JPH0565649B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an injection pipe used in a composite injection method in which a plurality of injection materials having different consolidation times are injected into the ground to solidify the ground, and in particular, The present invention relates to an injection pipe for ground injection that can consolidate the ground extremely quickly and easily by simultaneously injecting a plurality of injection materials having different consolidation times in the horizontal direction.

[Conventional technology]

As a technique for improving complex ground, a so-called composite injection method is generally used, in which grout with a short setting time and grout with a long setting time are injected into the ground.

Conventionally, this type of composite injection method uses double pipes to first inject grout with a short setting time into the ground to fill rough areas, weak areas, or voids around the injection pipe, and then takes a long time to set. A known method is to inject long grout between soil particles and allow it to penetrate into the ground.

Furthermore, using a triple pipe, the combined liquid (injected liquid with a short solidification time) of two liquids sent separately from two pipes is injected from the upper discharge port, and at the same time, the combined liquid (injected liquid with a long solidification time) is injected from the lower discharge port. A composite injection method in which grout is injected is known.

[Problem that the invention seeks to solve]

However, in the former double pipe, grouts with different setting times are injected separately, so it is necessary to switch between these grouts at the time of injection, which complicates the operation and makes quick and easy injection impossible. It is. Furthermore, this injection pipe does not allow for a large amount of liquid to be fed, resulting in low construction efficiency.

In addition, the latter triple pipe allows simultaneous injection of grouts with different solidification times, but because it is a triple pipe, the diameter of the injection pipe hole becomes large, resulting in high drilling costs and poor construction efficiency.

Furthermore, in this triple pipe, it is necessary to adjust the composition of the main material, the instant setting reactant mixture, and the slow setting reactant mixture, making it complicated. Further, in this triple tube, the injection liquid from the upper discharge port is injected in a horizontal direction, but the injection liquid from the lower discharge port is injected in a downward vertical direction. Usually, the ground targeted by the injection method is soft ground, and in this ground, it is common for layers of different permeability to be layered horizontally during the ground formation process. Therefore, the hydraulic conductivity is greater in the horizontal direction than in the vertical direction, and it is better for the outlet of the injection tube to be located in the side wall of the injection tube, facing horizontally, than in the end of the injection tube, facing downward and vertically. is injected without difficulty.

Therefore, the purpose of the present invention is to enable simultaneous injection in the horizontal direction using a small diameter injection pipe having two pipes such as a double pipe when injecting multiple injection materials with different consolidation times into the ground. Therefore, it is an object of the present invention to provide an injection pipe for ground injection which can consolidate the ground quickly and easily and which improves the above-mentioned drawbacks of the prior art.

[Means for solving problems]

In order to achieve the aforementioned object, according to the present invention:
It has two pipes and a plurality of discharge ports oriented in the horizontal direction at different positions in the axial direction, and each of the discharge ports has an injection port that communicates with one pipe line and an injection port that communicates with the other pipe line. At least two of the plurality of discharge ports are formed such that the aperture ratios of the injection ports opened therein are different from each other.

Hereinafter, the present invention will be explained using the accompanying drawings. FIGS. 1 and 2 are sectional views of a specific example of the injection pipe according to the present invention, with FIG. 1 showing the excavation water feeding state and FIG. 2 showing the injection state.
In FIGS. 1 and 2, reference numeral 1 indicates an injection pipe having two pipelines according to the construction method of the present invention, and shows an example of a double pipe. In addition to a double pipe, the injection pipe 1 may be a pipe in which two pipes are provided in parallel. (Not shown) The injection pipe 1 has an outer pipe line 2 and an inner pipe line 3, and the injection pipe 1 is located at different positions in the axial direction, that is, at different positions in the length direction of the injection pipe 1.
It has a plurality of discharge ports 5, 5...5 which are oriented in the horizontal direction and which communicate with the outside A of the discharge ports 5, 5...5.
Injection ports 4, 4, . . . 4, which communicate with one pipe line, for example, the inner pipe line 3, and injection ports 6, 6, .

