JP2007009422A - Chemical injection construction method and chemical injector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chemical injection construction method and a chemical injector for reducing cost for a ground improvement, by reducing the quantity of chemicals to be used, while maintaining the ground improvement effect. <P>SOLUTION: In this chemical injection construction method, an outer pipe 3a having a through-hole penetrating toward an outside surface from an inner surface is inserted into an injection hole 9 arranged in the ground, and an inner pipe 3b having a jetting part 3g delivering the chemicals to the tip side and having a packer 3h in an upper part and a lower part in the axial direction by sandwiching the jetting part 3g, is inserted into the outer pipe 3a, and after blocking up clearance between the outer pipe 3a and the inner pipe 3b by the packer 3h while making the depth of the through-hole and the jetting part 3g substantially coincide, the chemicals are injected into the ground via the through-hole by delivering the chemicals from the jetting part 3g. A micro-bubble generator 10 is arranged in the inner pipe 3b for including micro-bubbles while generating the micro-bubbles in the chemicals flowing in the inner pipe 3b, and the chemicals are injected into the ground including the micro-bubbles by passing through this micro-bubble generator 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a chemical injection method for improving the ground by injecting a chemical into the ground, and a chemical injection device used therefor.

  Conventionally, as a ground improvement method for increasing the strength or imperviousness of soft ground or groundwater aquifer ground, a chemical solution injection method for injecting a chemical solution (chemical solution injection material) into the soil particle gap of the ground has been frequently used. In this chemical injection method, various chemicals such as cement, bentonite, water glass, etc. exist as the chemicals used for this method, and among them, those mainly composed of water glass chemicals are frequently used. The chemical solution injection method using this type of chemical solution can easily set the curing time (gel time) by adjusting the mixing ratio of the main agent and the curing agent or auxiliary agent, or the curing agent and auxiliary agent (hereinafter referred to as curing agent), for example. It can be adjusted, has various selectivity according to the soil properties and purpose of the ground, and can make the ground to an appropriate hardness with the injected chemical solution, for example when excavating the ground after improvement It has many advantages such as being able to excavate suitably, and the mechanical equipment required for injecting the chemical solution is small, and the workability in a narrow place or a place with a height restriction is good.

  Such a chemical solution injection method is classified into a one-shot method, a 1.5-shot method, and a two-shot method depending on the method of injecting the chemical solution into the ground. In addition, a double-pipe strainer method and a double-packer method are distinguished depending on the difference in the injection pipe that is built in the ground and sends the chemical solution to a predetermined depth of the ground.

  Here, the one-shot method is a method in which the main agent and the curing agent are previously agitated and mixed by a chemical mixer at a predetermined blending ratio, and a one-component chemical solution in which the main agent and the curing agent are mixed is pumped and injected into the ground. It is. On the other hand, in the 1.5 shot system, the main agent and the curing agent are individually sent to the injection pipe by the liquid feed pump, the two liquids are combined at the head of the injection pipe, and the mixed chemical solution is discharged from the tip of the injection pipe. To be injected into the ground. Also, the 2-shot method is similar to the 1.5-shot method, in which the main agent and the curing agent are individually sent to the injection tube by the liquid feed pump, and the two liquids are combined and mixed at the moment when they are discharged from the tip of the injection tube. To do.

On the other hand, the double tube strainer method uses an injection tube (double tube rod) having an outer tube and an inner tube, and after drilling the ground to a predetermined depth, each inner hole of the outer tube and the inner tube The main agent and the curing agent are fed from the portion, and are used in a 1.5-shot or 2-shot system. On the other hand, in the double packer method, after drilling the ground into the casing, an outer tube having a plurality of through holes formed in the axial direction with a predetermined interval is inserted into the casing, and a jet part for discharging a chemical solution is provided at the tip. An inner tube provided with packers on the upper and lower sides in the axial direction across the jetting portion is inserted into the outer tube. And the depth of a through-hole and an ejection part is made to correspond, and a through-hole and an ejection part are located in one space, obstruct | occluding the clearance gap between an outer tube | pipe and an inner tube with an upper and lower packer. This double packer method is a one-shot method in which a chemical solution is discharged from an ejection part and injected into the ground through a through hole. In the case of using the double packer method, a plurality of through holes are formed at predetermined depths of the ground, and injection is performed while sequentially aligning the ejection portions with the respective through holes, so that the chemical solution is sequentially applied to the ground in the depth direction. It is possible to inject (for example, refer to Patent Document 1).
JP-A-9-3868

