JP2015071911A - Constant bearing core sample sampling method, constant bearing core sample marking method, and constant bearing core recess forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a constant bearing core sample sampling method, a constant bearing core sample marking method, and a constant bearing core recess forming device, in which a precise bearing in a stratum of a constant bearing core sample sampled from a stratum constituting the ground can be recognized.SOLUTION: A constant bearing core sample sampling method includes: a step of forming a recess 52 to specify a first bearing in a portion out of the center Cof the stratum 11 among the stratum 11 exposed from a bored hole 28, after forming the bored hole 28 of a depth of arriving at a core sampling area A of a stratum 11 in the ground; and a step of sampling a constant bearing core sample having a notch part, by cutting the stratum 11 of a portion corresponding to the core sampling area A so that a portion of the recess 52 may remain.

Description

  The present invention relates to a azimuth core sample sampling method, a azimuth core sample marking method, and a azimuth core recess forming apparatus that sample a stratum constituting a ground as a unidirectional core sample.

As one method of geological survey, there is a method of collecting a core sample by boring the stratum constituting the ground. Boring is widely used for surveys of underground reserves and structural support.
This method is a very useful means because it is possible to sample a sample of the stratum constituting the ground and directly observe or analyze it.
That is, it is possible to know the formation state of the formation, the kind of rock forming the formation, the strength, the inclusion, and the like from the core sample.

  In such a geological survey, it may be desired not only to collect a core sample but also to clarify the orientation of the collected core sample, that is, in which direction the core sample was located in the formation. When the direction of the core sample is clarified, the direction of the slope of the formation, the direction of rock joints, etc. can be known.

Specifically, for example, in order to clarify the direction of the crushed part and seam (laminated structure in which clay is sandwiched) constituting the fault fracture zone existing at a depth of several to several tens of meters below the surface of the earth In some cases, the orientation of the core sample is specified.
The seam may be distributed with a gentle slope having an inclination of about 10 degrees or less. The thickness of such a seam is about several cm to 20 cm.

As a conventional device capable of specifying the orientation of the core sample in the formation, there is a geological sampling device (boring device) having a double-tube fixed shaft as disclosed in Patent Document 1.
FIG. 17 is a cross-sectional view showing a schematic configuration of a general geological sampling device having a double tube fixed shaft.
Here, the configuration of the geological sampling device 200 will be described with reference to FIG.
The geological sampling device 200 includes a core bit 201, an outer tube 203, an inner tube head 204, a wire 206, an inner tube 207, a core lifter case 209, and a core lifter 211.

  The core bit 201 is substantially cylindrical. It is attached to the tip of the boring rod via the outer tube 203. The core bit 201 is rotationally driven around the axis line to form a boring hole.

The inner tube head 204 is suspended by a wire 206 inside the boring rod and outer tube 203. An inner tube 207 is rotatably joined to the inner tube head 204.
A core lifter case 209 that houses the core lifter 211 inside is attached to the tip of the inner tube 207.

The core lifter 211 is a short cylindrical spring member. The core lifter 211 is discontinuous at one place in the circumferential direction, and is externally clamped by a core sample (not shown, also referred to as “fixed orientation core sample”) cut into a cylindrical shape by the core bit 201. Yes.
The position of the core lifter 211 in the axial direction is constrained by the core core lifter case 209, and the core lifter 211 is pulled up together with the inner tube head 204 while holding the core, thereby collecting a core sample.

  In addition, sharp protrusions are formed at one location on the inner peripheral surface of the core lifter 211. When the core lifter 211 is extrapolated to the core sample, the protrusions are rubbed against the peripheral surface of the core sample, and the axial line is removed. It comes to make a mark.

  The position of the projection of the core lifter 211 is detected by the direction recording unit and collated with the direction with the streaks attached to the core sample, so that the direction of the core sample, that is, when it was in the formation It becomes possible to know the direction of the core sample.

As another conventional boring device capable of specifying the orientation of the core sample, there is a fixed orientation core sampling device disclosed in Patent Document 2.
In Patent Document 2, there are a plurality of bases that are inserted into boring holes drilled in the ground, and a plurality of bases that pass through the bases in the axial direction of the boring holes and are movable at least in the retreating direction with respect to the bases. There is disclosed a fixed orientation core sampling device having a shape probe needle, an azimuth recording means for recording the direction of the base portion in the boring hole, and a braking means for applying a load to the movement of the shape probe needle with respect to the base portion.

  In Patent Document 2, the tips of a plurality of shape probe needles supported in the axial direction of the borehole are pressed against the bottom of the borehole formed in the ground, and the relative positions of the tips of the shape probe needles are determined. A first step of storing, a second step of recording a relationship between the positions and orientations of the plurality of shape probe needles arranged in a predetermined pattern, and a core (core sample) by cutting the hole bottom And a fourth step of collating the shape of the upper end surface of the sampled core with the relative position of the tip of the shape probe stored in the first step. A core sampling method is disclosed.

Japanese Patent No. 60-93331 JP-A-9-242458

By the way, in the geological sample collection device 200 configured as shown in Patent Document 1 and FIG. 17, the cylindrical core sample cut and formed by the core bit 201 may not rotate from the original position until the core lifter 211 is inserted. It is a premise.
However, in practice, for example, the core sample may be broken and rotated, and if the core sample is rotated in this way, there is a problem that the exact orientation of the core sample cannot be known.

The orientation-oriented core sampling device disclosed in Patent Document 2 can be used when the formation upper surface where the boring hole is exposed has an undulating shape, but when the upper surface of the formation where the boring hole is exposed is flat I can not use it.
Also, when sampling a core sample from a soft stratum containing clay, when using the fixed orientation core sampling device disclosed in Patent Document 2, the tips of a plurality of shape probe needles sink into the stratum that becomes the core sample, There was a problem that the exact direction could not be known.

  Accordingly, the present invention provides a fixed-direction core sample sampling method, a fixed-direction core sample marking method, and a fixed direction capable of recognizing an accurate direction in a formation of a fixed-direction core sample sampled from the formation constituting the ground. It aims at providing a core recessed part formation apparatus.

  In order to solve the above-mentioned problem, according to the invention according to claim 1, there is provided a fixed orientation core sample sampling method for sampling a formation constituting the ground as a fixed orientation core sample, and a depth at which the formation reaches the formation on the ground. Forming a recess for identifying a first orientation in a portion of the formation exposed from the borehole that is off the center of the formation, and at least one of the recesses. And sampling the oriented core sample from the formation located below the borehole so that the portion remains. A method for sampling the oriented core sample is provided.

