JP4985235B2 - Hole permeability coefficient measuring device and hole permeability coefficient measuring method - Google Patents

Description

  The present invention relates to an in-hole permeability coefficient measuring device and an in-hole permeability coefficient measuring method, and more particularly to a technique for providing a test section for measuring a permeability coefficient in a desired section in a borehole.

  Conventionally, when measuring the hydraulic conductivity of the ground in the borehole drilled in the ground, a plurality of packers that block the movement of groundwater in the longitudinal direction of the bore are installed in the hole to form a sealed section. Techniques relating to in-hole permeability tests have been proposed in which the water pressure in such a sealed section, the flow rate of groundwater flowing through the ground, and the like are measured and the permeability coefficient is obtained based on these measurement results.

For example, in Patent Document 1, three or more inflatable and retractable packers inserted into a borehole drilled in a side wall of an underground mine, and pressurized fluid from a pressurized fluid in the mine to each packer are sent. In-hole hydraulic conductivity measurement with a pressurized fluid feed hose to be fed and a plurality of injection hoses arranged through each packer from the pressurized source in the tunnel and facing each injection section An apparatus is disclosed.
Japanese Patent No. 2804959

  By the way, there is a case where a crush zone due to a fault or the like is detected in the borehole and the hydraulic conductivity of the ground around the crush zone is desired to be measured. In such a case, in order to measure the pore water pressure of the ground around the crushing zone and the flow rate of water flowing in the ground, it is necessary to install a packer so as to sandwich the crushing zone and form a sealed section.

  However, in the in-hole hydraulic conductivity measuring device described in Patent Document 1, it is not disclosed at all that a packer is installed at a designated position in a borehole.

  The present invention has been made in view of the above points, and has an in-hole permeability coefficient measuring device capable of providing a test section for measuring a permeability coefficient in a desired section in a boring hole with a simple configuration. And an object thereof.

In order to achieve the above object, a hole permeability coefficient measuring device for measuring the permeability coefficient of the ground in a predetermined section in a borehole,
A plurality of packer rods having a rod body and an inflatable and contractible packer provided around the rod body;
A packer expansion / contraction tube that introduces or leads fluid to the packer;
Two measuring pipes for detecting the pore water pressure of the ground or the flow rate of the fluid flowing through the ground, in which a pipe port on one end side is arranged on the outer peripheral portion of the rod body other than the area where the packer is provided; ,
A plurality of first extension rods that can be connected to each other or connected to each other between the adjacent packer rods;
A plurality of second extension rods, which are connected to one of the boring holes closest to the hole of the boring hole and extend toward the hole, and can be connected to each other.
And an extension tube connectable to each of the packer expansion / contraction tube and the measurement tube (first invention).

  According to the in-hole hydraulic conductivity measuring apparatus of the present invention, a packer can be installed at a specified position by connecting these components in combination and inserting into the bore hole, so that a desired hydraulic conductivity can be measured in the bore hole. A test section can be provided.

  Note that the packer expansion / contraction tube for expanding and contracting the packer and the measurement tube for measuring the hydraulic conductivity of the test section are connected to the extension tube and extended to the outside of the borehole, Of course, expansion and contraction of the packer can be controlled from the outside, or the hydraulic conductivity can be measured.

  According to a second invention, in the first invention, the packer rod and the first or second extension rod are arranged such that a plurality of the packers are respectively arranged at a plurality of positions partitioning a predetermined section in the boring hole. And the packer expansion / contraction tube is extended to the outside of the boring hole by connecting the extension tube, and the one end side of the measuring tube is provided in the predetermined section. In addition, the measuring pipe is extended to the outside of the boring hole by being connected to the extension pipe, and is installed in the boring hole.

  According to a third invention, in the first or second invention, both ends of the packer rod, the first extension rod, and the second extension rod have a right male screw structure at one end and the other end at the other end. It has a left male screw structure, and between these rods, it has a right female screw structure in which the inner circumference of one end is screwed with the right male screw structure, and the inner circumference of the other end is screwed with the left male screw structure. It is connected by a connection nut having a left female screw structure.