  However, the conventional chemical solution injection method has a very excellent feature as described above, but has a problem that the cost of the chemical solution is high. For this reason, it has been strongly desired to reduce the cost related to the ground improvement by reducing the amount of the chemical used while maintaining the ground improvement effect by the chemical injection.

  In view of the above circumstances, an object of the present invention is to provide a chemical solution injection method and a chemical solution injection device that reduce the amount of chemical solution used while maintaining the ground improvement effect and reduce the cost related to ground improvement.

  In order to achieve the above object, the present invention provides the following means.

  The chemical injection method of the present invention includes a chemical mixer capable of storing a chemical, an injection pipe for discharging the chemical to a predetermined depth of the ground, and connected to the chemical mixer and the injection pipe via a liquid feed pump. In a chemical injection method for improving the ground by injecting the chemical into the ground, using a chemical injection device comprising a liquid supply circuit comprising an injection hose for supplying the chemical from the chemical mixer to the injection tube, in the liquid supply circuit And an air supply means for supplying air to the chemical liquid, and a fine bubble generator for making the air supplied by the air supply means fine so as to include fine bubbles in the chemical liquid. A chemical solution is injected into the ground.

  Further, the chemical solution injection method of the present invention inserts an outer tube having a through-hole penetrating from the inner surface toward the outer surface into the injection hole provided in the ground, and discharges the chemical solution to the distal end side in the outer tube. An inner tube with a packer inserted in the upper and lower portions in the axial direction across the jet portion, and the outer tube with the packer while substantially matching the depth of the through hole and the jet portion. In the chemical injection method for discharging the chemical liquid from the ejection part and injecting the chemical liquid into the ground through the through hole after closing the gap with the inner pipe, the chemical liquid flowing through the inner pipe is included while generating fine bubbles. A fine bubble generating device is provided in the inner pipe, and the chemical solution containing the fine bubbles is injected into the ground through the fine bubble generating device.

  The chemical injection device of the present invention is connected to a chemical mixer capable of storing a chemical, an injection pipe for discharging the chemical to a predetermined depth of the ground, and the chemical mixer and the injection pipe through a liquid feed pump. In the chemical liquid injection device comprising a liquid supply circuit comprising an injection hose for supplying the chemical liquid from the chemical liquid mixer to the injection pipe, air supply means for supplying air to the chemical liquid in the liquid supply circuit, and the air supply A fine bubble generating device is provided that refines the air supplied by the means and includes the fine bubbles in the chemical solution.

  Further, the chemical injection device of the present invention has an outer tube having a through-hole penetrating from the inner surface toward the outer surface, and a jet part for discharging the chemical liquid at the tip, and the upper and lower sides in the axial direction across the jet part. In the chemical solution injection device comprising an inner tube provided with a packer, a fine bubble generating device is provided in the inner tube for inclusion while generating fine bubbles in the chemical solution flowing through the inner tube. To do.

  Further, in the chemical solution injection device of the present invention, the fine bubble generating device is formed in a substantially cylindrical shape, and a small diameter portion whose inner diameter is smaller than the inner diameter of the inner tube is formed in an inner hole through which the chemical solution flows. It is desirable to provide a diameter-enlarged portion that gradually increases from the small-diameter portion toward the flow direction of the chemical solution.

  Furthermore, in the chemical solution injection device of the present invention, the fine bubble generating device is formed in a substantially cylindrical shape, and the chemical solution mixed with air in advance in the inner hole of the fine bubble generating device is circulated. You may provide the swirl | flow flow generation | occurrence | production member which generates the two-layer swirl | vortex flow of the said chemical | medical solution, and the collision body which collides the said air made into the said two-layer swirl | vortex and the said chemical | medical solution.