  According to the invention of claim 2, there is provided the fixed orientation core sample sampling method according to claim 1, wherein in the step of forming the recess, a hole having a cylindrical shape is formed as the recess. Is done.

  According to the invention of claim 3, in a state in plan view, a part of the inner wall of the hole is in contact with a part of the boring hole. A method is provided.

  According to the invention of claim 4, in the step of sampling the oriented core sample, by sampling the oriented core sample so as not to divide the recessed portion, the recessed core is sampled in the oriented core sample. 4. The method of sampling a fixed orientation core sample according to any one of claims 1 to 3, characterized in that all of the sample is left.

  According to the invention of claim 5, in the step of sampling the oriented core sample, the oriented core sample is sampled so as to divide a part of the recess, and the oriented core sample is formed. 4. The method of sampling a oriented core sample according to claim 1, wherein a notch is formed by leaving a part of the recess. 5.

  According to the invention of claim 6, in the step of sampling the oriented core sample, the oriented core sample is sampled in a state where the outer peripheral side surface of the oriented core sample is covered with the core sample containing tube. A fixed orientation core sample sampling method according to any one of claims 1 to 5 is provided.

  Moreover, according to the invention which concerns on Claim 7, with respect to the extension direction of the said fixed orientation core sample extract | collected by the fixed orientation core sample sampling method of any one of Claims 1 thru | or 6, A fixed orientation core sample marking method for marking the first orientation, the step of preparing a half member formed by halving a cylindrical member, and one of the ends of the half member, A step of marking a first mark on a portion located in the center of the half member, the concave portion remaining in the oriented core sample is disposed on one end side of the half member, and the half member Placing the fixed orientation core sample on the half member so that the inner surface of the fixed orientation core sample contacts the outer peripheral side surface of the fixed orientation core sample, and insertion inserted into the recess remaining in the fixed orientation core sample Part and the insertion part. And a disc portion covering an end face of the fixed orientation core sample located on one end side of the half member, and further, a second mark for identifying the first orientation on the disc portion, and Providing an orientation determining member on which a third mark for identifying a second orientation located on the opposite side of the first orientation is marked; the center of the recess remaining in the fixed orientation core sample; and Attaching the orientation determining member to the oriented core sample so that a virtual plane passing through the center of the oriented core sample passes through a straight line connecting the second mark and the third mark; By rotating the orientation determining member and the fixed orientation core sample integrally with respect to the half member, the first mark and the third mark are made to coincide with each other, whereby the second mark becomes A step of facing directly above, And a step of marking a straight line indicating the first orientation on the outer peripheral side surface of the fixed orientation core sample with respect to the extending direction of the fixed orientation core sample with reference to the mark of An orientation core sample marking method is provided.

  According to an eighth aspect of the present invention, the inner diameter of the cylindrical member serving as a base material of the half member is equal to the outer diameter of the structure including the fixed orientation core sample and the core sample storage tube. A fixed orientation core sample marking method according to claim 7 is provided.

  Moreover, according to the invention which concerns on Claim 9, in the process of mounting the said fixed orientation core sample, the inner surface of the said half member and the outer peripheral side surface of the said fixed orientation core sample are put through the said core sample storage tube. The method of claim 8, wherein the unidirectional core sample is placed on the half member so as to come into contact with the halved member.

  Moreover, according to the invention which concerns on Claim 10, the orientation core recessed part formation used after forming the drilling hole of the depth which reaches | attains this formation in the ground which has the formation containing the clay extract | collected as a fixed orientation core sample A first cylindrical member inserted into the boring hole and reaching the bottom surface of the boring hole; and an inner wall of the first cylindrical member, the center of the first cylindrical member A guide member including an opening portion disposed in a first orientation deviated from the rotation shaft, and a rotation shaft disposed in the first tubular member and guided by the guide member to be inserted into the opening portion. And cutting the formation that is connected to the upper end of the rotating shaft and rotates the rotating shaft, and connected to the lower end of the rotating shaft and serving as the fixed orientation core sample located below the opening. By doing so, a recess forming bead for forming a recess is formed. Oriented Core recess forming apparatus comprising: the bets, is provided.

  According to an eleventh aspect of the invention, the shape of the guide member is a tapered shape whose width becomes narrower from the upper end to the lower end of the first tubular member. The described oriented core recess forming device is provided.

  According to the invention concerning Claim 12, the said guide member is arrange | positioned in the lower end part of a said 1st cylindrical member, The fixed orientation core recessed part formation apparatus of Claim 10 or 11 provided Is done.

  Moreover, according to the invention which concerns on Claim 13, the said opening part is divided by the said guide member and the inner wall of a said 1st cylindrical member, Any of Claim 10 thru | or 12 characterized by the above-mentioned. A fixed orientation core recess forming apparatus according to claim 1 is provided.

  In addition, according to the invention of claim 14, the second cylindrical member that accommodates the first cylindrical member is provided with a gap interposed between the first cylindrical member and the first cylindrical member. A fixed orientation core recess forming device according to any one of claims 10 to 13 is provided.

  According to a fifteenth aspect of the present invention, the rotating shaft and the rotation driving unit are diverted from the rotating shaft and the rotation driving unit that constitute a boring hole forming device used when forming the boring hole. A fixed orientation core recess forming device according to any one of claims 10 to 14 is provided.

  Moreover, according to the invention which concerns on Claim 16, the said 2nd cylindrical member diverts the casing pipe for outer tubes of the said boring hole formation apparatus, The fixed orientation core recessed part of Claim 14 or 15 characterized by the above-mentioned. A forming apparatus is provided.

  According to the fixed-orientation core sample sampling method of the present invention, after forming a borehole having a depth reaching the formation in the ground, a portion of the formation exposed from the borehole is separated from the center of the formation. Including the step of forming a recess for specifying the orientation of 1 and the step of sampling the oriented core sample from the formation located below the borehole so that at least part of the recess remains. Even when the oriented core sample rotates when the oriented core sample is collected, a recess for identifying the first orientation of the oriented core sample in the formation remains in the oriented core sample. The exact orientation of the core sample at that time can be determined.

