JP3250433B2 - Photographing Collapsed Ground Using Borehole Camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for photographing an internal state of a ground which is easily collapsed.

[0002]

2. Description of the Related Art In order to photograph the internal state of a ground that is not collapsible, conventionally, a cavity is provided in a target ground by boring or the like, and the inside is photographed and recorded with a small camera.
An analysis has been done. Japanese Patent Publication No. 7-15383 discloses a photographing apparatus using a borehole camera having the structure shown in FIG.

As shown in FIG. 1, the borehole camera 5 has a side photographing section 51 formed at the top of a cylindrical main body, and the side photographing section 51 has a camera having a field of view in the long axis direction. 52, a cone-shaped reflecting mirror 53 whose vertex is directed toward the camera in the field of view of the camera 52, and an illumination 54 for illuminating the side direction, and a hole wall that moves to the reflecting mirror 53 is provided by the camera 52.
To obtain an annular unit image.

If the borehole camera 5 is moved in the axial direction within the hole and the hole wall is photographed and recorded, an annular unit image is continuously obtained as a concentric or cylindrical hole wall image. This cylindrical image can be developed into a planar image by the image processing device.

[0005]

The method for investigating the state of the ground by the borehole camera as described above is a good method that can be visually confirmed. In particular, the ground that needs to be investigated before construction is a collapsed ground such as a fault or shatter zone. However, in the case of such collapsed ground,
Even if a borehole is provided by boring or the like and a borehole camera is to be inserted, the hole wall collapses, and there is a problem that it becomes impossible to photograph the ground with the borehole camera. As described above, the conventional method of photographing the ground with a borehole camera has a problem that it is difficult to utilize the ground on a ground that requires special investigation.

Accordingly, an object of the present invention is to provide a method of enabling such a collapsed ground to be photographed by a borehole camera.

[0007]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, after piercing the ground with a piercing bit protruding from a distal end opening of a cylindrical casing, a hole wall is formed in the casing. With the borehole camera being inserted into the casing after being pulled out while holding it at the position and protruding from the tip into the hole, the borehole camera is photographed while the casing and the borehole camera are being pulled out. This is an imaging method for obtaining an image of the hole wall.

According to the second aspect of the present invention, a borehole camera is formed by piercing the ground with a piercing bit protruding from a distal end opening of a cylindrical casing, and then pulling out the piercing bit while holding the hole wall with the casing. By inserting into the casing, and by taking out the hole wall through a slit provided on the side surface of the casing with a borehole camera while pulling out the casing and the borehole camera, an image of the hole wall is obtained. is there.

According to the invention of claim 3, claim 1,
2, in a state where the borehole camera is projected from the tip of the casing into the hole, and when the casing and the borehole camera are pulled out and the borehole camera photographs the hole wall, the transparent and viscous material is formed in the bored hole. The hole wall is photographed while filling the ground holding material having fluidity.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a borehole camera 5 used in the first embodiment of the present invention has a cylindrical main body formed with a side photographing section 51 at the head thereof. The photographing unit 51 includes a camera 52 having a field of view in the long axis direction, a conical reflector 53 whose vertex is directed toward the camera in the field of view of the camera 52, and an illumination 54 for illuminating the side direction.
The camera 52 captures an image of a hole wall to be moved to the reflecting mirror 53.

As shown in FIG. 2, the piercing bit 2 is protruded by a wing bit or the like in the side direction at the time of piercing, and becomes larger than the diameter of the casing 1 at the time of piercing. It is an emergent bit type configured to be smaller than the inner diameter. In the embodiment of the present invention, using such a borehole camera 5, the casing 1, and the drill bit 2,

First, as shown in FIG.
The borehole 4 is pierced in the ground 3 while rotating the piercing bit 2 protruding from the front end opening 11. Next, the bit protruding in the side direction is retracted, and the perforated bit 2 is pulled out of the casing 1. At this time, since the surrounding hole walls are held by the casing 1, the hole walls do not collapse.

Next, as shown in FIG.
The borehole camera 5 is inserted into the casing 1 after having been pulled out, and the borehole camera 5 is projected from the tip of the casing 1 into the hole. In other words, at least the reflecting mirror 53 at the top of the borehole camera 5 is Protrude from 1. At this time, a liquid and viscous holding material 61 is filled into the hole at a high pressure from the injection pipe 6 to prevent collapse of the hole wall. Note that the holding material 61 may be directly filled between the casing 1 and the camera 5 in a pressurized state without necessarily filling the holding material 61 from the injection pipe 6.

