JP2002004257A - Permeability test method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permeability test method and a device therefor capable of inputting an output signal of a pressure sensor into a conventional ordinary data processing device for grouting device without widening a pilot hole when necessary in the permeability test and without generating an error due to the elongation caused by the gravity of the pressure sensor and a signal cable. SOLUTION: The permeability test method for evaluation of permeability in a specified test section of a boring hole, carried out ahead of injection of a grouting material, includes an insertion process of the permeability test device in which a permeability test instrument (29a) and a pressure sensor (24) are inserted into the boring hole (3) from the ground level, a permeability test execution process in which a coefficient of permeability (Lugeon value) in the test section (h) is measured, a recovering process in which the pressure sensor is recovered from the permeability test instrument (29A) in the boring hole (3) onto the ground level, a grouting process in which a grout is injected, and a recovery process in which the permeability test instrument (29a) is recovered onto the ground level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permeability test for evaluating the permeability of ground such as unconsolidated soft rock having a low strength and a cracked rock having high permeability, various permeability tests performed at the time of a geological survey, pore water pressure and the like. The present invention relates to a method and an apparatus for a permeability test performed for measuring a groundwater level.

[0002]

2. Description of the Related Art FIG. 9 shows a schematic configuration of a conventional permeability test apparatus 1A. That is, a test hole 3B is excavated vertically in the ground G, and a test section h having a length of about 5 m is formed in the test hole 3B.
, And the injection tube Pw reaching this test section h is inserted. The injection pipe Pw is equipped with an air packer Ap that separates the upper and lower portions of the test section h so that the upper and lower portions of the test section h are sealed and closed, a pressure gauge Rp is attached to the upper end of the injection pipe Pw protruding above the ground G, and the pump is connected via a flow meter Rf WP is connected.

In the above configuration, in the water permeability test (Lugeon test) for detecting the water permeability in the test section h, the pump WP
The injection pressure-injection curve is determined by a known method of injecting water from the reactor to apply a constant water pressure, and the lusion value is determined therefrom.

[0004] In the conventional method as described above, the groundwater level L
When the pressure is low, it is known that the pressure applied to the test section h cannot be accurately grasped and that the pressure cannot be measured at the surface hole of the test hole 3B. For this purpose, measuring instruments dedicated to the permeability test have been developed.

Here, the conventional test hole 3B usually has an inner diameter φ.
66 mm. Therefore, the measuring instrument for the water permeability test can be applied only to a bore hole diameter of φ66 mm or more. However, the diameter of a normal boring hole is φ46 mm. Therefore, it cannot be used with the above-mentioned ordinary boring holes. Further, the equipment for the water permeability test cannot be applied to the flow meter Rf in the water permeability test.

[0006] For these reasons, the conventional method for using a measuring instrument for permeability test is shown in Figs.
This is performed by six steps shown in FIG. Here,
The description will be made on the assumption that a normal boring hole 3 at the time of grouting is excavated at φ46 mm.

In FIG. 10, in order to conduct a water permeability test in a test section h, first, a φ66 into which a water permeability tester 29C enters is used.
The bore 3A is formed by expanding the diameter of the boring hole 3.
Next, the water permeability tester 29C is inserted into the opening 3A.

[0008] The permeability tester 29C is composed of a packer Pa and a device fitting for supplying an inflation gas to the packer Pa or applying a test water pressure to the test section h. The pressure sensor 24 penetrates the inner hole of the packer Pa. It is configured to be.

In FIG. 11, the packer Pa expands,
The pressurized water via the injection pipe 28 is supplied from the ground to the test section h, the water pressure is measured by the pressure sensor 24, the data is transmitted via the signal line 25, and the water permeability test is performed.

In FIG. 12, a water permeability tester 29C after the completion of the water permeability test is recovered on the ground from the expanded hole 3A and the boring hole 3.

In FIG. 13, an ordinary grouting packer P is inserted into the bottom of the widened hole 3A and set so that grouting can be performed.

In FIG. 14, grout mixed based on the result of the water permeability test is supplied at an appropriate pressure, grout is sprayed from a nozzle Nz mounted on the tip of the packer P, and grouting is performed.

In FIG. 15, after the predetermined grouting is completed, the packer P is collected on the ground. In this way, the performance of the water permeability test for the test section h requiring grouting and the grouting based on the lugion value based on the result are completed.