  According to the in-hole hydraulic conductivity measuring device of the present invention, when connecting the rods using the connection nut, the rod end of the right male screw structure is arranged on the right female screw structure side of the connection nut, and the left male screw By placing the rod end of the structure on the left female thread structure side of the connection nut and screwing the ends of each rod to both ends of the connection nut, rotating the connection nut in the direction to fasten with each rod, The connecting nut and both rods can be screwed together. That is, since the rods can be connected without rotating, the packer expansion / contraction tube, measurement tube or extension tube is not twisted or these multiple tubes are not entangled when connecting the rods. Measurements of water pressure, fluid flow rate, etc. flowing through the pipe are made properly, and hose breakage and the like can be prevented.

  According to a fourth invention, in any one of the first to third inventions, rod bodies of the packer rod, the first extension rod, and the second extension rod have a tube shape, and the packer expansion / contraction tube The measurement tube and the extension tube are provided in a tube of a rod body having the tube shape.

  According to the in-hole hydraulic conductivity measuring device of the present invention, the packer expansion / contraction tube, the measurement tube, and the extension tube can be accommodated in the rod tube, and the packer expansion / contraction occurs when the connected rod is inserted into the hole. It is possible to prevent troubles such as breakage due to friction with the hole wall of the tube, measuring tube, or extension tube, and catching with the hole wall of these tubes.

  In a fifth aspect of the present invention, in any one of the first to fourth aspects, the packer rod, the first extension rod, and the second extension rod are bent when connected and inserted into the boring hole. It is characterized by having a strength that does not occur.

  According to the in-hole hydraulic conductivity measuring device of the present invention, for example, when inserting and inserting a packer rod and first and second extension rods into a bored hole drilled in the horizontal direction, these rods Can be inserted without bending, so that the packer can be reliably installed at a predetermined position in the boring hole.

A sixth aspect of the invention is a method for testing the permeability coefficient of a ground for measuring the permeability coefficient of the ground in a predetermined section in a boring hole, comprising a rod body and an inflatable / contractable packer provided around the rod body. A plurality of packer rods, a packer expansion / contraction tube for introducing or deriving fluid to or from the packer, and a tube port on one end side disposed on the outer periphery of the rod body other than the region where the packer is provided , Two for detecting the pore water pressure of the ground or the flow rate of the fluid flowing through the ground, and one or a plurality of first extension rods that can be connected to each other, connecting the adjacent packer rods; A plurality of second extension rods connected to each other and connected to a packer rod closest to the hole of the boring hole and extending the packer rod toward the hole; A packer rod and an extension pipe connectable to each of the measurement pipes, and the packer rod and the first or first so as to arrange a plurality of packers at a position dividing a predetermined section in the boring hole. 2 in combination with an extension rod, and by connecting the extension tube to the packer expansion / contraction tube, the tube extends to the outside of the boring hole, and the tube on the one end side of the measurement tube within the predetermined section The mouth is arranged, and the extension pipe is connected to the measurement pipe so as to extend to the outside of the boring hole, installed in the boring hole, and the packer arranged in the boring hole, The predetermined section is sealed by inflating by feeding fluid from outside the boring hole through the extension pipe and the packer expansion / contraction pipe, and the water pressure in the predetermined section Alternatively, the flow rate of the fluid flowing through the ground is measured outside the boring hole through the measurement pipe and the extension pipe, and the hydraulic conductivity of the ground in the predetermined section is measured based on the water pressure or the fluid flow rate. It is characterized by that.

  According to the present invention, it is possible to provide an in-hole permeability coefficient measuring apparatus and method capable of providing a test section for measuring a permeability coefficient in a desired section in a boring hole with a simple configuration.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing components of the in-hole permeability coefficient measuring apparatus 10 according to the present embodiment.

  As shown in FIG. 1, the in-hole permeability coefficient measuring device 10 includes a packer rod 20, an extension rod 30, a connection nut 40 for connecting these rods, and various hoses installed in these packer rods 20. An extension hose 50 is provided as a component.

  The packer rod 20 is provided with a packer 26 around the cylindrical pipe 22, two measurement through holes 24 are provided on the outer periphery of the outer portion of the packer 26, and the packer rod 20 is inserted into the inner portion of the packer 26. A hole 25 is provided. Further, the packer rod 20 includes two measuring hoses 27 respectively connected to the respective measurement through holes 24 from one end portion (upper end portion in the drawing) of the cylindrical pipe 22 and similarly to the end portion of the cylindrical pipe 22. And a packer expansion / contraction hose 28 connected to the packer through hole 25 through the pipe.

