JPH085483A - Injection pressure measuring device - Google Patents

Abstract

PURPOSE:To provide an injection pressure measuring device which makes possible the strict grasp of the situation of injection of chemicals. CONSTITUTION:This injection pressure measuring device has a pressure converter 12, which uses a foil distortion gauge as a converting element, an upper filter member 15, which is made of porous material and is provided, at the center of the bottom, with a recess 16b for accommodating the pressure converter 12 bonded to the inner face of itself, and a lower filter member 1 7 bonded to the bottom of the upper filter member 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical liquid injection method for injecting a chemical liquid into a ground to improve the ground when it is necessary to improve the soft ground, such as when excavating and forming a tunnel in the ground. , An injection pressure measuring device used for detecting the injection pressure of the chemical liquid for the purpose of detecting the injection state of the chemical liquid.

[0002]

2. Description of the Related Art A chemical solution is injected into the ground by forming a chemical solution injection hole in the ground, filling the chemical solution injection hole with a seal grout, and installing a chemical solution injection pipe in the seal grout. It is performed by injecting the drug solution into the ground through the seal grout from the drug solution injection nozzle of the injection tube.
At this time, the detection of the injection pressure of the chemical liquid is important as a clue to know the injection status of the chemical liquid, and it is always monitored at the time of construction. The detection of the injection pressure of the chemical liquid is conventionally measured on the ground at the mouth of the chemical liquid injection pipe.

[0003]

However, if the injection pressure of the chemical liquid is measured at the mouth of the chemical liquid injection pipe on the ground as in the prior art, the injection hose that supplies the chemical liquid to the chemical liquid injection pipe based on the measured value. Since the pressure loss due to the chemical injection pipe, the chemical injection nozzle, the rubber sleeve, etc. is included, the measured value causes an error with respect to the actual injection pressure to the ground. An example of measuring this error is shown in FIGS.
FIG. 9 is a graph showing the relationship between the injection speed of the chemical liquid and the pressure loss, divided into the pressure loss due to the injection hose, the injection pipe, and the rubber sleeve, the pressure loss due to the injection hose and the injection pipe, and the pressure loss due to the injection hose. Is. FIG. 10 is a graph showing the difference in injection pressure between the mouth of the injection pipe and the vicinity of the chemical injection nozzle along with the passage of time from the start of injection.

Therefore, in order to more accurately measure the injection pressure of the chemical liquid into the ground, a pore water pressure gauge for measuring the pore water pressure is embedded in a seal grout that is filled in the gap between the injection pipe and the ground to form the chemical liquid. It is conceivable to directly measure the chemical injection pressure near the injection nozzle. However, since the gap between the injection pipe filled with the seal grout and the ground is usually as narrow as about 20 mm, a known pore water pressure gauge capable of accurately measuring the injection pressure is too large and the gap is small. It is difficult to bury. Further, in the conventional pore water pressure gauge, since only a filter member is provided so as to transmit the external pressure to a part of the case that surrounds and protects the pressure receiving portion that feels the pressure, it is possible to embed it. Even if there is, the filter member will be clogged with the seal grout material (cement bentonite). Therefore, the responsiveness deteriorates, and it is difficult to accurately measure the pressure change. Therefore,
Conventionally, there is a problem in that it is necessary to rely on the measured value of the injection pressure at the mouth of the liquid injection tube, and it is not possible to exactly grasp the injection state of the liquid chemical.

In view of the above circumstances, it is an object of the present invention to provide an injection pressure measuring device which enables a precise grasp of the injection state of a chemical solution.

[0006]

According to another aspect of the present invention, there is provided a pressure transducer having a pressure transducer having a foil strain gauge as a transducer, and a pressure transducer formed of a porous material. And a filter member provided so as to surround the portion.

[0007]

According to the injection pressure measuring device of the present invention, by using a pressure converter having a foil strain gauge as a conversion element, the size of the pressure converter can be reduced, and the pressure receiving portion is surrounded by the filter member, so that the soil can be obtained. The chemical liquid acts to flow into the pressure receiving portion while protecting the pressure from being transmitted to the pressure receiving portion.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 7, the ground 1 has its ground surface 1a.
A chemical liquid injection hole 2 is provided downward from the liquid chemical injection hole 2, and the chemical liquid injection hole 2 is filled with a seal grout 3. In the seal grout 3 in the chemical solution injection hole 2, the chemical solution injection pipe 5
Are buried all over the chemical solution injection hole 2 in the vertical direction, and the chemical solution injection pipe 5 is provided with five chemical solution injection nozzles 6 at predetermined intervals in the vertical direction. Chemical injection nozzle 6
2, is provided so as to radially inject and inject the chemical solution 7 horizontally toward the ground 1 through the seal grout 3 as shown in FIG.