Then, as shown in FIG. 5, while the casing 1 and the borehole camera 5 are simultaneously pulled out, the borehole camera 5 photographs the hole wall. Since the liquid holding material 61 is replenished under pressure from the injection pipe 6 into the gap formed by pulling out, the collapse of the hole wall is prevented.

According to the borehole camera 5, the reflecting mirror
Since the hole wall moving to 53 is photographed by the camera 52 to obtain a ring-shaped unit image, a large number of ring-shaped unit images can be obtained by photographing while simultaneously pulling out the casing and the borehole camera. These ring-shaped unit images are converted into digital values based on a predetermined threshold value and stored in the storage means, and the ring-shaped image digitized in this way, for example, with the downward direction as a reference point. By extracting the image data of each point on the circumference along the circumference and rearranging them on a straight line in that order, the annular image becomes a linear image. By repeating such processing, a planar image in which many linear images are arranged from many annular images can be obtained.

The planar image obtained in this manner is a developed image obtained by cutting out a cylindrical image of the hole wall. In this way, even in the case of collapsible ground, it is possible to obtain an image of the hole wall with the borehole camera while preventing the collapse of the hole wall by the casing and the holding material. Then, a developed image of the hole wall is obtained from the image thus obtained by image processing, and the state of the ground can be analyzed and grasped.

Incidentally, as shown in FIG.
If a slit 12 having a width of about 10 mm is formed near the tip of the borehole and the hole wall is photographed from the slit 12, the photographing can be performed with the side photographing part 51 at the head of the borehole camera 5 protected by the casing 1. This makes it possible to obtain the advantage that damage to the borehole camera is reduced. Glass may be fitted into the slit 12.

As the holding material 61, various materials can be used as long as they are transparent and fluid. For example, a CMC solution, liquid glycerin, liquid paraffin and the like can be used.

[0019]

According to the first aspect of the present invention, while the borehole camera is protruded from the front end of the casing, the casing and the borehole camera are simultaneously pulled out, and the hole wall is photographed. We can photograph while preventing. And according to the invention of claim 2,
Since a slit is provided on the side of the casing and the casing and the borehole camera are simultaneously pulled out, it is possible to photograph the hole wall through the slit while preventing collapse of the ground with the casing.

According to the third aspect of the present invention, since the hole wall is photographed while the hole is filled with the transparent and fluid ground holding material, it is possible to shoot while preventing the ground from being collapsed by the ground holding material.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a structure of a borehole camera used in a method of the present invention.

FIG. 2 is a side view showing the structure of a drill bit used in the method of the present invention.

FIG. 3 is a diagram illustrating a perforated state according to the method of the present invention.

FIG. 4 is a diagram illustrating a shooting state according to the method of the present invention.

FIG. 5 is a diagram illustrating a shooting state according to the method of the present invention.

FIG. 6 is a perspective view showing an example of a structure of a side surface photographing section of a casing according to the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 2 Drilling bit 3 Ground 5 Borehole camera 51 Side photographing part 61 Ground holding material

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-132588 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E21B 47/00 G01B 11/24 G01C 11 / 00

Claims (3)

(57) [Claims] After drilling holes in the ground with a drill bit protruding from the opening at the tip of a cylindrical casing, the drill bit is pulled out while holding the hole wall with the casing, and then a borehole camera is inserted into the casing. In a state in which the casing is protruded from the tip into the hole, by photographing the hole wall with the borehole camera while pulling out the casing and the borehole camera, the collapsible ground by the borehole camera is obtained by obtaining an image of the hole wall. Shooting method. 2. After piercing the ground with a piercing bit protruding from a distal end opening of a cylindrical casing, the piercing bit is pulled out while holding the hole wall with the casing, and then a borehole camera is inserted into the casing. By taking out an image of a hole wall through a slit provided on a side surface of the casing with a borehole camera while pulling out the casing and the borehole camera, the image of the collapsible ground by the borehole camera is obtained, Shooting method. 3. When the borehole camera is projected from the front end of the casing into the hole, and the casing and the borehole camera are pulled out and the borehole camera photographs the hole wall, a transparent and viscous material is formed in the bored hole. 3. The method for photographing a collapsible ground by a borehole camera according to claim 1 or 2, wherein the hole wall is photographed while filling a ground holding material having fluidity.