JP3044504B2 - Permeability test equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a test device and method for measuring the hydraulic characteristics of the ground, relates particularly to the permeability test apparatus suitable for measuring water permeability in deep.

[0002]

2. Description of the Related Art In recent years, the use of underground in civil engineering, geothermal heat, underground storage of fuel, waste disposal, etc., and the depth and scale of underground structures have been increasing. In order to conduct an assessment (impact assessment) on safety, etc., it is essential to conduct a highly accurate survey on groundwater and ground characteristics. Therefore, many boring holes are excavated on the ground at the site to provide measurement points, and various physical properties of groundwater at the original position are measured over a long period of time.

Investigations on the permeability of the ground are also important in terms of the design and construction of buildings as well as the quality of water, and the diffusion of harmful substances and the like. Conventionally, the permeability coefficient has been measured by various permeability test methods. Was. As one of the test methods for measuring this coefficient of water permeability, a steady test based on the so-called Lugion test, in which water is injected into the excavated borehole from above the ground and the water permeability is evaluated from the relationship between the water injection pressure and the amount of water injected. Was doing a lot. In this water injection test, the vicinity of the original position in the borehole was sealed with a packer, water was injected under the packer so as to always maintain a predetermined pressure (constant head pressure), and the water injection pressure and the water injection amount were compared. It measures the relationship, and has the advantage that it is a single-hole type and can be easily implemented.

[0004] In addition to measuring the storage coefficient for more accurate ground evaluation in addition to the hydraulic conductivity, a porous type measurement, that is, excavation of a plurality of boreholes and head difference between the respective boreholes, is required. Although there is a method to investigate the influence of this, there was a difficulty in implementation due to the large amount of work. In recent years, various unsteady methods have been proposed in which a pair of packers are inserted into a borehole to specify an in-situ test section, and the behavior is measured by changing the pore water pressure in the sealed test section. Has been reached.

In this non-stationary method, for example, a detection device as shown in FIG. 15 is disclosed. Such a detection device,
An upper packer 51a and a lower packer 51b, a closed space 52 formed at a measurement location of the boring hole 58 by expanding the packers 51a and 51b, and a rod provided above the upper packer 51a and communicating with the closed space 52. 59, an inner packer 53 which expands in the rod 59 to form a closed space 54 communicating with the closed space 52, and an inner packer 5
3 includes a pressurizing tube 57 communicating with the closed space 54 via an electromagnetic valve 55 disposed therein, and a pressure sensor 56 for measuring water pressure in the closed space 54.
Then, the so-called pulse method is used, in which the solenoid valve 55 is opened, the closed spaces 52 and 54 are once pressurized to a predetermined pressure by pressurization from the ground through the pressure tube 57, and then the recovery speed is measured. This is a device to perform a borehole spring pressure test.

[0006]

However, in the above-mentioned conventional Luzion test generally performed,
There were some problems as follows.

(1) Since a single packer seals above the boring hole at the measurement depth and pours water under the packer for measurement, it is necessary to repeat boring and measurement in order to measure the water permeability at each depth. The work efficiency is extremely low because continuous measurement cannot be performed. (2) In general, since a boring rod is used as a water pipe, moving work becomes troublesome as the measurement depth increases. (3) When targeting impervious rock, for example, 10 to 2 times until the injection pressure reaches a steady state in each pressurization step.
It takes a long time of 0 hours, and it takes an extremely long time to perform reliable measurement. (4) Since the pressure change in the hole is measured on the ground, it is necessary to compensate for the water pressure change at the measurement position due to the groundwater level and the pressure loss due to the boring rod, making high-precision measurement difficult.

[0008] On the other hand, the apparatus for performing the above-mentioned unsteady method has an excellent effect that it can perform continuous measurement at each depth with one boring hole, as compared with the conventional in-situ porous in-situ test. There were also the following problems.

(1) When the closed section is pressurized to a predetermined pressure, the pressure is applied from the above-ground portion. Therefore, in order to increase the responsiveness, it is necessary to repeatedly open and close the solenoid valve to set the pressure to the predetermined pressure. Pressing operation is difficult. (2) Accurately measure the gap pressure at the partitioned in-situ,
In order to perform measurement work quickly, it is necessary to provide a valve body that separates the test section.However, few solenoid valves can withstand high water pressure at large depths. I am worried about my sex. (3) Since the inner packer is used in addition to the upper and lower packers that partition the test section, and the solenoid valve is used, the structure is complicated and large, and it may be difficult to apply the above depending on the bore diameter of the boring hole.

By the way, as an apparatus for measuring the quality of groundwater other than the water permeability of the ground, the present inventors have previously provided a probe for measuring groundwater inserted into a borehole drilled in the ground. A groundwater measurement device is proposed. In this device, the probe inserted is P
A measuring unit having sensors for measuring H, conductivity, water temperature, etc. is provided, and expandable and contractable packers are respectively attached to the upper and lower sides of the measuring unit, and the measuring unit is fixed at a predetermined position in a borehole to be measured. Then, the groundwater characteristics are directly measured by draining the groundwater in a section partitioned by both packers through the measuring unit. According to this apparatus, there is an advantage that the error is small because the groundwater is directly measured, and the probe can be fixed by a telescopic packer regardless of the diameter of the excavation hole (Japanese Patent Application No. 1-2).
04284).

The present inventors have conducted intensive studies to apply the above-mentioned advantages of each measuring apparatus to a single-hole steady-state test and an unsteady-state test, and as a result, have solved the above-mentioned problems. SUMMARY OF THE INVENTION It is an object of the present invention to provide a water permeability test device capable of performing rapid continuous measurement and measuring a water permeability coefficient with high accuracy.

[0012]

Means for Solving the Problems In order to solve the above-mentioned problems, a first aspect of the water permeability test apparatus of the present invention is for performing a steady test quickly and with high accuracy, and is excavated in the ground. Having a substantially rod-shaped probe inserted into the drilled hole, a permeation test apparatus for injecting water into the borehole and detecting a change in pore water pressure at an insertion position of the probe to measure a permeability coefficient, The probe includes a pair of telescopic packers that are vertically positioned at predetermined intervals when inserted into the drilling hole, a water injection line that performs water injection into a section partitioned by these packers, and a water pressure in the section. It is basically that the pressure sensor is provided to measure.

[0013] In order to perform the water injection work efficiently ,
A water injection line on-off valve that opens and closes the water injection line
Is what it is .

