JP2007239358A - Soil sampler using gas flow and soil sampling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a soil sampler which eliminates the influence on a peripheral ground of an underground hole as much as possible by preventing the inflow of muddy water and bubbles into the ground. <P>SOLUTION: The soil sampler 1 consists of a rotary-type outer tube 22, a non-rotary-type inner tube 24 fitted in the outer tube, a bit 25 fixed to the lower end of the outer tube, and a slime carrier source 2. Then the soil sampler 1 moves the inner tube 24 in the underground direction while rotating the inner tube 24, and excavates a stratum by the bit 25. At the same time, the slime is discharged to the earth's surface with the stream of a slime carrier, and the soil samples which remain in the interior of the outer tube 22 are stored in the inner tube 24. Then the slime carrier is the gas which is sent from the slime carrier source 2, and the bit 25 of the soil sampler 1 is projected by 3 mm or more from the outer periphery of the outer tube toward the outside of the outer tube. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a soil sample sampler used for sampling a geological layer for the purpose of geological survey and the like, and a method for collecting a soil sample.

  Conventionally, mud water (mixed liquid of water and bentonite), air bubbles, and the like are used in the boring of the formation including collection of soil samples. The role of muddy water is (1) discharge of slime, (2) cooling of bit edge, (3) reduction of rotation resistance of rod, (4) protection of hole wall by mud cake, (5) hole wall by mud water pressure Stability.

  In addition, the conventional soil sampler includes an outer tube in which an upper end is integrally coupled to an upper sampler head integrally coupled to a lower end of a boring rod, and a metal crown is integrally coupled to the lower end, and a ball bearing device. The upper end of the upper sampler head and the lower sampler head having a two-stage structure are integrally coupled to the inner tube serving as a non-rotating type sampling tube that is fitted in the outer tube, and the lower end. By attaching a bulkhead outer tube integrally bonded to the metal crown to form a triple-pipe structure, a drilling channel in which drilled water flows between the outer tube and the bulkhead outer tube is formed. There is one in which the inner pipe in which is stored is isolated from the drilling water. (For example, refer to Patent Document 1).

JP 2003-129460 A

  There are a wide range of places where soil samples need to be collected, and there are places where it is not desirable to inject muddy water (hole water) or bubbles into the ground.

  The conventional soil sampler described above has various effects and prevents disturbance of the soil sample due to penetration of drilling water. For soil samples, the influence of muddy water (drilling water) can be avoided, but infiltration of muddy water into the ground around the underground hole cannot be avoided.

  On the other hand, the soil sample is preferably taken out in a state existing in the ground, that is, in an undisturbed state.

  Accordingly, an object of the present invention is to obtain a soil sampler that avoids the influence of the underground hole on the surrounding ground as much as possible by avoiding the injection of muddy water and bubbles into the ground. Another object of the present invention is to obtain a soil sample sampler capable of taking out a soil sample in a mechanically undisturbed state.

  Another object of the present invention is to obtain a soil sample collection method that solves the same problems as those of the above soil sample sampler.

  Problems of the present invention other than the above will become apparent from the description of the present invention.

  The inventors focused on using gas as a slime carrier in place of conventional mud and air bubbles.

  A soil sample sampler according to one aspect of the present invention includes a sampler head fixed to a lower end of a hollow boring rod that is rotationally driven, an outer tube having an upper end fixed to the sampler head, and a thrust bearing through the outer sample. A non-rotating inner pipe fitted in the pipe, a bit fixed to the lower end of the outer pipe, and a slime carrier source for feeding the slime carrier into the boring rod via a carrier swivel. The gap between the inner circumference of the inner pipe and the outer circumference of the inner pipe is the forward path of the slime carrier, and the gap between the outer circumference of the outer pipe and the hole wall of the underground hole drilled by the bit is the return path of the slime carrier. The boring rod is rotated and moved in the underground direction, and the soil layer is drilled by the bit, and at the same time, the slime carrier The slime carrier from the source passes through the carrier swivel, the inside of the boring rod, the forward path, the periphery of the bit, and the return path in order, and is placed on the flow of the slime carrier to discharge the slime to the ground surface, and the outer pipe In the soil sampler for accommodating the soil sample remaining in the inner pipe, the slime carrier sent from the slime carrier source is a gas, and the bit is disposed in a horizontal plane from the outer periphery of the outer pipe. It protrudes 3 mm or more toward the outside of the outer tube.

