Reflecting surface estimation device

Abstract

To provide a reflection surface estimation device capable of easily selecting a peak point of reflection surface intensity (horizontal specific point, vertical specific point) in comparison with the prior arts in order to solve the problems in the prior arts.SOLUTION: A reflection surface estimation device which estimates reflection in front of a tunnel working face based on depth slice obtained by elastic wave exploration of a three-dimensional reflection method, comprises depth slice storage means, vertical position designation means, horizontal position designation means, elastic wave velocity designation means, display control means, horizontal specific point designation means, vertical specific point designation means, horizontal reflection line setting means, vertical reflection line setting means, and plane calculation means. The plane calculated by the plane calculation means may be estimated as the reflection surface in front of the tunnel working face.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to exploration ahead of a tunnel face, and more specifically, to a reflection surface estimation device that can estimate the reflection surface present ahead of a tunnel face based on the results obtained by three-dimensional reflection elastic wave exploration. [Background technology]

[0002] It is said that roughly two-thirds of Japan's land area is mountainous, and as a result, roads, railway tracks, etc. (hereinafter referred to as "roads, etc.") almost always have sections that pass through mountainous areas. To build roads, etc. in mountainous areas, it is common to employ either the cut earth method, which excavates part of the slope, or the tunnel method, which hollows out the interior of the natural ground. Although the tunnel method tends to have a higher construction cost (construction cost per length of road, etc.) than the cut earth method, it tends to require less excavated soil (i.e., the amount of soil discharged) and has the advantage of allowing greater freedom in linear planning of roads, etc. (for example, shortcuts can be taken), and it is said that more than 10,000 tunnels have been constructed in Japan to date.

[0003] Until the 1970s, the main method of construction for mountain tunnels was the "sheet pile method," which combined steel arch supports with wooden sheet piles to support the natural ground, but now the New Austrian Tunneling Method (NATM), which actively utilizes the strength of the natural ground, has become mainstream. NATM's main feature is its design philosophy that relies on the strength of the natural ground (arch effect), which makes it possible to reduce the scale of the tunnel supports compared to the conventional sheet pile method, and also to increase the speed of construction, thereby reducing construction costs.

[0004] In addition, since NATM was first fully implemented, excavation technology has made great strides, and the development of various auxiliary methods has made it possible to handle a variety of ground conditions. Furthermore, advances in excavation machinery (particularly open-section excavators) have made it possible to choose mechanical excavation in addition to blasting excavation. This mechanical excavation generally requires the use of relatively low-strength concrete (for example, a uniaxial compressive strength of 49 N / mm 2 This method is often used for rock masses (see below), while blasting excavation is often used when bedrock is present in the target rock mass.

[0005] Here, we will briefly explain the excavation procedure of NATM with blasting. First, a drill jumbo is used to drill holes and load explosives (dynamite), and after workers and machines have evacuated, blasting is used to excavate. The excavation length (1 span length) for one cycle (1 span length) varies depending on the support pattern set according to the strength of the ground, but generally excavation is performed with a span length of 1.0m to 2.0m. After one span length is excavated, the debris is removed (debris removal) by a dump truck (or rail method) while "scrambling" is performed to remove unstable ground parts (loose stones, etc.). After the debris removal, the first concrete is sprayed, and then steel supports are erected as necessary (depending on the support pattern), the second concrete is sprayed, and then rock bolts are installed. The first concrete spraying and the second concrete spraying are performed for the excavated span length, that is, the inner surface of the tunnel in the unexcavated part (the surface from the side wall to the top).

[0006] In NATM, stabilizing the tunnel face is extremely important in terms of safe construction, and auxiliary construction methods are used for the tunnel face depending on the strength of the ground, spring water, or the behavior of the tunnel face, etc. For example, concrete spraying (spraying) or rock bolts (spraying bolts) are used to stabilize the tunnel face, drainage boring is performed, or forepoling or long forepiling as pre-supporting work is performed.

[0007] NATM is also a so-called information-based construction method that uses measurement work (A and B measurements) in conjunction with this, and the excavation pattern is changed or auxiliary methods are adopted depending on the measurement results. Measurement work includes internal displacement and top settlement to measure the behavior of the surrounding ground, rock bolt axial force measurement to measure the axial force of driven rock bolts, and tunnel face observation. This tunnel face observation is literally a measurement work that observes the tunnel face, and considering that the information that can be obtained from the tunnel face, where the ground is most exposed, is both useful and voluminous, it is one of the extremely important measurement works in proceeding with future excavation.

[0008] Furthermore, in addition to information about the tunnel face, information about the area ahead of the tunnel face (i.e., the area of ​​the ground where excavation will continue) is often useful. For example, in cases where there is a fault or a partially weak layer ahead of the tunnel face, knowing this in advance makes it possible to prepare countermeasures. Specifically, by reviewing the designed support pattern, carrying out pre-supporting work such as forepoling from the front, and injecting chemicals into appropriate areas, it is possible to excavate through faults and weak layers while stabilizing the tunnel face.

[0009] In order to obtain information ahead of the tunnel face, a boring survey may be conducted at the tunnel face. By boring from the tunnel face in the direction of excavation, the ground conditions ahead of the tunnel face can be estimated from the drilling speed (so-called chisel drop) and the state of the chips, or the ground conditions ahead of the tunnel face can be directly ascertained by taking a core. However, boring surveys at the tunnel face require a considerable amount of time and effort, and of course tunnel excavation must be stopped while the survey is being carried out, including the setup. In tunnel construction, labor costs and machinery rentals account for a relatively large proportion of the construction costs, so if the construction period (construction period) is extended, costs will increase accordingly, and so "stopping the tunnel face" is often avoided.

[0010] In order to obtain information ahead of the tunnel face, in addition to boring surveys of the tunnel face, elastic wave exploration, a type of geophysical exploration, may also be conducted. This type of exploration involves generating artificial earthquakes using an artificial source such as explosive blasting or hitting the ground with a hammer, and grasping the characteristics of the ground by receiving the elastic waves propagating through the ground with a seismometer (receiver). It can be broadly divided into refraction and reflection methods.

[0011] One of the features of elastic wave exploration using the refraction method is that it observes waves that propagate through the ground, propagate along the boundaries of strata, and then refract before reaching the ground surface. Specifically, a measurement line is set to a length 3 to 5 times the depth of the ground structure to be clarified, and receiving points (receivers) are placed at appropriate intervals along the line, and artificial earthquakes are generated near the ground surface to observe the elastic wave velocity with these receivers. Therefore, the refraction method is considered to be suitable for clarifying relatively shallow ground structures, and is mainly used for purposes such as foundation ground surveys for civil engineering structures and ground structure surveys.

[0012] When this refraction method of elastic wave exploration is applied to the exploration in front of the tunnel face, the depth direction is toward the back of the tunnel (in front of the face), and the survey line is set on the empty side of the tunnel, but it is possible that a sufficient length of the side line cannot be secured, meaning that the receiver cannot be placed appropriately. In the first place, it is difficult to predict the depth (distance from the face) of the ground structure to be clarified, and in that sense, it is also difficult to place the receiver appropriately. Moreover, blasting work for exploration is required near the face, and work such as installing and removing the receiver is also required, so it is unavoidable to stop the face during that time.