As described above, in the conventional water permeability test, when the need for the water permeability test arises, the diameter of the boring hole 3 having a diameter of 46 mm is increased to 66 mm to form a hole 3A, and a dedicated water permeability tester 29C is formed. A step of testing by inserting into 3A is required. In addition, the pressure sensor 2 used in this permeability test
4 is hung from the ground by the signal line 25, there is a drawback that the extension of the signal line 25 due to the weight of the sensor 24 and the signal line 25 causes an error in the pressure measurement depth position.

Further, since the measurement data processing device used for the water permeability tester 29C has a unique data format, it does not have a function of connecting to a data management device used for ordinary grouting, and must be input to a daily report preparing device for consistent processing. There is a drawback that can not be.

[0016]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and does not increase the diameter of a pilot hole when a water permeability test is required. It is an object of the present invention to provide a method and an apparatus for testing water permeability that do not cause packing, do not replace packers in the process, and can input an output signal of a pressure sensor to a data processing device of a conventional grouting device.

[0017]

According to the water permeability test apparatus of the present invention, in a water permeability test method for evaluating water permeability in a predetermined test section of a boring hole prior to injecting a grout material, a method for testing a hole in a boring hole is provided. A permeability tester insertion step of inserting a permeability tester and a pressure sensor from the ground, a permeability test execution step of measuring a permeability coefficient (Lugeon value) of a test section, and a step of transmitting the pressure sensor from the permeability tester in the boring hole. The method includes a pressure sensor collecting step of collecting on the ground, a grouting step of injecting a grout material, and a water permeability tester collecting step of collecting the water permeability tester on the ground after completion of the grouting step.

According to this, the permeability coefficient can be measured by inserting the permeability tester and the pressure sensor into the ordinary boring hole, so that the operation of expanding the bore hole which was conventionally required is eliminated, and the insertion and collection of the pressure sensor are performed. With only this, conventional grouting can be performed without changing the packer.

The water permeability tester has a cylindrical holding protector surrounding the pressure sensor at the tip of the water permeability tester.

As a result, the depth error caused by the vertical extension of the signal line due to the weight of the pressure sensor and its signal line does not occur.

Further, according to the water permeability test apparatus of the present invention, the water permeability test apparatus used for the water permeability test for evaluating the water permeability in a predetermined test section of the boring hole prior to the grout material injection is used. The water permeability tester used in the test apparatus includes a packer whose outer diameter when contracted is formed to have a smaller diameter than the boring hole, surrounds a pressure sensor described below, and is connected to the pressure sensor and a first pressure sensor connected to the pressure sensor. A cylindrical holding protector that supports the weight of the signal line is installed, and the outer periphery of the protector is provided with a plurality of holes that can be sprayed with grout, and the holding protector passes through the inner hole of the packer. A detachable pressure sensor is held, a first signal line connected to the pressure sensor is connected to a signal converter on the ground, and the signal converter is connected to the tester. A second signal line for transmitting a water pressure signal of the boring hole of the pressure water supplied to the section is connected, and a pressure signal from the first signal line and a hole water pressure signal from the second signal line are connected. A changeover switch for selectively receiving is provided, and the recording device and the data management device are connected to the signal conversion device via a third signal line.

The signal conversion device is a signal conversion device for converting a pressure signal sensed by a pressure sensor into a signal readable by a normal flow pressure gauge recording device of a grouting device. It may have a conversion function. With the above water permeability test apparatus, both the water permeability test and the grout material injection work can be performed.

[0023]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of a water permeability test method and apparatus according to the present invention.

FIG. 1 is a schematic configuration of a water permeability test apparatus indicated by reference numeral 1 as a whole. Boring hole 3 excavated in ground G
A permeability test section h is set at the bottom of. Above the test section h, a water permeability tester 29A having a packer 29 and a pressure sensor 24 are provided so as to be able to move up and down by the operation of a boring machine Bm on the ground.

The packer 29 is connected by a pipe 21 to a pressure vessel (nitrogen cylinder) 16 on the ground, and a pressure sensor 24 is connected by a first signal line 25 to a signal conversion device 23 via a cable extraction head 27 and a winding drum 26. It is connected to the.

The injection pipe 28 is connected to the upper part of the water permeability tester 29A, connected to the flow pressure gauge detecting section 13 via the pipe 32, and the flow pressure gauge detecting section 13 is connected to the grout pump 14 via the pipe 19. ing.