Furthermore, at least two of the above-mentioned discharge ports 5, 5...5 have injection ports 4 and 6 opened therein.
For example, as shown in FIG. 5, injection ports 4 (diameter Φ1.5 mm) and injection ports 6 (diameter Φ1.0 mm) in one discharge port 5 are formed with different aperture ratios.
As shown in FIG. 6, the diameter ratio of the injection ports 4 (diameter Φ1.0 mm) and 6 (diameter Φ1.5 mm) in the other discharge port 5 is 1.0. : formed to be 1.5.

Using the injection pipe 1 constructed in this way, one pipe line, for example, the inner pipe line 3, is connected as shown in FIG.
When the injection material as the main material is sent through the main material and the reactant is sent through the other pipe, for example, the outer pipe pipe 2, the main material is injected from the injection port 4 into the discharge port 5 and the reactant is injected from the injection port 6 into the discharge port 5, and both liquids merge within the discharge port 5 and are horizontally injected into the ground. At this time, the discharge ports 5, 5
... At least two of the injection ports 4 and 6 opened therein have different aperture ratios, so the merging ratio of the main material and reactant to be injected is different, and at least two or more types of injection with different solidification times are performed. The material is simultaneously injected into the ground.

In the present invention described above, both the injection ports 4 and 6 are formed with reduced diameters as shown in FIGS. 1 and 2. The diameter is narrowed to the extent that the injection material from the injection ports 4 and 6 generates a pressure with respect to the flow rate in the injection pipe, that is, to the extent that the injection material is injected at a certain speed. This injection pressure is 1Kg
It is preferable that it is f/cm ² or more.

Generally, when the fluid in the injection pipe is discharged into the air from the injection port on the ground, the pressure inside the injection pipe depends on the size of the injection port and the flow rate. On the other hand, as the flow rate increases, the pressure inside the injection pipe, that is, the injection pressure increases. Further, when the injection aperture is large relative to the flow rate, or when the flow rate is small relative to the injection aperture, almost no injection pipe pressure, that is, injection pressure is generated.

In the present invention, the injected liquid is in a sprayed state in this way, so even if the solidification time of the injected material from the discharge port 5 differs, and the water permeability of the ground around the discharge port 5 differs, as will be described later. Even if the penetration resistance of the ground changes due to the progress of gelation of the injected liquid, a nearly constant discharge amount can be obtained from the discharge ports 5, 5...5, and the soil can be reliably solidify.

The main agent used in the present invention is water glass or a pouring material that can solidify itself, such as a mixture of water glass and a reactant, non-alkaline water glass grout, cement grout, etc. Various setting agents or setting accelerators,
For mixed liquids of water glass and reactants, alkalis such as salt and lime, non-alkaline water glass mixed liquids, carbon dioxide gas, carbonated water, etc. For non-alkaline water glass grouts, water glass, cement, various alkali salts, etc. , water glass grout, etc. In contrast to cement grout, examples include water glass, various salts, non-alkaline water glass mixed liquids, etc.

Although not shown, a groove may be formed in the circumferential direction of the injection tube in place of the above-mentioned discharge port 5. In this case, a rubber ring is fitted into the groove instead of the stopper 7 in FIG.

[Effect]

In the injection tube of the present invention described above, first, as shown in FIG. 1, the closing fitting 9 of the inner tube 3a is placed apart from the lower outlet 8 of the outer tube 2a, and the terminal outlet 8 is opened. In this state, drilling water is sent through the outer pipe conduit 2 and discharged from the terminal outlet 8 in the direction of the arrow to drill a hole. At this time, the discharge port 5 is closed by a stopper 7, such as a rubber stopper, a rubber ring, or a steel stopper.

Next, as shown in FIG.
When the injection material as the main material, for example, a mixture of water glass aqueous solution and reactant, is fed through the liquid pressure, the closing fitting 9 falls down and closes the terminal outlet 8, and the stopper 7 is released to discharge the liquid. The outlets 5, 5...5 are opened, and the injection agent is injected to the outlets 5, 5...5 through the injection ports 4, 4...4.