[0013] Therefore, reflection elastic wave exploration is sometimes used for exploration in front of the tunnel face. For example, if a receiver is installed at a position away from the tunnel face (the tunnel entrance side) and an artificial earthquake is generated by blasting at the tunnel face, the receiver receives the direct waves (direct waves) generated by the blasting and the waves (reflected waves) reflected by the reflecting surface in front of the tunnel face. It is known that the greater the difference in acoustic impedance between two layers, the higher the reflection coefficient of the elastic wave, i.e., the easier it is to reflect. Here, acoustic impedance is a physical quantity that indicates the "difficulty of elastic wave transmission" expressed as the product of the speed of the elastic wave in that layer and the density of that layer. Therefore, when the receiver receives a reflected wave, it means that there is a reflecting surface where the acoustic impedance difference between the two adjacent layers is significant, which means that the existence of a fault or a partially weak layer is predicted. In addition, a case where the acoustic impedance difference between the two adjacent layers is significant is sometimes called a "reflection event", and the amplitude of the elastic wave reflected in this reflection event is larger than other cases.

[0014] In this way, elastic wave exploration using the reflection method makes it possible to estimate reflection events that exist in front of the tunnel face, such as faults and weak layers. Also, as in the invention disclosed in Patent Document 1, by permanently installing a receiver inside the tunnel (for example, at the head of a rock bolt) and installing a device inside the tunnel that detects blasting ignition signals and using regular blasting for tunnel excavation as an artificial seismic source, it is possible to carry out exploration in front of the face without interrupting the tunnel excavation cycle, that is, without stopping the face, and extremely frequently, such as at every face. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Patent No. 5587960 Summary of the Invention [Problem to be solved by the invention]

[0016] One of the features of the reflection method is that it observes waves reflected from the boundary surface (reflection surface) of the strata where the speed and density change, as mentioned above, and it is a method to estimate the ground structure based on information such as the arrival time and amplitude of the elastic waves acquired by the receiver. This method has been used in many resource explorations, especially for oil and coal, but in Japan it is also used for fault surveys and continental shelf surveys. In addition, with the development of telemetry-type elastic wave exploration systems, 3D reflection method elastic wave exploration has also become widely used. This 3D reflection method is a method in which receivers are arranged in a plane, and compared to the previous 2D reflection method, it allows simultaneous observation of multiple channels, and it is now possible to obtain 3D survey results where only 2D survey results were previously obtained.

[0017] The results obtained by the 3D reflection method are a three-dimensional data set, but a certain processing is required to present the analysis results three-dimensionally and visually. In general, the depth direction is divided into small sections, cross sections showing the exploration results at each position are created, and these sections are then superimposed to present the results three-dimensionally and visually. This cross section, also called a "depth slice," shows the reflection surface intensity (amplitude, other electrical signals, etc.) of the reflected wave reflected at that depth. More specifically, a depth slice is a representation of the reflection points (positions where the reflected wave is reflected on the reflection surface) of the reflected wave received by the receiver, which are connected like contour lines, and then colored (or shaded) according to the strength of the reflection intensity.

[0018] When a 3D reflection elastic wave exploration is performed as a tunnel face forward exploration, two types of depth slices are often created. That is, when the tunnel axis (X axis) is set in the axial direction of the tunnel (excavation direction), the horizontal axis (Y axis) perpendicular to this tunnel axis, and the vertical axis (Z axis) perpendicular to the tunnel axis are set, a depth slice (hereinafter referred to as "horizontal depth slice") is created on a plane (XY plane) set by the tunnel axis and the horizontal axis, and a depth slice (hereinafter referred to as "vertical depth slice") is created on a plane (XZ plane) set by the tunnel axis and the vertical axis. Of course, the horizontal depth slices are created at each position divided finely in the vertical direction (Z axis direction), and the vertical depth slices are created at each position divided finely in the horizontal direction (Y axis direction). In addition, the horizontal depth slices and the vertical depth slices are created for each different elastic wave speed. In other words, the number of horizontal depth slices created is the product of the "number of vertical directions" and the "number of elastic wave velocities," while the number of vertical depth slices created is the product of the "number of horizontal directions" and the "number of elastic wave velocities." Figure 12 shows a schematic of the many horizontal depth slices that are created, with the number of vertical directions (number on the vertical axis) being 7 and the number of elastic wave velocities (number on the horizontal axis) being 10, meaning that in this case 70 horizontal depth slices are created.

[0019] The reflection surface (reflection event) in front of the tunnel face is extracted in the following procedure. First, the point where the reflection surface intensity is maximum, i.e., the peak point (hereafter referred to as the "horizontal specific point") is selected from the many horizontal depth slices created, and the peak point of the reflection surface intensity (hereafter referred to as the "vertical specific point") is selected from the many vertical depth slices created in a similar manner. Then, a tangent line (hereafter referred to as the "horizontal reflection line") at the horizontal specific point is set in the distribution curve of the reflection surface intensity (a curve connecting the reflection points) displayed in the horizontal depth slice, and similarly, a tangent line (hereafter referred to as the "vertical reflection line") at the vertical specific point is set in the distribution curve of the reflection surface intensity displayed in the vertical depth slice. Then, in the three-dimensional space (XYZ coordinate system), the plane where the horizontal reflection line and the vertical reflection line are located at the same time is extracted as the "reflection surface". Note that if the horizontal reflection line and the vertical reflection line do not intersect (i.e., they are in a twisted position), plane 1 cannot be determined; however, considering that a reflective surface actually exists, the distance between the horizontal reflection line and the vertical reflection line (hereinafter referred to as the "distance between the lines") should not be very large, and plane 1 can be determined by translating parallel to the horizontal reflection line or the vertical reflection line until they intersect (or both).

[0020] In this way, a large number of depth slices (horizontal depth slices and vertical depth slices) are used to estimate the reflection surface (reflection event) in front of the tunnel face by performing elastic wave exploration using the 3D reflection method. Conventionally, horizontal and vertical specific points were selected while visually checking the depth slices printed on paper. Therefore, the person estimating the reflection surface was forced to print a large number of papers and visually check a large number of depth slices. Moreover, as a result of performing such a huge amount of work, it took a long time (for example, one day) to estimate the reflection surface, which meant that there was a problem of a delay in the timing of reflecting the results in the tunnel excavation work.

[0021] The object of the present invention is to solve the problems associated with the conventional technology, i.e. to provide a reflecting surface estimation device that can select peak points of reflecting surface intensity (specific horizontal points, specific vertical points) more easily than with the conventional technology. [Means for solving the problem]

[0022] The present invention was made with a focus on the fact that by displaying depth slices on an output means such as a display, and by varying the displayed depth slices in a manner similar to a picture-story show, it is possible to quickly and easily select the peak point of the reflection surface intensity, and is an invention based on an unprecedented idea.