[0014] Then, in order to function reliably despite the water pressure at great depth, the water injection line off valve comprises a body through-hole along its axis is formed in a substantially rod shape is opened, the through hole A cylinder chamber provided with an enlarged diameter of the through-hole in a part of the piston, a piston inserted into the cylinder chamber and urged toward one open end of the main body, and a piston attached to the piston; A stem extending toward the open end of the stem and slidably inserted into the through-hole, and a pair of seal members provided on the inner peripheral surface of the through-hole at which the distal end of the stem is located. A communication path connecting the through hole in a section partitioned by these seal members and the outside of the main body; and a pressurizing path communicating with the through hole between the pair of seal members and the cylinder chamber. Consists of
It is characterized by:

Further, as a second mode for preventing pressure fluctuation at the time of water injection and improving measurement accuracy, a water injection means for supplying water at a predetermined pressure to the water injection line is provided, and the water injection means is provided with the water injection means. An accumulator for storing water and pressurized by pressurized gas may be provided.

[0016]

[0017]

[0018]

[0019] The third aspect is to perform a quick measurement tasks more rapidly done expansion and contraction of the packers, the first to second <br/> each mode of carrying out the stationary test or unsteady test , A water supply means for supplying water to the pair of packers at a predetermined water pressure, a water supply line connecting the water supply means to the pair of packers, and a packer release valve for opening the water supply line to the probe. Is provided.

In order to ensure the function at a large depth, the fourth aspect of the water permeability test apparatus according to the present invention is the same as the third aspect , wherein the packer opening valve is formed in a substantially rod shape. A main body having a through-hole formed along the axis thereof, and a cylinder chamber provided with a part of the through-hole in which the diameter of the through-hole is increased,
A piston inserted into the cylinder chamber and attached to one open end of the main body, and attached to the piston;
A stem extended toward the one opening end side and slidably inserted into the through hole, and a pair of stems provided on the inner peripheral surface of the through hole where the distal end of the stem is located. A seal member, a communication path connecting the through hole in a section partitioned by the seal member and the outside of the main body, and pressurization communicating with the through hole between the pair of seal members and the cylinder chamber. And a route.

[0021]

[0022]

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A water permeability test apparatus according to the present invention (hereinafter referred to as this apparatus)
Say. 1) will be described with reference to FIGS.

FIG. 1 shows the overall configuration of the present apparatus.
This device can perform both a steady test and an unsteady test by water injection, and is generally suspended by a wire 6 from a crane 2 installed on a car 1 and excavated almost vertically in a ground G. A probe 4 inserted into a hole (boring hole) 8, a water supply unit 3 for supplying water to the probe 4 through a tube 7 for measurement, a data from the probe 4, and a control signal to the probe 4. And a measurement control unit 5 that outputs the same.

The probe 4, which is a main part of the present apparatus, comprises a pair of expandable and contractible packers 40, 42 which are vertically positioned at predetermined intervals when inserted into the excavation hole 8. A water injection line (not shown in FIG. 1) for injecting water into a section (original position) L where a partitioned measurement is to be performed, a pressure sensor 46 for measuring a water pressure in the section L, a water temperature sensor 44, and an unsteady state. A pump mechanism 45 used for the test, a water injection line opening / closing valve 41b and a packer opening valve 41a are provided, and the whole is formed in a substantially rod shape. The water injection line opening / closing valve 41b may be provided at the position of the packer opening valve 41a. In addition, the probe 4 adds a relay rod (not shown) which forms an axis according to the water permeability of the ground G, thereby increasing the length of the section L in a range of about 4 to 20 m every 1 m. The length can be set and the volume can be changed.

Hereinafter, these will be described in more detail.
Each of the packers 40 and 42 is a soft elastic bag formed of a resin sheet such as a synthetic rubber. Each of the packers 40 and 42 of the present embodiment is attached to the probe 4 and has an outer diameter when contracted. Is about 50-60mm, total length is about 100
0 mm, and the borehole 8 has a diameter of about 70 to 110 mm.
It can correspond to the thing of. When a predetermined water pressure is applied to the inside, it expands in the drilling hole 8, fixes the probe 4 at a predetermined position, and adheres to the wall surface of the drilling hole 8 and the upper packer 40 and the lower packer 4.
2 is maintained in a sealed state.

The pressure sensor 46 is connected to the packer 4.
This is for directly detecting the water pressure when water is injected into the section L partitioned by 0 or 42, or the pore water pressure of the spring water in the section L. Various elements can be used as the pressure sensor 46 in accordance with the working depth. However, in order to detect a slight difference in pressure and improve the measurement accuracy, a crystal transmission type element is preferable. If the maximum measurement range is 150kgf /
accuracy cm ² has become a ± 0.02kgf / cm ^2.
Similarly, the water temperature sensor 44 is of a platinum resistance type in terms of detection accuracy, and is -2 to + 55 ° C (accuracy ±).
(0.1 ° C.).

On the other hand, the injection line opening / closing valve 41b and the packer opening valve 41a provided in the probe 4 have the same configuration in the present embodiment, and their sectional structures are shown in FIG. . The injection line opening / closing valve 41b (packer opening valve 41a) has an open type mechanism, and cancels the external pressure regardless of the working depth.

The above water injection line opening / closing valve 41 shown in FIG.
In the configuration of b (packer release valve 41a), a through-hole 412 is formed along the axis of the main body 411 in a substantially rod-shaped main body 411 formed integrally. This body 411
Is stored in the probe 4 inserted into the drilling hole 8,
The maximum outer diameter is about 40 mm, and the total length is about 250 mm.

At approximately the center of the through hole 412,
Cylinder chamber 412a formed by expanding diameter of through hole 412
Is provided in the cylinder chamber 412a.
Is inserted. Further, the piston 413 has a body 4
A stem 414a extending toward one open end 411a of the main body 411 and slidably inserted into the through hole 412 to substantially constitute a part of the valve portion, and the other open end 411b of the main body 411. And a stem 414b for guiding the piston 413 when it moves.

The piston 413 is provided in the cylinder chamber 412
The stepped portion 412e, which is the end of a, stops and moves toward the other open end 411b in the state of FIG. 9, but is moved by the seal member 417c attached to the outer periphery of the piston 413. The airtightness of the cylinder chamber 412a is maintained. In addition, this piston 413
Is always provided with the stepped portion 4 by a resilient member (spring) 415.
12e, that is, one open end 4
11a.

Further, the piston 413 has a stepped portion 412e.
In a state where the stem 414a is in contact with the stem 414a, the tip of the stem 414a is slightly immersed into the through hole 412 from the one open end 411a (the state of FIG. 9), but the tip of the stem 414a is located. A pair of seal members 417a and 417b are provided on the inner peripheral surface of the through hole 412,
The sealing member 41 is in close contact with the peripheral surface of the stem 414a.
In a section S partitioned by 7a and 417b, airtightness of a minute gap between the through hole 412 and the stem 414a is maintained.