As shown in FIG. 2 to FIG.
In this example, A is formed to have a diameter of 39 mm in a normal state before the pressure expansion, and mainly includes a packer 29 which expands inward and outward in a radial direction and an injection pipe 28 attached inside. At the tip of the packer 29, a cylindrical holding protector 42 with a lid having a plurality of holes 42a on the outer periphery is attached.

The tip of the pressure sensor 24 is inserted into contact with the bottom of the holding protector 42. A first signal line 25 is connected to the other end of the pressure sensor 24. The pressure sensor 24 and the first signal line 25 can be lifted to the ground through an injection pipe 28 in a packer 29.

The injection pipe 28 is supplied with test pressure water through the pipe 32 during the water permeability test, and is supplied with grout after the water permeability test.

The grout pump 14 is connected to the grout mixer 15 via a pipe 20. Reference numeral 19a is a return tube.

The flow pressure gauge detector 13 is connected to the second signal line 30
Is connected to the signal converter 23.

The signal converter 23 receives the signal from the pressure sensor 24 and the water pressure signal of the hole from the flow pressure gauge detector 13 so that the data can be read by the flow pressure gauge recorder 12 as a recorder. It has a function of converting and transmitting. Then, the signal from the pressure sensor 24 and the signal from the flow pressure gauge detecting unit 13 are clearly separated,
Further, a changeover switch 23a for transmitting data via the third signal line 18 is provided. Further, an A / D conversion function is added as needed for data conversion of the signal conversion device 23.

The flow pressure gauge recording section 12 is a device having a conventional general function, has a function of mainly displaying measurement data in an analog form, and has a function of transmitting a received signal to the data management device 11.

The data management device 11 monitors and displays various data, organizes and stores it as digital data, and is connected to a daily report creating device 22 that creates various daily reports 22a via a storage medium such as a memory card 11a. It has become.

In the above water permeability test apparatus 1, a water permeability tester 29A and a signal conversion device 23 for processing an output signal of the water permeability tester 29A have a special configuration not included in a conventional grouting apparatus.

The operation of the water permeability test apparatus 1 will be described with reference to FIGS. FIG. 5 shows a process of inserting a permeability tester. Normal φ46mm drilled in ground G
Is inserted into the test section h, which is usually 5 m, in the borehole 3. The pressure sensor 24 is inserted into the permeability tester 29A, and is held in the protector 42. The first signal line 25 is connected to the packer 2 of the permeability tester 29A.
9 and is connected to the signal conversion device 23 through the internal hole.

FIG. 6 shows a process of conducting a water permeability test.
A known permeability test in which the holding protector 42 is disposed in the test section h, and the test section h and the upper part are pressure-divided by the expansion of the packer 29 to supply water at a constant pressure by the grout pump 14 to measure the amount of water permeated into the ground. Is carried out. The water supply pressure data from the pressure sensor 24 is
Then, it is converted to be processable and operable and sent to the flow pressure gauge recording unit 12. Then, the water permeability (Lugeon value) is determined from the test results.

FIG. 7 shows a pressure sensor recovery step and a grout material injection step. First, the pressure sensor 24 is pulled up to the ground together with the first signal line 25 from the permeability tester 29A used for the permeability test. This is the pressure sensor recovery step. Next, grout having the blending, pressure and amount according to the Ludion value obtained in the pre-permeability test execution step is pumped from the grout pump 14 through the injection pipe 28, and is supplied to the protector 42.
Are injected into the ground from the plurality of holes 42a through the inner wall of the boring hole 3 in the test section h. This is a grout material injection step.

FIG. 8 shows a process of collecting a permeability tester. This is a step in which the water permeability tester 29A used up to the previous step is pulled up from the boring hole 3 to the ground and collected to prepare for the next step.

As described above, the step of expanding the diameter of the boring hole 3, which is required in the conventional process, is omitted, and the permeability test data can be processed as integrated data of the grouting process.

