 10 toward the ground as indicated by an arrow WR. leak. Of course, the components A and B of the injected chemical liquid do not flow in the flow paths 20 and 22 during the perforation process.

When excavating to a predetermined depth and shifting from the drilling process of FIG. 1 to the chemical injection process of FIG. 2, compressed air N is supplied into the packer 16 through the flow path 18, and as shown in FIG. , The packer 16 is expanded until it comes into contact with the inner wall surface 10i of the boring hole 10. After the packer 16 expands, the composition A (solution A) of the injecting chemical solution flows in the flow path 20,
The component B (liquid B) flows through the flow path 22. The composition components A and B are mixed in the mixing chamber 17 to form the injection liquid A for ground improvement.
+ B (arrow A + B), the ground G through the ejection hole 19
Is injected into.

Here, the inner wall surface 10i of the boring hole 10
Since the space L between and is blocked only by the expansion of the packer 16, the injected chemical liquid A + B does not flow out to a region above the packer 16. For the same reason, the soil improvement by injecting chemical liquid A + B can be performed by the packer 16
Only for lower level areas.

The excavation process is restarted after the predetermined time has elapsed after the completion of the chemical solution injection process.
Compressed air is discharged from the packer 16 via 8. As a result, the state shown in FIG. 1 is obtained again. Then, the drilling water W is made to flow through the flow paths 20 and 22. At this time, the injection liquid A + B remaining in the chemical liquid injection process is washed with the drilling water W, so that the inconvenience due to the hardening of the remaining injection liquid is prevented.

Although the embodiment shown in FIGS. 1 and 2 is provided with only one hard rubber packer, it is possible to improve the sealing performance by providing a plurality of packers. 3 and 4 show an embodiment in which a plurality of packers are provided. In FIG.
The triple tube 3 and the tip portion 12 include three packers 16-1 and 1
6-2, 16-3 and the rod 30 are interposed. As shown in FIG. 4, the packers 16-1 to 16-3 have a substantially annular cross-sectional shape, and a circular inner peripheral surface 32.
And a polygonal outer peripheral surface 34. Further, the outer peripheral surface 34 is formed with a peak portion Y and a valley portion T at equal intervals, and the valley portion T causes the packer 1 in the embodiment of FIG.
6-1, 16-2, 16-3 are divided into 5 sections. The outer diameter of the rod 30, that is, the packer 16-1,
The inner diameters of 16-2 and 16-3 are 45 mm. Rod 3
Regarding the diameter of 0, if the inner diameter is 10 cm or less,
There are no particular limiting conditions.

Here, the peak portion Y and the valley portion T are provided without making the cross section of the packer into an annular shape, but if the annular shape is made into an annular shape, the restoring force when compressed air is discharged after the expansion of the packer is reduced. On the other hand, if the peaks Y and the valleys T are provided, the restoring force is maintained. As is clear from FIG.
When arranging the individual packers 16-1, 16-2, 16-3, it is a so-called "fold" in which the peak portions Y and the valley portions T of the front and rear packers are alternately arranged. This is because if the troughs T are arranged on the same straight line, the injected liquid may leak out from the troughs, but if they are arranged in a fold, the sealability is further improved by the same effect as the labyrinth seal. .

Next, the ground improvement work in the illustrated embodiment will be described in more detail with reference to FIGS.

In the work, first, temporary construction is performed (step S1 in FIG. 9), and then a boring machine or the like is installed (step S2). Next, the excavation or punching step shown in FIG. 5 is performed (step S3). In the drilling process,
As described with reference to FIG. 1, so-called hydraulic boring is performed in which the drilling water W (FIG. 1) is ejected to excavate the ground G.

After perforating to a predetermined level, the packer 16 is expanded as shown in FIG. 2 (step S4). The process corresponding to step S4 in FIG. 9 corresponds to an intermediate point between the process shown in FIG. 5 and the process shown in FIG.

After the packer 16 expands, the chemicals A and B are injected as an injection material for ground improvement (step S).
5). After the injection, the process waits for a time (for example, 20 minutes) corresponding to the effective time of the injection material (step S6). After the waiting time ends, the ground G in the region where the chemical solution is injected is improved.
In FIG. 5-8, the ground-improved area is indicated by reference numerals (1), (2), (3), ....

Next, compressed air is discharged from the packer 16 to restore the original state (step S7). In this state, when the ground improvement work is further performed along the same boring hole 10 (YES in step S8), step S3
Then, the punching operation is performed again (FIG. 7), and the above steps are repeated (FIG. 8). Here, as clearly shown in FIGS. 7 and 8, the descending method (step down) is performed in the illustrated embodiment.