The partitioned section S constitutes a valve portion. In the section S, the main body 411 has a through hole 41 formed therein.
A communication passage 416 connecting the second body 411 and the outside of the main body 411 is formed. That is, the communication path 416 and one open end 411
A fluid passage is constituted by the through hole 412 on the a side, and the passage is opened and closed by movement of the stem 414a.

The stem 414a, that is, the piston 4
In order to drive the pressure chamber 412b, a part of the through-hole 412 is slightly enlarged in diameter adjacent to the cylinder chamber 412a.
Are formed. Further, in the pressurizing chamber 412b,
In order to introduce the driving pressure of the piston 413, a pressurizing path 418 communicating therewith is provided.

The through hole 412 on the other open end 411b side of the cylinder chamber 412a is
Is further expanded than the cylinder chamber 412a in order to store the resilient member 41 on the other open end 411b.
A pressing member 420 for adjusting the amount of compression of the piston 5 and setting the driving pressure of the piston 413 is provided. The holding member 420 supports the stem 414b slidably inserted therein to prevent runout, and has a screw portion 419 formed on the inner peripheral side of the other opening end 411b, which is the largest major portion. It is formed to be movable in the axial direction of the main body 411 by being screwed and rotated.

As described above, the water injection line opening / closing valve 41b (packer opening valve 41a) is formed in a substantially rod shape and has a through hole 412 formed along its axis. A cylinder chamber 412a provided with an enlarged diameter of the hole 412, a piston 413 inserted into the cylinder chamber 412a and urged toward one open end 411a of the main body 411; Stem 414a extending toward the open end 411a of the slidably inserted through hole 412.
A pair of seal members 417 a and 417 b provided on the inner peripheral surface of the through hole 412 where the distal end of the stem 414 a is located;
a, 417b, through-hole 412 in section S partitioned by 417b
A communication path 416 connecting the outside of the main body 411 to the pair of seal members 417 a and 417 b and the cylinder chamber 41.
2a, a driving path (water pressure) is applied to the pressure path 418, and a gap (a pressure chamber 412b) between the stem 414a and the through hole 412 is provided. ) To push the piston 413 against the biasing force toward the other open end 411b, thereby causing the stem 414a to advance and retreat along the through hole 412,
In a section S partitioned by the pair of seal members 417 a and 417 b, a flow path formed by the communication path 416 and one opening end 411 a of the through hole 412 is formed by the stem 414.
It opens and closes at approximately the tip of a.

The pump mechanism 45 provided in the probe 4 shown in FIG. 1 is used for performing an unsteady test by reducing the pressure in the section L. , And two pumps 45a and 45b having different capacities. These pumps 4
5a and 45b have the same device configuration, and such a configuration is shown in FIG.
0 is shown.

The pump 45a (pump 45b) has a suction portion 451A and a drive portion 451B, and has a cylinder chamber 45 in a casing 451 formed entirely in a substantially long cylindrical shape.
1a and a drive room 451b are arranged in series.

The suction section 451A is provided in the cylinder chamber 451.
a and a piston 452 slidably inserted into the cylinder chamber 451a. A seal member 452e is annularly mounted on the outer periphery of the piston 452 so that the piston 452 and the inner peripheral surface of the cylinder chamber 451a are airtight. It is designed to hold. In the cylinder chamber 451a, a pair of packers 40, 4 of the probe 4 is provided on an end face located on the side opposite to the drive chamber 451b with respect to the cylinder chamber 451a.
A suction port 451x for introducing groundwater in the section L partitioned by 2 is provided. And, the cylinder chamber 451
The groundwater flowing into the space (the back side of the piston 452) of the cylinder chamber 451 a on the side opposite to the suction port 451 x with respect to the piston 452 is placed on the side wall adjacent to the drive chamber 451 b of the packers 40 and 42. A discharge port 451y for discharging to the outside of the section L partitioned by is provided.

That is, this pump 45a (45b)
Instead of transferring liquid or the like by suction and discharge, the apparent volume in a predetermined space is changed by the movement of the piston 452. Further, a shaft 453 that penetrates the boundary with the drive chamber 451b along the axis of the casing 451 is attached to the piston 452, and the penetrating portion has a drive chamber 45 with respect to the cylinder chamber 451a.
A seal member 451e for maintaining the airtightness of 1b is provided.

On the other hand, the driving section 451B is
1b, a pair of rotatable screw rods 455, 455 and a movable plate 454 screwed thereto, and a forward / reverse rotatable motor for driving the screw rods 455, 455. 459a and this motor 459a
And a control circuit 457 for controlling the operation.

The screw rods 455 and 455 have one ends supported by bearings 455f and 455f, and the other ends respectively provided by support plates 455g attached to a casing 451. (Not shown). Gears 456 and 456 are attached to the screw rods 455 and 455 on the support plate 455g side, respectively. Between the gears 456 and 456, a gear 459c screwed to both the gears 456 and 456 is interposed, and the rotational force from the motor 459a is applied to each screw rod 455.
, And each screw rod 455 is rotated in the same direction.

The shaft 453 connected to the piston 452 is attached to the moving plate 454,
4, the piston 452 moves into the cylinder chamber 45.
Although it reciprocates within 1a, it is sucked in accordance with the amount of spring water in the section L partitioned by the packers 40 and 42 of the excavation hole 8, that is, in consideration of the pressure change of the pore water in the section L. , It is necessary to drive the piston 452 at an extremely low speed, and the motor 459a is provided with a speed reducer 459b. Reference numerals 454l and 454h are limit switches for detecting the moving end of the moving plate 454, that is, the piston 452, respectively.

Further, in order to constantly drive the motor 459a at a constant speed, the motor 459a is provided with an encoder 458 for detecting the number of revolutions, and a voltage signal from the encoder 458 is fed back to the control circuit 457 as a correction signal. It is supposed to be.
Further, the control circuit 457 includes the measurement control unit 5 shown in FIG.
Based on the control signal and the correction signal sent from
A drive signal is output to the motor 459a.

As described above, the pump 45a (the pump 45
b) a cylinder chamber 451a having one end communicating with a section L partitioned by a pair of packers 40 and 42 and the other end communicating with the outside of the section L, and a constant speed inside the cylinder chamber 451a. A constant flow rate pump having a piston 452 that moves from one end to the other end of the cylinder chamber 451a to temporarily increase the apparent volume in the section L. The pressure of L is reduced.

The pump mechanism 45 is provided with a plurality of pumps 45a and 45b (two pumps in this embodiment) having a constant flow rate, and these pumps 45a and 45b are driven simultaneously or selectively. And the cylinder chamber volumes are different from each other, so that it can be handled regardless of the amount of spring water.