[0023] The reflection surface estimation device of the present invention is a device that estimates a reflection surface in front of a tunnel face based on a depth slice obtained by a three-dimensional reflection method elastic wave exploration, and includes a depth slice storage means, a vertical position designation means, a horizontal position designation means, an elastic wave velocity designation means, a display control means, a horizontal specific point designation means, a vertical specific point designation means, a horizontal reflection line setting means, a vertical reflection line setting means, and a plane calculation means. The depth slice is composed of a horizontal depth slice showing the reflection surface strength on a plan view set by the tunnel axis and the horizontal axis, and a vertical depth slice showing the reflection surface strength on a plan view set by the tunnel axis and the vertical axis. The depth slice storage means constituting the reflection surface estimation device is a means for storing horizontal depth slices created for each of multiple types of elastic wave velocities at multiple positions on the vertical axis, and storing vertical depth slices created for each of multiple types of elastic wave velocities at multiple positions on the horizontal axis. The vertical position designation means is a means for designating a position on the vertical axis by an operator's operation, the horizontal position designation means is a means for designating a position on the horizontal axis by an operator's operation, and the elastic wave velocity designation means is a means for designating an elastic wave velocity by an operator's operation. The display control means is a means for reading out a horizontal depth slice at a position designated by the vertical position designation means and associated with an elastic wave velocity designated by the elastic wave velocity designation means from the depth slice storage means and displaying it on the display means, and for reading out a vertical depth slice at a position designated by the horizontal position designation means and associated with an elastic wave velocity designated by the elastic wave velocity designation means from the depth slice storage means and displaying it on the display means. The horizontal specific point designation means is a means for designating a horizontal specific point selected by the operator on the horizontal depth slice displayed on the display means by an operator's operation, and the vertical specific point designation means is a means for designating a vertical specific point selected by the operator on the vertical depth slice displayed on the display means by an operator's operation. The horizontal reflection line setting means is a means for setting a horizontal reflection line on the horizontal depth slice based on the distribution of reflection surface intensity represented on the horizontal depth slice and specific horizontal points, and the vertical reflection line setting means is a means for setting a vertical reflection line on the vertical depth slice based on the distribution of reflection surface intensity represented on the vertical depth slice and specific vertical points.The plane calculation means is a means for calculating a plane located in a three-dimensional space based on the horizontal reflection line and the vertical reflection line. The plane calculated by the plane calculation means can be estimated as the reflection surface in front of the tunnel face.

[0024] The reflecting surface estimation device of the present invention may be configured to set the horizontal reflection line and the vertical reflection line by an operator operation. In this case, the operator sets the horizontal reflection line using the horizontal reflection line setting means while visually checking the distribution of the reflecting surface intensity and the horizontal specific points, and sets the vertical reflection line using the vertical reflection line setting means while visually checking the distribution of the reflecting surface intensity and the vertical specific points.

[0025] The reflecting surface estimating device of the present invention can also automatically set the horizontal reflection line and the vertical reflection line by calculation. In this case, the horizontal reflection line setting means sets the horizontal reflection line so as to be a tangent to the distribution curve of the reflecting surface intensity at a specific horizontal point, and the vertical reflection line setting means sets the vertical reflection line so as to be a tangent to the distribution curve of the reflecting surface intensity at a specific vertical point.

[0026] The reflecting surface estimation device of the present invention may be configured such that a vertical position scroll bar, a horizontal position scroll bar, and an elastic wave velocity scroll bar are displayed on the display means. In this case, when an operator operates the vertical position scroll bar displayed on the display means, a position on the vertical axis corresponding to the position of the vertical position scroll bar is specified by the vertical position specifying means, and when an operator operates the horizontal position scroll bar displayed on the display means, a position on the horizontal axis corresponding to the position of the horizontal position scroll bar is specified by the horizontal position specifying means. Similarly, when an operator operates the elastic wave velocity scroll bar displayed on the display means, an elastic wave velocity corresponding to the position of the elastic wave velocity scroll bar is specified by the elastic wave velocity specifying means. Then, the display control means changes the horizontal depth slices and the vertical depth slices to be displayed on the display means according to the positions of the vertical position scroll bar, the horizontal position scroll bar, and the elastic wave velocity scroll bar.

[0027] The reflecting surface estimating device of the present invention may further include a specific point canceling means and a specific point confirming means. The specific point canceling means is a means for canceling the "designated state" of a horizontal specific point already designated by an operator operation and canceling the "designated state" of a vertical specific point already designated. The other specific point confirming means is a means for confirming the horizontal specific point designated by the horizontal specific point designating means and the vertical specific point designated by the vertical specific point designating means by an operator operation. In this case, the horizontal specific point designating means can designate a new horizontal specific point when the designated state of the horizontal specific point is cancelled by the specific point canceling means, and the vertical specific point designating means can designate a new vertical specific point when the designated state of the vertical specific point is cancelled by the specific point canceling means. The plane calculating means calculates a plane to be placed in the three-dimensional space based on the horizontal reflection line related to the horizontal specific point confirmed by the specific point confirming means and the vertical reflection line related to the vertical specific point confirmed by the specific point confirming means.

[0028] The reflecting surface estimating device of the present invention may further include a warning output means for outputting a warning to an operator when the distance between the horizontal reflection line and the vertical reflection line arranged in the three-dimensional space exceeds a predetermined distance threshold. In this case, the plane calculation means calculates a plane arranged in the three-dimensional space when the distance between the lines falls below the distance threshold. Effect of the Invention

[0029] The reflecting surface estimating device of the present invention has the following advantages. (1) The peak points of the reflection surface strength (specific horizontal points, specific vertical points) can be selected more easily and quickly than with conventional technology, and as a result, the reflection surface existing in front of the tunnel face can be estimated more easily and quickly than with conventional technology. (2) Since it is possible to estimate the reflective surface in front of the tunnel face more easily and quickly than with conventional technology, the information can be quickly reflected in tunnel excavation work and more effective countermeasures can be prepared. (3) The task of selecting the peak point of the reflection surface intensity has become easier and shorter, which reduces human error due to fatigue, etc., thereby providing high-quality exploration results. [Brief description of the drawings]

[0030] [Figure 1] (a) is a plan view of the tunnel seen from above, (b) is a vertical cross-section of the tunnel, and (c) is an oblique view of the tunnel seen from the portal side to the face side. [Diagram 2] FIG. 1 is a model diagram showing an example of a depth slice. [Diagram 3] 1 is a flow diagram showing the main steps for creating depth slices. [Figure 4] A UI diagram for editing and processing waveforms obtained by elastic wave exploration. [Diagram 5] 1 is a block diagram showing the main configuration of a reflecting surface estimating device according to the present invention; [Figure 6] A UI diagram for specifying vertical position, horizontal position, and elastic wave velocity. [Figure 7] 3 is a flowchart showing a main process flow when using the reflecting surface estimating device of the present invention. [Figure 8] FIG. 11 is a flowchart showing the flow of main processes until a fixed horizontal specific point is fixed. [Figure 9] FIG. 11 is a flow diagram showing the flow of main processes until a confirmed vertical specific point is confirmed. [Figure 10] 11 is a flowchart showing a main process flow up to when a plane calculation means calculates a reflecting plane. [Figure 11] FIG. 2 is a model diagram showing an example of a reflecting plane created using the reflecting surface estimating device of the present invention. [Figure 12] A schematic model showing the multiple horizontal depth slices that will be created. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] An embodiment of the reflecting surface estimating device of the present invention will be described with reference to the drawings.

