JPH0649974B2 - Ground injection method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a composite pouring method for pouring a plurality of injection materials having different setting times into the ground to consolidate the ground, and particularly to The present invention relates to a ground pouring method for consolidating a ground extremely quickly and easily by pouring a plurality of different pouring materials simultaneously and horizontally.

[Conventional technology]

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

Conventionally, this type of composite pouring method uses a double pipe to inject grout with a short setting time into the ground to fill the rough parts, weak parts or voids around the injection pipe, and then set the setting time. It is known that a long grout is injected between soil particles to penetrate into the ground.

In addition, the confluent of the two liquids (injection liquid with a short solidification time) sent separately from the two conduits using a triple pipe is injected from the upper discharge port, and at the same time the solidification time from the lower discharge port is long. A composite injection method for injecting grout is known.

[Problems to be solved by the invention]

However, in the former method using a double pipe, grouts with different setting times are separately injected, and therefore it is necessary to switch these grouts during injection, which complicates the operation and makes injection quick and easy. Is impossible. further,
With this method, the amount of liquid to be sent cannot be increased and the construction efficiency is low.

Further, the latter method using a triple pipe enables simultaneous injection of grout with different solidification times, but since the triple pipe is used, the injection pipe hole diameter becomes large, the drilling cost is high, and the construction efficiency is poor.

Furthermore, this method requires complex adjustments of the main material, the reaction mixture composition for flash setting, and the reaction composition preparation for slow setting, which is complicated.
Further, in this method, the injection liquid from the upper discharge port is injected horizontally, but the injection liquid from the lower discharge port is injected vertically downward. Usually, the ground targeted by the pouring method is a soft ground, but it is customary that layers with different water permeability are piled up in the horizontal direction in the ground formation process. Therefore, the hydraulic conductivity is larger in the horizontal direction than in the vertical direction, and it is not possible to place the discharge port of the injection pipe in the horizontal direction on the side wall of the injection pipe rather than in the downward vertical direction at the end of the injection pipe. Injected without.

Therefore, an object of the present invention is to install a plurality of injection pipes having a small hole diameter and having two conduits such as double pipes in parallel in the ground when pouring a plurality of injection materials having different setting times into the ground. Therefore, simultaneous injection can be performed in the horizontal direction from the respective injection pipes, so that the ground can be consolidated quickly and easily, and a ground injection method in which the above-mentioned drawbacks existing in the prior art are improved is provided.

[Means for solving problems]

In order to achieve the above-mentioned object, according to the present invention, there is provided an injection pipe having two pipe lines and a plurality of discharge ports oriented in the horizontal direction at different positions in the axial direction. An opening that communicates with one of the conduits and an opening that communicates with the other of the conduits are opened, and at least two of the plurality of discharge openings have different diameter ratios of the injection openings. A plurality of formed injection pipes are installed in parallel in the ground, and the main material is sent from one of the two pipes of each of the injection pipes and the reactant is simultaneously sent from the other pipe. Thus, a plurality of injection materials having different consolidation times are injected from a plurality of outlets of the respective injection pipes in a horizontal direction and simultaneously into a predetermined injection target ground.

Hereinafter, the present invention will be described with reference to the accompanying drawings. FIG. 1 and FIG. 2 are cross-sectional views of a specific example of the injection pipe used in the method of the present invention. In FIG. 2, reference numeral 1 is an injection pipe used in the method of the present invention and having two pipe lines, showing an example of a double pipe. The injection pipe 1 may be a double pipe or two pipe lines provided in parallel.
The injection pipe 1 includes an outer pipe line 2 and an inner pipe line 3 (not shown).
And has a plurality of horizontally oriented discharge ports 5, 5, ... 5 leading to the outside A of the injection tube 1 at different positions in the axial direction, that is, at different positions in the length direction of the injection tube 1. Further, the discharge ports 5, 5 ... 5 are connected to one of the pipe lines, for example, the injection port 4, 4 ... 4 which communicates with the inner pipe line 3, and the other pipe line, for example, the injection port 6 which communicates with the outer pipe line 2. , 6 ... 6 are opened respectively.