  According to the chemical solution injection method and the chemical solution injection device of the present invention, by providing the air supply means and the fine bubble generating device in the chemical solution feeding circuit, the chemical solution can include fine bubbles. By injecting the contained chemical into the ground, it is possible to mix the chemical and fine bubbles in the soil particle gap. In addition, the presence of fine bubbles in the soil particle gap can make the ground unsaturated, increasing the strength of the ground compared to the conventional chemical solution saturated in the soil particle gap. Can be made. Therefore, it becomes possible to secure the design strength of the ground with a smaller amount of chemical solution used than before, and it is possible to reduce the cost per unit soil volume of the chemical solution injection method.

  According to the chemical solution injection method and the chemical solution injection device of the present invention, the microbubble generator is provided in the inner tube having the packer on the upper and lower sides in the axial direction across the ejection part, thereby circulating the inner tube. It is possible to include fine bubbles in the chemical solution to be injected, and by injecting the chemical solution containing the fine bubbles into the ground, the chemical solution and the fine bubbles can be mixed in the soil particle gap.

  Moreover, in the chemical injection device of the present invention, when the fine bubble generating device includes the small diameter portion and the large diameter portion in the inner hole, when the chemical solution mixed with air in advance passes through the small diameter portion of the fine bubble generating device. In addition, pressure is applied to the chemical solution, and air can be dissolved in the chemical solution. Then, the chemical solution in which the air is dissolved is decompressed by passing through the enlarged diameter portion, and the air dissolved in the chemical solution can be brought into a supersaturated state along with the decompression, and fine bubbles are generated and included in the chemical solution. It becomes possible.

  Furthermore, in the chemical solution injection device of the present invention, the fine bubble generating device includes the swirl flow generating member and the collision body, so that the swirl flow generating member is a two-layer swirl flow in the chemical solution mixed with air in advance. The air can be pulverized and refined by colliding the air and the chemical liquid that have been made into the two-layer swirl flow with the collision body. Thereby, it becomes possible to include fine bubbles in the chemical solution.

  Hereinafter, with reference to FIG. 1 to FIG. 4, a chemical solution injection method and a chemical solution injection device according to a first embodiment of the present invention will be described. The present embodiment relates to a chemical solution injection method for improving the ground by injecting, for example, a water glass-based chemical solution (chemical solution) into the ground, and a chemical solution injection device used for the method, and particularly includes while generating fine bubbles in the chemical solution. The present invention relates to a chemical injection method and a chemical injection device for injecting into the ground by a one-shot method using a double packer method.

  As shown in FIG. 1 to FIG. 2, the chemical liquid injector 1 of the present embodiment includes a main agent adjusted to a predetermined water glass concentration, and a curing agent or auxiliary agent adjusted to a predetermined concentration, or a curing agent and auxiliary agent (hereinafter referred to as “a curing agent”). A chemical liquid mixer 2 having a chemical liquid tank 2a for storing a chemical liquid produced by mixing them together, and an injection tube 3 composed of two tubes, an outer tube 3a and an inner tube 3b. The injection hose 4 connected to the chemical solution tank 2a of the chemical solution mixer 2 and the inner tube 3b of the injection tube 3 and the sending of the chemical solution from the chemical solution tank 2a of the chemical solution mixer 2 to the inner tube 3b via the injection hose 4 The liquid pump 5 is a main component. Here, the chemical liquid mixer 2, the injection tube 3, the injection hose 4, and the liquid supply pump 5 constitute a liquid supply circuit 6 through which the chemical liquid flows. In the present embodiment, the main component of the chemical solution is water glass, and the curing agent is, for example, a water-soluble inorganic acid, organic acid, salt, ester, aldehyde, or the like.