Schematic configuration of a boring device used in the formation before a recess is formed in the core sample collection region where the oriented core sample is collected and when the core sample collection region where the recess is formed is taken as the oriented core sample. FIG. It is sectional drawing of the BB line direction of the boring apparatus shown in FIG. It is sectional drawing which shows schematic structure of the fixed orientation core recessed part formation apparatus of this Embodiment. It is sectional drawing of the casing pipe (1st cylindrical member) which comprises the fixed orientation core recessed part formation apparatus shown in FIG. 3, a guide member, and the casing pipe for outer tubes. It is the top view which looked at the structure shown in FIG. It is the figure which expanded a part of outer peripheral side surface of a casing pipe. It is a top view which shows the other example of a guide member. It is sectional drawing (the 1) for demonstrating the fixed orientation core sample sampling method of this Embodiment. It is sectional drawing (the 2) for demonstrating the fixed orientation core sample sampling method of this Embodiment. It is sectional drawing (the 3) for demonstrating the fixed orientation core sample sampling method of this Embodiment. It is sectional drawing (the 4) for demonstrating the fixed orientation core sample sampling method of this Embodiment. It is sectional drawing (the 5) for demonstrating the fixed orientation core sample sampling method of this Embodiment, FIG.12 (a) is the outer peripheral side surface shown in FIG.12 (b) covered with the core sample accommodation tube. FIG. 12B is a cross-sectional view of the oriented core sample, and FIG. 12B is a plan view of the oriented core sample on the side where the notch is formed. It is sectional drawing (the 1) for demonstrating the fixed orientation core sample marking method of this Embodiment. It is sectional drawing (the 2) for demonstrating the fixed orientation core sample marking method of this Embodiment. It is sectional drawing (the 3) for demonstrating the fixed orientation core sample marking method of this Embodiment. It is sectional drawing (the 4) for demonstrating the fixed orientation core sample marking method of this Embodiment. It is sectional drawing which shows schematic structure of the general geological sampling apparatus which has a double tube | pipe type fixed shaft.

(Embodiment)
FIG. 1 shows a boring used before a concave portion is formed in a core sample collection region where a fixed orientation core sample is collected and when a core sample collection region with a concave portion is collected as a fixed orientation core sample. It is sectional drawing which shows schematic structure of an apparatus.
A shown in FIG. 1 indicates a region containing clay and where a fixed-orientation core sample is collected (hereinafter referred to as “core sample collection region A”). Further, FIG. 1 schematically shows a state in which the boring hole 28 is formed up to just above the core sample collection region A.
2 is a cross-sectional view of the boring apparatus shown in FIG. 1 in the BB line direction. 2, the same components as those of the boring apparatus 10 shown in FIG.

  First, referring to FIG. 1 and FIG. 2, a recess 52 (see FIG. 10) is formed in the core sample collection region A in which the oriented core sample 65 (see FIG. 12 (a)) is collected in the formation 11. The configuration of the boring apparatus 10 used when collecting the core sample collection area A in which the front and the recess 52 are formed will be described.

The boring apparatus 10 removes the oriented core sample 65 from the geological layer 11 including a pulverized portion and a seam (laminated structure in which clay is sandwiched) constituting a fault fracture zone existing at a depth of several m to several tens of m below the ground surface. A boring device 10 which is a device for sampling includes a support 12, a rotation drive unit 15, a casing pipe 17 for an outer tube, an inner tube 19, a rotating shaft 22, a bit 24, a lifting and lowering device (see FIG. (Not shown).

The support 12 has a rotation drive unit support 12A and a leg 12B. The rotation drive unit support unit 12 </ b> A is a member for supporting the rotation drive unit 15. The rotation drive unit support unit 12A is disposed above the ground surface 11a so as to face the core sample collection region A.
The leg 12B is a member for supporting the rotation drive unit support 12A in a state where the rotation drive unit support 12A is floated above the ground surface 11a.

  The rotation drive unit 15 includes a rotation shaft attachment unit 26. The rotation drive unit 15 is supported by the rotation drive unit support unit 12A so that the rotation shaft attachment unit 26 faces the core sample collection region A. As the rotation drive unit 15, for example, a motor can be used.

The outer pipe casing pipe 17 is supported by the support 12. The outer pipe casing pipe 17 is a cylindrical pipe. In the case of FIG. 1, the tip of the outer pipe casing pipe 17 reaches the bottom of the boring hole 28.
If the diameter is to be collected (Fig. 12 (a) see to be described later) the oriented core samples 65 which is a 88mm, inner diameter _{R 1} of the outer tube casing pipe 17 can be, for example, to 130 mm. In this case, the outer diameter _{R 2} of the outer tube casing pipe 17 can be, for example, to 140 mm.

The inner tube 19 is a pipe that is used when the bored hole 28 is formed and when the oriented core sample 65 (see FIG. 12A) is collected after the recess 52 (see FIG. 10) described later is formed.
The shape of the inner tube 19 is a cylindrical shape. On the inner peripheral surface of the inner tube 19, a core sample storage tube for preventing the fixed-oriented core sample 65 from collapsing by covering the outer peripheral side surface of the fixed-oriented core sample 65 when collecting the fixed-oriented core sample 65. 31 (core pack) is arranged.

In the case of FIG. 1, the inner tube 19 reaches the bottom surface 28 a of the boring hole 28. In the case of collecting the oriented core sample 65 having a diameter of 88 mm, the inner diameter R ₃ of the inner tube 19 can be set to 88 mm, for example. In this case, the outer diameter _{R 4} of the inner tube 19, for example, be 116 mm.

One end of the rotation shaft 22 is connected to the rotation shaft attachment portion 26, and the other end is connected to the upper end of the inner tube 19. Thereby, the rotating shaft 22 rotates the inner tube 19 when being rotated by the rotation driving unit 15.
The rotary shaft 22 has a pipe line (not shown) for supplying water toward the tip of the inner pipe 19 therein. The water supplied through the pipe line is collected in a collection pond (not shown) formed on the ground surface 11a through a gap between the inner pipe 19 and the outer pipe casing pipe 17, and again, It is supplied into the tube 19.
Outer diameter _{R 5} of the rotary shaft 22, for example, can be set to 40 mm.

The bit 24 is disposed at the tip of the inner tube 19. When the inner tube 19 is rotated, the bit 24 rotates with the inner tube 19 to cut the formation 11.
The lifting and lowering device (not shown) is a machine for lowering or lifting the outer pipe casing pipe 17 and the inner pipe 19 with respect to the vertical direction.