Further, at the same time, when a reactant is sent through the outer tube conduit 2, this liquid is jetted and merged with the jetted liquid in the discharge port 5 from the jetting port 6. At this time, the discharge ports 5, 5...
At least two of the injection ports 4 and 6 have different aperture ratios, so at least two or more types of injection materials with different convergence ratios of the main material and the reactant and different solidification times are simultaneously placed horizontally on the outside A of the injection pipe 1. Injected in the direction.

That is, in the injection tube of the present invention, an injection material having a short solidification time is injected from one discharge port 5, and an injection material having a long solidification time is simultaneously injected from the other discharge port 5 in a horizontal direction.

The injection function by injection in the present invention will be explained with reference to FIGS. 3 and 4.

When water is pumped into a pipe with an inner diameter of 4 cm, almost no pump pressure is generated. An example of the results of measuring the injection pressure (pump pressure) and discharge amount by attaching a tip with an injection port to the end of this tube is shown in FIGS. 3 and 4. For comparison, a tip with three 1 cm diameter discharge ports was attached to the end of the tube and water was conveyed at a rate of 1 to 20/m, but almost no discharge pressure was observed. .

Figure 3 shows a nozzle with a diameter of 1.0 mm, and Figure 4 shows a 1.5 mm discharge port, each of which is attached to a pipe, and the pump pressure is varied to feed water so that the pump pressure remains at a predetermined level. In addition, the downstream side of the injection port is also connected with a pipe, and resistance pressure is applied in the pipe by a valve to generate a pressure equivalent to the resistance pressure of the ground, and the flow rate (/min) discharged from the injection port in this case is This is a graph showing the results of measuring the resistance pressure (Kgf/cm ² ). As is clear from Figures 3 and 4, for example, if the pump pressure is 80Kg/ ^cm2 , even if the resistance pressure (Kg/ ^cm2 ) in the ground changes, the resistance pressure will be 50Kg/ ^cm2. Until then, the flow rate from the nozzle is constant.

In other words, despite changes in ground resistance pressure,
It can be seen from FIGS. 3 and 4 that there is a region where a constant ejection amount can be obtained. Therefore, even though the injection materials with different consolidation times are discharged from each outlet, a constant discharge amount can be obtained even if the permeability of the ground is different, and the material can be reliably consolidated into the ground. obtain. In other words, the injection material with a short consolidation time will harden faster than the injection material with a longer consolidation time, so the injection resistance of the surrounding ground will be greater, but despite this, a constant flow rate corresponding to the nozzle diameter is ensured, In addition, the permeability of the upper and lower layers of the ground is different, and therefore the injection resistance is different, but despite this, a constant flow rate is always secured, and the ground pressure (resistance pressure) due to various reasons
However, despite this, a constant flow rate is always ensured. Therefore, according to the injection pipe of the present invention, by selecting the pump pressure to a desired value, a constant discharge flow is ensured, and the ground is solidified securely.

Furthermore, the injection pipe of the present invention can reliably inject grouts with different setting times at the same time, and there is no need to change the injection liquid unlike conventional injection pipes, so it is simple and has high construction efficiency. For example, in the state shown in FIG. 2, injection can be carried out while pulling the injection tube from the lowest stage to the upper stage of the injection range. In this case, the grout with a short setting time fills the rough and fine parts of the upper layer from the upper outlet, and at the same time, the grout with a longer setting time is superimposed and injected into this area from the lower outlet.

FIG. 7 shows an example in which the structure of FIG. 2 is continued up to the upper part of the injection tube. In this case, all stages can be injected at once with a single injection tube without having to pull the injection stage upward. Even if the number of discharge ports is large, even if the gelation time of each discharge port is different, or even if the injection resistance of the surrounding ground is different, the specified injection can be ensured. When injected from outlet b at the same time, the injected liquid with a short gelation time mainly forms veins, and the injected liquid with a long gelation time mainly penetrates between soil particles, so the former is faster and penetrates into the surrounding area more quickly. This is because it fills the rough and weak areas, and then the latter slowly penetrates into the finer areas, allowing for reliable composite injection.

