JP2002213178A - Core barrel and core supporting body thereof, and method for gathering core of core barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a core barrel and a core supporting body, and a method for gathering a core of the core barrel, which make the core gathered efficiently by supporting the core by the core supporting body which is composed of an elastic material and mounted in close vicinity to a bit within an inner tube of the core barrel having a double-tube structure. SOLUTION: The core barrel K has the double-tube structure composed of an outer tube 1, whose lower end is provided with the bit 2, and the inner tube 3 inserted inside. The core supporting body 7, whose inner peripheral surface is formed with a flock of fine hair 8, is mounted in close vicinity of the bit in an inner surface of an extension tube 4 formed in such a manner as to be approximately equal in diameter to inner and outer peripheral surfaces 3a and 3b of the inner tube 3 of the core barrel K.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core barrel, a core support for the core barrel, and a method for collecting a core of the core barrel. In order to ensure quick and reliable sampling.

[0002]

2. Description of the Related Art Conventionally, rocks and the like are excavated in a columnar shape by a bit rotated by a boring rod via a swivel mechanism as a core collecting instrument for examining the properties and hardness of rocks and the like, and sent into a core barrel to form a core. There is something to collect. However, when the core is collected on a ground with many crushed layers and cracks, the core to be collected is easily broken, and there is a dimensional difference of about 2 mm between the outer diameter of the core and the inner diameter of the inner tube into which the core is fed. For this reason, in the process in which the core itself enters the inner tube, a part of the core may be broken and the feeding of the core may be hindered, resulting in a clogging of the core. When the core is clogged, the cutting operation is stopped. Therefore, it is necessary to lift the core barrel onto the ground for cleaning, insert the core barrel again into the borehole, and perform excavation. Therefore, when performing core collecting work on the ground with many crushed layers and cracks, the length of one excavation is as short as 20 to 30 cm, and the workability is poor. When the excavation depth becomes deeper, much labor and time are required for raising and lowering the collection tool itself, and the time for raising and lowering the collection tool becomes longer than the excavation time, resulting in lower work efficiency. Also, clogging of the core may result in breakage of the core. Conventionally, for example, a device as shown in FIG. 7 has been proposed as a solution to the inconvenience of these coring devices. That is, the outer tube a provided at the lower end of the bit c, and the inner tube b has a double tube structure that is inserted into the outer tube a, the inner tube b in the outer tube a A substantially cylindrical sleeve case d is detachably provided to the inner tube b between the bit c and the core lifter f via an inner extension e detachably provided inside the lower end of the sleeve case d. A core lifter case g to be accommodated is fitted. Then, the sleeve case d protruding the outer peripheral surface d ₂ except the mounting portion for the inner tube b in the radial direction R of the inner peripheral surface a ₁ of the outer tube a, also other than the attachment portion relative to the sleeve casing d of the inner extension e bag is formed into a bottomed cylindrical shape by synthetic resin plastic between the sleeve casing d and the inner extension e by projecting the inner peripheral surface e ₁ in the radial direction R from the inner circumferential surface b ₁ of the inner tube b h Is formed to form a storage section i for storing by folding. The storage portion i is provided with an open portion j at the upper inside for the bag h folded and stored therein to be fed out into the inner tube b by pushing up the core A 'entering the inner tube b. It is formed in a concave shape with a cross section and a bottom. Then, by pushing up the core A 'entering the inner tube b, the bag h folded in the storage portion i is drawn out from the open portion j and stored so as to cover the core A' in the bag h. It adopts a type bag feeding system, and aims to increase the core length for efficiency.