  The outer periphery of both ends of the cylindrical pipe 22 has a left male screw structure L1 at one end (upper end in the figure) and a right male screw structure R1 at the other end (lower end in the figure). Through 40, it can be connected to another packer rod 20 or extension rod 30.

  The packer 26 has a bag shape made of an elastic material such as natural rubber. The packer 26 is supplied with air or gas from the packer through hole 25 via the packer expansion / contraction hose 28 or discharged from the inside. And can be shrunk.

  As the measurement hose 27 and the packer expansion / contraction hose 28, a pipe made of a material having a certain rigidity is used in order to accurately measure the water pressure and the groundwater flow rate. Note that the ends of the connection side (upper end in the figure) of the measurement hose 27 and the packer expansion / contraction hose 28 also have a left male screw structure L1.

  The extension rod 30 is formed of, for example, a cylindrical pipe 32 having the same diameter as the packer rod 20, and both ends thereof have a left male screw structure L1 at one end (upper end in the figure) like the cylindrical pipe 22 and the other end. (Lower end in the figure) has a right male screw structure R1, and can be connected to the packer rod 20 or another extension rod 30 by a connection nut 40.

  In addition, a plurality of lengths of a variety of lengths are prepared in advance for the extension rod 30, and these and the packer rod 20 are connected in various combinations and inserted into the borehole so that the interior of the borehole can be obtained. The packer 26 can be arranged at a desired position.

  Further, the cylindrical pipes 22 and 32 that are the casing portions of the packer rod 20 and the extension rod 30 described above have a strength that does not bend when they are connected by a connection nut 40 described later and inserted into the boring hole. Preferably, for example, steel or vinyl chloride is used as the material.

  The connection nut 40 has a right female screw structure R2 in which the inner periphery of one end (upper end in the figure) of the connecting nut 40 engages with the right male screw structure R1 of the rod described above, and the other end (lower side in the figure). ) Has a left female screw structure L2 that is screwed with the rod left male screw structure L1 described above, so that the rods can be connected.

  When connecting the rods using the connection nut 40, the rod end of the right male screw structure R1 is arranged on the right female screw structure R2 side of the connection nut 40, and the rod end of the left male screw structure L1 is connected to the connection nut. 40 on the left female screw structure L2 side, and by rotating the connection nut 40 in the direction of fastening with each rod while screwing the ends of each rod into both ends of the connection nut 40, each rod is The connecting nut 40 and both rods can be screwed together without rotating.

  FIG. 2 is an enlarged cross-sectional view in which a connection portion between the connection nut 40 and the cylindrical pipes 22 and 32 in FIG. 1 is enlarged.

  As shown in FIG. 2, a guide taper 34 is formed at the distal ends of the cylindrical pipes 22 and 32 so that they can be smoothly inserted into the inner periphery of the connection nut 40.

  Further, an O-ring 42 made of an elastic material such as metal or rubber and having an inner diameter slightly smaller than the outer diameter of the cylindrical pipes 22 and 32 is inserted into the inner periphery of the connection nut 40. As a result, when the tip ends of the cylindrical pipes 22 and 32 are screwed to the inner periphery of the connection nut 40, the O-ring 42 is expanded by the insertion of the cylindrical pipes 22 and 32, and the cylindrical pipes 22 and 32 and the connection nut 40. Since the inside and outside of the cylindrical pipes 22 and 32 are kept in close contact with each other, intrusion of groundwater into the cylindrical pipes 22 and 32 is prevented.

  The extension hose 50 (see FIG. 1) is connected to the measuring hose 27 and the packer expansion / contraction hose 28 provided in each packer rod 20 installed in the borehole, and extends to the outside of the borehole. . At that time, the extension hose 50 is installed in the pipe of the packer rod 20 or the extension rod 30.

  Further, the extension hose 50 has, for example, a right male screw structure R1 at one end and a left male screw structure L1 at the other end similarly to the extension rod 30, and the same as the connection nut 40 described in FIG. By using the hose connection nut 52 having the structure, the connection between the extension hose 50 and the measurement hose 27 or the packer expansion / contraction hose 28 or the connection between the extension hoses 50 can be performed.

  Next, an example of installation in the borehole of the in-hole hydraulic conductivity measuring device 10 composed of such components will be described.

  FIG. 3 is a cross-sectional view showing a state of installation of the hydraulic conductivity measuring device in the borehole 60 drilled in the tunnel.