Further, as shown in FIG. 7, in the seal grout 3 in the chemical solution injection hole 2, the injection pressure is measured in the gap between the ground 1 forming the hole wall of the chemical solution injection hole 2 and the chemical solution injection pipe 5. A plurality of injection pressure detection units 11 of the device 10 are embedded, and each injection pressure detection unit 11 is located near each chemical liquid injection nozzle 6 of the chemical liquid injection pipe 5. The injection pressure detector 11 is shown in FIG.
As shown in FIG. 3, the pressure transducer 12 has a foil strain gauge as a transducer element, and the pressure transducer 12 has its pressure receiving surface 12a facing downward in FIG. The lead wire 13 electrically connected to a foil strain gauge (not shown) inside the pressure transducer 12 is provided upward, and the lead wire 1 is provided.
3 is inserted inside the cable 15. Cable 1
The reference numeral 5 extends upward in the chemical liquid injection hole 2 and extends to the ground.
Is electrically connected to a pressure measuring device (not shown) for measuring the pressure applied to the pressure receiving surface 12a.

On the upper surface of the pressure converter 12, a filter member upper part 16 formed of a porous material such as porous stone or porous metal and having a hole 16a penetrating in the vertical direction at the center is provided in the hole 16a. Lead wire 13
The filter member upper part 16 has a recess 16b at the center thereof. The pressure converter 12 is provided in the recess 16b, and at a position facing the lower surface of the filter member upper portion 16, the filter member lower portion 17 has an outer peripheral portion of the upper surface thereof and an outer peripheral surface of the lower surface of the filter member upper portion 16. It is provided by bonding the parts.

Since the chemical injection pipe 5, the injection pressure measuring device 10 and the like have the above-mentioned structure, the chemical solution 7 is placed in the ground 1.
When the soil is injected to improve the ground, first, as shown in FIG. 3, the ground 1 is excavated downward from the ground surface 1a to form the chemical solution injection hole 2, and the wall surface of the chemical solution injection hole 2 collapses. In order to prevent this, the cylindrical casing 8 is fitted into the chemical liquid injection hole 2. Next, as shown in FIG. 4, the seal grout 3 is filled in the chemical solution injection hole 2 in a state where the casing 8 is fitted and covered.

Next, as shown in FIG. 5, while the seal grout 3 in the chemical solution injection hole 2 does not solidify, the seal grout 3 filled in the chemical solution injection hole 2 is injected into the seal grout 3 together with the chemical solution injection pipe 5. The injection pressure detector 11 of the measuring device 10 is inserted. Then, the chemical solution injection pipe 5 is embedded in the seal grout 3 in the chemical solution injection hole 2 over the entire area in the vertical direction of the chemical solution injection hole 2, and each chemical solution injection nozzle 6 of the chemical solution injection pipe 5 is predetermined in the vertical direction. And the injection pressure detectors 11 are arranged so that the injection pressure detectors 11 are arranged at the intervals of.
Provide it so that it is located close to it.

At this time, the injection pressure detector 11 uses the pressure converter 12 whose conversion element is a foil strain gauge, so that the size can be reduced. Therefore, it can be embedded in the seal grout 3 filled in the gap (usually about 20 mm) between the chemical solution injection pipe 5 inserted into the chemical solution injection hole 2 and the ground 1 forming the hole wall of the chemical solution injection hole 2. I can.

Thereafter, as shown in FIG. 6, the chemical solution injection hole 2
The casing 8 which has been covered with is removed from the chemical liquid injection hole 2. At this time, the seal grout 3 is placed in the chemical injection hole 2.
Is filled, it is possible to prevent the wall of the chemical solution injection hole 2 from collapsing due to the pressure of the seal grout 3.

Therefore, after the seal grout 3 is solidified, as shown in FIG. 7, the chemical liquid 7 is injected from each chemical liquid injection nozzle 6 of the chemical liquid injection pipe 5 into the ground 1 through the seal grout 3. At this time, since cracks are generated in the seal grout 3, the chemical liquid 7 can be injected into the ground 1 through the seal gout 3.