In this embodiment, the pump 45a
Means that the diameter of the cylinder 415a is 16 mm, the stroke is 160 mm, and the moving speed of the piston 452 is 5 mm / h.
r. ~ 130 mm / hr. ), Effective suction volume (control range)
Is 1 to 25 cc / hr. And the pump 45b
The cylinder 415a has a diameter of 45 mm, a stroke of 320 mm, and a moving speed of the piston 452 of 12.5 m.
m / hr. ~ 320 mm / hr. , The effective suction amount (control range) is 20 to 500 cc / hr. It has become.

Next, water injection, water supply lines, etc., from the water supply section 3 to the probe 4 inserted into the drill hole 8 shown in FIG. 1 will be described with reference to FIGS.

The line shown in FIG. 2 is for performing a steady test by injecting water into a section L partitioned by a pair of packers 40 and 42. Reference numeral 33 denotes a water injection line, and a water supply section 3 (FIG. The water injection means 31 shown in FIG.
Is tied to The water injection line 33 has a flexible inner diameter of 9 m formed of a resin material having a multilayer structure.
A pressure-resistant tube having a diameter of 12 mm and an outer diameter of 12 mm is used, and is connected to the communication passage 416 of the water injection line opening valve 41b shown in FIG.

As shown in FIG. 3, accumulators 312a and 312b (actually, two accumulators 312a and 312b) and accumulators 312a and 312b are provided in the water injection means 31 for pumping test water into the water injection line 33. And a gas source 310 for supplying an inert pressurized gas such as nitrogen through a pressure regulator 311. Water injection line 3
The injection pressure to 3 depends on the accuracy of the pressure regulator 311,
In this embodiment, in order to improve the accuracy, the maximum adjustment range is 8
and used as the accuracy ± 0.1 kgf / cm ² in kgf / cm ^2.

The accumulators 312a, 312
2b have different cross-sectional areas, and a water level gauge (not shown) is attached to each side to form a so-called Marriott type flow meter, in which water once stored is introduced at a predetermined pressure. By the above-mentioned pressurized gas, valves 313 and 3
13 to the water injection line 33 and 1
0 ^{-1 to} 103 cc / min. The water level change is measured in the range. Of course about this flow measurement,
Automatic measurement may be used together using a differential pressure gauge or the like. FIG.
Accumulators 312a, 312b
However, the accuracy of the flow rate measurement can be further improved by providing more accumulators.

On the other hand, FIG. 4 shows a water supply line 34 for sending water to the pair of packers 40 and 42 when the probe 4 is inserted and moved and expanding the packers 40 and 42. 5 is provided from the water supply means 32 shown in FIG.
Both the 0 and lower packers 42 have two open ends leading into the bag. Further, in order to open the water supply line 34 when the packers 40 and 42 are contracted, the water supply line 3 is opened.
On the water supply means 32 side with respect to the packers 40 and 42 of No. 4,
The path is branched and connected to the aforementioned packer opening valve 41a.

That is, the branched water supply line 34
Is the communication passage 41 of the packer opening valve 41a shown in FIG.
6 and the packer opening valve 41a is disposed outside the section L partitioned by the two packers 40 and 42, so that when the packer opening valve 41a is operated, the inside of the packers 40 and 42 is The water pressure is released to the outside of the section L through the through hole 412 of the packer release valve 41a.

As shown in FIG. 5, the water supply means 32 for supplying water to the water supply line 34 supplies water at a pressure higher than the pore water pressure of the drilling hole 8 into which the probe 4 is inserted. A tank 320 and a compressor 321 for pressurizing a gas layer portion of the water storage tank 320;
Is connected to the water supply line 34.

A line for driving the packer opening valve 41a and the water injection line opening / closing valve 41b is indicated by reference numeral 37 in FIG. This drive line 37
Similarly, from the driving means 35 shown in FIG. 7 provided in the water supply section 3, in parallel with the packer opening valve 41 a and the water injection line opening / closing valve 41 b, and respectively, the pressurizing path of the valve body shown in FIG. 420.

Further, as shown in FIG. 7, the driving means 35 has a water tank 351 and a pump 350 for sucking water from the water tank 351 and increasing its pressure.
Is connected to the drive line 37, but two bleeder valves 35 are provided downstream of the pump 350.
3,355 are provided via gate valves 352,354, respectively. These bleeder valves 353, 355
For example, a check valve is used as a simple configuration, and each is adjusted to a different set pressure.

That is, the operating pressure of the packer opening valve 41a and the water injection line opening / closing valve 41b is, for example, 20 k
gf / cm ² and 10 kgf / cm ² in advance, and the bleeder valves 353, 35
5, and the gate valves 352, 3
By switching 54, the packer opening valve 41a and the water injection line opening / closing valve 41b are separately operated on one drive line 37.

FIG. 8 shows the discharge ports 45 of the pumps 45a and 45b of the pump mechanism 45 shown in FIG.
From 1y, the discharge line 36 communicating with the outside of the partitioned section L is shown. The discharge line 36 has an open end reaching the lower end of the probe 4 and the pumps 45a, 45a.
The conduction state between the back side of the piston 452 in the cylinder chamber 451a of b and the inside of the excavation hole 8 outside the section L is always maintained.

The above-described water supply line 34 and drive line 37
Are housed together with other control wires in a jacket 48 shown by a broken line, and between the water supply unit 3 on the ground and the probe 4, a multi-layer tube 7 having pressure resistance and flexibility. It has been passed through. In particular, since the drive line 37 is provided commonly to both the packer opening valve 41a and the water injection line opening / closing valve 41b, there is an advantage that the number of various lines inserted into the tube 7 can be reduced. .

On the other hand, the measurement control unit 5 provided on the ground unit includes conversion means including a data logger for A / D conversion and amplification of signals sent from the pressure sensor 46 and the water temperature sensor 44, observation data and sampling. A keyboard for inputting control data by manual operation such as an interval, an analysis control means including a microcomputer for analyzing data obtained therefrom based on a predetermined program and sending a control signal to the probe 4, and a display device for displaying measurement results And so on.

Next, FIG. 1 shows the steps of the present test method using the stationary method and the unsteady method using the present apparatus.
This will be described with reference to FIGS.

FIG. 14 is a flowchart showing a series of work procedures, and reference symbol S in the figure represents each step. In conducting the water permeability test, it is necessary to first measure the pore water pressure of the ground G. As shown in FIG. 1, the probe 4 is inserted into the borehole 8, the cable 6 and the tube 7 are extended, and the measurement point is measured. (Step 1).