In FIG. 7, it goes without saying that the outlet for grout having a short gelation time and the outlet for grout having a long gelation time may be provided alternately in the vertical direction.

〔Example〕

Using the injection pipe shown in Figure 1, test construction was carried out at the injection ground in Tokyo. In this case, the inner diameter of the outer tube is 4
cm, the inner diameter of the inner tube is 2 cm, and the inner tube wall pressure is 1 mm.

The interval between the discharge ports is 50 cm, the diameters of the jet ports 6 and 4 of the top discharge port 5 are 1.5 mm and 1.0 mm, respectively, and the diameters of the jet ports 6 and 4 of the middle and bottom discharge ports 5 are respectively 1.5 mm and 1.0 mm. , 1.0mm, and 1.5mm.

[Composition]

Liquid A: 35% water glass, 75% sulfuric acid 7% per 100%
Remaining water. (PH approx. 1.7) B liquid: 5 glasses of water per 100, remaining water.

When liquid A and liquid B are combined at a ratio of 0.5:1.0 (volume ratio),
It gels in 5 seconds, and when combined at a ratio of 1.0:0.5 (volume ratio), it gels in 30 minutes.

When excavated, it was found that the injected liquid from each discharge port had penetrated and solidified, and a cylindrical homogeneously permeated solid body with a cross-sectional area of approximately 1 m ² and a length of approximately 1.5 m was formed. was confirmed.

For comparison, an injection test was carried out by attaching to the end of the same double-walled tube as described above a tip with three discharge ports provided at intervals of 50 cm in the axial direction. The diameter of one discharge port was 1 cm. 15 liters of liquid A from the inner pipe above ground
Liquid B was pumped from the outer tube at 12 minutes per minute, but the pump pressure was almost zero. Inject the injection pipe into the ground, and inject the above liquids A and B from the inner and outer pipes respectively.
When excavating with a total of 600 injections at speeds of 15/min and 12/min, the bottom discharge port and bottom discharge port were clogged, and the injected liquid was being discharged only from the middle discharge port. was confirmed, and the injected liquid spread in a vein shape centered around the middle discharge port, and 2 times from the injection hole.
It was found that the particles were solidified non-uniformly in the form of veins over a range of ~5 m.

〔Effect of the invention〕

As described above, according to the injection pipe of the present invention, when injecting multiple injection materials with different solidification times into the ground, simultaneous injection can be performed using an injection pipe with a small hole diameter having two pipes such as a double pipe. This makes it possible to consolidate the ground quickly and easily, and
Regardless of differences or fluctuations in the injection resistance pressure, a predetermined discharge amount is maintained at each discharge port and is injected, thereby making it possible to solidify the ground reliably.

[Brief explanation of the drawing]

1 and 2 both show cross-sectional views of a specific example of the injection pipe of the present invention, and FIG. 1 shows the excavation water feeding state, FIG. 2 shows the injection state, and FIG. 3 shows the injection state. and FIG. 4 are graphs showing the relationship between the flow rate from the nozzle and the resistance pressure, respectively, and FIGS. 5 and 6 are enlarged partial cross-sectional views showing the discharge port portion of FIG. FIG. 7 shows another specific example of the injection tube of the present invention. 1...Injection pipe, 2...Outer pipe line, 2a...Outer pipe, 3...Inner pipe line, 3a...Inner pipe, 4, 6...
Spout port, 5...Discharge port, 8...Terminal discharge port, 9...
...Bundling fittings.

Claims (1)

[Claims] 1 It has two pipes and has a plurality of discharge ports oriented in the horizontal direction at different positions in the axial direction, and the discharge ports have an injection port communicating with one pipe line and a injection port communicating with the other pipe line. An injection pipe for ground injection, wherein at least two of the plurality of discharge ports are formed such that the diameter ratios of the injection ports opened therein are different from each other.