  As shown in FIG. 3, in a borehole 60 drilled from a tunnel, for example, a crush zone 62 due to a fault or the like is detected, and there is a case where it is desired to measure the hydraulic conductivity of the ground around the crush zone 62.

  In such a case, in order to measure the pore water pressure of the ground around the crushing zone 62 and the flow rate of water flowing in the ground, which are physical properties for obtaining the hydraulic conductivity, the crushing zone is provided inside the borehole 60. It is necessary to install the packer 26 so as to sandwich 62 and provide a sealed section A (hereinafter referred to as a test section A). Here, the position and length of the test section A are appropriately set according to the position and width of the crushing band 62 and the like.

  In this installation example, a plurality of the various types of packer rods 20 and extension rods 30 described above are prepared, these rods are connected in an appropriate combination, and inserted into the borehole 60 to obtain a test section. The packer 26 is arranged at a position where A is partitioned.

  Specifically, first, the two packer rods 20 are connected via one or a plurality of extension rods 30 such that the distance between the two packers 26 is the length of the test section A. Then, one or a plurality of the packer rods 20 are connected to the connected rod so that one packer 26 of the packer rod 20 is located on the front side of the crush band 62 and the other packer 26 is located on the front side of the crush band 62. The extension rod 30 is connected and inserted into the borehole 60 while extending the rod.

  Simultaneously with the extension of the rod, the packer expansion / contraction hose 28 and the measurement hose 27 in the packer rod 20 are similarly extended from the hole opening by connecting the extension hose 50.

  In this way, the in-hole hydraulic conductivity measuring device 10 is extended in the hole while being sequentially connected from the bore hole 60, so that the work can be easily performed even in a restricted tunnel as shown in FIG. can do.

  In addition, although the connection nut 40 is used for the connection between rods, since one screw of the connection nut 40 is a reverse screw, the connection nut 40 can be connected without rotating each rod by rotating in one direction. The nut 40 and both rods can be screwed together. Therefore, each hose inside the rod is not twisted or tangled.

  FIG. 4 is an enlarged cross-sectional view showing an installation state of the in-hole hydraulic conductivity measuring apparatus 10 in the crush zone peripheral region X of FIG.

  As shown in FIG. 4, in the crush zone peripheral region X, the packers 26 are respectively arranged so as to partition the test section A including the crush zone 62, and air flows from the tunnel through the extension hose 50 and the packer expansion / contraction hose 28. The test section A is sealed by being enclosed in the inside. In the test section A, two measurement through holes 24 provided in the cylindrical pipe 22 of the packer rod 20 are arranged.

  For example, a dedicated cap 54 is installed at the tip of the in-hole hydraulic conductivity measuring device 10 so that groundwater or the like does not enter the rod. The dedicated cap 54 has a female screw structure that can be screwed with the male screw structure at the tip of the cylindrical pipe 22 of the rod disposed at the tip of the connecting body, and groundwater or the like enters the pipe after screwing. It has a sealing function that does not come.

  In such a state, the pore water pressure of the ground in the test section A or the flow rate of the fluid flowing through the ground is measured from the tunnel through the measurement hose 27 and the extension hose 50, and based on the pore water pressure or the fluid flow rate. Obtain the hydraulic conductivity of the ground.

  In addition, as a test for calculating | requiring a hydraulic conductivity, generally known as a hydraulic conductivity test in a hole, for example, a pulse test, a constant flow test, a constant pressure test, etc. can be implemented.

  In the pulse test, the measurement hose 27 connected to the sealed test section A is temporarily opened after being temporarily opened, and the time change of the water pressure to recover to the initial pressure which is a steady state is measured. In the constant flow test, the water pressure in the test section A when water is poured into the test section A at a constant flow rate or pumped up from the test section A is measured by a pump installed in the tunnel shown in FIG. In the constant pressure test, the flow rate in the test section A is measured when a constant water pressure is applied to the test section A by the pressure control device shown in FIG. That is, the hydraulic conductivity is determined based on the water pressure or flow rate measured by these tests.

  After the test is completed, the air in the packer 26 is released to the tunnel through the extension hose 50 and the packer expansion / contraction hose 28, and the inserted in-hole hydraulic conductivity measuring device 10 is sequentially disassembled while being pulled out of the hole. It will be removed rather than going.