When the probe 4 reaches the original position, the compressor 32 of the water supply means 32 shown in FIG.
1 is actuated to pressurize the inside of the water storage tank 320 and open the valve 322 to pump the water in the water storage tank 320 to the water supply line 34 at a pressure of approximately 10 to 20 kgf / cm ² . The water supply line 34 has two open ends which reach inside both bags of a pair of elastic packers 40 and 42 which are positioned up and down at predetermined intervals when the probe 4 is inserted into the drilling hole 8. Therefore, water is supplied into the respective packers 40 and 42 and expands, and the probe 4 is fixed in the drill hole 8 by the reaction force because the expanders are in close contact with the sidewall of the drill hole 8 and press the sidewall. (Step 2).

Therefore, the probe 4 includes a pressure sensor 4 in a section L partitioned by the pair of packers 40 and 42.
Since the pressure sensor 6 is provided, the pressure sensor 46 measures the pore water pressure in the section L and confirms that the pressure reaches an equilibrium state. In other words, by measuring the pore water pressure, we can grasp the groundwater availability at the in-situ site,
The origin of the water injection pressure is confirmed (step 3).

Next, in the water permeability test, first, a test by a constant pressure water injection method (steady-state method) is performed. The probe 4 is provided with a water injection line 33 for injecting water into a section L partitioned by the packers 40 and 42, and as shown in FIG.
1 is provided with accumulators 312a and 312b that store water and are pressurized by a pressurized gas such as nitrogen. Then, the accumulator 312a or 312b is pressurized by setting the pressure regulator 311 to a predetermined pressure and the valve 313 is opened, and the accumulator 312a or 312 is opened.
The water in 12b is sent to the water injection line 33.

At the same time, since the water injection line 33 shown in FIG. 2 is provided with a water injection line opening / closing valve 41b, the water injection line opening / closing valve 41b is operated to supply water to the section L. To operate the water injection line, the pump 350 of the driving means 35 shown in FIG.
51 is pumped up and the water stored therein is sent to the drive line 37, but the bleeder valve 3 is located downstream of the pump.
Since 53 and 355 are provided, for example, 10 kgf
Only one of the bleeder valves 355 set to / cm ² (low pressure) is opened to communicate with the drive line 37.

Then, when water pressure of 10 kgf / cm ² or more is applied to the drive line 37 when water is pressurized and injected by the pump 350, the bleeder valve 355 is operated to discharge water into the drive line 37. Is 10kgf
10kgf / c without pressure increase to / cm ² or more
It is held by m ^2.

On the other hand, the packer opening valve 41a and the injection line opening / closing valve 4 connected to the drive line 37 shown in FIG.
1b, the packer opening valve 41a is 20 kgf / cm
² and the injection line opening / closing valve 41b is 10 kgf / cm ²
, It is possible to operate only the water injection line 41b. This injection line opening / closing valve 41b
As described with reference to FIG. 9, when water pressure is applied to the pressurizing path 420 through the drive line 37, the pressure in the pressurizing chamber 412b is also pressurized, whereby the piston 413 is pressed. Then, the piston 413 is pushed down to the other open end 411b (downward in FIG. 9) against the elastic member 415, and the stem 414a is also moved to the other open end 411b.
Moved to the side. Then, a gap between an approximately distal end portion of the stem 414a and the through hole 412 is maintained in a section S in which the pair of seal members 417a and 417b maintain an airtight state.
, The airtightness on the one seal member 417a side is released.

Thus, a communication passage 416 is provided between the seal member 417a and the seal member 417b and is connected to the water injection line 33 and communicates with the through hole 412. The passage 416 and the one open end 411a of the through hole 412 are electrically connected to each other to form a flow path. Then, the water pumped to the water injection line 33 flows into the section L of the probe 4 from one of the open ends 411a through the communication path 416 and the through hole 412.

The water supply line opening / closing valve 41b connected to the water supply line 33 has one open end 411a and the other open end 411b in the probe 4 even at a large depth of, for example, 1000 m or more. Are in the same water, and almost the same head pressure acts on the stem 414a and the stem 414b at all times. Therefore, the operation is performed only by the pressure applied to the cross section of the piston 413 without being affected by the external pressure. That is, the influence of the water pressure in the borehole 8 in the axial direction is offset by the opening of both ends, and the water pressure in the communication passage 416, in this case, the water injection pressure is increased by the pressurization at the ground part and the water head. Although the pressure is higher than the pressure in the drill hole 8, the axial force of the stem 414a is not generated by this. The piston 413 is moved only when it is larger.

In this steady test, the water permeability was 10-8 cm.
/ Sec. This applies to the ground G up to this point, but water is injected according to a pressure pattern as shown in FIG. In this case, the maximum effective pressure is 1.5 kgf / cm ^{2 based on} the injection pressure, that is, the detection pressure of the pressure sensor 46.
The pressure is increased in steps of 0.25 kgf / cm ^{2 in} steps of 6 until the pressure reaches 311, and then reduced stepwise. Conventionally, this pressure reduction has been performed following the same steps as the pressure increase. However, from a statistical viewpoint of data processing, it has been found that the pressure reduction may be performed in about three steps as shown in FIG. 11, for example. Was.

In the above-described pressurization and depressurization, the time is set so that the water pressure is maintained in an equilibrium state at each stage, and the pore water pressure and the amount of injected water at each stage are measured. At this time, the accumulators 312a, 312 of the water injection means 31 are used.
12b are different from each other in cross-sectional area and are provided with a water level gauge. Therefore, by using these accumulators 312a and 312b in accordance with the water permeation state, the change in the water level is measured so that the water injection amount can be precisely determined. Can be measured.

In this way, a permeability coefficient can be obtained from the measured pore water pressure and the amount of injected water according to the following relationship (step 4). K = Q · ln (L / r) / 2πL (H−h) where K: permeability coefficient, Q: water injection amount, H: water injection pressure head, h: initial gap pressure head, L: test section length, r A test hole (drilling hole) radius.

Next, when the hydraulic conductivity at one measurement depth is obtained, the probe 4 is moved to the next depth to be measured, and the same operation is performed. In this movement, the packers 40 and 42 are temporarily contracted. In this case, the bleeder valve 353 of the driving means 35 is used to operate the packer opening valve 41a.

Conversely, when the valve 354 is closed and the valve 352 is opened to connect the bleeder valve 353 to the drive line, the bleeder valve 353 is set to 20 k in the present embodiment.
Since the pressure is set to gf / cm ² , a water pressure of 20 kgf / cm ² can be applied to the packer opening valve 41a via the drive line 37, and the packer opening valve 41a can be operated. Of course, the above-mentioned injection line opening / closing valve 41
Since b is set at 10 kgf / cm ² , the water supply line opening / closing valve 41b also operates at the same time. However, in this case, there is no problem because the water supply means 31 is naturally stopped.