  As shown in FIG. 2, the outer tube 3a penetrates from the inner surface 3c toward the outer surface 3d and covers each of the through holes 3e and the through holes 3e that are arranged in parallel in the direction of the axis O1 (axial direction) at a predetermined interval. Thus, the elastic sleeve 3f is attached to the outer surface 3d. On the other hand, the inner tube 3b has an ejection portion 3g that discharges a chemical solution on the distal end side, and has packers 3h provided respectively above and below the axis O1 so as to sandwich the ejection portion 3g. . Further, in the inner tube 3b, a fine bubble generating device 10 is interposed in a portion (upstream side in the chemical flow direction) located above the upper packer 3h.

  As shown in FIGS. 2 and 3, the microbubble generator 10 is formed in a substantially cylindrical shape, and is provided with a ring-shaped flange portion 10d extending in a direction orthogonal to the outer surface 10c at an upper end 10a and a lower end 10b. It has been. In the fine bubble generating device 10, the flange portion 10d is fastened with a bolt to a ring-shaped flange portion 3i formed at the end of the inner tube 3b of the injection tube 3, and is integrated with the inner tube 3b. Further, in the state of being interposed in the inner tube 3b, the fine bubble generating device 10 has the axis O1 coincident with the axis O1 of the inner tube 3b, and the inner holes of the inner tube 3b and the fine bubble generating device 10 communicate with each other. ing.

  Moreover, this fine bubble generator 10 has an inner hole shaped like a Venturi tube. That is, the first inner hole 10e formed with substantially the same inner diameter as the inner tube 3b and extending from the upper end 10a to the lower end 10b of the fine bubble generator 10 while maintaining this inner diameter, and the lower end 10b side of the first inner hole 10e The second inner hole 10g extending from the end portion 10f to the lower end 10b of the fine bubble generating device 10 is configured. The second inner hole 10g is connected to the first inner hole 10e in a state where one end on the upper end 10a side is reduced in inner diameter of the first inner hole 10e, and the small diameter portion is a small diameter portion 10h. Further, the second inner hole 10g is formed such that a portion from one end to the other end gradually increases in diameter toward the flow direction T of the chemical solution, and this portion is an enlarged diameter portion 10i. . At this time, the inner diameter of the other end of the enlarged diameter portion 10i is substantially the same as the inner diameter of the inner tube 3b connected to the first inner hole 10e and the lower end 10b.

  As shown in FIG. 1, the injection hose 4 has one end connected to the chemical tank 2 a of the chemical mixer 2 and the other end connected to the inner pipe 3 b of the injection pipe 3. Further, a liquid feed pump 5 for feeding the chemical liquid stored in the chemical liquid tank 2a to the inner tube 3b is interposed between one end and the other end of the injection hose 4, and further, the other end and the liquid feed. Between the pumps 5, a flow meter 7 is installed for measuring the flow rate of the chemical solution flowing through the injection hose 4 and the pressure at the time of liquid feeding. Further, the liquid feed pump 5 is provided with an air regulating valve (air supply means) 8 for mixing a predetermined amount of air into the chemical liquid flowing through the injection hose 4.

  Next, a method for injecting a chemical solution into the gap between soil particles in the ground using the chemical solution injection device 1 having the above-described configuration will be described.

  First, as shown in FIGS. 1 to 2, the ground is drilled with a casing to a predetermined depth to form an injection hole 9. After completion of the drilling, a sleeve material such as a mixed solution (CB) of cement, bentonite and water is filled in the casing. This sleeve material is for filling the gap between the injection hole 9 and the outer tube 3a of the injection tube 3, and the chemical solution discharged from the through hole 3e of the outer tube 3a escapes outside the target ground region. It is for preventing it from doing. Next, the outer tube 3a is inserted into the casing filled with the sleeve material, and the casing is removed. Thereby, the sleeve material is filled between the outer tube 3a and the inner wall of the injection hole 9, and the outer tube 3a is built without causing the inner wall of the injection hole 9 to collapse. Incidentally, at this stage, since the plurality of through holes 3e arranged in parallel in the direction of the axis O1 of the outer tube 3a are covered with the elastic sleeve 3f, the sleeve material flows into the outer tube 3a or the through holes 3e are formed. It will not be blocked.

