JP6688606B2 - Front face exploration method - Google Patents

Description

The present invention relates to a method for exploring a face in front of a face , and more particularly to a method for exploring the ground ahead of a face in a tunnel by inserting a borehole camera into a horizontal boring hole.

  When carrying out civil engineering work, it is necessary to carry out ground exploration in order to understand the ground condition in advance. For example, when excavating a tunnel, it is necessary to grasp the situation of the ground before the tunnel excavation or in accordance with the progress of the tunnel excavation in order to perform a safe, appropriate and quick construction. Conventionally, various techniques have been proposed for conducting ground exploration. As such a conventional technique, there is a direct method using boring (hole drilling method, advanced boring). Further, as an indirect method, there is an elastic wave exploration (HSP method, TSP method, reflection tomography) by a reflection method.

  In addition, there is a method of capturing an internal image by inserting a borehole camera into the boring hole in order to grasp the situation inside the boring hole drilled in the vertical direction. Various techniques have been disclosed for observing an inner surface of a vertical boring hole or a vertical interhole joint with a borehole camera (see Patent Document 1). The in-tube imaging device described in Patent Document 1 includes a borehole camera for taking an image of the inside of the tube, and a capsule that includes the borehole camera in a watertight manner and has a transparent surface in the imaging direction. This in-pipe imaging device inserts a transparent capsule containing a borehole camera in a watertight manner into the joint pipe to a predetermined depth, removes muddy water (turbid water) filling the joint pipe by the width of the capsule, and shoots the inside of the joint pipe. It is supposed to be possible.

  Further, in order to search the ground condition (geological structure, etc.) in front of the face of a tunnel, a technique of inserting a borehole camera into a borehole drilled in a substantially horizontal direction to take an internal image is disclosed ( See Patent Document 2). In the method for exploring the natural ground / geological structure in front of the face of a tunnel described in Patent Document 2, a transparent pipe member is used for a relay pipe of a drilling machine to form a drilling hole. Then, a borehole camera is inserted into the transparent tube member, and the condition of the natural ground is photographed through the tube member.

JP, 2005-201717, A JP2012-12879A

  The technique described in Patent Document 1 described above is a technique for inserting a borehole camera into a joint pipe installed in the vertical direction and capturing an image inside the joint pipe. The borehole camera is hung vertically and inserted. Therefore, when inserting or removing the borehole camera, it is extremely unlikely that the borehole camera is caught on the inner surface (hole wall) of the joint pipe.

  On the other hand, in the case of a boring hole (naked hole) that is drilled in the horizontal direction, the borehole camera may get caught in cracks or protrusions existing in the hole wall, which may not only be difficult to insert but also may be difficult to insert. Even if it is possible, it may not be recoverable. In this regard, in the technique described in Patent Document 2, since a transparent pipe member is used for the relay pipe of the hole drilling machine and the borehole camera is inserted inside the pipe member for photographing, the borehole camera is mounted on the hole wall. The chance of getting caught is low.

  However, the technique described in Patent Document 2 photographs the inner surface (hole wall) of the boring hole by installing a transparent pipe member in the boring hole. Therefore, since the hole wall is protected by the pipe member, the actual geology may not be grasped from the captured image. Further, since the tube member is made of acrylic resin, polycarbonate resin, vinyl chloride resin or the like, the outer surface of the tube member may be scratched, and in the worst case, the tube member may be damaged. If the outer surface of the tube member is scratched or damaged, the image may become unclear or the image may not be captured.

The present invention has been proposed in view of the above-mentioned circumstances, and when exploring the ground condition in front of a tunnel face, the inner surface (hole wall) of a bore hole drilled in a substantially horizontal direction is directly exposed in a bare hole state. It is an object of the present invention to provide a front face exploration method capable of exploring the ground condition easily and accurately by photographing.

The face exploration method of the present invention has the following characteristic features in order to achieve the above-mentioned object. That is, the front face exploration method of the present invention is a method for exploring the ground situation in front of the tunnel face, and boring holes are drilled in a substantially horizontal direction toward the front face of the tunnel, and inserted into the boring holes. By pulling out the hollow rod while supplying the gel filler from the tip of the hollow rod for drilling, the translucent gel filler is filled in the boring hole, and the borehole camera is attached. While inserting the hollow support rod into the boring hole filled with the gel filler, while sucking the filler from the bore hole through the hollow part of the support rod, The borehole camera, and while pulling out the borehole camera, take a picture of the inner wall surface of the borehole and display the image taken by the borehole camera on the display device. It is characterized in analyzing the geology of the working face forward natural ground by.