[0003]

However, the conventional core collecting instrument shown in FIG. 7 has a sleeve case d attached to the lower end of the inner tube b and an inner extension e attached to the lower end of the sleeve case d.
And by projecting to the outer peripheral side of the outer peripheral surface d ₂ of the sleeve case d and recessed inner peripheral surface a ₁ of the outer tube a radially R, the inner peripheral surface e ₁ of the inner extension e to the inner peripheral side It is necessary to provide a storage portion i in the axial direction I for folding and storing a bag h for collecting the core A 'by protruding. Therefore, in order to the outer peripheral surface d ₂ of the inner circumferential surface a ₁ in the radial direction R in recessed and despite sleeve case d of the outer tube a adjacent to the bit c will protrude, clearance drilling fluid passes m is very narrowed, and the clearance m through which the drilling fluid passes cannot be sufficiently secured. Therefore, the influence of the pressure loss of the drilling fluid generated in this portion becomes large, and the drilling fluid pressure in the water groove (water way) q provided on the cutting edge surface of the bit c serving as the final outlet of the drilling fluid is accurately detected. Difficult to do. For this reason, the pressure change of the drilling fluid at the tip of the bit c, which should be the most important determination information even during the excavation, cannot be accurately detected, and the rock quality change during the excavation is difficult to understand. In addition, the water groove q itself of the bit c, which should be originally designed to correctly detect the drilling fluid pressure, cannot fully perform its function. In addition, the length l 'from the cutting edge of the bit c to the unwinding position F of the bag h, which is the starting point for collecting the core A', becomes longer. Therefore, 'the initial drilling, core A is entered from the inner extension e to the inner tube b' core A itself until it reaches the bag h Core A 'is in direct contact with the inner surface e ₁ of the inner extension e Therefore, the frictional resistance when the core A 'enters is increased, and the core is easily clogged at the beginning of the excavation of the core A'. Further, since a clearance k is generated between the inner tube b and the core A 'to be collected,
Since the core A 'is not centered (aligning operation) while the core A' enters the inner tube b, the core A 'to be sampled is excavated when excavating on a crushed layer or a ground with many cracks. The core enters the inner tube b in a state of being shifted at the broken portion, and the core does not enter smoothly. In such a case, the excavation work must be interrupted after all, and much work and time are required for the work, and the work cannot be performed efficiently.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional inconvenience and reduces the installation distance from a bit to a core collecting position without using a bag for storing a core or a storage portion for storing the bag. This greatly reduces core clogging at the beginning of excavation, and by centering the core, for example, when collecting a core from a broken ground etc., the core can smoothly enter the inner tube and be reliably collected. An object of the present invention is to provide a core barrel, a core support for the core support, and a method for collecting cores of the core barrel, which can be used and work efficiency is improved, and a handling operation of a core support used for collecting a core can be easily performed and repeated use is possible. It is.

[0005]

Means for Solving the Problems The present invention has been made in view of the above problems, and the invention according to claim 1 comprises an outer tube having a bit provided at a lower end and an inner tube inserted into the outer tube. In a core barrel having a double-pipe structure, wherein a substantially cylindrical extension tube is detachably provided between an inner tube and a bit, the extension tube has substantially the same diameter as an inner peripheral surface and an outer peripheral surface of the inner tube. A substantially cylindrical core support formed of an elastic material such as synthetic resin or rubber and formed with a group of cilia capable of supporting the core on the inner peripheral surface is provided inside the extension tube in close proximity to the bit. The present invention adopts a means characterized by being attached to a desired length over the circumference and the inner circumference of the inner tube.

According to a second aspect of the present invention, there is provided the outer tube according to the first aspect, wherein the inner peripheral surface is formed in the axial direction from the place where the bit is installed without any uneven surface in the radial direction. The inner tube inserted into the inner tube and the extension tube attached to the lower end of the inner tube are formed such that the outer peripheral surface is formed without any uneven surface in the radial direction from the bit in the axial direction, so that the inner peripheral surface of the outer tube is formed. A display that connects a change in drilling fluid pressure acting on a water groove provided in a bit to a ground pump by increasing the clearance formed between the drilling fluid and the outer peripheral surface of the inner tube to reduce the pressure loss of the drilling fluid passing therethrough. Means of detecting by means is adopted.

According to a third aspect of the present invention, in any one of the first and second aspects, the core support is detachably attached to an inner periphery of an extension tube and an inner periphery of an inner tube. Means that are characterized by the following.

According to a fourth aspect of the present invention, in any one of the first, second, and third aspects, the cilia group is provided on the inner peripheral surface of the core support in a cross-sectional centripetal direction. When the core is excavated and collected in the core barrel, the core is supported by the group of cilia so that the core can be centered when the core is excavated.