  Next, the inner tube 3b is inserted into the outer tube 3a. At this time, the packer 3h is inserted so as to be arranged at the upper and lower positions in the direction of the axis O1 sandwiching the through hole 3e of the outer tube 3a at the target injection position, and the packer 3h is expanded so that the upper and lower positions sandwiching the through hole 3e. Block. At this stage, primary injection is performed in the target ground. This primary injection is performed in order to make the ground in the vicinity of the injection hole 9 uniform so that the chemical solution uniformly penetrates into the ground by the secondary injection described later. For example, CB or the like is injected. . In this primary injection, CB discharged from the ejection portion 3g of the inner tube 3b located in the space closed by the packer 3h passes through the through hole 3e of the outer tube 3a and is discharged to the ground while expanding the elastic sleeve 3f. Thereby, CB is injected into the ground near the injection hole 9. This operation is sequentially performed at the installation positions of other through holes 3e formed in the direction of the axis O1 of the outer tube 3a, and the primary injection is completed.

  After the primary injection is completed, the chemical solution is injected as a secondary injection. The chemical solution to be injected by this secondary injection is first stored in the chemical solution tank 2a after being stirred and mixed with the chemical solution mixer 2 so that the main agent and the curing agent have a predetermined concentration. At this stage, the inner tube 3b is inserted into the outer tube 3a in the same manner as the primary injection, and the packer 3h is installed at the upper and lower positions in the direction of the axis O1 across the through hole 3e to expand the inner tube 3b into the closed space. The ejection part 3g is positioned. Next, the chemical solution is pumped to the inner tube 3 b of the injection tube 3 through the injection hose 4 while driving the liquid supply pump 5. At this time, the air regulating valve 8 provided in the liquid feed pump 5 opens according to the liquid feed pressure of the chemical liquid flowing through the injection hose 4, air is supplied to the injection hose 4, and the flow direction T is higher than the liquid feed pump 5. A predetermined amount of air is mixed into the chemical flowing through the injection hose 4 on the downstream side.

  The chemical solution mixed with air is sent to the inner tube 3 b of the injection tube 3 and passes through the fine bubble generating device 10. At this time, the second inner hole 10g of the fine bubble generating device 10 is provided with a small diameter portion 10h whose diameter is smaller than the inner diameter of the inner tube 3b or the first inner hole 10e on the upper end 10a side of the fine bubble generating device 10. The chemical liquid is circulated through the small-diameter portion 10h and rapidly pressurized, and the air mixed in the chemical liquid is dissolved in the chemical liquid by this pressurization. Further, the second inner hole 10g is formed with an enlarged diameter portion 10i formed so that its inner diameter gradually increases in the flow direction T, and is continuously formed with the small diameter portion 10h. As the portion 10i flows toward the lower end 10b, the pressure applied by the small diameter portion 10h gradually decreases. The air dissolved in the chemical liquid is supersaturated by the decompression accompanying this circulation, and appears and is contained as fine bubbles in the chemical liquid. Here, the fine bubbles included in the chemical solution in this way are fine bubbles having a diameter of several μm to several tens of μm.

  And the chemical | medical solution in which this fine bubble was included is discharged from the ejection part 3g. The discharged chemical solution passes through the through hole 3e of the outer tube 3a, is discharged while spreading the elastic sleeve 3f, and penetrates into the ground. Here, since the diameter of the fine bubbles is very small, from several μm to several tens of μm, the residence time in the chemical solution is long, and the fine bubbles are not defoamed when the chemical solution is injected into the ground. It is supposed to be. The chemical solution injected into the ground is gelated and solidified after a predetermined time has elapsed, thereby improving the strength of the ground and the water-imperviousness.

  In the present embodiment, since the fine bubbles are included in the chemical solution injected into the soil particle gap of the ground, the fine bubbles are mixed in the gel filling the soil particle gap, and the amount of the chemical solution used per unit soil volume is reduced. Only the volume of fine bubbles is reduced compared to the conventional chemical solution.