As shown in FIG. 8, each chemical solution injection nozzle 6
The chemical solution 7 injected from the seal grout 3 and the ground 1
When it penetrates into the inside to some extent, the injection pressure detection unit 11 of the injection pressure measuring device 10 provided near the chemical injection nozzle 6
The chemical solution 7 arrives. Then, in the injection pressure detection unit 11,
As shown in FIG. 1, the filter member upper part 16 and lower part 17
Since the pressure transducer 12 is surrounded by, the filter member upper part 16 and the lower part 17 support earth pressure. Therefore, the earth pressure is not transmitted to the pressure converter 12. Further, since the filter member upper part 16 and the lower part 17 are formed of the porous material, the pressure of the chemical liquid 7 can be transmitted to the pressure receiving surface 12 a of the pressure converter 12 via the filter member upper part 16 and the lower part 17. I can. Therefore, the pressure converter 12 can directly measure the injection pressure of the chemical liquid 7 injected from the nozzle 6 of the chemical liquid injection pipe 5 near the nozzle 6. Therefore, on the ground, at the mouth of the liquid medicine injection pipe 5, the liquid medicine 7
It is possible to detect the injection pressure of the chemical liquid with higher accuracy than in the conventional case where the injection pressure of is measured. As a result, the liquid medicine 7
The injection status of can be grasped exactly.

[0017]

According to the injection pressure measuring device of the first aspect, by using the pressure converter having the foil strain cage as the conversion element, it is possible to reduce the size of the device. The pressure transducer can be embedded in the seal grout that is filled in the gap between the chemical injection pipe and the ground forming the hole wall of the chemical injection hole. Further, since the pressure receiving portion of the pressure converter is surrounded by the filter member, it is possible to transmit only the injection pressure of the chemical liquid to the pressure receiving portion without transmitting the earth pressure to the pressure receiving portion. Therefore, the pressure converter can directly measure the injection pressure of the chemical liquid injected from the nozzle of the chemical liquid injection pipe near the nozzle. Therefore, the chemical solution injection pressure can be detected more accurately than in the conventional case where the chemical solution injection pressure is measured at the mouth of the chemical solution injection pipe on the ground. As a result, it is possible to accurately grasp the injection status of the liquid medicine.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an injection pressure measuring device of the present invention.

FIG. 2 is a diagram showing an injection pressure detection unit embedded in a seal grout filled in a gap between a chemical injection pipe inserted into the chemical injection hole and a ground forming a hole wall of the chemical injection hole.

FIG. 3 is a diagram showing a state in which a chemical solution injection hole is excavated in the ground and a casing is installed in the chemical solution injection hole.

FIG. 4 is a view showing a state in which a seal grout is filled in the chemical liquid injection hole provided in the casing of FIG.

5 is a diagram showing a state in which a chemical injection pipe and an injection pressure detection unit are inserted into the seal grout in the chemical injection hole of FIG.

6 is a view showing a state in which the casing is removed from the chemical liquid injection hole after the chemical liquid injection pipe and the injection pressure detection unit are inserted and installed in the seal grout in the chemical liquid injection hole of FIG.

FIG. 7 is a diagram showing a state in which a chemical liquid has started to be injected into the ground through a seal grout from a chemical liquid injection nozzle of the chemical liquid injection pipe of FIG.

FIG. 8 is a diagram showing a state where the chemical liquid injection of FIG. 7 has further advanced.

FIG. 9 is a graph showing the relationship between the injection speed of the chemical liquid and the pressure loss, divided into the pressure loss due to the injection hose, the injection pipe, and the rubber sleeve, the pressure loss due to the injection hose and the injection tube, and the pressure loss due to the injection hose. Is.

FIG. 10 is a graph showing a difference in injection pressure between the mouth of the injection pipe and the vicinity of the chemical liquid injection nozzle, along with the lapse of time from the start of injection.

[Explanation of symbols]

 10 ... Injection pressure measuring device 12 ... Pressure converter 12a ... Pressure receiving surface (pressure receiving part) 16 ... Filter member upper part (filter member) 17 ... Filter member lower part (filter member)

Claims (1)

[Claims] 1. A pressure transducer having a pressure receiving portion using a foil strain gauge as a converting element, and a filter member formed of a porous material and provided so as to surround the pressure receiving portion of the pressure transducer. An injection pressure measuring device characterized by the above.