[0041]

The effects of the present invention are listed below. (1) With the miniaturization of the water permeability tester with a packer that could not be used unless it was a bore hole of φ66 mm or more, a water permeability test can be performed without expanding the diameter of a normal bore hole of φ46 mm. Therefore, the hole expanding step can be omitted, and the construction period can be shortened and the cost can be reduced. (2) Since the pressure sensor and the signal line can be removed through the permeability tester, the operation can be shifted to grouting work without replacing the packer, and the work process is simplified. (3) Since the signal output of the water permeability test is passed through a signal conversion device that converts the signal output into a signal connectable to a conventional recording device and data management device, the conventional recording device and analysis device can be used as they are. (4) By attaching the holding protector that holds the pressure sensor, an error due to the extension of the signal line does not occur, accurate depth data can be obtained, and measurement accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a water permeability test device of the present invention.

FIG. 2 is a side sectional view of a water permeability tester into which the pressure sensor used in FIG. 1 is inserted.

FIG. 3 is a side view of the pressure sensor.

FIG. 4 is an external side view of FIG. 2;

FIG. 5 is an explanatory view of a water permeability tester insertion step of the water permeability test method of the present invention.

FIG. 6 is an explanatory diagram of a water permeability test execution step of the water permeability test method of the present invention.

FIG. 7 is an explanatory view of a pressure sensor collecting step and a grouting step of the water permeability test method of the present invention.

FIG. 8 is an explanatory diagram of a permeability tester collecting step of the permeability test method of the present invention.

FIG. 9 is a configuration diagram showing an outline of a conventional water permeability test apparatus.

FIG. 10 is an explanatory view of a permeation tester insertion step of a conventional permeation test method.

FIG. 11 is an explanatory view of a water permeability test execution step of a conventional water permeability test method.

FIG. 12 is an explanatory diagram of a permeation tester collecting step of a conventional permeation test method.

FIG. 13 is an explanatory view of a step of inserting a water permeability tester (packer) in a conventional water permeability test method.

FIG. 14 is an explanatory view of a grouting process in a conventional water permeability test method.

FIG. 15 is an explanatory view of a permeation tester (packer) collecting step of a conventional permeation test method.

[Explanation of symbols]

 Bm · · · boring machine G · · · ground 1 · · · permeation test device 3 · · · borehole 11 · · · data management device 11a · · · recording medium 12 · · · flow pressure gauge recording unit 13 · · · flow pressure gauge detection unit 14. Grout pump 15. Grout mixer 16. Nitrogen cylinder 18. Third signal line 19, 19a, 20. Pipe 22. Daily report generator 23. Signal converter 23a. Switch 24 .. Pressure sensor 25 First signal line 26 Winding drum 27 Signal line extraction head 28 Injection pipe 29A Water permeability tester 29 Packer 30 Second signal line 32 Tube

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Tadashi Hamako, Inventor, 8-14-14 Ginza, Chuo-ku, Tokyo Inside Nippon Special Construction Co., Ltd. (72) Yorihiro Tanaka, 8-chome, Ginza, Chuo-ku, Tokyo No. 14 F-term in Nippon Special Construction Co., Ltd. (reference) 2D040 AA01 AB01 GA01 2D043 AA05 AC05 BB04

Claims (3)

[Claims] 1. A water permeability test method for evaluating water permeability in a predetermined test section of a boring hole prior to grout material injection, wherein a water permeability test device and a pressure sensor are inserted into the boring hole from the ground. Vessel insertion step, a permeability test execution step of measuring the permeability coefficient of the test section, a pressure sensor recovery step of recovering the pressure sensor from the permeability tester in the borehole to the ground, and a grouting step of injecting a grout material. A water permeability tester collecting step of collecting the water permeability tester on the ground after completion of the grouting step. 2. The water permeability test method according to claim 1, wherein the water permeability test device includes a cylindrical holding protector surrounding the pressure sensor at a tip of the water permeability test device. 3. A water permeability tester used for a water permeability test for evaluating water permeability in a predetermined test section of a boring hole prior to grout material injection. Is provided with a packer having an outer diameter when contracted smaller than the boring hole, and surrounding a pressure sensor described later, and supporting a weight of the pressure sensor and a first signal line connected to the pressure sensor. Of the protector is mounted, and on the outer periphery of the protector are provided a plurality of holes capable of spraying grout,
The holding protector holds a detachable pressure sensor that penetrates through the inner hole of the packer, and a first signal line connected to the pressure sensor is connected to a signal converter on the ground, and is connected to the signal converter. Transmits a water pressure signal at the borehole of the pressure water supplied to the test section.
And a changeover switch for selectively receiving a pressure signal from the first signal line and a hole water pressure signal from the second signal line.
A recording device and a data management device are connected via the signal line of (1).