  According to the in-hole permeability coefficient measuring apparatus 10 of the present embodiment described above, the packer rod 20, the extension rod 30, the connection nut 40 for connecting these rods, and various hoses installed in these rods are provided. An extension hose 50 is provided as a component, and the number of connections of the extension rods 30 is changed during assembly, or the extension rods 30 of a predetermined length are selected and connected to the packer rods 20 so that the inside of the bore hole 60 Since the packer 26 can be installed at a desired position inside the boring hole 60 by inserting it into the boring hole 60, a test section A for measuring the permeability coefficient is simply provided in the desired section inside the boring hole 60. be able to.

  Further, according to the in-hole hydraulic conductivity measuring device 10 of the present embodiment, both ends of the packer rod 20 and the extension rod 30 have a right male screw structure R1 at one end and a left male screw structure L1 at the other end. Between these rods, there is a right female screw structure R2 in which the inner circumference of one end is screwed with the right male screw structure R1, and the left female screw structure L2 in which the inner circumference of the other end is screwed with the left male screw structure L1. When connecting the rods using the connection nut 40, the rod end of the right male screw structure R1 is disposed on the right female screw structure R2 side of the connection nut 40. The rod end of the left male screw structure L1 is disposed on the left female screw structure L2 side of the connection nut 40, and the connection nut 40 is fastened to each rod while the ends of each rod are screwed to both ends of the connection nut 40. Rotate in the direction And it makes it possible screwing a connecting nut 40 and the rods. That is, since the rods can be connected without rotating, the packer expansion / contraction hose 28, the measurement hose 27, or the extension hose 50 may be twisted or the plurality of hoses may be entangled when connecting the rods. Therefore, the water pressure flowing through the measurement hose 27, the fluid flow rate, and the like can be appropriately measured, and the hose can be prevented from being broken.

  Further, according to the in-hole hydraulic conductivity measuring device 10 of the present embodiment, the casing portions of the packer rod 20 and the extension rod 30 are the cylindrical pipes 22 or 32, and the packer expansion / contraction hose 28, the measurement hose 27, and the extension hose 50. Is installed inside the cylindrical pipe 22 or 32, and the packer expansion / contraction hose 28, which is generated when the rod connected with the packer expansion / contraction hose 28, the measurement hose 27 and the extension hose 50 is inserted into the hole, It can prevent from troubles, such as damage with the measurement hose 27 and the hole wall of the extension hose 50, and a hook with the hole wall of these hoses.

  Further, according to the in-hole hydraulic conductivity measuring device 10 of the present embodiment, the cylindrical pipe 32 of the packer rod 20 and the extension rod 30 are connected in combination and can be bent when inserted into the borehole 60. For example, when the packer rod 20 and the extension rod 30 are connected and inserted into the bored hole drilled in the horizontal direction, the rods can be inserted without bending. Therefore, the packer 26 can be reliably installed at a predetermined position in the boring hole.

  In addition, the in-hole hydraulic conductivity measuring apparatus 10 which concerns on this embodiment can also provide a some test area in a boring hole by combining and connecting the component parts 20-54, and inserting in a boring hole.

  In addition to the test for determining the water permeability coefficient, a hole for measuring a water pressure response between holes by evaluating each of the water pressure responses between the holes by installing each in a plurality of bored holes 60. It can also be used for inter-permeability tests.

  Moreover, in the in-hole hydraulic conductivity measuring apparatus 10 which concerns on this embodiment, although the pipe was used as the housing part of the packer rod 20 and the extension rod 30, it is not restricted to this, For example, it does not have a cylindrical form, for example, a rod-shaped thing Good. In this case, the measurement hose 27, the packer expansion / contraction hose 28, and the extension hose 50 are installed along the peripheral surface of the rod.

It is sectional drawing which shows the component of the hydraulic conductivity measuring apparatus 10 in a hole which concerns on this embodiment. FIG. 2 is an enlarged cross-sectional view in which a connection portion between a connection nut 40 and a cylindrical pipe 22 and a cylindrical pipe 32 in FIG. 1 is enlarged. It is sectional drawing which shows the installation condition of the hydraulic conductivity measuring apparatus to the boring hole 60 drilled in the tunnel. It is an expanded sectional view which shows the installation condition of the hydraulic conductivity measuring device in a hole in the crushing zone periphery area | region X of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Permeability coefficient measuring device 20 Packer rod 22, 32 Cylindrical pipe 24 Measurement through hole 25 Packer through hole 26 Packer 27 Measurement hose 28 Packer expansion / contraction hose 30 Extension rod 34 Guide taper 40 Connection nut 42 O-ring 50 Extension hose 52 Hose Connection nut 54 Dedicated cap 60 Boring hole 62 Crush zone A Test section L1 Left male screw structure L2 Left female screw structure R1 Right male screw structure R2 Right female screw structure X Area around the crush zone