In the soil sampler according to a preferred embodiment of the present invention, a carrier flow dividing plate having a flow dividing hole that is a passage of the slime carrier is provided in the sampler head, and the flow dividing hole in a horizontal plane is provided. When the cross-sectional area is S and the cross-sectional area in the horizontal plane of the forward path is U, the relationship of Expression (1) may be established.
U ≦ S Formula (1)

  In the present invention, the flow dividing holes of the flow dividing plate play only the role of guiding the gas flow that is the slime carrier to the forward path. As a result, the portion where the flow restrictor for the gas flow is opened becomes the peripheral portion of the bit that is the outlet of the forward pass, and the velocity of the gas flow is increased at that portion, so that the efficiency of slime conveyance can be improved. Further, since the flow dividing plate does not serve as a flow restrictor for the gas flow, the amount of the gas flow can be increased and the efficiency of slime conveyance can be increased.

  When there are a plurality of diversion holes, the cross-sectional area of each diversion hole in the horizontal plane is obtained, and the sum of the cross-sectional areas is S. Further, when the cross-sectional area in the horizontal plane differs in one diversion hole depending on the cross-sectional position, the minimum value of the cross-sectional area is set as the cross-sectional area of the one diversion hole.

  The soil sampler according to a preferred embodiment of the present invention may have a sample collection tube fitted in the inner tube.

  In the present invention, the sampling tube filled with the soil sample can be removed from the soil sampler and taken back to the laboratory. For this reason, it becomes a soil sample sampler that is easier to use. In addition, a soil sample in a state existing in the ground is directly collected in the sampling tube, and the soil sampler is more suitable for collecting a soil sample in an undisturbed state.

  In the soil sampler according to another preferred embodiment of the present invention, the sampling tube may be made of a transparent acrylic resin.

  In the present invention, since the sampling tube is transparent, it is directly visible, and at the sampling site, the sampling status can be immediately fed back to improve the soil sampling conditions. It becomes a soil sampler.

  In the soil sampler according to another preferred embodiment of the present invention, an air collecting mount disposed on the surface is provided, and the air collecting mount covers the surface opening of the underground hole and has an outlet. The outlet may be connected to a dust collector, and the dust collector may separate the slime and the slime carrier.

  In the present invention, since the dust collecting device is provided and the slime and the slime carrier are separated, the work environment can be maintained.

  A method for collecting a soil sample according to another aspect of the present invention includes a rotary outer tube having a bit attached to a tip, and a non-rotational inner tube fitted into the outer tube via a thrust bearing. And, using a device that creates a flow of slime carrier that returns from the ground surface to the ground surface, passes around the bit, moves the outer tube in the ground direction, drills in the soil layer with the bit, In the method of collecting a soil sample, the slime generated by drilling is placed on the flow of the slime carrier and discharged to the ground surface, and the soil sample remaining in the outer tube is accommodated in the inner tube and pulled up to the ground surface. A gas is used as a carrier.

  In the present invention, the gas includes air, nitrogen gas, carbon dioxide gas, argon gas, and the like. Among these, air is preferable from the viewpoint of cost saving.

  The present invention described above, preferred embodiments of the present invention, and components included in these can be implemented in combination as much as possible.

  The soil sampler according to the present invention adopts a gas flow as a slime carrier, so it is possible to avoid the injection of muddy water and bubbles into the ground, and to eliminate the influence of the underground hole on the surrounding ground as much as possible when collecting soil samples. can do. In addition, the soil sample sampler according to the present invention can take out the soil sample in an undisturbed state without the risk of mixing artificial substances such as muddy water and bubbles into the collected soil sample.

  Since the method for collecting soil samples according to the present invention employs a gas flow as a slime carrier, injection of muddy water and air bubbles into the ground can be avoided, and the influence of the underground hole on the surrounding ground can be avoided when collecting soil samples. This is a method that can be eliminated as much as possible. In addition, the method for collecting a soil sample according to the present invention is a method in which the soil sample can be taken out in an undisturbed state without the risk of mixing artificial substances such as muddy water and bubbles into the collected soil sample.