According to a fifth aspect of the present invention, there is provided one of an extension tube and an inner tube, or an extension tube, on one side of a flexible base sheet made of an elastic material such as synthetic resin or rubber. And a mounting surface that is in contact with both the inner tube and the inner tube, and a cilia group capable of supporting the core is formed on the other surface of the base sheet.

According to a sixth aspect of the present invention, in the fifth aspect, the installation direction of the vertical cross-section of the cilia of the cilia group is more than 90 degrees with respect to the direction of entry of the core into the core barrel by excavation of the bit. Means characterized by being formed at a small acute angle to allow entry of the core at the time of excavation of the core, and to be formed in a direction suitable for supporting the core and preventing falling off after the core is entered. It was adopted.

According to a seventh aspect of the present invention, the cilia of the cilia group according to any one of the fifth and sixth aspects is characterized in that:
A means is adopted in which a desired density, a desired length, and a desired thickness are formed according to the hardness and the like.

According to an eighth aspect of the present invention, in any one of the fifth, sixth and seventh aspects, the cilia of the cilia group are arranged in a direction in which the core of the core barrel enters due to the excavation of the bit. Accordingly, the installation direction of the vertical cross section of the cilia is arranged at an acute angle smaller than 90 degrees from the lower end to the upper end of the base layer sheet, and the angle is sequentially increased, and according to the properties, hardness, etc. of the ground from which the core is collected. Means of increasing the density of the cilia, increasing the length of the cilia, and further increasing the thickness of the cilia was adopted.

According to a ninth aspect of the present invention, there is provided an unfolded base layer sheet made of an elastic material such as synthetic resin or rubber and having a group of cilia capable of supporting a core formed between an outer tube and a bit. A desired length is attached to the inner peripheral surface of the inner tube from the extension tube close to the bit by being rounded against flexibility to fit the inner peripheral surface of the extension tube and the inner tube of the inner tube detachably attached between them. The core is excavated and collected while being supported by the cilia group.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. A first embodiment of the present invention will be described with reference to FIGS. Reference numeral 1 denotes an outer tube provided with a bit 2 provided below, and the outer tube 1 is driven by a boring rod and passively rotates through a swivel head assembly (not shown) mounted on an upper end thereof. It is free. 3 is outer tube 1
The inner tube 3 is fixed to the bearing portion of the swivel head, and is arranged so as to be able to separate the rotational motion from the boring rod, and cooperates with the outer tube 1 to form a double tube. It is inserted into the outer tube 1 so as to be stationary so as to form a structure. The outer tube 1 and the inner tube 3 form a core barrel K having a double pipe structure. The core barrel K is provided with a substantially cylindrical extension tube 4 at the lower end of the inner tube 3 so as to be detachable from the bit 2. This is similar to the conventional excavator shown in FIG.

However, in the present embodiment, the outer tube 1 has an inner peripheral surface 1a formed without any uneven surface in the radial direction R in the axial direction I from the place where the bit 2 is installed, and the extension tube 4 is formed of the inner tube 1 3 have substantially the same diameter on the inner peripheral surface 3a and the outer peripheral surface 3b. Thus, the inner tube 3 inserted into the outer tube 1 and the extension tube 4 attached to the lower end of the inner tube 3 have the outer peripheral surface 3b,
4b is formed from the bit 2 in the axial direction I in the axial direction I without any uneven surface in the radial direction R, so that the inner peripheral surface 1a of the outer tube 1, the outer peripheral surface 3b of the inner tube 3, and the outer peripheral surface of the extension tube 4b are formed. The clearance 5 formed between the core barrel K and the core barrel K is secured as a constant space having no uneven surface in all parts.
The pressure loss generated when passing through the inside is reduced as much as possible, and the drilling fluid pressure acting on the water groove Q provided in the bit 2 which is the final outlet of the drilling fluid is applied to a ground pump (not shown). The change in rock quality at the tip portion during excavation by the bit 2 can be accurately determined from the pressure fluctuation value of the excavation fluid 6 displayed on display means such as a pressure gauge provided.