  Further, in addition to the above-mentioned configuration, it is preferable that the borehole camera is installed at the tip of the hollow tube.

In the face forward exploration method according to the present invention, the filling material (for example, a gel-like substance) is filled in the horizontal boring hole drilled toward the ground ahead of the face face without using a hole-holding pipe or the like. The state of the bare hole can be maintained, and in this state, the inner surface (hole wall) of the boring hole can be directly photographed.

  Therefore, it becomes possible to easily and accurately search the ground condition, as compared with the case where the image is taken through a hole-holding tube or the like. In addition, since the filler (eg, gel-like substance) that fills the horizontal boring hole has a higher viscosity than water, it does not leak from the opening of the horizontal boring hole by performing appropriate leak prevention. .

The schematic diagram which shows the structure of the borehole camera used with the front face exploration apparatus which concerns on embodiment of this invention. The schematic diagram which shows the installation state of the face forward exploration device which concerns on embodiment of this invention. Explanatory drawing which shows the procedure of the front face exploration method which concerns on embodiment of this invention.

Hereinafter, an embodiment of a front face exploration method according to the present invention will be described with reference to the drawings. 1 to 3 are diagrams for explaining a face forward exploration method according to an embodiment of the present invention, FIG. 1 is a block diagram showing the configuration of a face forward exploration device used in the face forward exploration method, and FIG. 2 is a face forward exploration. The schematic diagram which shows the installation state of an apparatus, FIG. 3 is explanatory drawing which shows the procedure of a front face exploration method.

<Outline of front face exploration device and front face exploration method>
As shown in FIG. 2, the face forward exploration device and the face forward exploration method according to the embodiment of the present invention is a technique for directly exploring the ground condition in front of the face face using a borehole camera 30. A substantially horizontal boring hole 10 is bored in the front ground, the translucent filling material 20 is filled in the boring hole 10, and the borehole camera 30 is inserted so that the inner surface of the boring hole 10 (hole wall). ) Is directly photographed to investigate the condition of the natural ground (geology, etc.). The face forward exploration device of the present invention displays the boring hole 10 and the translucent filling material 20 that fills the boring hole 10, the borehole camera 30 that can be inserted into the boring hole 10, and an image captured by the borehole camera 30. And a display device 50.

<Borehole camera>
As shown in FIG. 1, the borehole camera 30 is a camera for taking an internal image of the boring hole 10 or a hollow pile, and a commercially available one can be used. As shown in FIG. 1, the borehole camera 30 includes a housing 31, an image pickup lens system 32, an image pickup element 33, and a lighting device 34 as a basic configuration. Further, a mirror 35 for bending the imaging light from the imaging surface may be provided for performing lateral imaging, and the mirror 35 may be an attachment member that is attachable to and detachable from the housing 31. Further, a zooming mechanism, a focus mechanism, a pan / tilt mechanism, etc. may be provided.

  The image pickup light that has entered the image pickup lens system 32 forms an image on the image pickup element 33, and is taken into a personal computer (not shown) or the like via a signal cable 36 as a video signal of the image pickup target surface. Although not shown, the image of the imaging target surface (inner surface (hole wall) of the boring hole 10 in the present invention) is displayed by the display device 50 connected to the personal computer.

<Boring hole>
The boring hole 10 is drilled substantially horizontally toward the front of the face. The term “substantially horizontal” means not only a completely horizontal state but also a state in which a slight inclination is allowed. Although the number of boring holes 10 to be drilled is not particularly limited, a suitable number of boring holes 10 are drilled depending on the size of the tunnel cross section, the bending state of the tunnel, the condition of the ground known in advance, and the like. In order to form the boring hole 10, for example, as shown in FIGS. 3A to 3C, the hollow rod may be inserted into the natural ground while supplying water from the tip portion of the hollow rod.