  Hereinafter, a soil sampler according to an embodiment of the present invention and a method for collecting a soil sample will be further described with reference to the drawings. The dimensions, materials, shapes, relative positions, etc. of the members and parts described in the embodiments of the present invention are not intended to limit the scope of the present invention only to those unless otherwise specified. It is just an illustrative example.

  1 is an overall conceptual diagram of the soil sample sampler 1, FIG. 2 is a cross-sectional explanatory view of a sampler portion 20 of the soil sample sampler 1, and FIG. 3 is a bottom view of the sampler portion 20 viewed from the lower surface side. FIG. 4 is a plan view of the carrier flow dividing plate 20 as viewed from the upper surface side. The arrows written in FIGS. 1 and 2 indicate the flow direction of the gas flow as the slime carrier.

  With reference to FIG. 1, a sampler portion 20 of the soil sample sampler 1 is connected to a boring rod 10. The rotational driving force generated by the driving device 6 and the driving force for moving in the vertical direction are transmitted to the boring rod 10 via the swivel head 5.

  A gas stream which is a slime carrier is sent out from the slime carrier source 2. In this embodiment, the slime carrier is an air flow, and the slime carrier source 2 is an air compressor. The air flow is subjected to temperature adjustment, humidity adjustment, sterilization, filtration, and the like by the air adjustment device 3. The air conditioner 3 can adjust the air flow according to the requirements specific to the sampling ground. The air conditioner 3 is an additional component of the soil sampler 1, and the air conditioner 3 may be omitted if there is no special requirement from the sampling ground.

  The air flow leaving the air conditioner 3 is guided to the inside of the boring rod 10 through the connection flow path 7 and the carrier swivel 4. The carrier swivel 4 is the same as the water swivel used in a conventional boring device using mud water, and the driving device 6, the swivel head 5, and the boring rod 10 are also the driving device and swivel head used in the conventional boring device using mud water. The same as a boring rod.

  The slime carrier source 2, the air conditioning device 3, and the driving device 6 are placed on the ground surface 11. The underground hole 12 is a hole that is dug into the ground toward the ground as the soil sample is collected. The air flow that has traveled downward in the boring rod 10 travels toward the ground surface together with slime (excavated waste) that is generated during soil sample collection, which will be described later. In the underground hole 12, the air flow passes through the gap between the outer periphery of the boring rod 10 and the hole wall of the underground hole 12.

  An air collection mount 41 is provided at the surface opening of the underground hole 12. The air collecting mount 41 guides an air flow containing slime to the outlet 42 of the air collecting mount. The air flow exiting the outlet 42 reaches the intake device 8. The air intake device 8 assists the flow of the air flow, and may be omitted depending on the air supply capability of the slime carrier source 2.

  The air flow leaving the intake device 8 reaches the dust collector 9. The dust collector 9 has a plurality of mesh filters inside, and separates air and slime when the slime conveyed in the air flow collides with the mesh and falls. The dust collector 9 may be based on other operating principles (for example, a liquid level collision type, a centrifugal type, etc.). The dust collector 9 contributes to the improvement of the working environment when collecting soil samples.

  An air conditioner may be added downstream or upstream of the dust collector 9 to perform sterilization or deodorization. In this way, the working environment in terms of hygiene is improved.

  The intake device 8 and the dust collector 9 are installed on the ground surface 11.

  Referring to FIG. 2, the sampler unit 20 has a sampler head 21 fixed to the lower end of the boring rod 10. The upper end of the outer tube 22 is fixed to the sampler head 21. The outer tube 22 has a substantially cylindrical shape. A carrier flow dividing plate 31 is fixed inside the upper portion of the outer tube 22. On the lower surface side of the center portion of the carrier flow dividing plate 31, there is a cylindrical protrusion 33. The inner tube 24 is engaged with the protruding portion 33 through a thrust bearing 23 provided on the upper portion of the inner tube 24. The inner tube 24 has a substantially cylindrical shape and is nested in the outer tube 22.