When the packer opening valve 41a operates in the same manner as the water injection line opening / closing valve 41b, the water pressure of the water injection line in the packers 40 and 42 whose opening ends can be extended and contracted as shown in FIG. Probe 4 through valve
And the packers 40 and 42 can be contracted (step 5).

As described above, the water permeability test is sequentially performed along the excavation hole 8 according to the preset depth.
In the water supply line 33 and the water supply line 34, when the water supply means 31 and the water supply means 32 are stopped, almost the same water head pressure as in the borehole 8 is applied. Since the probe 41 has the water supply line opening / closing valve 41b and the water supply line opening / closing valve 41b, the operation of the water supply means 31 and the water supply means 32 at the new measurement point allows the packer operation and water supply to be immediately performed again. That is, as compared with the prior art, as the depth increases, the response in injecting water into the probe portion and the like deteriorates, and the work efficiency decreases significantly, so that the measurement work can be advanced in a remarkably short time.

By the way, according to the present apparatus, when the water permeability test is carried out only by the steady method by water injection, the work at one measurement point is approximately one as shown in FIG.
It can be implemented in a day.

When a steady test is initially performed at one measurement point and the permeability of the target ground G is low and an accurate measurement result cannot be expected, during the initial steady test, The measurement is stopped at and the test is changed to an unsteady test. At that time, after stopping the steady test, the pore water pressure is measured, and it is confirmed that the water pressure has returned to the initial pressure (step 6).

In the unsteady test, first, an approximate hydraulic conductivity is predicted from the first steady test, and the pump-up amount is determined. That is, in this unsteady test, a change in pore water pressure with time due to a constant flow rate pump-up (pressure reduction operation) is measured (Pressure Drawdown).
n Test) and measurement of the pressure recovery process after stopping pump-up (Pressure Buildup T)
est).

First, the pump mechanism 45 provided in the probe 4 is operated based on the set pump-up amount. In the present device, the pump mechanism 45 has the maximum suction amount 25c.
c / hr. Pump 45a and the maximum suction amount 500cc /
hr. Of the pump 45b, either of them, depending on the pump-up amount,
Alternatively, both can be operated simultaneously.

The pumps 45a and 45 shown in FIG.
In b, the piston 452 inserted into the cylinder chamber 451a of the suction part 451A is initially located on the suction port 451x side. The control signal from the measurement control unit 5 is
When input to the control circuit 457 provided in 51B, the control circuit 457 outputs a signal of a constant voltage as a drive signal to the motor 459a, and the motor 459a starts rotating. At this time, the drive voltage is always detected by the encoder 458 attached to the motor 459a,
This is fed back to the control circuit 457, and the motor 459a always maintains the set rotation speed.

The reduction gear 459b provided in the motor
When the gear 459c is further rotated to a lower speed by rotating the gear 459c, a pair of gears 456, 456 screwed to this gear are rotated.
Rotate in the same direction. These gears 456, 45
6 is attached to the pair of screw rods 455, 455. When the screw rods 455, 455 rotate in the same direction, the moving plate 454 screwed to them moves along the screw rods 455, 455. Then, the movement is started at a constant speed from the cylinder chamber 451a side to the motor 459a side (from the lower side in FIG. 10 to the upper side). Then, together with the moving plate 454, a piston 452 attached to the moving plate 454 via a shaft 453 gradually moves toward the discharge port 451y.

In this case, as shown in FIG. 8, the discharge line 36 is connected to the discharge port 451y, and the open end of the discharge line 36 communicates with the inside of the digging hole 8 outside the probe 4. When the piston 452 is initially located on the suction port 451x side, the piston 45 in the cylinder chamber 451a
Groundwater is flowing into the back side of 2, and this groundwater is discharged into the excavation hole 8 through the discharge line as the piston 452 moves. Thus, when the piston 452 is initially set to the suction port 451x side, the cylinder 451
The pump 45a (45b) is prevented from being overloaded without generating a decompression or vacuum state in the valve a, and an external force is prevented from being applied when the piston 452 is moved at a constant speed. Constant speed movement is guaranteed.

The operation of the pumps 45a and 45b causes the pair of packers 4 in the borehole 8 where the probe 4 is located to be located.
The apparent volume in the section L partitioned by 0, 42 can be increased by the movement of the piston 452, and the pore water pressure in the section L can be temporarily reduced. Then, the water permeability of the ground G can be evaluated by measuring the change over time in the flow rates (suction amounts) of the pumps 45a and 45b and the pore water pressure at this time (step 7).

The calculation of the hydraulic conductivity by such measurement is as follows. That is, if the output of the Darcy's radial flow equation is constant and dimensionless under an infinite boundary, the pressure behavior at reduced pressure can be expressed by the following equation. _{P i -P wf = (141.2)} · qBμ / Kh _{[P D (t D, ...)} + s ] _{Here, t D = 0.0002637Kt / φμc t} r w 2 ... However, P _i; initial pore water pressure , P _wf : drop pressure, q: pump-up amount, B: volume coefficient, μ: viscosity, K: permeability,
h: test section length, s: skin factor, t: time,
φ; porosity, ct; total compression ratio, r _w ; test hole (drilled hole)
Radius, P _D; dimensionless time; dimensionless pressure, t _D. At this time, if t _D > 100, P _D = １ ／ [ln (t _D ) +0.80907] Therefore, the test section pressure (the pressure in section L) is P _wf = P _i −162.6qBμ / Kh [ log (t) +
_{log (K / φμc t r w} 2) -3.2275 + 0.86
859 s], that is, the relationship between the slope m and the permeability in a straight line obtained at the point of measurement pressure and log (calculation time) is as follows. m = -162.6 qBμ / Kh From this, the water permeability K can be determined. K = -162.6qBμ / mh ... Also, the storage coefficient S _s can be determined from the above formula as _{S s} = φc _t.

As described above, when the water permeability is poor at one measurement point, the above-mentioned unsteady test is performed to evaluate the water permeability. Good (step 5). Also, as described above, once the permeability of the ground G is predicted by the steady test, when switching to the unsteady test, it can be carried out immediately by simply confirming that the pore water pressure returns to the equilibrium state. According to the test method, as shown in FIG. 13, it was possible to measure at one point in about 25 hours.