FIG. 3 is a cross-sectional view showing a schematic configuration of the oriented core recess forming apparatus of the present embodiment. In FIG. 3, the same components as those in the structure shown in FIG.
4 is a cross-sectional view of a casing pipe (first cylindrical member), a guide member, and a casing pipe for an outer pipe that constitute the fixed-orientation core recess forming apparatus shown in FIG. In FIG. 4, the same reference numerals are given to the same components as those in the fixed orientation core recess forming apparatus 40 shown in FIG. 3.
5 is a plan view of the structure shown in FIG. In FIG. 5, the same components as those shown in FIGS. 2 and 4 are denoted by the same reference numerals.

  Referring to FIGS. 3 to 5, the fixed-orientation core recess forming apparatus 40 is a recess for specifying a first orientation (for example, north) in a core sample collection region A in which a core sample is collected in the formation. 52 (see FIG. 10) is an apparatus used to form the support 12, the rotation drive unit 15, the outer pipe casing pipe 17 (second cylindrical member), the rotary shaft 22, and the casing pipe. 41 (first cylindrical member), a guide portion 43, and a recess forming bit 46.

That is, the concave portion 52 (see FIG. 10) for specifying the first orientation (for example, “north”) is formed in the core sample collection region A from which the fixed orientation core sample 65 (see FIG. 12A) is collected. The fixed-orientation core recess forming apparatus 40 is configured such that the support 12, the rotation drive unit 15, the outer pipe casing pipe 17, and the rotation shaft 22 that constitute the boring apparatus 10 shown in FIG. 1 can be used.
For this reason, the cost (cost) required for collection of the oriented core sample 65 can be reduced as compared with the case where a separate oriented core recess forming device in which all components are different from the boring device 10 is prepared.

The casing pipe 41 is accommodated in the outer pipe casing pipe 17 and functions as an inner pipe. The casing pipe 41 has a cylindrical shape. The center C ₁ of the casing pipe 41 coincides with the center of the outer pipe casing pipe 17.
If the diameter as the core sample is taken core samples of 88mm, inner diameter _{R 6} of the casing pipe 41 can be, for example, to 100 mm. At this time, the outer diameter _{R 7} of the casing pipe 41 may be a 115 mm.

  FIG. 6 is an enlarged view of a part of the outer peripheral side surface of the casing pipe. In FIG. 6, the same components as those of the structure shown in FIG.

5 and 6, the casing pipe 41 has a configuration in which a plurality of pipes (only the pipes 41-1 and 41-2 are illustrated in FIG. 6) are connected.
Of the pipes 41-1 and 41-2, one pipe functions as a female thread, and the other pipe functions as a male thread.
On the outer peripheral side surfaces of the pipes 41-1 and 41-2, linear scratches 48 extending in the extending direction of the pipes 41-1 and 41-2 are formed. The pipes 41-1 and 41-2 are connected so that the scratches 48 become one straight line.

In the state (state in which E view of the structure shown in FIG. 4) shown in FIG. 5, wound 48, a vicinity of the opening 43A, and the center line of the center line C ₂ and the casing pipe 41 of the opening 43A C ₁ is arranged at a position facing ₁ .
The flaw 48 is a mark for adjusting the position of the casing pipe 41 so that the flaw 48 faces a first direction (for example, “north”) when the casing pipe 41 is disposed in the boring hole 28.

  Thus, the casing pipe 41 is bored by forming the straight scratches 48 extending in the extending direction of the pipes 41-1 and 41-2 on the outer peripheral side surfaces of the pipes 41-1 and 41-2. The position of the casing pipe 41 is adjusted so that the scratch 48 faces a first orientation (for example, north) when placed in the inner space 28 (in other words, the opening 43B is oriented so that the opening 43B faces the first orientation). The direction of the portion 43B can be adjusted).

  Three markings 49 are formed on the scratch 48 located at the end connected to the pipe 41-2 among the both ends of the pipe 41-1. In addition, three markings 49 are formed on the scratch 48 located at the end connected to the pipe 41-1 among the both ends of the pipe 41-2.

In this way, scratches formed on the pipes to be connected by forming various types of markings on both ends of the plurality of pipes constituting the casing pipe 41 and connecting the ends of the pipes of the same type to each other. 48 positions can be matched.
Thereby, the direction of the opening 43B can be accurately adjusted so that the opening 43B faces the first direction.

3 to 5, the guide portion 43 is provided on the inner wall of the casing pipe 41. Guide portion 43, a first orientation (in this case, "the north") offset from the center line C ₁ of the casing pipe 41 has an opening 43A on.

The shape of the guide member 43 is a tapered shape whose width becomes narrower from the upper end of the casing pipe 41 toward the lower end of the casing pipe 41.
Therefore, when the recess forming bit 46 disposed at the tip (lower end) of the rotating shaft 22 is brought into contact with the guide member 43, the recess forming bit 46 disposed at the leading end of the rotating shaft 22 is opened 43A. The lower end of the rotating shaft 22 is inserted into the opening 43A.
Thereby, the recess forming bit 46 is disposed below the opening 43A, and the position thereof is regulated from the start of the formation of the recess to the end of the formation of the recess 52 (see FIG. 10).

The shape of the opening 43A can be, for example, a cylindrical shape. If the inside diameter _{R 6} of the casing pipe 41 is 100 mm, the diameter _{R 8} of the opening portion 43A, for example, it can be set to 45 mm.

  The guide member 43 may be disposed at the lower end portion of the casing pipe 41. Thereby, when the recessed part formation bit 46 rotates and the formation 11 is cut, it can suppress that the recessed part formation bit 46 moves to a horizontal direction. Thereby, the recessed part 52 can be reliably formed in the 1st direction of the core sample collection area | region A. FIG.

Further, as shown in FIG. 5, the opening 43 </ b> A may be partitioned by the guide member 43 and the inner wall of the casing pipe 41.
Thus, an opening 43A of the rotary shaft 22 is inserted, by partitioning in the inner wall of the guide member 43 and the casing pipe 41, a recess 52 in the farthest position from the center line C ₁ of the casing pipe 41 Therefore, when the fixed orientation core sample 65 (see FIG. 12A) is collected, the orientation of the fixed orientation core sample 65 can be easily specified.

  FIG. 7 is a plan view showing another example of the guide member. In FIG. 7, the same components as those of the structure shown in FIG.