Further, at least two of the above-mentioned discharge ports 5, 5, ... 5 are formed such that the diameter ratios of the injection ports 4 and 6 opened therein are different from each other. For example, as shown in FIG. Injection port 4 in one discharge port 5 (diameter Φ1.5 mm)
And the diameter ratio of 6 (diameter Φ1.0 mm) is 1.5: 1,
Further, as shown in FIG. 6, the other injection ports 5 are formed such that the injection ports 4 (diameter Φ1.0 mm) and 6 (diameter Φ1.5 mm) have a diameter ratio of 1.0: 1.5.

In the present invention, a plurality of injection pipes configured in this way are installed in parallel in the ground as shown in FIG. 8, and the injection pipes 1, 1 ... 1 are connected to one of the injection pipes as shown in FIG. When the injection material as the main material (Liquid A) is sent through the other pipeline, for example, the inner pipeline 3, and the reactant (B liquid) is sent through the other pipeline, for example, the outer pipeline 2, The main material is ejected from the ejection port 4 into the ejection port 5 and the reactive agent is ejected from the ejection port 6 into the ejection port 5, and both liquids merge in the ejection port 5 and are horizontally injected into the ground. It The main agent (solution A) and the reaction agent (solution B) are sent by pumps P ₁ and P ₂ , respectively, as shown in FIG. At this time, at least two of the ejection ports 5, 5, ... 5 have different caliber ratios of the ejection ports 4 and 6 opened therein, and hence the confluence ratios of the main material and the reactant to be ejected are different, so that the consolidation is performed. At least two kinds of injecting materials having different times are simultaneously injected into a predetermined injection target ground.

In the above-described present invention, the injection ports 4 and 6 are both formed with a reduced diameter as shown in FIGS. 1 and 2. The squeezing of the diameter is performed to such an extent that the injection material from the injection ports 4 and 6 produces a pressure with respect to the flow rate in the injection pipe, that is, to an extent that the injection material is injected at a certain speed. This injection pressure is preferably 1 kgf / cm ² or more.

Generally, in the above-ground part, when the fluid in the injection pipe is discharged into the air from the injection port, the pressure in the injection pipe depends on the size and flow rate of the injection port. On the other hand, the higher the flow rate, the higher the pressure in the injection pipe, that is, the injection pressure. Further, when the injection port diameter is large with respect to the flow rate or when the flow rate is small with respect to the injection port diameter, the injection pipe internal pressure, that is, the injection pressure hardly occurs.

According to the present invention, since the injection liquid is in the injection state in this way,
As will be described later, even if the solidification time of the injection material from the discharge port 5 is different and the water permeability of the ground around the discharge port 5 is also different, the ground is caused by further progress of gelation of the injected liquid. Even if the permeation resistance of the
・ ・ Almost constant discharge can be obtained from 5, and the ground is firmly solidified.

The main agent used in the present invention is water glass or an injectable material which can be solidified by itself, and examples thereof include a mixed solution of water glass and a reactive agent, non-alkaline water glass grout, cement grout, and the like. Various solidifying agents or solidifying accelerators, for a mixed solution of water glass and a reaction agent, alkali such as salt or lime, non-alkaline water glass compounding solution, carbon dioxide gas, carbonated water, etc., non-alkaline water glass Examples of the grout include water glass, cement, various salts of alkali, water glass grout, and the like, and examples of the cement grout include water glass, various salts, and a non-alkaline water glass compounding liquid.

Although not shown in the figure instead of the above-described discharge port 5, a groove may be formed in the circumferential direction of the injection pipe. In this case, a rubber ring is fitted in the groove instead of the plug 7 shown in FIG.

[Action]

In the above-described method of the present invention, first, as shown in FIG. 1, the closing bundle metal fitting 9 of the inner pipe 3a is arranged apart from the lower discharge port 8 of the outer pipe 2a, and the end discharge port 8 is opened. In this state, the drilling water is sent through the outer pipe line 2 and discharged from the end discharge port 8 in the direction of the arrow to drill a hole. At this time, the discharge port 5 is closed by a stopper 7, for example, a rubber stopper, a rubber ring, a steel stopper or the like.

Next, as shown in FIG. 2, when an injection material as a main material, for example, a mixed solution of a water glass aqueous solution and a reactant is sent through the inner pipe line 3, the closing bundle metal fitting 9 falls due to this liquid pressure. , The end discharge port 8 is closed and the stopper 7 is discharged to open the discharge ports 5, 5, ...
.. is jetted to the discharge ports 5, 5 ,.