[0032] 1.Definition In describing the embodiment of the reflecting surface estimation device of the present invention, the definitions of the terms used here are first provided. The terms defined up to this point will also be defined here again just to be sure. Furthermore, the reflecting surface estimation device of the present invention is a technology for processing the results of elastic wave exploration using a 3D reflection method, and therefore, unless otherwise specified, the term "elastic wave exploration" simply means "elastic wave exploration using a 3D reflection method."

[0033] (reflective surface) One of the features of the reflection surface estimation device of the present invention is that it grasps reflection events existing in front of a tunnel face based on the results of elastic wave exploration using a 3D reflection method, and these reflection events can contribute to the prediction of faults and partial weak layers. As described above, elastic wave exploration using a 3D reflection method is an exploration method that observes waves reflected at a geological boundary surface (i.e., a reflection event) where the velocity and density change. For convenience, the reflection event generated by such a geological boundary surface is referred to as a "reflection surface", the wave reflected at this reflection surface is referred to as a "reflected wave", and the energy of the reflected wave as a wave is referred to as the "reflection surface intensity". Examples of the reflection surface intensity include wave energy such as the amplitude of the reflected wave and other electrical signals that represent the intensity of the wave and can be received by a receiver.

[0034] (Tunnel 3D space) The reflecting surface is naturally arranged in a three-dimensional space. Therefore, for convenience, the description will be given with a coordinate system of three orthogonal axes as shown in FIG. 1, and the space formed by the coordinate system of the three orthogonal axes will be referred to as the "tunnel three-dimensional space". FIG. 1 is a diagram for explaining the tunnel three-dimensional space, in which (a) is a plan view of the tunnel seen from above, (b) is a cross-sectional view of the tunnel cut along a vertical section, and (c) is a perspective view of the tunnel seen from the entrance side to the face side. As shown in FIG. 1, the first axis of the three orthogonal axes is the "tunnel axis (X-axis in the diagram)" along the axis of the tunnel (the excavation axis, so to speak), the second axis is the "horizontal axis (Y-axis in the diagram)" perpendicular to the tunnel axis (X-axis) and set horizontally, and the third axis is the "vertical axis (Z-axis in the diagram)" perpendicular to the tunnel axis (X-axis) and set vertically. In other words, the three-dimensional space of a tunnel is a space defined by a coordinate system consisting of three orthogonal axes: the tunnel axis (X-axis), horizontal axis (Y-axis), and vertical axis (Z-axis). As shown in Figure 1(b), it is recommended that the horizontal axis (Z=0) be set at the spring line SL position, and the vertical axis (Y=0) be set at the tunnel center CL position.

[0035] (Depth Slice) To visually represent the analysis results of the three-dimensional data set obtained by the 3D reflection method, cross-sectional views showing the exploration results at each finely divided position in the depth direction are sometimes created and these cross-sections are then superimposed. Here, these cross-sectional views are called "depth slices." As shown in Figure 2, these depth slices are two-dimensional views in which the reflection points (positions where the reflected waves are reflected on the reflecting surface) of the reflected waves received by the receiver are connected like contour lines, and then colored (or shaded) according to the strength of the reflection.

[0036] In addition, when a three-dimensional reflection elastic wave exploration is performed as an exploration ahead of the tunnel face, two types of depth slices may be created, and the present invention also uses two types of depth slices. The first depth slice is a depth slice expressed on a plane (XY plane) set by the tunnel axis (X axis) and the horizontal axis (Y axis), and for convenience, it is referred to as a "horizontal depth slice." The second depth slice is a depth slice expressed on a plane (XZ plane) set by the tunnel axis (X axis) and the vertical axis (Z axis), and for convenience, it is referred to as a "vertical depth slice." The horizontal depth slices are created at each position (hereinafter referred to as "vertical position") finely divided in the vertical direction (Z axis direction), and the vertical depth slices are created at each position (hereinafter referred to as "horizontal position") finely divided in the horizontal direction (Y axis direction), and further, the horizontal depth slices and the vertical depth slices are created for each different elastic wave speed.

[0037] Depth slices are generally created according to the procedure shown in Figure 3. First, the data (waveform) acquired by the receiver is loaded into a computer (Step 10 in Figure 3), and the waveform is edited. Figure 4 shows an example of an operation screen (UI: User Interface) of an application that edits waveforms acquired by elastic wave exploration. The editing process involves inputting geometry such as the coordinates of the artificial seismic source (seismic point) and the coordinates of the receiving point (Step 20 in Figure 3), removing direct waves (Step 30 in Figure 3), improving the signal-to-noise ratio (S / N ratio) by using a bandpass filter (Step 40 in Figure 3) or a tap filter, or by performing stacking processing, and performing a Fourier transform to convert the time series data of elastic waves into the frequency domain. When the editing process is completed, migration is performed using a method such as differential migration, Kirchhoff migration, or fk migration (Step 50 in FIG. 3), and the depth slices (horizontal depth slices and vertical depth slices) are output as image format files (Step 60 in FIG. 3). The image files of the depth slices output here are stored in a depth slice storage means 101, which will be described later.

[0038] (specific point) As described above, the depth slice shown in FIG. 2 is a two-dimensional diagram in which the reflection points of the reflected wave are connected like contour lines and further colored (or shaded) according to the strength of the reflection intensity. The shape of the connected reflection points is a curved shape close to an ellipse or circle, and multiple curves are drawn in a roughly concentric shape. For convenience, this curve is referred to as the "reflection surface intensity distribution curve." In addition, since the reflection intensity is colored (or shaded) according to the strength of the reflection intensity, the peak point where the reflection intensity is maximum can be confirmed by visually inspecting the depth slice. For convenience, this peak point is referred to as the "specific point," and in particular, the peak point confirmed in the horizontal depth slice is referred to as the "horizontal specific point," and the peak point confirmed in the vertical depth slice is referred to as the "vertical specific point."

