JPS635526B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chemical injection method and an apparatus therefor.

Conventionally, this type of chemical injection method has been widely used for stabilizing soft ground. In general, it is considered extremely difficult to treat heterogeneous soft ground centered on alluvium, sandy soil saturated with groundwater, or complex ground mixed with clayey soil.

However, according to the method described in JP-A No. 52-48217, it has been found that this kind of ground stabilization treatment can be carried out extremely easily, and it has been widely used instead of the conventional general injection method. .

Unlike conventional methods, which use chemicals with a gel time of 60 seconds or more, this method has a gel time of less than 30 seconds and solidifies instantly, and each chemical is pumped independently to the injection site. This is a breakthrough that completely changes the concept of conventional methods in that it allows merging and contact mixing at the injection part or outside, and can reliably treat a limited improvement area while preventing clogging in the injection pipe. It is said to be a traditional construction method.

However, in this method, when each chemical solution is discharged from a pair of discharge ports to join and mix by contact, it is not necessarily the best practice to angle the discharge ports and have them uniformly merge on the outside. The inventor's experiments have revealed that this is not the case.

On the other hand, in recent years, instead of mixing two-component curable chemicals on the ground or at the junction of Y-shaped pipes, a mixing chamber is configured inside the injection pipe, as in JP-A No. 53-117209, for example. A method in which a mixing member is provided, one of the chemical liquids is applied thereto, and it is scattered, and the scattered chemical liquid is mixed with the other chemical liquid that is pumped in the same direction, or a similar in-tube mixing method in which liquid B is mixed with liquid A. Methods have been developed in which liquids are mixed by merging from the sides. However, in all of these methods, although the flow is angled, the liquids are flowed in the same direction and mixed together, so that the mixing properties are not perfect. Furthermore, since the merging contact time is extremely short, it is possible that the mixture may be injected into the surrounding ground without being reliably mixed. Furthermore, in the case of in-tube mixing, since there is still a distance from the mixing point to the injection port, clogging due to solidification of the chemical solution cannot be avoided. Moreover, mixing the two liquids at a predetermined ratio requires constant monitoring of the feed pressure, which is impossible in actual construction.

By the way, in the construction method described in the above-mentioned Japanese Patent Application Laid-Open No. 52-48217, a spool valve is moved to switch between the lubricant flow path and the injection flow path during boring.
In this construction method or the conventional construction method, a check valve is generally used to prevent backflow into the injection pipe. In the method disclosed in the publication, in order to ensure that the chemical liquid does not flow downward during injection and is guided to the discharge port, the inlet to the check valve is closed with a conical closing part at the lower end of the spool valve. However, in order to reliably close the valve, the spool valve must be pressed down at all times with high pressure, and this remains a major problem when attempting to inject at low pressure. Furthermore, installing two valves, a spool valve and a check valve, inside a pipe causes structural restrictions and is economically disadvantageous.

On the other hand, the present inventor has conducted experiments and research on countercurrently contacting and mixing the respective liquids of the two-component curable chemical liquid on the peripheral wall of the injection tube. It has been found that this method allows injection with excellent mixing properties. However, in this construction method or device, the inlet must be located midway between the discharge ports of each liquid, so when using a suspension-type chemical, cement particles may settle at the bottom of the mixing chamber and cause clogging. Conceivable. If we talk about the classification method of chemical liquids, in general, chemical liquids can be roughly divided into water glass suspension type, such as water glass to cement type, and solution type, which is a combination of water glass and various solutions. In any case, the water glass suspension type is considered to be the same as the suspension type using only cement or clay milk in the sense that the particles cause a sedimentation phenomenon, and in this specification, these suspension types are This also includes suspension-type products.

In the present invention, when contact-mixing the two-component curable materials, mixing is extremely ensured by orthogonal contact inside the peripheral wall of the injection tube, and
Because of orthogonal contact mixing, the injection port can be formed at the lower side of the natural flow of the drug, and as a result, the drug does not stay inside the injection pipe and flows smoothly to the outside, making it possible to inject suspension-type drugs. It has been found that this method is particularly effective.