  Here, tests were conducted on the examples of the present invention and the conventional example. As a result of this test, FIG. 4 shows the relationship between the uniaxial compressive strength of the specimen into which the chemical liquid containing fine bubbles and the conventional chemical liquid not containing were injected, and the wet density of the specimen. In this figure, the solid line and the broken line are regression lines obtained by the method of least squares, the solid line indicates the regression line when the fine bubbles according to the embodiment are included in the chemical solution, and the broken line is the regression line when the conventional chemical solution is used. Is shown. Further, here, a solution type active silica injection material (trade name: Permalock ASF-N) is used as a main agent as a chemical solution. Furthermore, by adjusting the silica concentration to 4%, the gel time (time until gelation) is set to 1440 minutes. In addition, Toyoura standard sand is used for the sample into which each chemical solution was injected.

  By comparing the uniaxial compressive strength of the test specimen formed using the chemical solution including the fine bubbles and the conventional chemical solution, the uniaxial compressive strength of the test specimen using the chemical solution including the fine bubbles is reduced. It was confirmed that the sample was 20 to 30% larger than the specimen using the conventional chemical solution that was not included.

  Therefore, in the chemical injection method and the chemical injection device described above, since the fine bubble generating device 10 having the substantially venturi-shaped inner hole is provided in the injection tube 3, air is mixed into the second inner hole 10g. It is possible to dissolve the air in the chemical liquid by applying a pressurizing force simply by circulating the chemical liquid, and to include the fine liquid bubbles in the chemical liquid by reducing the pressure. Thereby, it becomes possible to inject | pour the chemical | medical solution containing the fine bubble to the ground, and it becomes possible to reduce the usage-amount of the chemical | medical solution per unit soil volume. In addition, by including fine bubbles in the chemical solution, the effect of increasing the strength can be increased as compared with the case where the conventional chemical solution is used. Therefore, compared with the conventional chemical solution injection method, it is possible to reduce the cost related to ground improvement while maintaining the effect of ground improvement.

  As mentioned above, although embodiment of the chemical injection method and the chemical injection device 1 concerning this invention was described, this invention is not limited to said 1st Embodiment, In the range which does not deviate from the meaning, it can change suitably. is there. For example, in the above embodiment, the fine bubble generating device 10 is formed in a substantially cylindrical shape, and has a first inner hole 10e formed with a substantially same inner diameter as the inner hole of the injection tube 3, and the first inner hole 10e. A second inner hole 10g extending from an end 10f on the lower end 10b side to a lower end 10b of the fine bubble generating device 10, and the second inner hole 10g includes a small diameter portion 10h and an enlarged diameter portion 10i. However, the microbubble generator 10 of the present embodiment is configured so that a part thereof has an inner hole smaller in diameter than the inner hole of the inner tube 3b of the injection tube 3 and applies pressure to the passing chemical liquid. It is sufficient that the first inner hole 10e is not provided.

  In the fine bubble generating device 10 of the present embodiment, the passing chemical solution is loaded with pressure and decompressed to generate fine bubbles. For example, the mixed air is ultrasonically mixed. In order to make fine bubbles, the one that mixes the mixed air and the chemical solution and rotates vigorously to generate a two-layer swirling flow and shears the air, or the chemical solution mixed with air permeates through the microfilter. It may be one that generates fine bubbles in the chemical solution by other methods such as a generating method.

  Furthermore, in the present embodiment, the fine bubble generating device 10 is installed immediately above the packer 3h provided in the inner tube 3b, but the position of the fine bubble generating device 10 is higher than the ejection portion 3g. If it is arranged in the (chemical solution distribution direction T upstream side), the installation position does not need to be limited.

  In addition, the air to be refined by the fine bubble generating device 10 is supplied from the air regulating valve 8 of the liquid feeding pump 5, but the supply position and supply method of the air to the chemical liquid need not be particularly limited. Is.

  Furthermore, in the present embodiment, the chemical solution is described as being a water glass chemical solution, but is not limited to this, and the present invention may be applied to other chemical solutions as long as it is a solution type. It is.

  Next, a chemical solution injection method and a chemical solution injection device according to a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, the same code | symbol is attached | subjected with respect to the structure which is common in 1st Embodiment, and the description about the detail is abbreviate | omitted.