At the same time, when the reactant is sent through the outer pipe line 2,
This liquid is jet-merged from the jet port 6 to the jet liquid in the discharge port 5. At this time, since at least two of the discharge ports 5, 5, ... 5 have different diameter ratios of the injection ports 4 and 6, at least two kinds of injection materials having different consolidating times with different merging ratios of the main material and the reactant. At the same time, the liquid is injected into the outside A of the injection pipe 1 in the horizontal direction.

That is, in the method of the present invention, the injection material having a short setting time is injected from one discharge port 5 and the injection material having a long setting time is injected simultaneously and horizontally from the other discharge port 5.

The injection function by injection in the present invention is shown in FIGS.
This will be described with reference to the figure.

When pumping water to a pipe with an inner diameter of 4 cm, almost no pump pressure is generated. FIGS. 3 and 4 show examples of the results of measuring the injection pressure (pump pressure) and the discharge amount by mounting the tip end portion having the injection port at the end of this pipe. For comparison, a tip having three discharge ports each having a diameter of 1 cm was attached to the end of the pipe to feed water to 1 to 20 / m, but almost no discharge pressure was observed. .

Fig. 3 shows a nozzle with a 1.0 mm nozzle diameter, and Fig. 4 has a 1.5 mm discharge port attached to a pipe, the pump pressure is changed variously, and water is sent so that the pump pressure maintains a predetermined pressure. Moreover, the downstream side of the injection port is also connected by a pipe line, and a resistance pressure is applied by a valve in the pipe line to generate a pressure corresponding to the resistance pressure of the ground, and the flow rate discharged from the injection port in that case (/
Min) and resistance pressure (kgf / cm ² ) were measured, and the results are shown in the graph. As is clear from FIGS. 3 and 4, for example, using a pump pressure of 80 kg / cm ² , even if the resistance pressure (kg / cm ² ) in the ground changes, the resistance pressure of about 50 kg / cm ² Up to a constant flow rate from the nozzle.

That is, there is a region where a constant discharge amount can be obtained despite changes in the ground resistance pressure.
You can see from the figure. Therefore, even if the injection materials having different setting times are discharged from the respective discharge ports, a constant discharge amount can be obtained even if the water permeability of the ground is different.
Can be firmly solidified in the ground. That is, since the injection material with a short setting time is more quickly solidified than the injection material with a long setting time, the injection resistance of the surrounding ground is large, but nevertheless, a constant flow rate corresponding to the nozzle diameter is secured, In addition, although the soil has different water permeability in the upper and lower layers and therefore the injection resistance is different, nevertheless, a predetermined flow rate is always secured, and the soil pressure (resistive pressure) changes due to various causes. Nevertheless, a predetermined flow rate is always secured, and therefore, according to the method of the present invention, a predetermined discharge flow is secured by selecting the pump pressure to a desired value, and the ground is reliably consolidated.

Furthermore, the method of the present invention is capable of simultaneously and reliably injecting grouts having different setting times by using the double injection tube, and does not need to change the injecting liquid as in the conventional injecting method, which is simple and highly efficient. For example, in the state of FIG. 2, the injection can be performed while pulling up the injection pipe from the lowest stage to the upper stage of the injection range. In this case, the grout having a short solidification time fills the rough or fine portion of the upper layer from the upper discharge port, and at the same time, the grout having a long solidification time is superposed and injected into this region from the lower discharge port.

FIG. 7 shows an example in which the structure of FIG. 2 is continued up to the top of the injection pipe. In this case, all stages can be injected at one time with one injection tube without pulling the injection stage upward. What is required is that even if the number of discharge ports is increased, the gelation time of each discharge port is different, and the injection resistance of the surrounding ground is different, it is difficult to ensure a predetermined injection, and the discharge ports a and When the injection from the outlet b is performed at the same time, the injection solution with a short gel time mainly consists of veins, and the injection solution with a long gel time mainly consists of penetration between soil particles, so that the former is faster than the surrounding area. This is because the rough and weak parts are filled, and the latter gradually penetrates into the fine parts, so that reliable composite injection is possible.

Note that, in FIG. 7, it is a matter of course that the grout discharge port having a short gel time and the grout discharge port having a long gel time may be alternately provided in the vertical direction.