  When the boring rod 10 rotates, the outer tube 22 rotates, and the inner tube 24 fitted in the outer tube 22 does not rotate. A spring 29 is interposed between the upper surface of the inner tube 24 and the lower surface of the carrier flow dividing plate 31 to absorb the impact of the vertical movement of the inner tube 24 accompanying the vertical movement of the outer tube 22.

  A cutting shoe 46 is provided around the entire lower end of the inner tube 24 to assist the accommodation of the soil sample in the inner tube 24. Further, an air vent hole 30 is formed in the upper plate of the inner tube 24 to assist the accommodation of the soil sample in the inner tube 24.

  A sampling tube 28 that is an acrylic resin pipe is fitted inside the inner tube 24. The inner periphery of the inner tube 24 and the outer periphery of the sampling tube 28 are fitted with no gap. The upper inner peripheral surface of the cutting shoe 46 and the inner peripheral surface of the sampling tube 28 are flush with each other. The sampling tube 28 can be easily taken out from the inner tube 24. After the soil sample sample is accommodated in the sampling tube 28, the sampler portion 20 is pulled up to the ground surface, and the sampling tube 28 is taken out from the inner tube 24. A new sample collection tube can be fitted into the inner tube 24 to collect a soil sample.

  The sampling tube 28 is transparent. The term “transparent” means that the transparency is usually 85 to 100%, preferably 90 to 100%, more preferably 95 to 100%. Further, it is preferably colorless and transparent, but it may be colored and transparent. Within this range, the state of sampling of the soil sample in the sampling tube 28 can be immediately observed, so feedback is immediately provided, and the soil sampling conditions (air flow pressure, air flow rate, boring rod rotation speed, The magnitude of reaction force, etc.) can be improved. In addition, observation is easy after taking it back to the laboratory.

  The sampling tube 28 is not limited to a transparent acrylic resin but may be a hard vinyl chloride tube or an iron tube. Furthermore, the soil sample sample may be directly stored in the inner tube without using the sample collection tube 28, and after being pulled up to the ground surface, the soil sample sample may be transferred to an appropriate container.

  Four bits 25 are attached to the lower end of the outer tube 22. The number of bits 25 may be one or more. The bit 25 cuts the ground into a cylindrical shape by the rotation and downward movement of the boring rod 10.

  In the sampler section 20, the airflow flows toward the bit 25 with the gap between the inner periphery of the outer tube 22 and the outer periphery of the inner tube 24 as an outward path 26. Since the air flow passing through the forward path 26 does not contain slime, there is no special requirement for slime transport. Therefore, there is no particular restriction on the interval of the forward path 26, and the same interval as in a conventional boring device using mud water, for example, the inner diameter of the outer tube 22 can be 95 mm and the outer diameter of the inner tube can be 90 mm.

  The air flow descending through the forward path 26 changes its direction around the bit 25 and flows toward the surface of the ground with the gap between the outer periphery of the outer tube 22 and the hole wall of the underground hole 12 as a return path 27. The air flow passing through the return path 27 conveys slime. In order for the air flow to efficiently transport the slime, the interval in the horizontal plane of the return path 27 needs to be a certain value or more. Here, the gap of the return path 27 in the horizontal plane is created by ground cutting by the bit 25.

  For this reason, the bit 25 faces the outside of the outer tube 22 in a horizontal plane (that is, in a plane perpendicular to the rotation axis of the outer tube 22) and is usually 3 mm or more, preferably 4 mm or more than the outer periphery of the outer tube 22. More preferably, it protrudes by 5 mm or more. Referring to FIG. 3, the protruding length of the bit 25 is indicated by a distance d.

The protrusion length d of the bit 25 is preferably increased from the viewpoint of slime conveyance. On the other hand, from the viewpoint of energy required for cutting, speed of depth progression, reduction of slime amount, reduction of ground load, etc., it is preferable to reduce the protrusion length d of the bit 25. For this reason, the upper limit of the protrusion length d of the bit 25 is usually 10 mm or less, preferably 8 mm or less, more preferably 6 mm or less.
When there are a plurality of bits 25 and the protruding lengths d of the individual bits are different, the longest protruding length is set as the protruding length d.

  Referring to FIG. 4, the flow dividing plate 31 has flow dividing holes 32 that are twelve through holes. The diversion holes 32 are not limited to cylindrical holes, and may have other shapes. Further, the number of flow dividing holes is not limited to 12 and may be an appropriate number.