  As in the first embodiment, the present embodiment relates to a chemical injection method and a chemical injection device that injects a water glass chemical containing fine bubbles into the ground by a one-shot method using a double packer method.

  As in the first embodiment, the microbubble generator 20 of the present embodiment is interposed in a portion of the inner tube 3b located above the upper packer 3h, as shown in FIG. As shown in FIG. 5, the microbubble generator 20 includes a specially-structured mixing vane 21 (a swirl flow generating member) and a projecting collision body 22 in a casing 20a formed in a substantially cylindrical shape. ing. The mixing vane 21 intersects the chord side edges 21c and 21d of the pair of split ellipsoidal plates 21a and 21b in an X shape, and between the chord side edges 21c and 21d on the upstream side of the intersecting portion inside the casing 20a. The structure is closed by a triangular partition plate 21e that bisects in the axial direction, and is arranged so that the arc-side edges 21f and 21g of the pair of split ellipsoidal plates 21a and 21b are joined to the inner wall of the casing 20a. Yes. The microbubble generator 20 configured as described above is, for example, a microbubble generator disclosed in JP-A-9-150044.

  When the chemical liquid injection device 1 provided with the fine bubble generating device 20 as described above in the inner tube 3b of the injection tube 3 is used, the chemical liquid and the air mixed therein pass through the mixing vane 21, It is converted into a spiral flow. Then, a strong centrifugal force acts on the chemical liquid and air, and light air is arranged on the inside in the radial direction of the fine bubble generator 20 and the chemical liquid is arranged on the outside in the radial direction. A swirling flow will be generated. The chemical liquid and the air that have been converted into the two-layer swirl flow in this manner flow through the casing 20a and are mixed while being violently collided with the collision body 22, and generate ultrasonic waves exceeding 40 kHz, for example. By this ultrasonic wave, air in the chemical solution is pulverized to generate fine air bubbles of several μm to several tens of μm. Thus, the chemical | medical solution containing the fine bubble is discharged from the ejection part 3g, and is inject | poured into the ground through the through-hole 3e similarly to 1st Embodiment.

  Therefore, in the above-described chemical solution injection method and chemical solution injection device 1, a mixed vane (swirl flow generating member) 21 that generates a two-layer swirl flow by circulating a chemical solution mixed with air in advance and a two-layer swirl flow are used. By providing the fine bubble generating device 20 including the collision body 22 in which the chemical liquid and air collide, it becomes possible to include the fine bubbles in the chemical liquid. Thereby, compared with the conventional chemical | medical solution injection | pouring method, it becomes possible to aim at reduction of the cost which concerns on ground improvement, maintaining the effect of ground improvement.

  As mentioned above, although embodiment of the chemical injection method and the chemical injection device 1 concerning this invention was described, this invention is not limited to said 2nd Embodiment, In the range which does not deviate from the meaning, it can change suitably. is there. For example, in this embodiment, the swirl flow generating member 21 that generates a two-layer swirl flow is a pair of split ellipsoidal plates 21a and 21b. However, the present invention is not limited to this, and a chemical solution mixed with air in advance is circulated. If the two-layered swirling flow is generated by this and the fine bubbles are generated by colliding with the colliding body 22, the swirling flow generating member 21 and the colliding body 22 provided in the fine bubble generating apparatus 20 are used. The configuration of is not particularly limited. Moreover, although the fine bubble generator 20 of this embodiment shall be provided just above the upper packer 3h like 1st Embodiment, it is arrange | positioned in the distribution direction T upstream rather than the ejection part 3g. If so, the installation position need not be particularly limited. The present invention is also applicable to, for example, a double-pipe strainer type chemical injection method other than the chemical injection method shown in the present embodiment.