[0016] 7 is a core support to be attached to a desired length L ₁ over the inner periphery of the inner periphery and the inner tube 3 of the extension tube 4 adjacent to the bit 2, the core support 7 is synthetic resin or rubber The cilia group 8 is formed of an elastic material, and can support the core A to be collected on the inner peripheral surface under the assembled state. That is, in the embodiment shown in FIG. 4, the core support 7 has a mounting surface 7 a ₁ in contact with both the extension tube 4 and the inner tube 3 on one side of the flexible base sheet 7 a as shown in FIG. 4. The cilia group 8 is formed on the other surface of the base sheet 7a so as to support the core A. And
When the core A excavated by the bit 2 is collected in the core barrel K, the cilia group 8 supports the core A so that the core A can be centered as shown in FIG.
Is provided on the inner peripheral surface thereof such that the front end faces in the cross-section centripetal direction O.

In order to attach the core support 7, the base sheet 7 a in the unfolded state as shown in FIG. 4 is attached to the extension tube 4 and the inner tube 3.
The core support 7 is moved from the extension tube 4 close to the bit 2 by utilizing the resilience when releasing the pressing force in the case of rounding by rounding against the flexibility according to the inner peripheral curved surface of the extension tube 4. It is attached to the inner peripheral surface of the inner tube 3 by pressing. This embodiment is a preferred example,
The core support 7 is attached to both the substantially cylindrical extension tube 4 and the inner tube 3. However, when the extension tube 4 is formed longer than shown, the core support 7 is provided only on the inner periphery of the extension tube 4. The body 7 may be attached, or the core support 7 may be attached only to the inner periphery of the inner tube 3 when the extension tube 4 is not used.

Reference numeral 9 denotes an annular groove 1 provided on the inner periphery of the core lifter case 10 to prevent the core support 7 from sliding down.
A stop ring 9a is provided inside 0a, and this stop ring 9 expands and contracts in the radial direction R against spring properties.

The installation direction of the longitudinal section of the cilia 8a of the cilia group 8 is set at an acute angle α smaller than 90 degrees with respect to the entry direction B of the core A of the core barrel K by excavating the bit 2 as shown in FIG. By being formed, the core A is allowed to enter at the time of excavation, and after the core A is entered, the core A is formed to be suitable for supporting the core A and preventing the core A from falling off. The cilia 8a are formed to have a desired density, a desired length, and a desired thickness in accordance with the properties, hardness, and the like of the ground from which the core A is collected so as to support the core A.

This embodiment is constituted as described above, and the operation will be described below in the order of steps together with the method of collecting the core. First,
The substantially cylindrical extension tube 4 into which the core lifter case 10 is inserted at the lower end is formed to have substantially the same diameter as the inner peripheral surface 3a and the outer peripheral surface 3b of the inner tube 3, so that a step is formed not only on the outer peripheral side but also on the inner peripheral side. Since there is no such material, one side (inner peripheral side) of the flexible base layer sheet 7a made of an elastic material such as synthetic resin or rubber is formed on the inner peripheral surface 4a of the extension tube 4 and the inner peripheral surface 3a of the inner tube 3.
The core support member 7 forming the cilia group 8 is fitted to the inner peripheral curved surfaces of the extension tube 4 and the inner tube 3 by hand, and the upper side is attached to the inner tube 3 and the lower side is attached to the lower tube. Is inserted into the extension tube 4.

At this time, the inner tube 3 is
If the tension tube 4 has been removed,
Core for tube 3 and extension tube 4
Quick and reliable insertion and mounting of the support 7 above and below
You can do it. That is, above the core support 7
Part into the inner tube 3 and push it to the set position
After that, as shown in FIG.
Core support 7 for manually rolling the base sheet 7a
Release the pressure on
To the inner peripheral surface 3a of the inner tube 3 by the applied pressing force.
When the substantially cylindrical core support 7 is pressed.
The mounting surface 7a of the core support 7 ₁Is supported in specified dimensions
Is done. At this time, it is stored in the extension tube 4.
Base layer sheet 7a to be ejected from inner tube 3
The core is stored after excavation.
When pulling out the core support 7 from the inner tube 3,
It is convenient if there is a grip allowance that can be grasped by hand. After this,
Rest of base layer sheet 7a protruding from inner tube 3
To accommodate the extension tube
4 is incorporated in the inner tube 3. This installation method
The extension tube 4 close to the bit 2
Over the inner circumference of the inner tube 3 and the inner circumference of the inner tube 3.
L₁Can be attached to the core support 7. Soshi
The annular groove 10 provided on the inner periphery of the core lifter case 10.
a by a stop ring 9 fitted in the core support 7.
Slipping will be regulated. In this way,
Of the tension tube 4 and the inner tube 3
Cilia group 8 was formed on the inner circumference in the vicinity of bit 2
A substantially cylindrical core support 7 can be attached.

