JP2017049198A - Working face front survey device and working face front survey method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily precisely survey the ground status of a working face front using an elastic wave tomography technique between holes.SOLUTION: A working face front survey device includes: a vibration receiving device 40 to be installed in at least one of a plurality of boreholes 10 that is drilled toward a working face front; an oscillation device 30 to be installed in the borehole 10 other than the borehole 10 in which the vibration receiving device 40 is installed; filler 20 to be filled in the borehole 10 in which at least the vibration receiving device 40 is installed; and a geological analysis device 50 for analyzing the elastic wave speed distribution of the natural ground between the oscillation device 30 and the vibration receiving device 40 based on a distance between the oscillation device 30 and the vibration receiving device 40 and the propagation time of an elastic wave.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a face forward exploration device and a face forward exploration method, and more particularly, to an invention relating to face forward exploration using inter-hole elastic wave tomography technology.

  When tunnel excavation, it is necessary to grasp the condition of natural ground beforehand in order to perform safe, appropriate and quick construction. For this reason, various techniques for grasping the condition of natural ground prior to tunnel excavation or in accordance with the progress of tunnel excavation have been proposed. As such a prior art, there is a direct method by boring (hole drilling method, advanced boring). Indirect methods include elastic wave exploration (HSP method, TSP method, reflection tomography) by the reflection method.

  For example, there has been proposed a technique for continuously monitoring the natural ground condition and grasping in advance the possibility that an abnormality will occur (see Patent Document 1). The technique described in Patent Document 1 monitors the drilling status of a plurality of rock bolts to be driven from a pit wall to a natural ground, and receives a plurality of the rock bolts to be subjected to a vibration probe and Use as a probe for oscillation. And the first exploration process which grasps the ground condition in the depths of the pit wall by the refracted elastic wave exploration method, and the excavator that excavates the face is used as the oscillation source by using the plurality of placed rock bolts as receiving probes. By performing the second exploration process to grasp the ground condition in front of the face using the reflected reflection elastic wave exploration method, it is possible to grasp the ground condition without interrupting the construction and catch signs of the change. It is said.

  In addition, a technique for predicting the geological situation in front of the tunnel has been proposed (see Patent Document 2). The technique described in Patent Document 2 estimates the approximate position and scale of the crushing zone by measuring the elastic wave velocity of the natural ground along the route by preliminary investigation of the tunnel to be excavated. Then, the necessary section for the front exploration of the face is judged from the obtained information, first the existence of a discontinuous surface up to a predetermined distance in front of the face is predicted by the elastic wave exploration reflection method, and then the face approaches the discontinuous surface At that time, drilling logging is performed using a hole by a drill jumbo to obtain a fracture energy coefficient. Next, velocity logging is performed on the hole that has been drilled, and the geological condition is predicted from the elastic wave velocity, and if the correlation between the elastic wave velocity and the fracture energy coefficient can be confirmed, drilling logging is performed thereafter. Just to predict the geological situation.

Japanese Patent Laying-Open No. 2015-90032 JP-A-11-174046

  However, there are various problems with the conventional technique for exploring the front of the face. Since the technique described in Patent Document 1 uses a lock bolt as an essential component, it cannot be applied to all tunnel methods. In addition, the technique described in Patent Document 2 needs to perform drilling logging using a drill jumbo hole after predicting the presence of a discontinuous surface up to a predetermined distance in front of the face by an elastic wave exploration reflection method. , It takes time to grasp the natural conditions.

  In addition, the elastic wave exploration technique based on the reflection method can catch discontinuous surfaces distributed in the tunnel transverse direction, but cannot catch discontinuous surfaces distributed in the tunnel longitudinal direction. In other words, the elastic wave oscillated toward the front face of the face may go straight forward to the face of the face, and the reflected wave may not return. Under such circumstances, the discontinuous surface in the tunnel longitudinal direction cannot be explored. .

  Also, the elastic wave exploration technique using the reflection method detects not only the reflected wave limited to the excavation area in front of the face but also the reflected wave around the existing tunnel, so it is mistaken for a discontinuous surface existing in front of the face. And the accuracy of exploration of ground conditions is inferior.

  In the case of vertical inter-hole elastic wave tomography, by accumulating water in the borehole, the elastic wave from the oscillation device is transmitted to the ground, and the elastic wave propagated in the ground is transmitted to the receiving device. It is like that. That is, in the case of the inter-hole elastic wave tomography in the vertical direction, the water filled in the boring hole plays a role of transmitting the elastic wave (vibration). However, in the case of a horizontal boring hole, it is difficult to collect water in the boring hole. Furthermore, compared with the hole wall of a vertical boring, the hole wall of a horizontal boring is easy to collapse, and it is difficult to insert a vibration receiving device or an oscillation device. For this reason, the vertical inter-hole elastic wave tomography cannot be directly applied to the horizontal inter-hole elastic wave tomography.