The present invention will be explained below using specific examples. FIGS. 1 and 2 show the tip device, with FIG. 1 showing the hole drilling state and FIG. 2 showing the state during injection. Each unit double injection tube is connected to the upper part of each figure, and although the upper part is a swivel, illustration is omitted. 1 is the outer tube, and at the bottom is the joint tube 2.
and the cutting blade 3 are connected. An injection port 4 is formed in the outer tube 1 . Further, a valve chamber 5 is removably housed inside the outer tube 1. This valve chamber 5
Inside, a cylindrical spool valve 6 is arranged to be able to freely slide up and down, and the inside of this valve chamber 5 is connected to the base side via an inner pipe joint 7, and the side and top surfaces of the spool valve 6 are connected to each other. A first flow path 9 is constituted by a flow path formed in an L-shape by connecting the two. Reference numeral 8 designates an annular check valve provided between the inner pipe joint 7 and the outer pipe 1, made of a flexible material such as rubber, and having a tongue piece 8a on the inside. A tip passage 10 is provided in the axial direction on the side of the valve chamber 5.
a is formed and communicates with the main flow path 10b between the outer tube 1 and the inner tube (not shown), and these side flow paths 1
A second flow path 10 is constituted by the main flow path 0a and the main flow path 10b.

A pair of first and second discharge ports 11 and 12 are formed in the side wall of the valve chamber 5 . This discharge port 1
Recesses are formed in the outer circumferential surface of the valve chamber 5 at the locations 1 and 12, and a guide chamber 14 is formed between the valve chamber 5 and the guide wall 1a, which is a part of the outer tube 1. A communication hole 16 is formed in the side wall of the valve chamber 5 on the opposite side, and communicates the side flow path 10a of the second flow path 10 with the inside of the valve chamber 5.

A through hole 1 passing through the middle part of the spool valve 6
7 is formed, and this formation position is at the lower limit position of the spool valve 6 shown in FIG.
and a position communicating with the communication hole 16.
Further, inside the spool valve 6, a guide hole 18 is formed which communicates with the communication hole 16 at its upper limit position (FIG. 1) and passes through the inside and exits downward.

On the other hand, the injection port 4 is connected to the guide chamber 14 (guide wall 1
a), and communicates the guide chamber 14 with the outside. The guide chamber 14 draws a smooth curve and is connected to the lower surface of the injection port 4. 19
19 is a fixing pin for stopping rotation of the spool valve 6 in the circumferential direction with respect to the valve chamber 5, and 19' is a fixing pin for stopping rotation of the valve chamber 5 with respect to the outer pipe 1.

Furthermore, a stepped portion 20 is formed inside the joint pipe 2,
A spring 21 is installed between the stepped portion 20 and the spool valve 6.
is arranged to urge the spool valve 6 upward. Further, a communication hole 22 is formed inside the joint pipe 2, and a check valve 23 having a conical center portion is provided below the communication hole 22. A guide 24 is screwed into the lower part of the joint tube 2 and is housed inside the cutting blade 3 with a slight gap 25. A recess 26 is formed in the upper part of the guide 25, and a radial path 27 is formed from the bottom of this recess 26, and a horizontal path 2
It is connected to 8. A spring 29 urges the check valve 23 upward. Further, a discharge hole 30 and a jet hole 31 are formed in the cutting blade 3, and a small gathering chamber 32 is formed between the upper surface of the cutting blade 3 and the guide 28.

When injecting a chemical solution, first, rotate the injection tube around the axis or without rotating it, and open the second flow path 1.
Water W etc. is pumped through 0. The spool valve 6 is biased by the spring 21 and is at the upper limit position,
The pressure-fed water W enters the guide hole 18 from the side flow path 10a through the communication hole 16 while bending the tongue piece 8a of the check valve 8 toward the main body, and enters the guide hole 18 from the communication hole 22 to the check valve 23.
enters the recess 26 while pressing down, and enters the radiation paths 27, 2.
The air gap 25 passes through the horizontal path 28 and splits outward through the
The liquid enters the air, gathers again in the gathering chamber 32, and is ejected through the ejection hole 30 and the ejection hole 31. The injection tube is installed at a predetermined location while continuing the spouting of water W and the pushing and rotation of the injection tube.