In order to excavate the core A, the outer tube 1 and the inner tube 3 inserted into the outer tube 1 are rotated via a boring rod with respect to the core barrel K having a double pipe structure from the ground. The point of excavation by transmitting the excavation power is the same as before.

In this embodiment, the outer tube 1 is formed such that the inner peripheral surface 1a is formed without any irregularities in the radial direction R in the axial direction I from the place where the bit 2 is installed, and is inserted into the outer tube 1. Inner tube 3
The extension tube 4 which is detachably attached to the lower end of the inner tube 3 has substantially the same diameter on the inner peripheral surface 3a of the inner tube 3 and has no uneven surface, so that the core support is made of an elastic material such as synthetic resin or rubber. By rounding the extension tube 7, the extension tube 4 and the inner tube 3 are formed in a substantially cylindrical shape without forming an uneven surface close to the bit 2.
It can be attached over the inner circumference of the desired length L _1.

As shown in FIG. 7, the inner extension e is applied to the core A 'which enters the inner tube b by excavating the bit c.
Open more projecting inwardly and folded bags h in the holding section i by forming so as to protrude from the inner circumferential surface a ₁ of the outer tube a sleeve case d toward the outer periphery of the inner tube b In a conventional core extracting device which adopts a bag feeding method in which the core A 'is covered in the bag h so as to be drawn out by pushing up the core A' from the portion j and the bag h is fed out from the bit c. Opening j
In this embodiment, the extension tube 4 is formed to have substantially the same diameter as the inner tube 3 such that the inner peripheral surface 4a as well as the outer peripheral surface 4b have no irregularities. The core support 7 formed of an elastic material such as a synthetic resin or rubber is attached in a cylindrical shape from the inner peripheral surface 4a of the inner tube 3 to the inner peripheral surface 3a of the inner tube 3. The installation distance 1 is reduced to about 1/3 of the conventional distance, and becomes closer to the bit 2. Therefore, when the core A excavated by the bit 2 enters the extension tube 4, it is immediately inserted into the core support 7.

The core support 7 has a substantially cylindrical shape made of an elastic material such as synthetic resin or rubber, and a cilia group 8 is formed on one side (inner peripheral side) of a flexible base sheet 7a. Therefore, the core A excavated by the bit 2 and entering the extension tube 4 is immediately supported by the cilia group 8 of the core support 7. For this reason, the frictional resistance of the extension tube 4 against the inner surface of the extension tube 4 is reduced by the cilia group 8, so that the core A smoothly enters and the core clogging is prevented.

At this time, in the cilia group 8, as shown in FIG. 6, the installation direction of the vertical section of the cilia 8a is smaller than 90 degrees with respect to the entry direction B of the core A into the core barrel K by excavation of the bit 2. Since the core A is formed at the acute angle α, the core A is allowed to enter when the core A is excavated, and after the core A has entered the core support 7, the core A is surely supported by the cilia 8 a and downward. To prevent falling off. The cilia 8a is selected to have a desired density, a desired length, and a desired thickness in accordance with the properties, hardness, and the like of the ground of the core A to be collected so that the core A can exhibit an optimum core storage function. I do.

[0027] Moreover, as shown in FIG. 5, since ciliary 8a is provided toward the tip cross-sectional centripetal direction O on the inner peripheral surface of the core support 7, the core A drilled by bit 2 et click < The center tube 4 can be supported from the tension tube 4 in the inner tube 3. Due to this centering, when the core A is excavated on the ground where a crushed layer, cracks, or the like are generated, the core support 7 is also excavated at the broken part of the ground in the process of passing the core A from the extension tube 4 through the inner tube 3. The situation in which the core is further collapsed by the action and the progress of the core A itself is hindered can be greatly reduced.