  The present invention has been proposed in view of the above-described circumstances, and can use the inter-hole elastic wave tomography technique to easily and accurately search the ground condition (elastic wave velocity distribution) in front of the face. An object of the present invention is to provide an exploration device and a method for exploring the front of a face.

  The face forward exploration device and the face forward exploration method of the present invention have the following features in order to achieve the above-described object. That is, the face front exploration device according to the present invention is a device for exploring the ground condition in front of the tunnel face, and includes a plurality of bore holes drilled in a substantially horizontal direction toward the front face of the face, and at least of the bore holes. A vibration receiving device installed in one, an oscillation device installed in a boring hole other than the boring hole where the vibration receiving device is installed, a filler filled in at least the boring hole where the vibration receiving device is installed, and an elasticity generated by the oscillation device A geological analyzer that receives a wave by a receiving device and analyzes the elastic wave velocity distribution of a natural ground between the oscillating device and the receiving device based on the distance between the oscillating device and the receiving device and the propagation time of the elastic wave; It is characterized by comprising.

  In addition to the above-described configuration, it is preferable to install a plurality of vibration receiving devices and oscillation devices along the length direction of the boring hole.

  In addition to the above-described configuration, the oscillation device can generate an elastic wave by any one of blasting, mechanical hitting, vibration generated at the time of drilling, or a combination thereof.

  In addition to the above-described configuration, the geological analysis device can analyze the geology ahead of the face in consideration of the receiving situation of the reflected wave oscillated from the oscillation device and reflected in the natural ground.

  A face front exploration method of the present invention is a method for exploring a ground condition in front of a tunnel face, wherein a plurality of bore holes are drilled in a substantially horizontal direction toward the front face of the face, and at least one of the bore holes is obtained. A vibration receiving device is installed in the borehole other than the borehole where the vibration receiving device is installed, and at least the filling material is filled in the borehole where the vibration receiving device is installed, and the elastic wave generated by the vibration device is generated. It is received by a vibration receiving device, and based on the distance between the oscillation device and the vibration receiving device and the propagation time of the elastic wave, the elastic wave velocity distribution of the natural ground between the vibration device and the vibration receiving device is analyzed. It is.

  In the face forward exploration device and the face forward exploration method according to the present invention, a filling material (for example, a gel-like substance) is filled in a horizontal boring hole in which the oscillation device and the vibration receiving device are installed, so that it is similar to the vertical boring hole. The elastic wave oscillated from the oscillation device and received by the vibration receiving device can be reliably propagated. That is, in the horizontal boring hole, unlike the vertical boring hole, water leaks out from the hole opening even when trying to fill with water, and the elastic wave cannot be reliably propagated. In this regard, the filler (for example, a gel-like substance) does not leak out from the hole of the horizontal boring hole by performing appropriate leakage prevention.

  Therefore, according to the face forward exploration device and the face forward exploration method according to the present invention, using the technique of inter-hole elastic wave tomography in the horizontal boring hole that has not been realized so far, the ground condition (elastic wave in front of the face) (Velocity distribution) can be explored easily and appropriately.

The block diagram which shows the structure of the face front search apparatus which concerns on embodiment of this invention. The schematic diagram which shows the installation state of the face front exploration apparatus which concerns on embodiment of this invention. Explanatory drawing which shows the procedure of the face front search method which concerns on embodiment of this invention.

  Hereinafter, with reference to the drawings, an embodiment of a face forward exploration device and a face forward exploration method according to the present invention will be described. FIG. 1 to FIG. 3 are for explaining a face front exploration device and a face front exploration method according to an embodiment of the present invention. FIG. 1 is a block diagram showing the configuration of the face front exploration device, and FIG. FIG. 3 is an explanatory view showing the procedure of the face front search method.

<Overview of the face front exploration device and face front exploration method>
The face forward exploration device and the face forward exploration method according to the embodiment of the present invention are techniques for exploring the ground condition in front of the face using the inter-hole elastic wave tomography technique, and in particular, in the ground in front of the face. A horizontal boring hole is drilled, and the elastic wave velocity distribution of the natural ground is searched by inter-hole elastic wave tomography using the boring hole. As shown in FIG. 1 and FIG. 2, the face front exploration device of the present invention includes a boring hole 10 and a filler 20 filled therein, an oscillation device 30 that oscillates an elastic wave, and a vibration receiving device 40 that receives the elastic wave. And a geological analysis device 50 that analyzes the elastic wave velocity distribution of the natural ground between the oscillation device 30 and the vibration receiving device 40 based on the distance between the oscillation device 30 and the vibration receiving device 40 and the propagation time of the elastic wave. ing.