When the ground improvement carried out along the boring hole 10 is completed (step S9), the boring machine 2 or the like is moved so as to construct the ground improving method in another boring hole (not shown). Install at the location of the boring hole (step S2). If the boring hole is not constructed (NO at step S9), the ground improvement method is completed and the equipment is removed (step S9).
10).

It should be noted that the illustrated embodiment is merely an example and does not limit the technical scope of the present invention.

[0035]

The effects of the present invention are listed below.

(1) The ground improvement work can be repeated from the upper side to the lower side, and the chemical solution can be injected by the so-called step-down method, so that the work efficiency is greatly improved.

(2) Since it is not necessary to use the instantaneous curing material, the number of types of chemical liquid to be injected is reduced, and the structure of the chemical liquid injection equipment can be simplified accordingly.

(3) Since the inconvenience due to the mixing of the instant-curing type curing material and the long-medium-curing type curing material is completely prevented, the burden on the operator is reduced and the working cost is reduced.

(4) Unlike the conventional mechanical packer, the ground is not deformed, and the space between the inner wall of the boring hole and the boring means can be reliably sealed to completely prevent the injected chemical solution from flowing out.

(5) Since the packer can be expanded and restored by supplying and discharging compressed air, it is easy to increase the fluid pressure, and the high-pressure equipment is simplified accordingly.

(6) Without using the instant setting type curing material,
The curing time can be set to about 20 minutes.

[Brief description of drawings]

FIG. 1 is a front view of a packer used in the present invention.

FIG. 2 is a front view showing a state where the packer of FIG. 1 is inflated.

FIG. 3 is a front view showing another packer.

FIG. 4 is a cross-sectional view showing a planar shape of the packer of FIG.

FIG. 5 is a front view showing one step of the ground improvement method according to the illustrated embodiment.

FIG. 6 is a front view showing one step of the ground improvement method according to the illustrated embodiment.

FIG. 7 is a front view showing one step of the ground improvement method according to the illustrated embodiment.

FIG. 8 is a front view showing one step of the ground improvement method according to the illustrated embodiment.

FIG. 9 is a flowchart showing the procedure of the ground improvement method shown in FIG. 5-9.

FIG. 10 is a view showing a conventional ground improvement method.

[Explanation of symbols]

1 ... Chemical injection device 2 ... Boring machine 3 ... Triple tube 4 ... 50% sodium silicate agitation tank 5 ... Instant curing type agitation tank 5S ... Instant curing type 6・ ・ ・ Medium-long binding type hardener stirring tank 6S ・ ・ ・ Medium-long binding type curing material 7 ・ ・ ・ Grout pump 8 ・ ・ ・ Pressure flow meter 9 ・ ・ ・ Grout monitor 10 ・ ・ ・ Boring hole 10i ・ ・ ・Inner wall surface of boring hole 12 ... Tip part of boring machine 14 ... Ring bit for excavation 16, 16-1, 16-2 ... Packer 17 ... Mixing chamber for mixing chemical liquid components 18, 20, 22 ... Flow path 19 ... Ejection hole G ... Ground L ... Space between boring machine and inner wall of boring hole N ... Compressed air A ... Composition of injected chemical liquid ( A liquid) B ... Composition of injected chemical liquid (B liquid) A + B ... For ground improvement Injection liquid 30 ... Rod 32 ... Inner peripheral surface 34 ... Outer peripheral surface Y ... Crest T ... Valley (1), (2), (3), (4), (5 ) ・ ・ ・ Ground improved area (section)

Claims (3)

[Claims] 1. A chemical injection method for injecting a chemical solution to improve the ground, comprising a step of digging and piercing the ground to be improved, and expanding a packer to bring it into contact with the inner wall surface of the pierced hole. It includes a pucker expansion step of sealing, a chemical solution injection step of injecting a chemical solution from below the expanded pucker, and a packer contraction step of contracting the packer to restore its original state after the injected chemical solution is cured. The chemical solution characterized by repeating the perforation step, the packer expansion step, the chemical solution injection step, and the packer contraction step for each excavation distance, and continuously performing ground improvement processing for each predetermined section from the upper side to the lower side. Injection method. 2. The chemical liquid injection device for performing the chemical liquid injection method according to claim 1, further comprising: a boring means for excavating and boring the ground to be improved, and a chemical liquid injection means for injecting the chemical liquid for ground improvement. A pucker for preventing an injectable liquid from flowing out from between the inner wall of the perforated hole and the perforating means, the pucker being formed of a flexible member which is expandable by fluid pressure, Further, the chemical liquid injector is connected to the fluid pressure supply means and the fluid pressure discharge means. 3. The packer has an inner peripheral surface having a circular sectional shape and an outer peripheral surface having a polygonal sectional shape, and the outer peripheral surface is formed with ridges and valleys at equal intervals, The liquid injector according to claim 2, wherein the packer is divided into two or more sections by the valley.