The main effect of this embodiment is as follows. A pair of expandable and contractable packers 40 and 42 which are vertically positioned at predetermined intervals when inserted into the excavation hole 8 are inserted into the probe 4 of the present apparatus. And these packers 40,4
Since the water supply line 33 for injecting water into the section L partitioned by 2 and the pressure sensor 46 for measuring the water pressure in the section L partitioned are provided, the probe 4 is raised to the ground every time the measurement depth is changed. Measurement can be continuously performed at a set depth without performing the drilling of the excavation hole 8 without having to go through the excavation hole 8 every time the measurement is performed. Particularly, the greater the depth, the more efficient the measurement operation.

Further, a water injection line 33 is connected to the probe 4.
If the water injection line opening / closing valve 41b that opens and closes is provided, the water injection line 33 can be partitioned immediately before the section L to be measured, so that the ground part of the water injection line 33 and the water injection line opening / closing valve 41b are connected. Water can be always held in the middle, and even after the probe 4 moves, quick pressurized water injection work can be performed only by adding a differential pressure, without newly injecting water from the ground part.

Further, the injection line opening / closing valve 41b is
A main body 411 having a substantially rod shape and having a through hole 412 formed along the axis thereof;
12, a cylinder chamber 411a provided with an enlarged diameter, a piston 413 inserted into the cylinder chamber 412a and urged toward one opening end 411a of the main body 411, and a piston 413 attached to the piston 413, Open end 411
a stem 414a extending toward the side a and slidably inserted into the through-hole 412; and a pair of seals provided on the inner peripheral surface of the through-hole 412 where the distal end of the stem 414a is located. A member 417a, 417b, a communication passage 416 connecting the through hole 412 of the section S partitioned by the seal members 417a, 417b and the outside of the main body 411, and the pair of seal members 417a, 417
b and the pressurizing path 420 communicating with the through-hole 412 between the cylinder chamber 412a and the cylinder chamber 412a, it is possible to store the probe in the small-diameter probe 4 and insert it into the drilling hole 8, so that the section L The responsiveness in water injection into the hole is enhanced, and when the water injection line opening / closing valve 41b is inserted into the excavation hole 8, the effect of the water pressure is canceled regardless of the depth, so that the restriction by the external pressure like a solenoid valve is applied. It can be reliably operated without receiving any electrical trouble or the like.

Further, accumulators 312 a, 3 a, which store water and are pressurized with a pressurized gas such as nitrogen, are supplied to water injection means 31 for supplying water at a predetermined pressure to water injection line 33.
When 12b is provided, water can be injected at a stable pressure without causing pulsation as in the case of pumping by a pump, so that measurement accuracy can be further improved.

On the other hand, in addition to the pair of packers 40 and 42 and the pressure sensor 46 for measuring the water pressure in the section L, the apparent volume in the section L is increased in the probe 4 of the present apparatus. With the provision of the pump mechanism 45, the permeability test by the unsteady method can be continuously performed even on the ground G having poor permeability, and in this case, the section L is temporarily depressurized. Since there is no need to pump water to the ground every time it is set at the measurement location, measurement work can be performed extremely efficiently, and pressure reduction operation is performed inside the probe 4 and pressure is directly measured, so high accuracy is achieved. Can be measured.

The pump mechanism 45 has a plurality of pumps 45 of a constant flow rate which are driven simultaneously or selectively.
If a, 45b,... are provided and the cylinder volumes are different from each other, an unsteady test can be performed correspondingly regardless of the amount of spring water.

Further, the pumps 45a, 45b of the above-mentioned constant flow rate
, Each of which has one end connected to the section L and the other end connected to the outside of the section L.
And a piston 452 that moves at a constant speed in the cylinder chamber 451a, the front side and the back side of the piston 452 always receive substantially the same hydraulic pressure. Accurate constant-speed movement can be performed without receiving a biased load from the outside, and measurement accuracy can be further improved.

The water supply means 32 for supplying water to the pair of packers 40 and 42 at a predetermined water pressure, and the water supply means 3
When the probe 4 is provided with a packer opening valve 41a for opening the water supply line 34, the packer contracts immediately when the probe 4 moves. The work efficiency can be further improved in continuous measurement. The packer opening valve 41a has the same structure as the water injection line opening / closing valve 41b, so that it can be reliably operated regardless of the depth.

In the present test method using such an apparatus, a pair of expandable and contractable packers 40 and 42 which are positioned vertically at predetermined intervals when inserted into the excavation hole 8,
Inserting a probe 4 provided with a pressure sensor 46 for measuring the pore water pressure in the section L partitioned by the above and a water injection line 33 for injecting water into the section L into a predetermined position of the drilling hole 8; A pair of packers 40, 4
2 by supplying water to them to expand them.
And a step of injecting water into the section L with the water injection line 33, and a step of measuring a temporal change in pore water pressure in the section L with the pressure sensor 46. In addition, by repeating the expansion and contraction of the packers 40 and 42, the steady test can be continuously performed. In particular, the greater the depth, the higher the efficiency of the measurement work.

Further, in this test method for carrying out the unsteady test, a pair of elastic packers 40, 4 which are vertically positioned at predetermined intervals when inserted into the drilling hole 8 are provided.
2, a pressure sensor 46 positioned in a section L partitioned by the above, and a pump mechanism 45 for increasing the apparent volume of the section L.
And a step of inserting the pair of packers 40, 4
By inflating them by supplying water to
And a step of driving the pump mechanism 45 to reduce the pore water pressure in the section L, and a step of measuring a temporal change of the pore water pressure with the pressure sensor 46. As a result, continuous measurement can be performed on the ground with poor water permeability by the unsteady method, and every time the probe 4 is moved, there is no need to pump water to the ground, so that measurement can be performed quickly and Since the pressure is reduced, a very accurate measurement result can be obtained.

[0098]

According to the present invention as described above, the following effects can be obtained.

(1) According to the permeability test apparatus according to the present invention, there is provided a substantially rod-shaped probe to be inserted into a drilled hole excavated in the ground. A permeability test apparatus that measures pore water pressure and measures water permeability in the probe, wherein the probe has a pair of expandable and contractible packers positioned vertically at predetermined intervals when inserted into the borehole, A water injection line that injects water into the section partitioned by these packers,
A pressure sensor for measuring the water pressure in the section is provided, and each time the measurement depth is changed, the probe is not pulled up, and each time the measurement is performed, the measurement is continuously performed at a preset depth without excavating the excavation hole. The measurement can be performed more efficiently as the depth increases.

(2) If the above-mentioned probe is provided with a water injection line opening / closing valve for opening / closing the water injection line, the water injection line can be partitioned almost at the original position. Without pouring water from
Simply pressurizing the pressure difference allows quick pressurized water injection work.