  The diversion holes 32 serve to guide the airflow that has flowed through the boring rod 10 into the forward path 26. In a conventional boring device using muddy water, the diversion hole plays a role of throttling the muddy water flow. On the other hand, in the present invention using a gas flow as a slime carrier, it is necessary to increase the gas amount as the gas velocity increases in order to transport the slime. For this reason, it is not preferable that the flow dividing holes 32 serve as a throttle.

That is, when S is the cross-sectional area of the shunt holes in the horizontal plane (the sum of the cross-sectional areas of the twelve shunt holes in this embodiment) and U is the cross-sectional area of the forward path in the horizontal plane, ) Is preferably established.
U ≦ S Formula (1)
More preferably, the relationship of the formula (2), more preferably the formula (3) is established.
1.14U ≦ S Formula (2)
1.28U ≦ S Formula (3)

On the other hand, if the cross-sectional area S in the horizontal plane of the diversion holes is too large, the role of guiding the air flow to the forward path 26 cannot be achieved. For this reason, the relationship between the cross-sectional area S in the horizontal plane of the diversion holes and the cross-sectional area U in the horizontal plane of the forward path preferably satisfies the formula (4), more preferably the formula (5).
S ≦ 2.00U Formula (4)
S ≦ 1.50U Formula (5)

  In the sampler portion 20 of the soil sampler 1 according to the present invention, the portion where the airflow passage restrictor is opened becomes the peripheral portion of the bit 25 that is the outlet of the forward passage 26, and the velocity of the airflow increases in this portion. The slime is efficiently transported.

  Then, the sampling method of the soil sample using the soil sample sampler concerning this invention is demonstrated. While the air flow is sent from the slime carrier source 2, the driving device 6 is driven, and the boring rod 10 is rotated while pressing the boring rod 10 downward. The bit 25 rotates and the ground is cut into a cylindrical shape. Slime generated by cutting is conveyed to an air stream and discharged to the ground.

 On the other hand, the remaining cylindrical portion of the ground cut into a cylindrical shape is accommodated inside the sampling tube 28. When the boring rod 10 is lowered by the length of the sampling tube 28, the rotation of the boring rod 10 is stopped, the sampler unit 20 is pulled up to the ground surface, the sampling tube 28 is removed, and the soil sample is taken out. If necessary, attach a new sampling tube and repeat the sampling operation again.

  Other air may be sufficient as the air used as a slime carrier demonstrated above. A gas means a substance that is in a gaseous state at room temperature. For example, nitrogen gas, carbon dioxide gas, argon gas and the like are included. Among these, air is preferable from the viewpoint of cost saving. On the other hand, if an inert gas such as nitrogen gas is used, the soil sample can be taken out in an undisturbed state chemically and the scope of application of the present invention is expanded.

  The soil sampler 1 according to the present invention can be modified and implemented without changing the gist thereof. For example, a metal crown may be fixed to the lower part of the outer tube 22 and a bit may be attached to the lower end of the metal crown.

  In addition, when the soil sample to be collected is started from a portion of a certain depth (for example, 0.5 m) or less, an underground hole is dug up to 0.5 m below the surface using an auger or the like, and then the present invention is applied. A soil sample can also be collected using the soil sampler 1.

  Using the soil sampler according to the present invention, soil samples were collected from the ground where clay and sand have an alternating layer structure.

The main dimensions of the used soil sampler are as follows.
Outer diameter of outer tube 22 100mm
Inner diameter of outer tube 22 95mm
Inner diameter of inner tube 24 90mm
Bit protruding length d 5mm
Sampling tube outer diameter 75mm
Inner diameter of sampling tube 71mm
Length of sampling tube 1020mm (1-6 sampling points, use 4-6 as needed)

Cross-sectional area in horizontal plane of diversion holes (sum of cross-sectional areas of 12 diversion holes) (S) 942 mm ²
Cross-sectional area in the horizontal plane of the outward path (U) 726mm ²
(1.30U = S)
Air compressor discharge air volume (capacity) 3.5m ³ / min
Average air pressure (actual measurement) 0.15 MPa (gauge pressure)
Average moat speed (actual value) 20-34mm / min
Number of sampling points 3

  A soil sample sample having a depth of 4 to 6 m in the ground could be taken out.