Instead of the guide member 43 shown in FIG. 5, a guide member 55 shown in FIG. 7 may be used. The guide member 55 is configured in the same manner as the guide member 43 except that the outer peripheral portion of the opening 43 is partitioned only by the guide member.
In this case, in a plan view state (the state shown in FIG. 7), at the opening 43A only needs spaced apart and the center line C ₂ of the center line C ₁ and the opening 43A of the casing pipe 41 is in the formation 11 orientation from the viewpoint of accurately obtaining the constant azimuth core samples 65 (see FIG. 12 (a)), it is preferable to possible separating the center line C ₁ and the center line C _2.

The recess forming bit 46 is connected to the lower end of the rotating shaft 22. The recess forming bit 46 is configured to be movable in the vertical direction. When the rotating shaft 22 rotates, the recess forming bit 46 rotates to cut the formation 11 that becomes the fixed orientation core sample 65 located below the opening 43A, thereby forming the recess 52.
The diameter of the recess forming bit 46 can be set to 42 mm, for example.

According to the orientation-oriented core recess forming apparatus of the present embodiment, the orientation-oriented core recess 65 is inserted into the borehole 28 having a depth reaching the formation 11 containing clay collected as the orientation-oriented core sample 65 (see FIG. 12A). , casing pipe 41 to reach the bottom surface 28a of the borehole 28 (first tubular member), provided on the inner wall of the casing pipe 41 is disposed in a first orientation offset from the center line C ₁ of the casing pipe 41 The guide member 43 including the opening 43A and the casing pipe 41 are arranged and guided by the guide member 43 so that the rotary shaft 22 inserted into the opening 43A and the upper end of the rotary shaft 22 are connected to rotate. The stratum 11 (core sample collection region A), which is connected to the rotation drive unit 15 that rotates the shaft 22 and the lower end of the rotation shaft 22 and is the fixed orientation core sample 65 located below the opening 43A, By having the recess forming bit 46 that forms the recess 52 (see FIG. 10) by cutting, the recess 52 is formed in the core sample collection area A, and then the fixed orientation core sample 65 is collected. Even when the orientation core sample 65 rotates, it is possible to collect the fixed orientation core sample 65 in which at least a part of the recess 52 for specifying the first orientation remains. An accurate orientation of the fixed orientation core sample 65 can be obtained.

  8 to 12 are cross-sectional views for explaining the method of sampling the oriented core sample according to the present embodiment. 8-12, the same code | symbol is attached | subjected to the same component as the structure shown in FIGS. 1-5.

Next, with reference mainly to FIG. 8 to FIG. 12, the method of sampling the oriented core sample according to the present embodiment will be described. Here, in order to clarify the directionality of the clay-containing layer 56 (also referred to as “seam”) in which clay is sandwiched, a case where the oriented core sample 65 is collected will be described.
A case where the oriented core sample 65 is collected so as to include the clay-containing layer 56 having an inclination angle of about 10 degrees and a thickness of about several centimeters will be described.

First, in the process shown in FIG. 8, the boring apparatus 10 shown in FIG. 1 is assembled on the ground surface 11 a located above the core sample collection region A of the formation 11. At this time, it arrange | positions so that the rotating shaft attaching part 26 of the rotation drive part 15 may oppose the core sample collection area | region A. FIG.
Next, the formation 11 is dug by a well-known method using the boring device 10 until the upper surface of the core sample collection region A is exposed. Thereby, the boring hole 28 is formed.
At this time, the depth of the boring hole 28 is formed as a shallow hole of several m to several tens m with reference to the ground surface 11a. Moreover, the opening diameter of the boring hole 28 can be 116 mm, for example.

Next, in the step shown in FIG. 9, the oriented core recess forming device 40 shown in FIG. 3 is assembled on the ground surface 11 a located above the core sample collection region A of the formation 11. At this time, it arrange | positions so that the rotating shaft attaching part 26 of the rotation drive part 15 may oppose the core sample collection area | region A. FIG.
Further, the direction of the casing pipe 41 is adjusted so that the scratch 48 (see FIG. 5) of the casing pipe 41 described above faces the north side. Thus, the opening 43A can be reliably arranged on the north side of the core sample collection region A by adjusting the direction of the casing pipe 41 with high accuracy.

After the adjustment of the orientation of the casing pipe 41 is completed, the recess forming bit 46 is disposed on the bottom 28a of the boring hole 28 through the opening 43A.
Then, the recess-forming bits 46 to rotate, by cutting a portion of the upper end of the core sampling region A deviates from the center C ₃ of the bottom surface 28a of the borehole 28, at least part of the core sampling area A A recess 52 for specifying the first orientation (in the present embodiment, “north” as an example) is formed.

When the shape of the recess forming bit 46 is a cylindrical shape, a hole 61 having a cylindrical shape is formed as the recess 52.
In this case, the hole 61 may be formed so that a part of the inner wall of the hole 61 is in contact with a part of the boring hole 28 in a plan view.
Thereby, it becomes possible to form the notch 66 for specifying the first orientation in the fixed orientation core sample 65 collected in the steps shown in FIGS. 11 and 12 described later. Thereby, it is possible to easily specify the first orientation of the fixed orientation core sample 65.

As described above, the fixed core recess forming device 40 has a configuration in which the support 12, the rotation driving unit 15, the outer pipe casing pipe 17, and the rotating shaft 22 constituting the boring device 10 shown in FIG. 1 are diverted. Has been.
For this reason, the cost (cost) required for collection of the oriented core sample 65 can be reduced as compared with the case where a separate oriented core recess forming device in which all components are different from the boring device 10 is prepared.

Next, in the step shown in FIG. 10, the rotating shaft 22 and the casing pipe 41 shown in FIG. 9 are pulled up to the ground surface 11a. In FIG. 10, the support body 12, the rotation drive device 15, the outer pipe casing pipe 17, and the rotation shaft 22 shown in FIG. 9 are omitted so that the outer shape of the boring hole 28 and the recess 52 can be easily understood. When collecting the fixed orientation core sample 65 (see FIG. 12A), the support 12, the rotary drive device 15, the outer pipe casing pipe 17, and the rotary shaft 22 shown in FIG. An operation of assembling the casing pipe 41 provided with the guide member 43 constituting the orientation core recess forming device 40 and the recess forming bit 46 is performed.
Thereby, compared with the case where the fixed orientation core recessed part formation apparatus from which all the components differ from the boring apparatus 10 is prepared, work efficiency can be improved.