(3) The water injection line on-off valve is formed in a substantially rod-like shape and has a through-hole formed along its axis, and a part of the through-hole is provided such that the diameter of the through-hole is enlarged. A cylinder chamber, a piston inserted into the cylinder chamber and urged toward one open end of the main body, and attached to the piston and extended toward the one open end side to be slidable in the through hole. , A pair of seal members provided on the inner peripheral surface of the through hole where the distal end of the stem is located, and the through hole and the main body in a section partitioned by the seal members And a pressurizing path between the pair of seal members and the cylinder chamber, the pressurizing path communicating with the through-hole, which is housed in the probe and inserted into the drilling hole. In-situ water injection The responsiveness is enhanced, and when inserted into a wellbore, the effect of the depth is canceled out, and the device can be reliably operated without any restrictions.

(4) Water injection means for supplying water to the water injection line at a predetermined pressure is provided, and the water injection means is provided with an accumulator for storing water and pressurized by a pressurized gas. In this case, water can be injected at a stable pressure without causing pulsation, and the measurement accuracy can be further improved.

[0103]

[0104]

[0105]

(5) A water supply means for supplying water to the pair of packers at a predetermined water pressure, and a water supply line connecting the water supply means and the pair of packers are provided, and the water supply line is opened to the probe. When the packer release valve is provided, the packer can be contracted immediately when the probe is moved, and the movement efficiency of the probe in the continuous measurement can be improved.

(6) Since the packer opening valve has the same configuration as the water injection line opening / closing valve, it can be reliably operated regardless of the depth, similarly to the water injection line opening / closing valve.

[0108]

[0109]

[Brief description of the drawings]

FIG. 1 is a side view showing an outline of a permeability test apparatus and a probe thereof according to the present invention.

FIG. 2 is a flowchart showing a water injection line for injecting water into a test section.

FIG. 3 is a flowchart showing a configuration of a water injection means.

FIG. 4 is a flowchart showing a water supply line for supplying water to a packer.

FIG. 5 is a flowchart showing a configuration of a water supply unit.

FIG. 6 is a flowchart showing a drive line for driving a valve.

FIG. 7 is a flowchart illustrating a configuration of a driving unit.

FIG. 8 is a flowchart showing a discharge line from a pump mechanism.

FIG. 9 is a cross-sectional view showing a configuration of a water injection line opening / closing valve and a packer opening valve.

FIG. 10 is a sectional view showing a configuration of a pump of a pump mechanism.

FIG. 11 is a graph showing pressurization and decompression patterns in a steady test.

FIG. 12 is a process chart when a steady test is performed.

FIG. 13 is a process chart when an unsteady test is also performed.

FIG. 14 is a flowchart showing an operation procedure of a water permeability test.

FIG. 15 is a side view showing an example of a conventional unsteady test apparatus.

[Explanation of symbols]

 4 Probe L section 5 Measurement control unit 8 Drilling hole (boring hole) 31 Water injection means 33 Water injection line 310 Gas source 311 Pressure regulator 312a, 312b Accumulator 32 Water supply means 34 Water supply line 35 Drive means 37 Drive line 352, 354 Valve 353 355 Bleeder valve 36 Discharge line 40, 42 Packer 41a Packer opening valve 41b Water injection line opening / closing valve 411 Body 411a One open end 411b The other open end 412 Through hole 412a Cylinder chamber 413 Piston 414a, 414b Stem 415 Repellent member 416 Communication passage 417a, 417b, 417c Sealing member 418 Pressing member 420 Pressurizing path S Section 44 Water temperature sensor 45 Pump mechanism 45a, 45b Pump 451A Suction unit 451B Drive unit 451a Cylinder 451x inlet 451y discharge port 452 piston 454 moves plate 455 threaded rod 457 the control circuit unit 458 encoder 459a Motor 459b reducer 46 pressure sensor

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takaho Oike 2--20-2, Tsurumichuo, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Tsurumi Seiki Co., Ltd. (72) Inventor Toshiyuki Hokari 1-3-2 Shibaura, Minato-ku, Tokyo No. Shimizu Corporation (72) Inventor Shigeo Aoyama 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Tateo Adachi 1-2-3 Shibaura, Minato-ku, Tokyo Inside Shimizu Corporation (72) Inventor Taku Ishii 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Masakuni Hotta 1-2-3 Shibaura, Minato-ku, Tokyo Shimizu (56) References JP 3-69793 (JP, A) JP 3-161610 (JP, A) JP 1-312115 (JP, A) (58) Fields surveyed ( Int.Cl. ⁷ , DB name) E02D 1/00- 1/08

Claims (4)

(57) [Claims] 1. A probe having a substantially rod-like shape inserted into a borehole drilled in the ground, injecting water into the borehole, and detecting a change in pore water pressure at a position where the probe is inserted to determine a hydraulic conductivity. A permeability test device for measuring, wherein the probe has a pair of elastic packers which are positioned vertically at predetermined intervals when inserted into the drilling hole, and injects water into a section partitioned by these packers. And a pressure sensor for measuring the water pressure in the section.
The probe has a water injection line for opening and closing the water injection line.
An on-off valve is attached, and the water injection line on-off valve is formed in a substantially rod shape and a through hole is opened along its axis.
A body provided with a part of the through-hole having an enlarged diameter of the through-hole;
A cylinder chamber, which is inserted into the cylinder chamber and faces one open end of the body.
Piston and a piston attached to the piston and facing the one open end side.
An elongated stem slidably inserted into the through hole
And the through hole where the tip of the stem is located
A pair of seal members provided on the inner peripheral surface of the member, and the through hole in a section partitioned by these seal members
And a communication passage connecting the outside of the main body, and the communication passage between the pair of seal members and the cylinder chamber.
A permeability test device comprising a pressurized path leading to a through hole . 2. A water supply means for supplying water at a predetermined pressure to the water supply line, and the water supply means is provided with an accumulator that stores water and is pressurized by a pressurized gas. The permeability test apparatus according to claim 1, wherein: 3. A water supply means for supplying water to said pair of packers at a predetermined water pressure, and a water supply line connecting said water supply means and said pair of packers, and said water supply line is opened to said probe. The permeation test device according to claim 1 or 2, further comprising a packer release valve. 4. The packer release valve has a main body formed in a substantially rod shape and having a through hole formed along an axis thereof, and a cylinder chamber provided with a part of the through hole in which the diameter of the through hole is increased. A piston inserted into the cylinder chamber and urged toward one open end of the main body; and a piston attached to the piston and extended toward the one open end side to be slidable in the through hole. A pair of seal members provided on the inner peripheral surface of the through hole where the distal end of the stem is located, and the through hole and the main body in a section partitioned by the seal members of the communication path connecting the outer, in between the cylinder chamber and the pair of sealing members according to claim 3, characterized in that, characterized in that comprising a pressurizing path communicating with the through hole Permeability test equipment.