Next, as shown in FIG. 2, one of the liquids A of the suspension type two-component curable chemical liquid G is fed under pressure to the first flow path 9,
The other liquid B is force-fed to the second channel 10. As a result, the spool valve 6 is pushed downward by the feeding pressure of the liquid A, overcoming the biasing force of the spring 21. Therefore, the first flow path 9 and the first discharge port 11 communicate with each other, and the liquid A flows from the first discharge port 11 to the guide chamber 14.
discharged inside. On the other hand, by moving the spool valve 6 to the lower limit position, the communication hole 16 is closed by the spool valve 6, but comes to communicate with the through hole 17. As a result, the liquid B passes from the communication hole 16 through the through hole 17 and through the second discharge port 12 to the guide chamber 14.
Exhaled inward. Further, the A liquid discharged from the discharge port 11 collides with the guide wall 1a, changes its flow there, and flows downward along the guide wall 1a. At this time, B
The liquid is discharged from the discharge port 12 and comes into contact with the flowing liquid A at right angles, and both liquids A and B are mixed, and from the injection port 4 below the liquid is uniformly distributed to the surrounding ground almost horizontally. is injected into.

Note that, prior to this injection, it is desirable to fill the gap between the injection tube and its drilling surface with a packing material P made of the same material as the injection chemical or a different material. In this case, it is sufficient to wait for the packing material P to solidify before injecting the next chemical solution.

When injecting a chemical solution, the injection tube is rotated around the axis as necessary and moved in the axial direction while being raised or lowered.

Here, the apparatus of the present invention is most suitable when using a suspension type two-component curing material with a short gel time. That is, the device of the present invention has a discharge port 11,
Since the flow paths up to 12 are independent, there is no clogging due to solidification of the chemical solution in the injection tube up to this point, and this effect is especially great when injecting a drug solution with an extremely short gel time, as will be described later.

In addition, even if liquid A is made of cement, slaked lime, gypsum, etc. as the main ingredient and liquid B is water glass-based and pumped and injected, even if the injection is stopped once, the guide chamber 1
The remaining chemical solution will naturally flow from the injection port 4 and will not remain in the pipe, and particles will not settle to the lower part of the guide chamber 14 and block the guide chamber 14 or the injection port 4 over a long period of time. Therefore, it can withstand the use of suspension-type medicinal solutions. Further, when a suspension type chemical solution is used, troubles tend to occur in the sliding of the spool valve 6. However, as in the above example, the space at the top of the spool valve 6 is made large and the spool valve 6 is made to sink into the valve chamber 5 when it is moved, so that it is possible to always prevent chemical liquid from adhering to the spool valve 6 and prevent it from moving. can be carried out smoothly.
Furthermore, the lower end of the first flow path 9 of the spool valve 6 is smoothly bored to form a smooth flow change part from the discharge port 11 to the guide chamber 14, so that smooth flow is achieved without creating a dead area of flow. , so there is no chemical deposits.

In the present invention, the gel time of the chemical solution used is within 30 seconds, preferably within 10 seconds, and more preferably within 5 seconds. It would be highly desirable for the packing material to have such a gel time. The reason for this is that if you seal with a cement-bentonite type material that has a long gel time as in the past, it will often escape to the ground that is not targeted and high strength cannot be expected. When this is done, it initially fills the vicinity of the injection port and solidifies there. The subsequent packing material searches for weaker areas than the solidified areas, and some of it pushes out the semi-solidified packing material that has already been injected, eventually filling the gap firmly.

After filling with packing material P, chemical solution G
When injected, the chemical solution G breaks the packing material P,
While cutting, it is injected near the injection site to strengthen the ground.

The reason for using a chemical solution with an extremely short gel time compared to conventional methods is as follows.
In other words, if the gel time is 60 seconds or more as in the past, especially on non-uniform ground, it will escape in an unsolidified liquid state along the weak layer outside the target improvement area, causing material damage. Not only does this cause a large amount of loss, but it also contaminates the ground outside the improvement area, and the target improvement area is not sufficiently strengthened. This is because since solidification begins in the vicinity, it is possible to concentrate and reliably treat a limited area for the purpose of improvement, and to solve the problems of the conventional method all at once.

Note that if an instant-setting chemical solution is used, the packing material as in the above example is not necessarily required. That is, since the medicinal solution injected after convergence and mixing begins to solidify immediately near the injection port, there is no outflow or escape of the medicinal solution even if it is not filled with a packing material. As a result, the filling process becomes unnecessary and there is a great economic advantage.

By the way, in the construction method of the present invention, the chemical solutions A and B are orthogonally joined and contacted and mixed. By making the merging orthogonal, it is possible to solve at once the problem of low mixing properties in the conventional parallel flow merging mixing system described above. In other words, if they are orthogonally merged and contacted, the respective liquids will inevitably and reliably merge, and along with orthogonal merging, the mutual liquids will mix together and become one. Significantly enhances the mixing effect.