[0039] The number of horizontal depth slices created is the product of the number of vertical positions and the number of elastic wave velocities. Each horizontal depth slice has a horizontal specific point, and the horizontal specific point showing the maximum reflection intensity is used for subsequent processing. In other words, while checking a large number of horizontal depth slices, horizontal specific points are provisionally determined, and then the horizontal specific points are finally determined. For convenience, the provisionally determined horizontal specific points are referred to as "provisional horizontal specific points" and the determined horizontal specific points are referred to as "determined horizontal specific points." Similarly, the provisionally determined vertical specific points are referred to as "provisional vertical specific points" and the determined vertical specific points are referred to as "determined vertical specific points." In addition, the provisional horizontal specific points and the provisional vertical specific points are collectively referred to simply as "provisional specific points," and the determined horizontal specific points and the determined vertical specific points are collectively referred to simply as "determined specific points."

[0040] (reflection line) The specific point is a point that constitutes the reflecting surface intensity distribution curve, in other words, the specific point is located on the reflecting surface intensity distribution curve. Therefore, if the reflecting surface intensity distribution curve is approximated to a predetermined curve (e.g., an ellipse or a circle) that can be expressed by a mathematical formula, a tangent line passing through the specific point can be set. For convenience, this tangent line is referred to as a "reflection line", and in particular, a reflection line passing through a horizontal specific point on a horizontal depth slice is referred to as a "horizontal reflection line", and a reflection line passing through a vertical specific point on a vertical depth slice is referred to as a "vertical reflection line".

[0041] (reflection plane) The horizontal reflection line and the vertical reflection line are located in orthogonal planes, that is, the horizontal reflection line is located on the XY plane, and the vertical reflection line is located on the XZ plane. When the horizontal reflection line and the vertical reflection line intersect, a plane is determined on which the horizontal reflection line and the vertical reflection line are located at the same time. Of course, this plane is located in the three-dimensional space of the tunnel (X-axis-Y-axis-Z-axis), and for convenience, this plane will be specifically referred to as the "reflection plane" here. This reflection plane can be considered to be set due to a reflection event such as a geological boundary surface, and therefore the reflection plane located in the three-dimensional space of the tunnel is a "reflection surface" and can be considered to be a ground structure such as a fault or a partially soft layer.

[0042] 2. Reflective surface estimation device Next, the reflecting surface estimation device of the present invention will be described. Fig. 5 is a block diagram showing the main components of the reflecting surface estimation device 100 of the present invention. As shown in this figure, the reflecting surface estimation device 100 of the present invention includes a depth slice storage means 101, a vertical position designation means 102, a horizontal position designation means 103, an elastic wave velocity designation means 104, a display control means 105, a horizontal specific point designation means 106, a vertical specific point designation means 107, a horizontal reflection line setting means 108, a vertical reflection line setting means 109, a plane calculation means 110, and a display means 115, and may further include a specific point release means 111, a specific point determination means 112, a warning output means 113, a line distance calculation means 114, and the like.

[0043] The vertical position designation means 102, horizontal position designation means 103, elastic wave velocity designation means 104, display control means 105, horizontal specific point designation means 106, vertical specific point designation means 107, horizontal reflection line setting means 108, vertical reflection line setting means 109, plane calculation means 110, specific point release means 111, specific point confirmation means 112, warning output means 113, and line distance calculation means 114 (vertical position designation means 102 to line distance calculation means 114) constituting the reflecting surface estimation device 100 can be manufactured as dedicated devices, or a general-purpose computer can be used. For example, each process (function) executed by the vertical position designation means 102 to line distance calculation means 114 can be constructed as one application software (program), and the program can be executed by a computer. This computer is equipped with a processor such as a CPU, storage and memory such as a ROM and a RAM, and may further include input means such as a mouse and a keyboard, and a display, and examples of such computers include portable terminal devices such as tablet computers (iPad (registered trademark), etc.) and smartphones, as well as personal computers (PCs), servers, etc. If the computer has a display, it is preferable to use this display as the display means 115.

[0044] The depth slice storage means 101 can be a computer storage device or can be built in a database server. When built in a database server, it can be placed in a local network (LAN: Local Area Network) or can be a cloud server that stores data via the Internet (for example, wireless communication).

[0045] Below, each of the main elements constituting the reflecting surface estimating apparatus 100 will be described in detail.

[0046] (Depth slice storage means) The depth slice storage means 101 is a means for storing the results obtained by the three-dimensional reflection elastic wave exploration, and more specifically, stores the "depth slice image file" described with reference to Fig. 3. As described above, the number of horizontal depth slices created is the product of the "number of vertical positions" and the "number of elastic wave velocities", and similarly, the number of vertical depth slices created is the product of the "number of horizontal positions" and the "number of elastic wave velocities", so naturally the depth slice storage means 101 stores the number of horizontal depth slices created by the product of the "number of vertical positions" and the "number of elastic wave velocities", and stores the number of vertical depth slices created by the product of the "number of horizontal positions" and the "number of elastic wave velocities".

[0047] (Each designation method) The vertical position designation means 102 is a means for designating the "vertical position" where the horizontal depth slice was created, the horizontal position designation means 103 is a means for designating the "horizontal position" where the vertical depth slice was created, and the elastic wave velocity designation means 104 is a means for designating the "elastic wave velocity" by an operator's operation. When designating by the operator's operation, it is advisable to use the vertical position scroll bar 102B, the horizontal position scroll bar 103B, and the elastic wave velocity scroll bar 104B displayed on the display means 115 as shown in FIG. 6. When using such a UI, the operator slides the sliders with a pointing device (mouse, touch panel, pen tablet, touch pad, track pad, track ball, etc.) to designate the desired vertical position, horizontal position, and elastic wave velocity. This allows the operator to intuitively and easily perform the designation operation. Of course, in addition to using the scroll bar, various other methods can be adopted, such as directly entering numbers using a keyboard, pressing buttons such as "Next" and "Previous," or automatically displaying depth slices continuously and stopping at that depth slice when the "STOP" button is pressed.

[0048] (Display control means) The display control means 105 is a means for displaying the depth slices read from the depth slice storage means 101 on the display means 115. More specifically, the display control means 105 queries the depth slice storage means 101 with the "vertical position" specified by the vertical position specification means 102 and the "elastic wave velocity" specified by the elastic wave velocity specification means 104, reads out the corresponding "horizontal depth slice" and displays it on the display means 115. Similarly, the display control means 105 queries the depth slice storage means 101 with the "horizontal position" specified by the horizontal position specification means 103 and the "elastic wave velocity" specified by the elastic wave velocity specification means 104, reads out the corresponding "vertical depth slice" and displays it on the display means 115. Therefore, when the UI shown in FIG. 6 is used, the horizontal depth slices displayed momentarily change in response to the slider operation of the vertical position scroll bar 102B, and the vertical depth slices displayed momentarily change in response to the slider operation of the horizontal position scroll bar 103B, so that the depth slices transition continuously like an electronic picture book. Note that when the slider of the elastic wave velocity scroll bar 104B is operated, both the horizontal depth and the vertical depth slices are changed simultaneously.