<Boring hole>
The boring hole 10 is drilled substantially horizontally toward the front of the face. Note that “substantially horizontal” means not only a completely horizontal state but also a state in which a slight inclination is allowed. The number of drilling holes in the borehole 10 is not particularly limited, but an appropriate number is drilled according to the size of the tunnel cross section, the bending state of the tunnel, the condition of the natural ground previously known, and the like. In order to form the boring hole 10, for example, as shown in FIGS. 3A to 3C, the hollow rod 60 may be inserted into the natural ground while supplying water from the tip of the hollow rod 60. . In addition, according to the condition of the natural ground which drills the boring hole 10, you may employ | adopt the drilling methods, such as using a hole-holding pipe.

<Filler>
By filling the filling material 20 into the boring hole 10, the elastic wave oscillated from the oscillation device 30 and received by the vibration receiving device 40 can surely propagate to the ground. The filler 20 is filled in at least the boring hole 10 in which the vibration receiving device 40 is installed. However, depending on the configuration of the oscillating device 30, the filling material 20 is also filled in the boring hole 10 in which the oscillating device 30 is installed. The filler 20 also contributes to hole wall protection and propulsive force and friction reduction when the vibration receiving device 40 and the oscillation device 30 are inserted. In addition, it is difficult to self-support the hole wall, and even when the hole-holding tube is installed, the elastic wave can be propagated by injecting the filler 20 along the outer periphery of the hole-holding tube. The filler 20 is preferably a gel-like substance.

<Oscillator>
The oscillation device 30 is a device for oscillating an elastic wave, and any vibration source may be used. For example, the elastic wave is vibrated by blasting, mechanical hitting, vibration that is vibrated during drilling, or the like. The number of boring holes 10 in which the oscillation device 30 is installed may be one or two or more.

<Vibration device>
The vibration receiving device 40 is a device for receiving an elastic wave generated by the oscillation device 30, and for example, a piezoelectric accelerometer or the like can be used. In particular, in order to accurately grasp the state of the elastic wave that has reached the vibration receiving device 40, it is preferable to use the vibration receiving device 40 capable of receiving the three orthogonal components. 2 and 3 (f) to (i), for example, the vibration receiving device 40 includes a plurality of vibration receivers 41 arranged at predetermined intervals on a support rod 42 made of a PVC pipe, By installing the support rod 42 in the hole 10, a plurality of geophones 41 can be installed along the length direction of the boring hole 10. The position and number of the bore holes 10 in which the vibration receiving device 40 is installed are not particularly limited. However, depending on the size of the cross section of the tunnel, the bending state of the tunnel, the state of the ground known in advance, etc. The device 40 is installed. By installing a plurality of receiving devices 40 (receivers 41), a plurality of elastic wave propagation paths from the oscillating device 30 can be set, and the elastic wave velocity distribution in the natural ground in front of the face is more accurately investigated. can do.

<Geological analyzer>
The geological analysis device 50 receives the elastic wave generated by the oscillation device 30 by the vibration receiving device 40, and based on the distance between the oscillation device 30 and the vibration receiving device 40 and the propagation time of the elastic wave, the oscillation device 30 and the vibration receiving device. 40 is an apparatus for analyzing the elastic wave velocity distribution of the natural ground between and 40, and can be constituted by, for example, a personal computer, an application program installed therein, and an accessory device of the personal computer. The attached devices of the personal computer are peripheral devices that operate together with the personal computer, such as an input device such as a keyboard and a mouse, an output device such as a display device and a printer, and a storage device such as an HDD. The inter-hole elastic wave tomography technique is an established technique, and the geological analysis apparatus 50 according to this embodiment analyzes the geology of the ground in front of the face using the analysis method in the inter-hole elastic wave tomography technique. To do.

<Combination with other exploration methods>
In the face front exploration device and face front exploration method of the present embodiment, the inter-hole elastic wave tomography technique in which the elastic wave oscillated from the oscillation device 30 is directly received by the vibration receiving device 40 is a main element of the geological analysis. In addition to this, the geology in front of the face may be analyzed in consideration of the receiving situation of the reflected wave oscillated from the oscillation device 30 and reflected in the natural ground. In this case, the accuracy of exploration by the reflection method can be increased by fixing a highly accurate exploration result using direct waves.

  Furthermore, it is possible to comprehensively evaluate two types of information at the same point by using the drilling logging data obtained at the time of horizontal boring and the elastic wave velocity distribution obtained by the exploration of this embodiment. This makes it possible to predict geology ahead of the face with higher accuracy.

<Procedure of exploration method>
Next, with reference to FIG. 3, an example of the method for exploring the front face of the face according to the present invention will be described. In the face front exploration method of the present invention, the tunnel front exploration device having the above-described configuration is used for exploring the ground condition (geology) in front of the face when excavating a tunnel.