Claims (6)

An in-hole permeability coefficient measuring device that measures the permeability coefficient of the ground in a predetermined section in a borehole,
A plurality of packer rods having a rod body and an inflatable and contractible packer provided around the rod body;
A packer expansion / contraction tube that introduces or leads fluid to the packer;
Two measuring pipes for detecting the pore water pressure of the ground or the flow rate of the fluid flowing through the ground , in which a pipe port on one end side is arranged on the outer peripheral portion of the rod body other than the area where the packer is provided; ,
A plurality of first extension rods that can be connected to each other or connected to each other between the adjacent packer rods;
A plurality of second extension rods, which are connected to one of the boring holes closest to the hole of the boring hole and extend toward the hole, and can be connected to each other.
An in-hole permeability coefficient measuring device comprising: an extension pipe connectable to each of the packer expansion / contraction pipe and the measurement pipe. The packer rod and the first or second extension rod are combined and connected so that a plurality of the packers are arranged at a plurality of positions partitioning a predetermined section in the boring hole, and the packer expansion The contraction tube is extended to the outside of the boring hole by connecting the extension tube,
A tube port on the one end side of the measuring tube is disposed in the predetermined section, and the measuring tube is extended to the outside of the boring hole by connecting the extension tube, and is inserted into the boring hole. The in-hole permeability coefficient measuring device according to claim 1, which is installed. Both ends of the packer rod, the first extension rod, and the second extension rod have a right male screw structure at one end and a left male screw structure at the other end,
Between these rods, there is a connecting nut having a right female screw structure in which the inner circumference of one end is screwed with the right male screw structure and an inner circumference of the other end is screwed with the left male screw structure. The in-hole permeability coefficient measuring device according to claim 1, wherein the in-hole permeability coefficient measuring device is connected by means of the above.   The rod body of the packer rod, the first extension rod, and the second extension rod has a tube shape, and the packer expansion / contraction tube, the measurement tube, and the extension tube have the tube shape. The in-hole permeability coefficient measuring device according to claim 1, wherein the in-hole permeability coefficient measuring device is provided in a pipe of the main body.   2. The packer rod, the first extension rod, and the second extension rod are strong enough not to bend when connected and inserted into the boring hole. The in-hole hydraulic conductivity measuring apparatus in any one of -4. A hole permeability test method for measuring the permeability coefficient of ground in a predetermined section in a borehole,
A plurality of packer rods having a rod body and an inflatable and contractible packer provided around the rod body;
A packer expansion / contraction tube that introduces or leads fluid to the packer;
Two measuring pipes for detecting the pore water pressure of the ground or the flow rate of the fluid flowing through the ground , in which a pipe port on one end side is arranged on the outer peripheral portion of the rod body other than the area where the packer is provided; ,
A plurality of first extension rods that can be connected to each other or connected to each other between the adjacent packer rods;
A plurality of second extension rods, which are connected to one of the boring holes closest to the hole of the boring hole and extend toward the hole, and can be connected to each other.
An extension tube connectable to each of the packer expansion / contraction tube and the measurement tube,
The packer rod and the first or second extension rod are connected in combination so as to arrange the plurality of packers at positions that partition the predetermined section in the boring hole, and the extension to the packer expansion / contraction tube By connecting a tube, it extends outside the borehole,
A tube port on the one end side of the measuring tube is arranged in the predetermined section, and the measuring tube is extended to the outside of the boring hole by connecting the extension tube, and is installed in the boring hole. ,
The packer disposed in the borehole is expanded by feeding a fluid from outside the borehole through the extension pipe and the packer expansion / contraction pipe to seal the predetermined section,
The water pressure in the predetermined section or the flow rate of the fluid flowing through the ground is measured outside the boring hole through the measurement pipe and the extension pipe, and the water permeability of the ground in the predetermined section is determined based on the water pressure or the fluid flow rate. An in-hole hydraulic conductivity measuring method, characterized by measuring a coefficient.

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