[0049] (Specific point designation means) The horizontal specific point designation means 106 is a means for designating a "horizontal specific point" and the vertical specific point designation means 107 is a means for designating a "vertical specific point" by an operator's operation. More specifically, the operator searches for a peak point at which the reflection intensity is maximum while visually checking the horizontal depth slice displayed on the display means 115, and designates the horizontal specific point using a pointing device or the like. Similarly, the operator searches for a peak point at which the reflection intensity is maximum while visually checking the vertical depth slice displayed on the display means 115, and designates the vertical specific point using a pointing device or the like. Of course, instead of the operator designating the specific point by, so to speak, manual input, it is also possible to automatically extract the peak point at which the reflection intensity is maximum using various image recognition techniques that have been conventionally used, and set it as the horizontal specific point or the vertical specific point.

[0050] (Reflection line setting means) The horizontal reflection line setting means 108 is a means for setting a "horizontal reflection line setting," and the vertical reflection line setting means 109 is a means for setting a "vertical reflection line setting." Setting of the reflection line setting can be performed manually or automatically. In the case of manual setting, the operator manually sets the horizontal reflection line using a pointing device or the like while visually observing the horizontal depth slice displayed on the display means 115 so that the horizontal reflection line is a tangent to the reflection surface intensity distribution curve at a specific horizontal point, and similarly, the operator manually sets the vertical reflection line using a pointing device or the like while visually observing the vertical depth slice displayed on the display means 115 so that the vertical reflection line is a tangent to the reflection surface intensity distribution curve at a specific vertical point.

[0051] On the other hand, in the case of automatic setting, for example, at the timing when a specific horizontal point is designated, a reflecting surface intensity distribution curve related to the specific horizontal point in the horizontal depth slice is approximated to a predetermined curve (e.g., an ellipse or a circle) that can be expressed by a mathematical formula, and a tangent to the reflecting surface intensity distribution curve at the specific horizontal point is calculated as a horizontal reflection line and displayed on the display means 115. Similarly, at the timing when a specific vertical point is designated, a reflecting surface intensity distribution curve related to the specific vertical point in the vertical depth slice is approximated to a predetermined curve, and a tangent to the reflecting surface intensity distribution curve at the specific vertical point is calculated as a vertical reflection line and displayed on the display means 115.

[0052] (Plane calculation means) The plane calculation means 110 is a means for calculating a "reflection plane" to be placed in the tunnel three-dimensional space (X-axis-Y-axis-Z-axis) based on the horizontal reflection line and the vertical reflection line. As described above, the horizontal reflection line is placed on the XY plane, and the vertical reflection line is placed on the XZ plane. When the horizontal reflection line and the vertical reflection line intersect, a plane on which the horizontal reflection line and the vertical reflection line are simultaneously placed is determined, so that the reflection plane can be calculated geometrically. Note that when the horizontal reflection line and the vertical reflection line do not intersect, that is, when there is a distance between the horizontal reflection line and the vertical reflection line (hereinafter referred to as "inter-line distance"), it is advisable to move in parallel (moving while maintaining the direction of the reflection line) until either the horizontal reflection line or the vertical reflection line (or both) intersect, and then calculate the reflection plane.

[0053] In principle, the operator specifies a vertical specific point from the reflecting surface intensity distribution curve corresponding to the reflecting surface intensity distribution curve related to the horizontal specific point. However, the operator may specify a wrong vertical specific point (or horizontal specific point) due to an operation error, and in this case, a large distance may occur between the horizontal reflection line and the vertical reflection line, that is, the line distance may show a large value. Therefore, the warning output means 113 may output warning information to alert the operator. Specifically, the warning output means 113 may compare the line distance calculated by the line distance calculation means 114 with a predetermined threshold value (hereinafter referred to as the "distance threshold value"), and output warning information when the line distance exceeds the distance threshold value. At this time, the plane calculation means 110 may not calculate the reflecting plane, and may calculate the reflecting plane only when the line distance is below the distance threshold value. The warning information may be in various formats, such as text information displayed on the display means 115, audio information, and vibration information.

[0054] (Specific point release means and specific point determination means) As described above, while checking a large number of horizontal depth slices, tentative horizontal specific points are determined and then finally definite horizontal specific points are determined, and while checking a large number of vertical depth slices, tentative vertical specific points are determined and then finally definite vertical specific points are determined. In other words, the tentative horizontal specific points and the tentative vertical specific points are only tentative and may be changed at any time. On the other hand, when a plurality of tentative horizontal specific points and tentative vertical specific points are designated by the horizontal specific point designation means 106 and the vertical specific point designation means 107, confusion occurs when determining the definite horizontal specific points and the definite vertical specific points. Therefore, when changing the tentative horizontal specific points and the provisional vertical specific points, that is, when designating new tentative horizontal specific points and provisional vertical specific points, it is advisable for the operator to operate the specific point cancellation means 111 to cancel the previous tentative horizontal specific points and provisional vertical specific points (i.e., to cancel the designated state of the specific points), and then designate new provisional horizontal specific points and provisional vertical specific points. Specifically, as shown in Fig. 6, the operator can cancel the tentative horizontal specified point and tentative vertical specified point by pressing a "Cancel button 111B" displayed on the display means 115 using a pointing device or the like, and then specify a new tentative horizontal specified point and tentative vertical specified point.

[0055] When the confirmed horizontal specific point and the confirmed vertical specific point are finally determined, the operator determines them by operating the specific point determination means 112. Specifically, as shown in Fig. 6, the operator presses the "ok button 112B" displayed on the display means 115 using a pointing device or the like, whereby the tentative horizontal specific point at that time is determined as the confirmed horizontal specific point, and the tentative vertical point at that time is determined as the confirmed vertical specific point. Then, a horizontal reflection line is set for this confirmed horizontal specific point, and a vertical reflection line is set for this vertical reflection line.

[0056] (Display means) As shown in FIG. 6, the display means 115 displays the vertical position, horizontal position, elastic wave velocity, and the like, together with the vertical position scroll bar 102B, horizontal position scroll bar 103B, elastic wave velocity scroll bar 104B, cancel button 111B, and ok button 112B. The display means 115 can also simultaneously display horizontal depth slices and vertical depth slices as shown in this figure. In this figure, the horizontal depth slice is displayed on the left side, and the vertical depth slice is displayed on the right side. Furthermore, the display means 115 can simultaneously display (for example, above and below) the horizontal depth slice currently being confirmed and the horizontal depth slice related to the tentative horizontal specific point up to that point. This allows the user to easily compare the tentative horizontal specific point up to that point with the current horizontal specific point, which can contribute to the decision of whether or not to change the tentative horizontal specific point. Of course, the vertical depth slice can also be displayed in the same way. In this case, it is preferable to display two horizontal depth slices above and below the left side (or right side) and two vertical depth slices above and below the right side (or left side).

[0057] (Processing flow) Next, the flow of main processes when using the reflecting surface estimating device 100 of the present invention will be described with reference to Fig. 7. Fig. 7 is a flow diagram showing the flow of main processes of the reflecting surface estimating device 100. In this flow diagram, the central column shows the processes to be performed, the left column shows input information required for the processes, and the right column shows output information resulting from the processes.