<Filler>
The filling material 20 has a light-transmitting property, and by filling the inside of the boring hole 10, the stability of the hole wall is maintained, and at the same time, the lubricant between the borehole camera 30 and the hole wall or the borehole camera 30 is maintained. Serves as a propellant. Further, since the filling material 20 has a light-transmitting property, even if it exists between the borehole camera 30 and the hole wall, it does not hinder the photographing of the hole wall. As the filler 20, it is preferable to use a gel-like substance.

<Display device>
The display device 50 is a device for displaying a video image captured by the borehole camera 30, and includes a liquid crystal display device (monitor) or the like. When printing an image taken by the borehole camera 30, the printer functions as the display device 50. That is, the device for displaying an image is a device that can visualize and show an image, and is a concept including a monitor, a projection device, a printer, and the like.

<Combination with other exploration methods>
In the face forward exploration device and the face forward exploration method of this embodiment, the image captured by the borehole camera 30 is the main element of the geological analysis. In addition to this, the drilling obtained when drilling the horizontal boring hole 10 is performed. By using logging data, resistivity distribution data, elastic wave velocity distribution data, etc. together, it is possible to comprehensively evaluate two or more types of information at the same point, and even more accurate geological prediction in front of the face Is possible.

<Procedure of exploration method>
Next, with reference to FIG. 3, an example of the method for exploring the face ahead of the present invention will be described. According to the front face research method of the present invention, when excavating a tunnel, the front face research device configured as described above is used to search the ground condition (geology) in front of the front face.

  In the front face exploration method of the present invention, first, the horizontal boring hole 10 is drilled in the ground in front of the front face. The boring hole 10 is formed by, for example, installing the hollow rod 60 in the ground and supplying water from the tip of the hollow rod 60 (a). After drilling the boring hole 10 to a predetermined length, the water supply is stopped. In this state, water existing in the boring hole 10 leaks from a rock crack or the mouth of the hollow rod 60 (b).

  Then, the filler 20 is supplied into the boring hole 10 from the tip of the hollow rod 60 (c), and the hollow rod 60 is pulled out while continuing the supply of the filler 20 (d). When the pulling out of the hollow rod 60 is completed, the inside of the boring hole 10 is filled with the filler 20 (e).

  The borehole camera 30 is attached to the tip of the support rod 40 made of a hollow PVC pipe or the like. Then, the tip of the support rod 40 having the borehole camera 30 attached is inserted into the boring hole 10 (f), and the filler 20 is sucked from the boring hole 10 through the hollow portion of the support rod 40 while being supported. The rod 40 is inserted and installed in the boring hole 10 (g). At this time, a negative pressure is generated in the boring hole 10 by sucking the filling material 20, and the support rod 40 having the borehole camera 30 attached thereto can be propelled into the boring hole 10 due to the friction reducing effect of the filling material 20. Yes (h). After inserting the support rod 40 to a predetermined position on the inner side of the borehole 10 (i), the borehole camera 30 photographs the hole wall while pulling the support rod 40 out of the borehole 10 (j). Then, the geology of the ground in front of the cutting face is analyzed based on the image displayed on the display device 50.

10 Boring Hole 20 Filling Material 30 Borehole Camera 31 Housing 32 Imaging Lens System 33 Imaging Device 34 Illuminator 35 Mirror 36 Signal Cable 40 Support Rod 50 Display Device 60 Hollow Rod

Claims (2)

A method for exploring the ground conditions in front of the tunnel face,
Drill a boring hole in a substantially horizontal direction toward the front of the face,
By pulling out the hollow rod while supplying the gel filler from the tip of the hollow rod for drilling inserted into the bore hole, a gel filler having translucency in the bore hole is obtained. Filling,
While inserting the hollow support rod with the borehole camera into the boring hole filled with the gel-like filler, the hollow rod of the support rod sucks the filler from the inside of the boring hole to support it. Insert the rod into the boring hole, install the borehole camera,
While pulling out the borehole camera, shoot the inner wall surface of the borehole,
Analyzing the geology of the ground in front of the cutting face by displaying the image taken by the borehole camera on a display device,
A front face exploration method characterized by the above. The front face exploration method according to claim 1, wherein the borehole camera is installed at a tip portion of the support rod.

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