JPH0621451B2 - 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 solidifying a ground extremely quickly and easily by pouring a plurality of different pouring materials at the same time.

[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 reduced.

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.

Therefore, an object of the present invention is to enable simultaneous injection using a small-injection pipe having two pipe paths such as a double pipe when pouring a plurality of injection materials having different consolidation times into the ground. Therefore, it is an object of the present invention to provide a ground pouring method in which the ground is solidified quickly and easily and the above-mentioned drawbacks existing in the prior art are improved.

[Means for solving problems]

In order to achieve the above-mentioned object, according to the present invention, there is provided an injection pipe having an inner pipe line and an outer pipe line, wherein a lower discharge port is provided at a tip of the injection pipe, and the inner pipe is further provided. A valve is arranged at the tip of the pipe so as to separate from the lower discharge port and to drop downward due to the hydraulic pressure from the inner pipe line to close the lower discharge port. In the inner pipe line, a plurality of injection ports communicating with the outside of the injection pipe through the discharge port provided across the outer pipe line are provided at different positions in the axial direction. First, while the valve is separated from the lower discharge port and the lower discharge port is opened, the drilling water is sent through the outer pipe line, and the lower discharge port is used. Jet from the outlet into the ground to make a hole, then through the inner pipe line The grout was sent to Re may itself consolidated,
This hydraulic pressure causes the valve to drop to close the lower discharge port, and to inject it into the ground from the discharge port through the injection port, and further to send the solidification accelerator through the outer pipe line, and to perform the injection. It is characterized in that it is injected and mixed from the mouth to the outlet and injected into the ground, whereby a plurality of injection materials having different consolidation times are simultaneously injected into the ground.

Hereinafter, the present invention will be described with reference to the accompanying drawings. FIG. 1 and FIG. 2 are, respectively, a cross-sectional view of a specific example of an injection pipe used in the method of the present invention and an explanatory view of 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 has an outer pipe line 2 and an inner pipe line 3, and one of these pipe lines, for example, the inner pipe line 3, has an injection port 4, 4, ... 4, which communicates with the outside A of the injection pipe 1. Are provided in desired positions in different positions in the axial direction, that is, in different positions in the length direction of the injection tube 1. The injection ports 4, 4 ... 4 communicate with the outside A of the injection pipe 1 through discharge ports 5, 5 ... 5 that cross the outer pipe line 2.

Furthermore, an injection port 6 is provided in a part of the discharge port 5, for example, the uppermost discharge port 5 in FIG. When the injection material which can be solidified by itself is sent through the inner pipe line 3 as shown in FIG. It is injected and injected into the ground from the discharge ports 5, 5, ... further,
When the caking accelerator is sent through the outer pipe line 2, the caking accelerator is injected and mixed from the injection port 6 into the injection liquid of the injectable material that passes through the discharge port 5 and can be solidified by itself. It is injected into the ground as an injection material with a short setting time.

In the above-mentioned method of the present invention, the injection material from the injection ports 4 and 6 needs to be injected. As a result, the injection material is injected and injected into the ground from the discharge port 5, so that the water permeability of the ground around the discharge port 5 is maintained even if the setting time of the injection material from the discharge port 5 is different, as described later. Even if they are different or the resistance pressure (or the ground pressure) during the injection is changed, a substantially constant discharge amount can be obtained from any of the discharge ports 5, 5 ... 5 to surely consolidate the ground. .

[Action]

In the above-described method of the present invention, first, as shown in FIG. 1, the tip valve 9 of the inner pipe 3a is arranged apart from the lower discharge port 8 of the outer pipe 2a, and the lower discharge port 8 is opened. The drilling water is sent through the outer pipe line 2 by the
From the direction of the arrow to make a hole. At this time, the discharge port 5
Is closed by a cork stopper 7.