As described above, the outer tube 1
Has an inner tube 3 inserted into the outer tube 1 and a lower end of the inner tube 3 having a circumferential surface formed in the radial direction R from the installation position of the bit 2 in the axial direction I without any irregularities. The extension tube 4 is formed by forming the outer peripheral surfaces 3b, 4b without irregularities in the radial direction R from the bit 2 in the axial length direction I and the inner peripheral surface 1a of the outer tube 1 and the inner tube 3
The clearance 5 formed between the outer peripheral surface 3b of the extension tube 4 and the outer peripheral surface 4b of the extension tube 4 is extended as shown in FIG. 7 so that the storage portion i of the bag h is formed between the sleeve case d and the inner extension e. Since the part where the clearance m becomes narrow due to the installation of the core collecting tool of the system can be eliminated, the water passage through which the drilling fluid passes is secured as a constant space without any uneven surface, and the drilling fluid during the drilling is applied to the core barrel K. The pressure loss generated when passing through the inside is reduced as much as possible, and the drilling fluid pressure acting on the water groove Q provided at the cutting edge of the bit 2 which is the final outlet of the drilling fluid is connected to the ground pump, for example, Since the pressure fluctuation value of the drilling fluid 6 displayed on the display means such as a gauge can be directly grasped, the rock quality change at the tip of the bit 2 during the drilling can be accurately determined. It can be determined.

When the core A having a desired length is excavated in a columnar shape, the excavation by the bit 2 is stopped, and the core barrel K is pulled up from the hole. Bit 2 to outer tube 1
And remove the core lifter case 10 from the extension tube 4 and the extension tube 4
Is detached from the inner tube 3 and separated, and the base sheet 7a of the core support 7 exposed therefrom is gripped and pulled out from the inner tube 3, so that the core A itself stored in the core support 7 is also taken together. Take out and finish collecting core A. Further, since the used core support 7 is made of a rigid material such as synthetic resin or rubber, it can be reused repeatedly by washing with water.

In the illustrated embodiment, the cilia group 8 formed on the core support 7 to support the core A to be collected
The setting direction of the longitudinal section of the cilia 8a along the direction B of entry of the core A into the core barrel K by the excavation of the bit 2 is uniform on one side (the inner peripheral side) of the base sheet 7a.
By forming an acute angle α smaller than the degree, the core A is formed into a shape that is easy to enter and hardly falls, but the cilia 8a is not limited to this, and the angle is set from the lower end to the upper end of the base sheet 7a. The angle is gradually increased at an acute angle α smaller than 90 degrees toward
The core A enters and falls by increasing the density of the cilia 8a, increasing the length of the cilia 8a, and further increasing the thickness of the cilia 8a in accordance with the properties and hardness of the ground from which the cilia are collected. Prevention can be further ensured.

In the illustrated embodiment, the core support 7 is configured such that one unfolded base layer sheet 7a is rounded into a substantially cylindrical shape so as to be attached to and detached from the extension tube 4 and the inner tube 3. But
The present invention is not limited to this, and the core support 7 previously formed in a substantially cylindrical shape can be attached to or detached from the extension tube 4 and the inner tube 3.

[0032]

According to the first aspect of the present invention, as described above, a double pipe structure comprising an outer tube having a bit provided at the lower end and an inner tube inserted into the outer tube. In a core barrel in which a substantially cylindrical extension tube is detachably provided between a bit and an inner tube, the extension tube is formed to have substantially the same diameter on the inner and outer circumferences of the inner tube, and is made of synthetic resin or A substantially cylindrical core support made of an elastic material such as rubber and having a group of cilia capable of supporting the core on the inner peripheral surface is provided near the bit and the inner periphery of the extension tube and the inner periphery of the inner tube. The invention according to claim 9 is made of an elastic material such as synthetic resin or rubber,
The expanded base sheet in which the group of cilia capable of supporting the core is formed is fitted to the extension tube detachably attached between the outer tube and the bit and the inner peripheral curved surface of the inner tube to resist flexibility. A bag for accommodating a core, which is characterized in that it is attached to a desired length from the extension tube to the inner peripheral surface of the inner tube in the vicinity of a bit by being rounded, and is collected while being excavated and supported by the cilia group. Eliminating the distance from the bit to the starting point of core collection by eliminating the storage part for storing the core and bags can greatly prevent core clogging at the time of excavation, and by performing centering on the core, crushed layers and cracks can be formed. Even when collecting cores from a lot of ground, make sure that the cores enter the inner tube smoothly Preparative is performed, and workability is efficient and handling operations of the core support used to collect core is simple, can be performed repeated use.