Incidentally, according to the findings of the present inventor, the gel time when stirring manually in a beaker was about 15 seconds, but when actually dispensing using the same material and the above device, the gel time was 4 to 4 seconds. 5
Mix evenly in an extremely short time. This means that
In the present invention, the mixing method is orthogonal, and it is thought that the orthogonal method significantly improves the mixability, increases the stirring force compared to manual stirring, and shortens the gel time.

Furthermore, when using an instant-setting grout with a gel time of less than 30 seconds as mentioned above, it is necessary to mix it reliably in a short period of time, and from this point of view, the orthogonal mixing method is Benefits become more tangible.

In addition, in the method of the present invention, the orthogonal merging point is located on the peripheral wall of the injection pipe, and the mixture is immediately injected after mixing. Therefore, it is possible to prevent clogging due to solidification of grout in the pipe, which occurs even in the recently developed in-pipe mixing system.

On the other hand, in the device of the present invention, since the guide wall 1a constituting the guide chamber 14 is formed corresponding to the discharge port, the A discharged from the discharge ports 11 and 12 is
The liquid is caused to flow down along the guide wall 1a, and the B liquid can be brought into contact with and mixed with the liquid orthogonally thereto. The guide wall 1a also has the effect of preventing slime from flowing back into the tube. Furthermore, the spool valve 6
Since it is provided, the flow path can be easily switched by moving it. When injecting grout, it is injected only from the injection port 4, so the packing material P
Excellent cutting and breaking properties. Japanese Patent Publication No. 52-48217
In the method No. 1, cutting and fracturing are performed using grout from each outlet, but grouting from a single grout as in the present invention has better cutting and fracturing properties than that method. be. Moreover, if the mixing chamber is configured in an annular shape around almost the entire circumference of the injection pipe and a large number of injection ports are formed in the guide wall 1a, the entire circumferential direction can be improved at the step position without rotating the injection pipe. This has the advantage that it is possible to use a strainer for injection.

According to the above example, once the injection is stopped, the grout solidifies in the guide chamber 14 and the discharge port 1
It may appear that 1 and 12 are occluded. However, according to the inventor's experiments, most of the grout naturally flows down from the injection port 4, and when the grout is pumped again, the semi-solidified or solidified grout mass in the guide chamber 14 flows out from the injection port 4 relatively smoothly. It turned out that there was no blockage at all.

Furthermore, in the device of the present invention, the spool valve 6 is devised to also have the function of a check valve. As a result, the internal structure is simplified, which is economically advantageous. When the spool valve 6 moves, its circumferential surface and the inner surface of the valve chamber 5 block the flow path downward from the second flow path 10. Even if the pressure pump pulsates, the feeding pressure is only applied to the peripheral surface, so the spool valve 6 does not move. When the injection pressure is stopped, the spring 21 momentarily blocks the discharge ports 11 and 12, thereby preventing backflow.

Furthermore, if the spool valve structure is as shown in the above example,
At least the supply pressure to the first flow path 9 is maintained by the spring 21.
Since the spool valve 6 moves downward if the urging force is stronger than the urging force, the spool valve 6 can be moved with a small feeding pressure, which is convenient for low-pressure injection.

Further, in the above device, the outer tube 1, the valve chamber 5, and/or the spool valve 6 are separate bodies. In the device described in the publication, the valve chamber and the outer pipe are integrated. If it is a separate device like the above device, if wear occurs on the outer tube 1 during boring and pouring,
Only the outer tube 1 needs to be replaced. Moreover, as acidic grout has come to be used in recent years, the entire equipment must be made of corrosion-resistant materials such as stainless steel, but stainless steel is not only expensive but also susceptible to wear, so it has been decided to make it separate. Therefore, you can select the appropriate material.

Furthermore, in the above device, the small gathering chamber 32, the small-diameter discharge hole 30, and the ejection hole 31 are used to prevent backflow of the chemical solution and slime due to the injection of the chemical solution. That is, although chemical liquid and slime may enter the ejection hole 31 due to the injection of the chemical liquid, almost only slime enters the ejection hole 30 and only a small amount of slime enters the gathering chamber 32. If water W or the like is pumped again, these will be smoothly discharged to the other side.