  The soil sample sampler and the soil sample collecting method according to the present invention can be used for collecting soil samples in a special environment where foreign matter injection into the ground is prohibited. It can be used to collect soil samples on rich ground.

1 is an overall conceptual diagram of a soil sample sampler 1. FIG. It is a cross-sectional explanatory drawing of the sampler section 20 of the soil sample sampler 1. It is the bottom view which looked at the sampler part 20 of the soil sample sampler 1 from the lower surface side. It is the top view which looked at the carrier shunt plate 20 from the upper surface side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Soil sampler 2 Slime carrier source 3 Air conditioning device 4 Carrier swivel 5 Swivel head 6 Drive device 7 Connection flow path 8 Intake device 9 Dust collector 10 Boring rod 11 Ground surface 12 Ground hole

DESCRIPTION OF SYMBOLS 20 Sampler part 21 Sampler head 22 Outer pipe 23 Thrust bearing 24 Inner pipe 25 Bit 26 Outward path 27 Return path 28 Sampling pipe 29 Spring 30 Air vent hole 31 Carrier shunt plate 32 Diverging hole 33 Protrusion part 41 Collecting mount 42 Outlet 46 Cutting shoe d Bit protrusion length

Claims (6)

A sampler head fixed to the lower end of a hollow boring rod that is driven to rotate;
An outer tube having an upper end fixed to the sampler head;
A non-rotating inner pipe fitted into the outer pipe via a thrust bearing;
A bit fixed to the lower end of the outer tube;
Consisting of a slime carrier source that feeds the slime carrier into the boring rod via a carrier swivel,
The gap between the inner periphery of the outer tube and the outer periphery of the inner tube is the forward path of the slime carrier,
The return path of the slime carrier is the gap between the outer circumference of the outer tube and the hole wall of the underground hole drilled by the bit,
The boring rod is rotated and moved in the ground direction, and the soil layer is perforated by the bit. At the same time, the slime carrier from the slime carrier source is moved to the carrier swivel, the inside of the boring rod, the forward path, the bit of the bit In the soil sample sampler that passes the periphery and the return path in order, puts the slime on the surface of the slime carrier and discharges the slime to the ground surface, and stores the soil sample left in the outer pipe in the inner pipe.
The slime carrier sent from the slime carrier source is a gas;
The bit sample protrudes 3 mm or more from the outer periphery of the outer tube toward the outside of the outer tube in a horizontal plane. In the soil sample sampler according to claim 1,
In the sampler head, a carrier flow dividing plate having a flow dividing hole which is a passage of the slime carrier is provided,
The soil sample sampler according to claim 1, wherein the relationship of the formula (1) is established, where S is a cross-sectional area of the diversion hole in the horizontal plane and U is a cross-sectional area of the forward path in the horizontal plane. .
U ≦ S Formula (1) In the soil sample sampler according to claim 1 or 2,
The soil sampler according to any one of claims 1 to 2, further comprising a sampling pipe fitted in the inner pipe. In the soil sampler according to claim 3,
The soil sampler according to claim 3, wherein the sampling tube is made of a transparent acrylic resin. In the soil sample sampler according to any one of claims 1 to 4,
An air collecting mount is installed on the ground surface.
The air collecting mount covers the ground surface opening of the underground hole and has an outlet,
The soil sample sampler according to any one of claims 1 to 4, wherein the outlet is connected to a dust collector, and the dust collector separates the slime and the slime carrier. It has a rotating outer tube with a bit attached to the tip and a non-rotating inner tube fitted in the outer tube through a thrust bearing, and returns from the ground surface to the ground surface through the bit periphery. Using a device that creates a slime carrier flow,
Rotating the outer tube while moving in the underground direction, drilling in the soil layer by the bit, the slime generated by the drilling is discharged on the ground surface on the flow of the slime carrier,
In the sampling method of the soil sample, the soil sample left in the outer tube is accommodated in the inner tube and pulled up to the ground surface.
A method for collecting a soil sample, wherein a gas is used as the slime carrier.

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