[0058] First, image files of depth slices are created, for example, according to the procedure shown in Fig. 3, and these image files of depth slices are stored in the depth slice storage means 101. Then, the operator specifies the elastic wave velocity by operating, for example, the elastic wave velocity scroll bar 104B shown in Fig. 6 (Step 210 in Fig. 7).

[0059] Once the elastic wave velocity is specified, a definite horizontal specific point is determined (Step 220 in FIG. 7), and a definite vertical specific point is determined (Step 230 in FIG. 7). Note that, although FIG. 7 shows the flow of determination in the order of definite horizontal specific point, it is of course possible to determine the definite vertical specific point, then the definite horizontal specific point. Hereinafter, the flow of processing up to the determination of a definite horizontal specific point will be described with reference to FIG. 8. As in FIG. 7, this flow chart shows the processing to be performed in the center column, the input information required for that processing in the left column, and the output information resulting from that processing in the right column.

[0060] When the elastic wave velocity is designated, the operator designates the vertical position by operating, for example, the vertical position scroll bar 102B shown in FIG. 6 (Step 221 in FIG. 8). As a result, the display control means 105 reads out the corresponding horizontal depth slice from the depth slice storage means 101 and displays it on the display means 115 (Step 222 in FIG. 8), and the operator designates the horizontal specific point while visually observing the horizontal depth slice. At this time, if the horizontal specific point related to the currently displayed horizontal depth slice is to be set as the tentative horizontal specific point instead of the tentative horizontal specific point already designated (Yes in Step 223 in FIG. 8), the operator presses, for example, the cancel button 111B shown in FIG. 6 to cancel the tentative horizontal specific point up to that point (Step 224 in FIG. 8), and then designates a new tentative horizontal specific point (Step 225 in FIG. 8). On the other hand, if the tentative horizontal specific point already designated is to be maintained (No in Step 223 in FIG. 8), the process proceeds to the next process (Step 226 in FIG. 8). If a tentative horizontal specific point has not yet been specified, the process of determining whether to change the specific point (Step 223 in FIG. 8) and the process of canceling the specific point (Step 224 in FIG. 8) are omitted, and a tentative horizontal specific point is specified (Step 225 in FIG. 8).

[0061] When the series of processes (Step 221 in FIG. 8 to Step 225 in FIG. 8) have not been executed for all planned vertical positions (No in Step 223 in FIG. 8), the vertical position is changed (Step 221 in FIG. 8) and then the series of processes (Step 222 in FIG. 8 to Step 225 in FIG. 8) are executed. On the other hand, when the series of processes (Step 221 in FIG. 8 to Step 225 in FIG. 8) have been executed for all planned vertical positions (Yes in Step 227 in FIG. 8), the operator presses, for example, ok button 112B shown in FIG. 6, and the tentative horizontal specified point at that time is confirmed as a confirmed horizontal specified point (Step 225 in FIG. 8).

[0062] After the fixed horizontal specific points are determined, the fixed vertical specific points are determined in the order shown in Fig. 9. The flow of processing up to the determination of the fixed vertical specific points will be explained below with reference to Fig. 9. In this flow chart, as in Fig. 7 and Fig. 8, the processing to be performed is shown in the center column, the input information required for that processing is shown in the left column, and the output information resulting from that processing is shown in the right column.

[0063] When the fixed horizontal specific point is fixed, the operator operates the horizontal position scroll bar 103B shown in FIG. 6 to specify the horizontal position (Step 231 in FIG. 9). As a result, the display control means 105 reads out the corresponding vertical depth slice from the depth slice storage means 101 and displays it on the display means 115 (Step 232 in FIG. 9), and the operator specifies the vertical specific point while visually observing the vertical depth slice. At this time, if the vertical specific point related to the currently displayed vertical depth slice is to be set as the provisional vertical specific point instead of the provisional vertical specific point already specified (Yes in Step 233 in FIG. 9), the operator presses the cancel button 111B shown in FIG. 6, for example, to cancel the provisional vertical specific point up to that point (Step 234 in FIG. 9), and then specifies a new provisional vertical specific point (Step 235 in FIG. 9). On the other hand, if the provisional vertical specific point already specified is to be maintained (No in Step 233 in FIG. 9), the process proceeds to the next process (Step 236 in FIG. 9). In addition, if a provisional vertical specific point has not yet been specified, the process of determining whether to change the specific point (Step 233 in FIG. 9) and the process of canceling the specific point (Step 234 in FIG. 9) are omitted, and a provisional vertical specific point is specified (Step 235 in FIG. 9).

[0064] When the series of processes (Step 231 in FIG. 9 to Step 235 in FIG. 9) have not been executed for all planned vertical positions (No in Step 233 in FIG. 9), the horizontal position is changed (Step 231 in FIG. 9) and the series of processes (Step 232 in FIG. 9 to Step 235 in FIG. 9) are subsequently executed. On the other hand, when the series of processes (Step 231 in FIG. 9 to Step 235 in FIG. 9) have been executed for all planned vertical positions (Yes in Step 237 in FIG. 9), the operator presses, for example, the ok button 112B shown in FIG. 6, to confirm the tentative vertical specific point at that time as the confirmed vertical specific point (Step 235 in FIG. 9).

[0065] When the series of processes (Step 210 in FIG. 7 to Step 230 in FIG. 7) have not been performed for all the planned elastic wave velocities (No in Step 240 in FIG. 7), the elastic wave velocities are changed (Step 210 in FIG. 7) and the series of processes (Step 220 in FIG. 7 to Step 230 in FIG. 7) are subsequently performed. On the other hand, when the series of processes (Step 210 in FIG. 7 to Step 230 in FIG. 7) have been performed for all the planned elastic wave velocities (Yes in Step 240 in FIG. 7), the horizontal reflection line setting means 108 sets a horizontal reflection line setting and the vertical reflection line setting means 109 sets a vertical reflection line setting (Step 250 in FIG. 7), and the plane calculation means 110 calculates a reflection plane to be placed in the three-dimensional space of the tunnel (Step 260 in FIG. 7).