The above example describes the case of downward injection, so the injection port 4 is provided at the lower position of the guide chamber 14, which is the position where the drug solution flows down naturally.On the other hand, in the case of upward injection, the gravity flow downward side is Since it is located above the guide chamber 14 in the drawing, the injection port 4 is formed there. During this upward injection, since the check valve 8 is provided, it is possible to prevent the chemical liquid from flowing back in the flow path when the pressure feeding of the chemical liquid is stopped.

4 and 5 show an example of an injection device having a different aspect, in which a guide tube 50 is screwed into the position of the first discharge port 11 of the above example, and a guide tube 50 is inserted into the guide tube 50 from the periphery. A discharge port 51 facing the center is formed. In this case, the through hole 17 as in the above example is not necessary. Now, when both liquids A and B are pumped, the spool valve 6 is pushed down by the feeding pressure of liquid A.
The discharge port 52 communicates with the injection port 53 of the guide tube 50 . At this time, liquid B passes between the outer tube 1 and the valve chamber 5, is discharged into the guide tube 50 from each discharge port 51, 51..., is brought into contact with liquid A orthogonally, and is mixed from the injection port 53 to the surrounding area. Injected into the ground. In this example as well, the same effects as in the above example can be expected.

As described above, according to the method of the present invention, each liquid of the two-component curing chemical is independently pumped to the paired discharge ports in the peripheral wall, so even if the chemical has a short gel time, clogging in the pipe can be completely removed. This can be prevented, and mixing is ensured since the liquids are brought into contact and merged orthogonally. Furthermore, when it is desired to form the injection port at a position where the chemical solution naturally flows down, as in the above example, this becomes possible due to the orthogonal mixing. Further, according to the device of the present invention, not only can the above method be carried out smoothly, but also the flow paths of each liquid can be switched by moving the spool valve.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing the drilling state in the present invention, Fig. 2 is a longitudinal sectional view showing the injection state, and Fig. 3 is a longitudinal sectional view showing the drilling state in the present invention.
The drawings are a sectional view taken along the line X--X in FIG. 1, a longitudinal sectional view of a different embodiment, and FIG. 5 an enlarged cross-sectional view of the guide tube. 1... Outer pipe, 1a... Guide wall, 2... Joint pipe,
3...Cutting blade, 4...Inlet, 5...Valve chamber, 6...
...Spool valve, 9...First flow path, 10...Second flow path, 11...First discharge port, 12...Second discharge port,
14...Guidance room, 23...Check valve.

Claims (1)

[Scope of Claims] 1. A two-component curable chemical solution with a gel time of 30 seconds or less is independently pressure-fed to a pair of discharge ports spaced apart in the axial direction formed on the peripheral wall of the injection tube, and from the discharge ports. In the method of merging and contact-mixing the respective liquids and injecting the mixed liquid into the surrounding ground, a guide wall is formed outside each of the discharge ports of the chemical liquid, and the inside of the injection pipe where the guide wall and the discharge port are formed. A guide chamber is formed with the main body, and an injection port is formed in a guide wall at a position below the natural flow of the chemical liquid away from the area between the respective discharge ports, and the flow of the discharge stream from each of the discharge ports is changed by the guide wall. A chemical liquid injection method characterized in that the liquid mixture is guided to an injection port and collided orthogonally in a guide chamber, and the mixed liquid after the collision is injected from the injection port into the surrounding ground. 2. First and second channels configured independently up to the discharge point of the injection pipe, a valve chamber formed in the vicinity of the discharge point, a spool valve that is slidable within the valve chamber, and a valve chamber and its a pair of first and second discharge ports communicating with the outside; when the spool valve moves, the first flow path communicates with the first discharge port; and the flow path communicates with the second discharge port. In the chemical liquid injector configured to do so, a guide wall is formed outside the valve chamber to form a guide chamber between the outer wall surface of the valve chamber, and a guide wall is formed between the first and second discharge ports. An injection port is formed at a position below the natural flow of the chemical solution that has moved out of the region position, and when the spool valve is not moved, a communication hole that communicates between the inside and outside of the valve chamber formed in the valve chamber forming a part of the second flow path is used. , the second flow path is in communication with a flow path connected to a jet hole formed on the distal end side of the spool valve of the injection pipe, and when the spool valve is moved, the flow connected from the communication hole to the jet port is communicated with the second flow path. A chemical liquid injector characterized in that an entrance of the flow path to the channel is closed by a wall of the valve chamber, and the communication hole communicates only with the second discharge port.