Here, the shape and size of the recess 52 will be described. The shape of the recess 52 is not limited to a cylindrical shape, and may be any shape.
When the diameter of the oriented core sample 65 (in other words, the core sample collection region A) is 88 mm, the length of the oriented core sample 65 is 1 to 2 m, and the shape of the recess 52 is a cylindrical shape, the diameter of the recess 52 R ₉ can be 88 mm, for example. In this case, the depth D of the recess 52 can be appropriately set within a range of 50 to 150 mm, for example.

  FIG. 10 schematically shows a case where a part of the recess 52 is formed outside the core sample collection region A as an example of the location where the recess 52 is formed.

In the process shown in FIG. 10, the guide member 55 shown in FIG. 7 is used instead of the guide member 43 shown in FIG. 9, so that it does not protrude from the core sample collection area A. The recess 52 may be formed only on the surface.
In this case, all of the concave portions 52 remain at the upper end portion of the sampled oriented core sample 65.

  Next, in the step shown in FIG. 11, the boring device 10 is arranged in the boring hole 28 and above the boring hole 28. At this time, the front end of the outer pipe casing pipe 17 is brought into contact with the bottom surface 28a of the boring hole 28 shown in FIG. At this stage, the inner peripheral side surface of the inner tube 19 is covered with the core sample storage tube 31.

  Next, the oriented core sample 65 is cut out by cutting the formation 11 positioned around the core sample collection region A with the bit 24 arranged at the tip of the rotating inner tube 19. At this time, the oriented core sample 65 is cut out while the formation 11 corresponding to the core sample collection region A cut by the bit 24 is covered with the core sample storage tube 31. For this reason, the outer peripheral side surface of the oriented core sample 65 is covered with the core sample storage tube 31.

  In this way, by covering the outer peripheral side surface of the oriented core sample 65 with the core sample containing tube 31, the brittle oriented core including the clay-containing layer 56, which is taken out from the inner tube 19 in the step shown in FIG. It can suppress that sample 65 collapses.

Further, as shown in FIG. 10, a part of the recess 52 (in the case of the present embodiment, the hole 61) is disposed outside the core sample collection region A. For this reason, in the step shown in FIG. 11, the oriented core sample 65 is sampled so as to divide a part of the recess 52.
Accordingly, a part of the recess 52 shown in FIG. 10 remains in the upper end portion of the fixed orientation core sample 65, so that a notch for specifying the first orientation is formed in the upper end portion of the fixed orientation core sample 65. A portion 66 (in other words, a recess 52 (see FIG. 10) remaining in the oriented core sample 65) is formed (see FIGS. 12A and 12B described later).

  Thus, by forming the notch portion 66 for specifying the first orientation at the upper end portion of the fixed orientation core sample 65, the first orientation for specifying the first orientation at the upper end portion of the fixed orientation core sample 65 is determined. Compared with the case where all the recesses 52 remain, the center of the bore hole 28 and the center of the recess 52 can be arranged farthest from each other, and the recess 52 has a center opposite to the center of the bore hole 28. Since it becomes possible to form the notch part 66, the specific precision of a 1st direction can be improved.

  Next, in the steps shown in FIGS. 12A and 12B, the inner tube 19 that accommodates the oriented core sample 65 collected in the step shown in FIG. 11 is pulled up to the ground, and the oriented core sample 65 is removed from the inner tube 19. Take out. At this stage, the outer peripheral side surface of the oriented core sample 65 is covered with the core sample storage tube 31.

According to the fixed orientation core sample sampling method of the present embodiment, the formation 11 exposed from the borehole 28 after forming the borehole 28 having a depth reaching the formation 11 including the clay-containing layer 56 constituting the ground. among the steps of forming a recess 52 for identifying a first orientation in a part off the center C ₃ geological 11, such that a portion of the recess 52 remains, located below the borehole 28 A step of forming a notch 66 at the upper end of the fixed-orientation core sample 65 by sampling the fixed-orientation core sample 65 from the formation 11 to be formed, and then forming the recess 52 in the core sample collection region A. Even when the oriented core sample 65 rotates when the oriented core sample 65 is collected, it is possible to collect the oriented core sample 65 in which a part of the recess 52 for specifying the first orientation remains. And Therefore, the exact orientation of the fixed orientation core sample 65 when in the formation 11 can be specified.

  In the present embodiment, as an example, the case where the oriented core sample 65 is sampled from the formation 11 located below the boring hole 28 so that a part of the recess 52 remains is described as an example. For example, the oriented core sample 65 may be sampled from the formation 11 located below the boring hole 28 so that the entire recess 52 remains.

  That is, in this embodiment, in the step of sampling the oriented core sample 65, the oriented core sample 65 is sampled from the formation 11 located below the borehole 28 so that at least a part of the recess 52 remains. That's fine.

  FIG. 13 to FIG. 16 are cross-sectional views for explaining the fixed orientation core sample marking method of the present embodiment. 13 to 16, the same components as those shown in FIGS. 12A and 12B are denoted by the same reference numerals.

Next, with reference mainly to FIGS. 13 to 16, the fixed orientation core sample marking method of the present embodiment will be described. In addition, the process shown in FIG. 13 is a process processed after the process shown in FIG.
First, in the step shown in FIG. 13, a half member 71 formed by dividing a cylindrical member is prepared. At this time, as the cylindrical member (not shown) serving as a base material of the half member 71, a member whose inner diameter is equal to the outer diameter of the structure composed of the fixed orientation core sample 65 and the core sample storage tube 31 is used. Good.
As a result, the gap between the core sample storage tube 31 and the cut part of the half member 71 is reduced, so that it is possible to mark an accurate orientation with respect to the extending direction of the fixed orientation core sample 65. It becomes.

  As a material of the cylindrical member (not shown) and the half member 71, for example, vinyl chloride can be used. When vinyl chloride is used as the material of the half member 71 and the diameter of the oriented core sample 65 is 88 mm, the thickness of the half member 71 can be set to, for example, 5.0 to 10.0 mm.

  Next, the half member 71 is placed on the upper surface of the work table (not shown) so that the cut surface of the half member 71 is parallel to the upper surface of the work table (not shown). Then, the position of the half member 71 is regulated by sandwiching the half member 71 with a plurality of blocks 73 from the direction orthogonal to the extending direction of the half member 71.

Then, among the one end 71A of the half member 71, the portion located in the center of the half member 71, to mark the first mark G _1. The first marking mark G _1, for example, may be used permanent marker.