Next, as shown in FIG. 2, an injectable material which can be solidified by itself through the inner pipe line 3, for example, a mixed solution of a water glass aqueous solution and a reactant, which has a long solidification time, is delivered. Then, due to this hydraulic pressure, the valve 9 falls and the lower discharge port 8
The cork stopper 6 and the discharge port 5, 5
.. 5 is opened, and the injection material is injected and injected into the ground through the injection ports 4, 4, ... 4, From the discharge ports 5, 5 ,.

Further, at the same time, when the solidification accelerator is sent through the outer pipe line 2, this liquid is injected and mixed from the injection port 6 into the injection liquid in the discharge port 5, and the outside A of the injection pipe 1 is injected as an injection material having a short setting time. Is injected into.

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 from the other discharge port 5 at the same time.

FIG. 3 shows the resistance pressure (ground pressure) (kg / cm ² ) at each injection pressure from the injection port 4 (expressed as a pump pressure when the injection material is sent) and the flow rate from the injection port (nozzle) ( / M
in.), and FIG. 4 is a graph showing the same relationship as in FIG. 3 when the nozzle diameter (injection diameter) is changed. As is apparent 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 flow rate from the nozzle is constant up to a resistance pressure of 50 kg / cm ² .

Therefore, in the method of the present invention, if the pump pressure is increased to about 1.2 to 1.3 times or more than the resistance pressure, the injection materials having different setting times are discharged from the respective discharge ports regardless of the change of the resistance pressure. Nevertheless, even if the water permeability of the ground is different, a constant discharge amount can be obtained, and the ground can be reliably consolidated. In other words, the injection material with a short setting time is harder than the injection material with a long setting time, so that the injection resistance of the surrounding ground is large, but nevertheless,
A constant flow rate corresponding to the nozzle diameter is secured, and the soil has different permeability in the upper and lower layers, and therefore the injection resistance is different, nevertheless, a constant flow rate is always secured, and the ground has various causes. Although the ground pressure (resistive pressure) changes due to this, a constant flow rate is always ensured nevertheless. Therefore, according to the method of the present invention, a constant discharge flow rate is secured by selecting the pump pressure to a desired value. The ground is firmly solidified.

〔The invention's effect〕

As described above, according to the method of the present invention, when injecting a plurality of injection materials having different consolidation times into the ground, simultaneous injection using an injection pipe with a small hole diameter having two conduits such as a double pipe is performed. This enables quick and easy ground consolidation, and maintains a constant discharge rate by setting the pump pressure to the desired value, regardless of the difference or fluctuation of the injection resistance pressure. It is injected, 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 an injection pipe used in the method of the present invention and an explanatory view of the method of the present invention, and FIGS. 3 and 4 are flow rates from a nozzle with respect to resistance pressure. It is a graph showing the relationship of. 1 ... injection pipe, 2 ... outer pipe line, 2a ... outer pipe, 3 ... inner pipe line, 3a ... inner pipe, 4,6 ... injection port, 5 ... discharge port, 8 ... … Lower discharge port, 9… valve.

Claims (1)

[Claims] 1. An injection pipe having an inner pipe line and an outer pipe line, wherein a lower discharge port is provided at a tip of the injection pipe,
Further, a valve is arranged at the tip of the inner pipe line so as to separate from the lower discharge port and drop downward due to hydraulic pressure from the inner pipe line to close the lower discharge port. Moreover, in the inner pipe line of the injection pipe, a plurality of injection ports communicating with the outside of the injection pipe through the discharge port provided across the outer pipe line are provided at different axial positions. An injection pipe configured to have an injection port is provided in the portion, and first, with the valve separated from the lower discharge port and opening the lower discharge port, the drilling water is sent through the outer pipe line. Then, it is injected into the ground from the lower discharge port to make a hole, and then an injection material which can be solidified by itself is sent through the inner pipe line. The outlet is closed and the ground is discharged from the discharge port through the injection port. Then, the solidification accelerator is delivered through the outer pipe line, injected and mixed from the injection port to the ejection port, and injected into the ground, whereby a plurality of injection materials with different consolidation times are injected. Ground injection method characterized by injecting into the ground simultaneously.