It is a figure which shows the chemical injection device which concerns on 1st Embodiment of this invention. It is an enlarged view which shows the injection tube of the chemical | medical solution injection apparatus of FIG. It is sectional drawing which shows the microbubble generator of FIG. 1 and FIG. It is a figure which shows the difference of the injection | pouring effect of the chemical | medical solution containing the fine bubble and the conventional chemical | medical solution. It is a figure which shows the fine bubble generator of the chemical injection device which concerns on 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chemical liquid injection device 2 Chemical liquid mixer 2a Chemical liquid tank 3 Injection pipe 3a Outer pipe 3b Inner pipe 3e Through-hole 3g Injection part 3h Packer 4 Injection hose 5 Liquid supply pump 6 Liquid supply circuit 7 Flowmeter 8 Air adjustment valve (air supply means)
9 Injection hole 10 Fine bubble generating device 10a Upper end 10b Lower end 10e First inner hole 10g Second inner hole 10h Small diameter portion 10i Large diameter portion 20 Fine bubble generating device 21 Mixed vane (swirl flow generating member)
22 Collision body O1 axis (axis)
T Distribution direction

Claims (6)

A chemical mixer capable of storing a chemical liquid, an injection pipe for discharging the chemical liquid to a predetermined depth of the ground, and connected to the chemical liquid mixer and the injection pipe via a liquid feed pump from the chemical liquid mixer to the injection pipe In a chemical injection method for improving the ground by injecting the chemical into the ground, using a chemical injection device equipped with a liquid supply circuit comprising an injection hose for sending the chemical,
Provided in the liquid feeding circuit is an air supply means for supplying air to the chemical liquid, and a fine bubble generating device for miniaturizing the air supplied by the air supply means to include fine bubbles in the chemical liquid, A chemical solution injection method characterized by injecting a chemical solution containing fine bubbles into the ground. An outer tube having a through-hole penetrating from the inner surface toward the outer surface is inserted into the injection hole provided in the ground, and a jet part for discharging a chemical solution is provided in the outer pipe, and the jet part is sandwiched between the outer pipe and the outer pipe. After inserting the inner pipe with the packer in the upper and lower parts in the axial direction, and closing the gap between the outer pipe and the inner pipe with the packer while substantially matching the depth of the through hole and the ejection part In the chemical injection method for discharging the chemical from the ejection part and injecting the chemical into the ground through the through hole,
A fine bubble generating device is provided in the inner tube to cause the chemical liquid flowing through the inner pipe to be contained while generating fine bubbles, and the chemical liquid containing the fine bubbles is passed through the fine bubble generating apparatus to the ground. A chemical injection method characterized by injection. A chemical mixer capable of storing a chemical liquid, an injection pipe for discharging the chemical liquid to a predetermined depth in the ground, and connected to the chemical liquid mixer and the injection pipe via a liquid feed pump from the chemical mixer to the injection pipe In a chemical injection device comprising a liquid supply circuit consisting of an injection hose for sending the chemical to the
An air supply means for supplying air to the chemical liquid and a fine bubble generator for miniaturizing the air supplied by the air supply means to include fine bubbles in the chemical liquid are provided in the liquid supply circuit. A chemical injection device characterized by comprising: An outer tube having a through-hole penetrating from the inner surface toward the outer surface, and an inner tube having a jet part for discharging a chemical solution at the tip and having packers on the upper and lower sides in the axial direction across the jet part In the chemical injection device provided,
A chemical liquid injection device characterized in that a fine bubble generating device is provided in the inner tube for generating and containing fine bubbles in the chemical solution flowing through the inner tube. In the chemical injection device according to claim 4,
The fine bubble generating device is formed in a substantially cylindrical shape, and an inner hole through which the chemical solution flows has a small-diameter portion whose inner diameter is smaller than the inner diameter of the inner tube, and the flow direction of the chemical solution from the small-diameter portion A chemical solution injection device comprising a diameter-enlarged portion having an inner diameter that gradually increases toward the surface. In the chemical injection device according to claim 4,
The fine bubble generating device is formed in a substantially cylindrical shape, and the swirl that generates a two-layer swirling flow of the air and the chemical solution while the chemical solution in which air is mixed in the inner hole of the fine bubble generating device is circulated. An apparatus for injecting a chemical solution, comprising: a flow generating member; and a collision body that collides the air and the chemical liquid that are made into the two-layer swirl flow.

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