[0033] The invention described in claim 2 of the present invention provides:
The outer tube according to claim 1, wherein the inner peripheral surface is formed without any uneven surface in the radial direction from the installation position of the bit in the axial direction, and is attached to the inner tube inserted into the outer tube and the lower end of the inner tube. With the extension tube, the clearance formed between the inner peripheral surface of the outer tube and the outer peripheral surface of the inner tube is increased by forming the outer peripheral surface without any uneven surface in the radial direction from the bit in the axial length direction. The change in the drilling fluid pressure acting on the ditch formed in the bit by reducing the pressure loss of the drilling fluid passing through is detected by the display means connected to the ground pump, so from the pressure change value of the drilling fluid Changes in rock quality during excavation can be accurately determined, and boring for core extraction can be performed reliably. In addition, the bit mounted on this core barrel can exhibit the original performance of the bit efficiently by uniquely designing the water groove of the bit that matches the geological formation and the boring conditions, and more efficient drilling You can get the environment.

According to a third aspect of the present invention, in any one of the first and second aspects, the core support is detachably attached to the inner circumference of the extension tube and the inner circumference of the inner tube. Therefore, attachment and detachment of the core support can be easily performed.

According to a fourth aspect of the present invention, there is provided a method according to any one of the first, second and third aspects.
The cilia group is characterized in that the cilia group supports the core so that the core can be centered when the core is excavated and collected in the core barrel by being provided with the front end facing in the transverse direction on the inner peripheral surface of the core support. Therefore, when excavating a crushed layer or fragile ground and collecting cores, core entry is performed in a state close to the specified core shape and dimensions by centering the core with the core support. Core entry resistance can be greatly reduced.

According to a fifth aspect of the present invention, an extension tube or an inner tube, or an extension tube, is formed on one side of a flexible base sheet made of an elastic material such as synthetic resin or rubber. And a mounting surface that comes into contact with both the inner tube and the other surface of the base sheet is characterized by forming a group of cilia capable of supporting the core. It can be manufactured in large quantities and at low cost.

According to a sixth aspect of the present invention, in the fifth aspect, the installation direction in the longitudinal section of the cilia of the cilia group is more than 90 degrees with respect to the entry direction of the core of the core barrel due to the excavation of the bit. Since it is formed at a small acute angle, it allows the core to enter during excavation of the core, and is formed in a direction suitable for supporting the core and preventing falling off after the core is entered, The core can be collected smoothly and quickly.

According to a seventh aspect of the present invention, the cilia of the group of cilia according to any one of the fifth and sixth aspects is characterized in that: the properties of the ground from which the core is collected so as to support the core;
A desired density, a desired length, and a desired thickness are formed in accordance with the hardness and the like.
The cilia of the group of cilia according to any one of claims 6 and 7, wherein a setting direction of a vertical cross section of the cilia moves from a lower end to an upper end of the base sheet according to a direction in which a core enters a core barrel by excavation of a bit. At an acute angle smaller than 90 degrees, and increasing the angle of the cilia according to the properties and hardness of the ground from which the core is collected, increasing the length of the cilia, and further increasing the thickness of the cilia Since the core is formed with an increased height, the core can be smoothly and reliably supported and easily sampled.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a core barrel of the present invention.

FIG. 2 is an exploded perspective view in which the core support is cut away.

FIG. 3 is a perspective view showing an example of a state in which a core support constituting the present embodiment is mounted.

FIG. 4 is a plan view of an expanded state showing an example of a core support constituting the present embodiment.