Next, the halved member 71 has a fixed orientation so that the inner surface of the halved member 71 whose position is regulated by the plurality of blocks 73 and the outer peripheral side surface of the fixed-oriented core sample 65 are in contact with each other via the core sample storage tube 31. The core sample 65 is placed.
At this time, the notch 66 (in other words, the recess 52 (see FIG. 10) remaining in the fixed orientation core sample 65) is arranged on the one end 71A side of the half member 71.
Thereafter, the notched portion 66 and the core sample storage tube 31 disposed around the notched portion 66 are peeled off to expose the outer peripheral side surface of the fixed orientation core sample 65 located around the notched portion 66.

Next, the insertion portion 76 to be inserted into the notch portion 66 (in other words, the concave portion 52 (see FIG. 10) remaining in the fixed orientation core sample 65), and one of the half members 71 are integrated with the insertion portion 76. The disc portion 78 that covers the end face 65a of the fixed orientation core sample 65 located on the end 71A side of the disc 71, and further for specifying the first orientation (“north” in the case of the present embodiment) in the disc portion 78. Direction in which the third mark G ₃ for identifying the second mark G ₂ and the second direction (in this embodiment, “south”) located on the opposite side of the first direction is marked The determination member 75 is prepared.
The orientation determining member 75, the straight line L connecting the second mark G ₂ and the third mark G ₃ are marked. As a material of the orientation determining member 75, for example, wood, vinyl chloride, or metal can be used.

Although it is difficult to understand in FIG. 13, the second and third marks G ₂ and G ₃ are marked on the circular surface of the disk part 78 on the side to which the insertion part 76 is not connected and the side surface of the disk part 78. Yes. The second and third marks G ₂ and G ₃ can be marked using, for example, an oily magic.

Next, in the process shown in FIG. 14, the virtual plane passing through the center of the notch 66 formed in the oriented core sample 65 and the center of the oriented core sample 66 is the second mark G ₂ and the third mark. so as to pass through the straight line L connecting the G _2, thereby attaching the orientation determining member 75 in a fixed orientation core samples 65.
At this stage, a mark H indicating the first orientation is written on the fixed orientation core sample 65.

Next, in the step shown in FIG. 15, the orientation determining member 75 and the fixed orientation core sample 65 are integrally rotated with respect to the half member 71, and the first mark G ₁ and the third mark G ₃ are changed. by matching, the second mark G ₂ is to face directly above.

Then, on the core sample receiving tube 31 which is exposed from the half member 71, a core sample holding corresponds to the outer shape of the tube 31, and a fourth mark G ₄ is centering half member 81 which is marked in the intermediate position Place.
Next, the straight line L, the second to fourth marks G _{2 to} G ₄ , and the right angle ruler 83 are used to ensure that the second mark G ₂ faces directly above.

Then, in a step shown in FIG. 16, while peeling off the core sample receiving tube 31 which covers the constant azimuth core samples 65 shown in FIG. 15, based on the second mark G _2, with respect to the extending direction of the oriented core samples 65 Then, a straight line J indicating the first orientation is marked on the outer peripheral side surface of the fixed orientation core sample 65.
Although not shown in the figure, the oriented core sample 65 marked with the straight line J is cut at a necessary portion (for example, shown in FIG. 12A), and a geological inspection of the cut portion is performed.

As described above, the orientation core sample marking method according to the present embodiment uses a orientation core sample sampling method shown in FIGS. 8 to 12 to collect a orientation core sample 65, and then attaches a cylindrical member (not shown). marking preparing a half member 71 which is formed by halves, of the one end 71A of the half member 71, the portion located in the center of the half member 71, the first mark G ₁ A notch portion 66 of the oriented core sample 65 is disposed on one end 71A side of the half member, and the inner surface of the half member 71 and the oriented core sample 65 are disposed via the core sample storage tube 31. A step of placing the oriented core sample 65 on the halved member 71 so that the outer peripheral side surface of the inserted member is in contact with each other, an insertion portion 76 inserted into the notched portion 66 of the oriented core sample 65, and the insertion portion 76; Of the half member 71 It has a disk part 78 covering the end face 65a of the fixed orientation core sample 65 located on the one end 71A side, and further, the second mark G ₂ for specifying the first direction on the disk part 78, and the first mark preparing a third orientation determining member 75 which mark G ₃ is marking for identifying the second orientation opposite the orientation, the center and the constant of the notch 66 of the oriented core samples 65 as imaginary plane passing through the center of the azimuth core samples 65 passes through the straight line L connecting the second mark G ₂ and the third mark G _3, mounting the orientation determining member 75 in a fixed orientation core samples 65 a step for half member 71, the orientation determining member 75 and the oriented core samples 65 rotate integrally, by matching the first mark G ₁ and the third mark G _3, the a step of second mark G ₂ is to face directly above, the As a reference mark G ₂ of, with respect to the extending direction of the oriented core samples 65, the outer peripheral side surface of the oriented core samples 65, a step of marking a straight line J that indicates the first orientation, the.

  Thereby, the exact azimuth | direction in the formation 11 of the fixed orientation core sample 65 sampled from the formation containing clay can be recognized easily, without depending on an operator's skill level.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Deformation / change is possible.

In the present embodiment, the case where one guide member 43 is provided at the lower end portion of the casing pipe 41 has been described as an example, but not only the lower end portion of the casing pipe 41 but also the central portion of the casing pipe 41. May also be arranged.
Thus, by arranging the guide member 43 also in the central portion of the casing pipe 41, the guide member 43 can reduce the swing of the central portion of the rotating rotating shaft 22. Thereby, since the swinging of the recess forming bit 46 arranged at the tip (lower end) of the rotating shaft 22 is reduced, the positional accuracy of the recess 52 formed by the recess forming bit 46 can be improved.

  In this embodiment, the case where “north” is used as an example of “first orientation” has been described as an example. However, an orientation other than north may be used as the first orientation. Even in this case, the same effect as the present embodiment can be obtained.

  The present invention is a fixed orientation core sample sampling method, a fixed orientation core sample marking method, and a fixed orientation core sample marking method capable of recognizing an accurate orientation in a formation of a fixed orientation core sample sampled from a clay-containing formation among the formations constituting the ground, and The present invention is applicable to a fixed orientation core recess forming apparatus.