[0066] Hereinafter, the flow of processing up to when the plane calculation means 110 calculates the reflection plane will be described with reference to FIG. 10. In this flow chart, as in FIG. 7 to FIG. 9, the central column shows the processing to be performed, the left column shows input information required for the processing, and the right column shows output information resulting from the processing. When the horizontal reflection line setting means 108 sets the horizontal reflection line and the vertical reflection line setting means 109 sets the vertical reflection line, the line distance calculation means 114 calculates the line distance between the horizontal reflection line and the vertical reflection line (Step 271 in FIG. 10). Then, when the line distance exceeds the distance threshold (Yes in Step 272 in FIG. 10), the warning output means 113 outputs warning information by text information, audio information, vibration information, or the like (Step 273 in FIG. 10). On the other hand, when the line distance is below the distance threshold (No in Step 272 in FIG. 10), the plane calculation means 110 calculates the reflection plane (Step 260 in FIG. 7). An example of a reflecting plane created using the reflecting surface estimation device 100 of the present invention is shown in Fig. 11. As shown in this figure, the reflecting surface estimation device 100 of the present invention can calculate multiple reflecting planes (two in this figure) for each reflecting surface intensity distribution curve based on the same elastic wave exploration result. [Industrial Applicability]

[0067] The reflecting surface estimation device of the present invention can be used in the excavation of various tunnels, such as road tunnels, railway tunnels, and pedestrian tunnels. According to the present invention, a high-quality tunnel can be completed by excavating the tunnel face in a stable state, and the tunnel can be quickly used again. In addition, the safety of the workers can be ensured while construction is carried out. Considering this, the present invention can be expected to not only be used industrially, but also to make a great contribution to society. [Explanation of symbols]

[0068] 100 Reflecting surface estimation device of the present invention 101 Depth slice storage means (of reflecting surface estimation device) 102 (Reflecting surface estimation device) vertical position designation means 102B Vertical position scroll bar (for specifying vertical position) 103 (Reflection surface estimation device) horizontal position designation means 103B Horizontal position scroll bar (for specifying horizontal position) 104 (Reflection surface estimation device) Elastic wave velocity designation means 104B Elastic wave velocity scroll bar (for specifying elastic wave velocity) 105 Display control means (of reflecting surface estimation device) 106 (Reflection surface estimation device) horizontal specific point designation means 107 (Reflection surface estimation device) vertical specific point designation means 108 (Reflection surface estimation device) horizontal reflection line setting means 109 (Reflection surface estimation device) vertical reflection line setting means 110 (Reflecting surface estimation device) plane calculation means 111 (Reflection surface estimation device) specific point release means 111B (specific point release means) Cancel button 112 (Reflecting surface estimation device) specific point determination means 112B (specific point confirmation method) OK button 113 (Reflecting surface estimation device) warning output means 114 (Reflecting surface estimation device) Line distance calculation means 115 Display means (of reflecting surface estimation device) CL Tunnel Center SL Spring Line

Claims

1. A device for estimating a reflection surface in front of a tunnel face in a three-dimensional space consisting of a tunnel axis set in the axial direction of the tunnel, a horizontal axis perpendicular to the tunnel axis, and a vertical axis perpendicular to the tunnel axis, based on a depth slice that represents a plan view of reflection surface intensity obtained by a three-dimensional reflection method elastic wave exploration, the device comprising: the depth slices are composed of a horizontal depth slice showing the reflective surface intensity in a plan view defined by the tunnel axis and the horizontal axis, and a vertical depth slice showing the reflective surface intensity in a plan view defined by the tunnel axis and the vertical axis; a depth slice storage means for storing the horizontal depth slices created for each of a plurality of types of elastic wave velocities at a plurality of positions on the vertical axis, and for storing the vertical depth slices created for each of a plurality of types of elastic wave velocities at a plurality of positions on the horizontal axis; a vertical position designation means for designating a position on the vertical axis by an operator's operation; a horizontal position designation means for designating a position on the horizontal axis by an operator's operation; An elastic wave velocity designation means for designating an elastic wave velocity by an operator's operation; a display control means for reading out from the depth slice storage means the horizontal depth slice at the position designated by the vertical position designation means and associated with the elastic wave velocity designated by the elastic wave velocity designation means and displaying it on a display means, and for reading out from the depth slice storage means the vertical depth slice at the position designated by the horizontal position designation means and associated with the elastic wave velocity designated by the elastic wave velocity designation means and displaying it on the display means; a horizontal specific point designation means for designating a horizontal specific point selected by an operator on the horizontal depth slice displayed on the display means by an operator operation; a vertical specific point designation means for designating a vertical specific point selected by an operator on the vertical depth slice displayed on the display means by an operator operation; a horizontal reflection line setting means for setting a horizontal reflection line on the horizontal depth slice based on the distribution of the reflection surface intensity represented on the horizontal depth slice and the horizontal specific point; A vertical reflection line setting means for setting a vertical reflection line on the vertical depth slice based on the distribution of the reflection surface intensity represented on the vertical depth slice and the vertical specific point; a plane calculation means for calculating a plane disposed in the three-dimensional space based on the horizontal reflection line and the vertical reflection line, The plane calculated by the plane calculation means can be estimated as the reflection surface in front of the tunnel face. A reflecting surface estimation device comprising:

2. an operator sets the horizontal reflection line using the horizontal reflection line setting means while visually observing the distribution of the reflection surface intensity and the horizontal specific point; an operator sets the vertical reflection line using the vertical reflection line setting means while visually observing the distribution of the reflection surface intensity and the vertical specific point; 2. The reflecting surface estimating device according to claim 1.

3. the horizontal reflection line setting means sets the horizontal reflection line so as to be a tangent to the distribution curve of the reflection surface intensity at the horizontal specific point; the vertical reflection line setting means sets the vertical reflection line so as to be a tangent to the distribution curve of the reflection surface intensity at the vertical specific point; 2. The reflecting surface estimating device according to claim 1.

4. when an operator operates a vertical position scroll bar displayed on said display means, said vertical position designation means designates a position on said vertical axis corresponding to the position of said vertical position scroll bar; when an operator operates a horizontal position scroll bar displayed on the display means, a position on the horizontal axis corresponding to the position of the horizontal position scroll bar is specified by the horizontal position specifying means; When an operator operates an elastic wave velocity scroll bar displayed on the display means, the elastic wave velocity designation means designates an elastic wave velocity corresponding to the position of the elastic wave velocity scroll bar, the display control means changes the horizontal depth slices and the vertical depth slices to be displayed on the display means according to a position of the vertical position scroll bar, a position of the horizontal position scroll bar, and a position of the elastic wave velocity scroll bar.

4. The reflecting surface estimating device according to claim 1, wherein the reflecting surface estimating device is a reflecting surface estimating device.

5. a specific point canceling means for canceling a specified state of the horizontal specific point already specified and canceling a specified state of the vertical specific point already specified by an operator operation; a specific point determination means for determining, by an operator operation, the horizontal specific point designated by the horizontal specific point designation means and the vertical specific point designated by the vertical specific point designation means, the horizontal specific point designation means is capable of designating a new horizontal specific point when the designated state of the horizontal specific point is released by the specific point release means, the vertical specific point designation means is capable of designating a new vertical specific point when the designation state of the vertical specific point is released by the specific point release means, the plane calculation means calculates the plane located in the three-dimensional space based on the horizontal reflection line associated with the horizontal specific point determined by the specific point determination means and the vertical reflection line associated with the vertical specific point determined by the specific point determination means.

5. The reflecting surface estimating device according to claim 1,

6. a warning output unit that outputs a warning to an operator when a line distance between the horizontal reflection line and the vertical reflection line arranged in the three-dimensional space exceeds a predetermined separation threshold value; the plane calculation means calculates the plane disposed in the three-dimensional space when the line distance falls below the separation threshold value.

6. The reflecting surface estimating device according to claim 1,

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