FIG. 5 is a cross-sectional view showing a state in which the core support is mounted in an extension tube.

FIG. 6 is a longitudinal sectional view showing a state in which the core support is mounted in an extension tube.

FIG. 7 is a longitudinal sectional view showing an example of this type of conventional excavator.

[Explanation of symbols]

 Reference Signs List 1 outer tube 1a inner peripheral surface 2 bit 3 inner tube 3a inner peripheral surface 3b outer peripheral surface 4 extension tube 4a inner peripheral surface 4b outer peripheral surface 5 clearance 7 core support 8 cilia 8a cilia A core B traveling direction I axis length direction R Radial direction

Claims (9)

[Claims] 1. A double-tube structure comprising an outer tube having a bit provided at a lower end thereof and an inner tube inserted into the outer tube, wherein a substantially cylindrical extension tube is provided between the inner tube and the bit. In the core barrel provided detachably, the extension tube is formed with substantially the same diameter on the inner peripheral surface and the outer peripheral surface of the inner tube, is made of an elastic material such as synthetic resin or rubber, and supports the core on the inner peripheral surface. A core barrel having a substantially cylindrical core support having a group of possible cilia formed thereon at a desired length in the vicinity of the bit over the inner periphery of the extension tube and the inner periphery of the inner tube. 2. The outer tube has an inner peripheral surface formed with no irregularities in the radial direction in the axial direction from the place where the bit is installed, and is attached to an inner tube inserted into the outer tube and a lower end of the inner tube. The extension tube that is formed has a clearance formed between the inner peripheral surface of the outer tube and the outer peripheral surface of the inner tube by forming the outer peripheral surface without any uneven surface in the radial direction from the bit in the axial direction. The change in the drilling fluid pressure acting on the water channel provided in the bit by increasing the pressure loss of the drilling fluid passing therethrough is detected by a display means connected to the ground pump. Core barrel. 3. The core barrel according to claim 1, wherein the core support is detachably attached to an inner circumference of an extension tube and an inner circumference of an inner tube. 4. The cilia group is provided on the inner peripheral surface of the core support with its tip directed in the cross-section centripetal direction, so that the core can be centered by the cilia group when the core is excavated and collected in the core barrel. 4. The core barrel according to claim 1, wherein the core barrel is supported. 5. A mounting surface which is made of an elastic material such as synthetic resin or rubber and which is in contact with one of an extension tube and an inner tube, or both an extension tube and an inner tube, is provided on one side of a flexible base layer sheet. A core support mounted on a core barrel, wherein a cilia group capable of supporting the core is formed on the other surface of the base sheet. 6. The installation direction of the vertical cross section of the cilia of the cilia group is formed at an acute angle smaller than 90 degrees with respect to the direction of entry of the core into the core barrel by excavation of the bit, so that the core is excavated at the time of excavation of the core. 6. The core support according to claim 5, wherein the core support is formed in a direction suitable for supporting the core and preventing the core from falling off after the core has entered. 7. The cilia of the group of cilia are formed to have a desired density, a desired length, and a desired thickness according to properties, hardness, and the like of a ground from which the core is collected so as to support the core. The core support according to claim 5. 8. The cilia of the group of cilia may be arranged such that an installation direction of a vertical section of the cilia is smaller than 90 degrees from the lower end to the upper end of the base sheet according to the direction of entry of the core into the core barrel by excavation of the bit. It is formed by increasing the angle of the cilia in order, increasing the density of the cilia, increasing the length of the cilia, and further increasing the thickness of the cilia according to the properties, hardness, etc. of the ground from which the core is collected. The core support according to any one of claims 5, 6, and 7, wherein 9. An extension tube, which is made of an elastic material such as synthetic resin or rubber, and in which a base layer sheet in which a group of cilia capable of supporting a core is formed is detachably attached between an outer tube and a bit. A desired length is attached to the inner peripheral surface of the inner tube from the extension tube in the vicinity of the bit by rounding against the flexibility according to the inner peripheral curved surface of the inner tube, and a core is excavated and supported by the cilia group A method for collecting cores in a core barrel, wherein the cores are collected while collecting.