DESCRIPTION OF SYMBOLS 10 ... Boring apparatus, 11 ... Geologic formation, 11a ... Ground surface, 12 ... Support body, 12A ... Rotation drive part support part, 12B ... Leg part, 15 ... Rotation drive part, 17 ... Casing pipe for outer pipes, 19 ... Inner pipe, 22 DESCRIPTION OF SYMBOLS ... Rotating shaft, 24 ... Bit, 26 ... Rotating shaft attaching part, 28 ... Boring hole, 28a ... Bottom surface, 31 ... Core sample accommodation tube, 40 ... Unidirectional core recessed part formation apparatus, 41 ... Casing pipe, 41-1, 41 -2 ... pipe, 43, 55 ... guide member, 43A ... opening, 46 ... recess forming bit, 48 ... scratch, 49 ... engraving, 52 ... recess, 56 ... clay-containing layer, 61 ... hole, 65 ... fixed orientation core samples, 65a ... end surface, 66 ... notch, 71 ... half member, 71A ... end 73 ... block, 76 ... insertion portion, 78 ... disc part, A ... core sampling _region, C 1, _{C 2} ... center line, C 3 _... center line G 1 _... first mark, G 2 _... second mark, G 3 _... third mark, G 4 _... fourth mark, H ... Mark, L, J ... _{linear, R 1, R 3, R} 6 ... inner diameter, R ₂ , R ₄ , R ₅ , R ₇ ... outer diameter, R ₈ , R ₉ ... diameter

Claims (16)

A azimuth core sample sampling method for sampling a stratum constituting a ground as a unidirectional core sample,
After forming a borehole having a depth reaching the formation in the ground, a recess for specifying a first orientation is formed in a part of the formation exposed from the borehole that is off the center of the formation. Forming, and
Sampling the oriented core sample from the formation located below the borehole so that at least a portion of the recess remains.
A method of sampling a oriented core sample characterized by comprising:   The method according to claim 1, wherein in the step of forming the concave portion, a hole having a cylindrical shape is formed as the concave portion.   3. The method of sampling a azimuthal core sample according to claim 2, wherein a part of the inner wall of the hole is in contact with a part of the boring hole in a plan view.   The sampling of the oriented core sample comprises sampling the oriented core sample so as not to divide the recessed portion, whereby all the recessed portions remain in the oriented core sample. 4. The method of sampling a fixed orientation core sample according to any one of items 3 to 3.   In the step of sampling the oriented core sample, the oriented core sample is sampled so as to divide a part of the recess, and a part of the recessed part is left in the oriented core sample, thereby cutting the oriented core sample. 4. The method of sampling a oriented core sample according to claim 1, wherein a notch is formed.   6. The step of sampling the oriented core sample, wherein the oriented core sample is sampled in a state where an outer peripheral side surface of the oriented core sample is covered with a core sample containing tube. Among them, the method of sampling a unidirectional core sample according to any one of the above. 7. A fixed orientation core sample, wherein the first orientation is marked with respect to an extending direction of the fixed orientation core sample collected by the fixed orientation core sample sampling method according to any one of claims 1 to 6. A marking method,
Preparing a halved member formed by halving the cylindrical member;
Marking a first mark on a portion of one end of the half member located at the center of the half member;
The half portion is arranged such that the concave portion remaining in the oriented core sample is disposed on one end side of the half member, and the inner surface of the half oriented member and the outer peripheral side surface of the oriented core sample are in contact with each other. Placing the fixed orientation core sample on a member;
An insertion part inserted into the recess remaining in the fixed-orientation core sample, and a disk part integrated with the insertion part and covering an end surface of the fixed-orientation core sample located on one end side of the half member And a second mark for specifying the first orientation on the disk portion, and a third mark for specifying a second orientation located on the opposite side of the first orientation. Preparing a marked orientation determining member;
The fixed plane is such that an imaginary plane passing through the center of the concave portion remaining in the oriented core sample and the center of the oriented core sample passes through a straight line connecting the second mark and the third mark. Attaching the orientation determining member to the orientation core sample;
By rotating the orientation determining member and the fixed orientation core sample integrally with respect to the half member, the first mark and the third mark are made to coincide with each other, whereby the second mark becomes A process of facing directly above,
Marking a straight line indicating the first orientation on the outer peripheral side surface of the fixed orientation core sample with respect to the extending direction of the fixed orientation core sample with respect to the second mark;
A method of marking a oriented core sample characterized by comprising:   8. The oriented core sample marking according to claim 7, wherein an inner diameter of the cylindrical member serving as a base material of the half member is equal to an outer diameter of a structure including the oriented core sample and the core sample containing tube. Method.   In the step of placing the fixed orientation core sample, the fixed member is placed on the half member so that the inner surface of the half member and the outer peripheral side surface of the fixed core sample are in contact with each other via the core sample storage tube. 9. The method of marking a oriented core sample according to claim 8, wherein the oriented core sample is placed. A fixed-orientation core recess forming apparatus that is used after forming a borehole having a depth reaching the formation in the ground having a formation containing clay collected as a fixed-oriented core sample,
A first cylindrical member inserted into the boring hole and reaching the bottom surface of the boring hole;
A guide member including an opening provided on an inner wall of the first tubular member and disposed in a first orientation shifted from the center of the first tubular member;
A rotation shaft that is disposed in the first tubular member and is guided by the guide member, and is inserted into the opening;
A rotation drive unit that is connected to an upper end of the rotation shaft and rotates the rotation shaft;
A recess forming bit that forms a recess by cutting the formation, which is connected to the lower end of the rotating shaft and is the fixed orientation core sample located below the opening,
A fixed orientation core recess forming device characterized by comprising:   The fixed orientation core recess forming device according to claim 10, wherein the shape of the guide member is a tapered shape whose width becomes narrower from the upper end to the lower end of the first cylindrical member.   The fixed orientation core recess forming device according to claim 10 or 11, wherein the guide member is arranged at a lower end portion of the first cylindrical member.   The fixed orientation core recess forming apparatus according to any one of claims 10 to 12, wherein the opening is defined by the guide member and an inner wall of the first cylindrical member.   The second cylindrical member that accommodates the first cylindrical member in a state where a gap is interposed between the first cylindrical member and the first cylindrical member. The fixed orientation core recessed part formation apparatus of any one of Claims.   15. The rotating shaft and the rotation driving unit are diverted from a rotating shaft and a rotation driving unit that constitute a boring hole forming device used when forming the boring hole. 2. A fixed orientation core recess forming apparatus according to claim 1.   16. The fixed orientation core recess forming device according to claim 14, wherein the second cylindrical member is a casing pipe for an outer tube of the boring hole forming device.

Images