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

  Subsequently, the filler 20 is supplied from the tip of the hollow rod 60 into the boring hole 10 (c), and the hollow rod 60 is pulled out while continuing to supply the filler 20 (d). When the extraction of the hollow rod 60 is completed, the inside of the bore hole 10 is filled with the filler 20 (e). Note that the filler 20 may be filled after the receiving device 40 is installed in the boring hole 10.

  In addition, the vibration receiving device 40 is formed by attaching the vibration receiving devices 41 at predetermined intervals in the length direction of the support rod 42 made of a hollow PVC pipe or the like. And the front-end | tip part of the support rod 42 which attached the geophone 41 was inserted in the boring hole 10 (f), and it was supported, attracting | sucking the filler 20 from the boring hole 10 through the hollow part of the support rod 42. The rod 42 is inserted and installed in the bore hole 10 (g). At this time, suction of the filler 20 causes a negative pressure in the borehole 10, and the support rod 42 to which the vibration receiving device 41 is attached can be pushed into the borehole 10 due to the friction reducing effect of the filler 20. Yes (h). When the support rod 42 is inserted to a predetermined position on the back side of the boring hole 10, the installation of the vibration receiving device 40 is completed (i).

  In this state, an elastic wave is oscillated from the oscillation device 30 and the elastic wave propagating through the natural ground is received by the vibration receiving device 40. Based on the distance between the oscillation device 30 and the vibration receiving device 40 and the propagation time of the elastic wave, the geological analysis device 50 determines the elastic wave velocity distribution of the natural ground between the oscillation device 30 and the vibration receiving device 40 (the state of the ground). ) Is analyzed (j).

<Comparison with conventional technology>
According to the face front exploration device and the face front exploration method of the present invention, since the elastic wave velocity distribution around the tunnel excavation ground and the tunnel, which is the most important information for tunnel construction, can be intensively explored, it is more specific. Study of excavation method and excavation method, tunnel support and auxiliary method can be designed.

  In conventional exploration of the front of the face, the geological structure in front of the face is uncertain at the time of receiving work, mirror bolt work, and water stoppage planning, so the construction range and specifications were determined based on the standard layout. On the other hand, the face front exploration device and the face front exploration method of the present embodiment can intensively construct the specifications that are optimal for the defective ground, so that effective countermeasures can be planned economically. It becomes. In addition, the drilling accuracy can be improved by using a drill jumbo with computer control and navigation functions that can accurately record the hole position and hole angle. Furthermore, the exploration accuracy is further improved by using the hole bending measurement together.

DESCRIPTION OF SYMBOLS 10 Boring hole 20 Filler 30 Oscillator 40 Vibration receiving device 41 Vibration receiving device 42 Support rod 50 Geological analysis device 60 Hollow rod

Claims (5)

A device for exploring ground conditions in front of a tunnel face,
A plurality of boring holes drilled in a substantially horizontal direction toward the front of the face;
A vibration receiving device installed in at least one of the boring holes;
An oscillation device installed in a borehole other than the borehole in which the vibration receiving device is installed;
A filler for filling at least the borehole in which the vibration receiving device is installed;
The elastic wave generated by the oscillation device is received by the vibration receiving device, and the ground between the oscillation device and the vibration receiving device is determined based on the distance between the oscillation device and the vibration receiving device and the propagation time of the elastic wave. A geological analyzer that analyzes the elastic wave velocity distribution in the mountains;
A device for exploring the front of the working face.   The face forward exploration device according to claim 1, wherein a plurality of the vibration receiving devices are installed along a length direction of the boring hole. The oscillation device oscillates an elastic wave by any one of blasting, mechanical hitting, vibration generated at the time of drilling, or a combination thereof,
The face forward exploration device according to claim 1 or 2, characterized by the above. The geological analysis device analyzes the geology in front of the face in consideration of the receiving situation of the reflected wave that is oscillated from the oscillation device and reflected in the ground.
The face forward exploration device according to any one of claims 1 to 3. A method for exploring ground conditions in front of a tunnel face,
Drill a plurality of boring holes in a substantially horizontal direction toward the front of the face,
A vibration receiving device is installed in at least one of the boring holes,
An oscillation device is installed in a borehole other than the borehole in which the vibration receiving device is installed,
Filling at least a boring hole in which the vibration receiving device is installed,
The elastic wave generated by the oscillation device is received by the vibration receiving device, and the ground between the oscillation device and the vibration receiving device is determined based on the distance between the oscillation device and the vibration receiving device and the propagation time of the elastic wave. Analyzing the elastic wave velocity distribution of the mountain,
A method for exploring the front of the face.

Images