FIG. 8 is a schematic view of a specific example of the method of the present invention, in which a predetermined injection target ground is simultaneously injected from a plurality of injection pipes, and the improvement of construction efficiency is immeasurable.

〔Example〕

A plurality of the injection pipes shown in Fig. 1 were installed in parallel on the injection ground in Tokyo as shown in Fig. 8, and a test construction was performed. In this case, the inner diameter of each injection tube is 4 cm, and the inner diameter is 2 cm.
Inner tube wall pressure is 1 mm.

The distance between the discharge ports is 50 cm, the diameters of the discharge ports 6 and 4 of the uppermost discharge port 5 are 1.5 mm and 1.0 mm, respectively, and the diameters of the discharge ports 6 and 4 of the middle and lowermost discharge ports 5 are respectively. , 1.0m
m and 1.5 mm.

[Compound]

 Solution A: Water glass 35 per 100, 75% sulfuric acid 7 and remaining water. (PH about 1.7) Solution B: Water glass 5 per 100, remaining water.

When liquids A and B are combined at 0.5: 1.0 (volume ratio), gelation occurs in 5 seconds, and when combined at 1.0: 0.5 (volume ratio), gelation occurs in 30 minutes.

When excavated, it was confirmed that the injection liquid from each discharge port had solidified and solidified, and that a column-shaped, homogeneously solidified solid with a cross-sectional area of approximately 1 m ² and a length of approximately 1.5 m was formed. Was confirmed.

For comparison, the same end of the double tube as above was axially
An injection test was conducted by mounting a tip portion provided with three discharge ports at cm intervals. The diameter of one discharge port was 1 cm. At the above-ground part, liquid A from the inner pipe is 15 / min, liquid B from the outer pipe is 12 / min
Although the liquid was dispensed, the pump pressure was almost zero. When the injection pipe was installed in the ground and the above liquids A and B were injected from the inner and outer pipes at a rate of 15 / min and 12 / min, respectively, for a total of 600 injections, the lowermost discharge port and the lowermost discharge were performed. The outlet was clogged, and it was confirmed that the injection liquid was being discharged only from the middle discharge port. The injection liquid spreads in a pulse pattern centering on the middle discharge port, and within a range of 2 to 5 m from the injection hole. It was found that the veins were nonuniformly consolidated throughout.

〔The invention's effect〕

As described above, according to the method of the present invention, when injecting a plurality of injection materials with different consolidation times into the ground, a plurality of injection pipes having a small hole diameter having two conduits such as a double pipe are arranged in parallel. Installed in the ground, simultaneous injection is possible, which enables quick and easy ground consolidation, and maintains a predetermined discharge amount at each discharge port regardless of differences in injection resistance pressure or fluctuations. Is injected into the ground, which makes it possible to firmly solidify the ground.

[Brief description of drawings]

1 and 2 are cross-sectional views of a specific example of the injection pipe used in the method of the present invention, and FIGS. 3 and 4 are graphs showing the relationship between the resistance pressure and the flow rate from the nozzle. FIG. 5 and FIG. 6 are enlarged partial sectional views showing the discharge port portion of FIG. 2, and FIG. 7 is an explanatory view showing the injection state from the injection pipe of the present invention. FIG. 8 is a schematic diagram for explaining a specific example of the method of the present invention. 1 ... Injection pipe, 2 ... Outer pipe line, 2a ... Outer pipe, 3 ... Inner pipe line, 3a ... Inner pipe, 4,6 ... Spray port, 5 ... Discharge port, 8 ... … Terminal discharge port, 9 …… Closed brace.

Claims (1)

[Claims] 1. An injection pipe having two pipe lines and having a plurality of horizontally oriented discharge ports at different axial positions, wherein the discharge port has an injection port communicating with one of the pipe lines. And a plurality of injection pipes that are formed so that at least two of the plurality of discharge ports have different diameter ratios of the injection ports that are opened therein. Then, the main material is sent from one of the two conduits of each of the injection pipes and the reactant is simultaneously sent from the other conduit of each of the injection pipes, so that a plurality of solidification times with different consolidation times can be obtained. The ground injection method, wherein the injection material is injected horizontally from a plurality of outlets of the respective injection pipes and simultaneously into a predetermined injection target ground.