JP7558376B2 - Mobile measurement object - Google Patents

Description

The present invention relates to a technology for displaying the state of a tunnel face during excavation, and more specifically, to a technology for displaying the state of a tunnel face using color information obtained based on a three-dimensional model of the tunnel face.

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 use either the cut earth method, which excavates part of the slope, or the tunnel method, which hollows out the inside 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, the amount of excavated soil (i.e. the amount of soil discharged) tends to be less than the cut earth method, and it has the advantage of allowing greater freedom in the linear planning of roads, etc. (for example, shortcuts can be taken), and it is said that more than 10,000 tunnels have been built in Japan to date.

Until the 1970s, the "sheet pile method," which combined steel arch supports with wooden sheet piles to support the ground, was the mainstream construction method for mountain tunnels, but now the New Australian Tunneling Method (NATM), which actively utilizes the strength of the ground, has become mainstream. NATM's main feature is its design philosophy that relies on the strength of the 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 construction speed, thereby reducing construction costs.

In addition, since NATM was first fully implemented, excavation technology has made great strides, and the development of various auxiliary construction methods has made it possible to handle a variety of natural ground, and the advancement of excavation machines (particularly open-face excavators) has made it possible to choose mechanical excavation in addition to blasting excavation. Although mechanical excavation depends on the excavation cross-sectional area and linearity, it is generally often used for natural ground with relatively low strength (for example, uniaxial compressive strength of 49 N/ ^mm2 or less), while blasting excavation is often used when bedrock is present in the target natural ground.

Here, we will briefly explain the excavation procedure using NATM. First, the tunnel face is excavated. In the case of blast excavation, a drill jumbo is used to drill a hole, explosives (dynamite) are loaded, and the blasting takes place after the workers and machines have evacuated. On the other hand, in the case of mechanical excavation, the tunnel face is cut using a free-face excavator. The excavation length (one span length) for one cycle varies depending on the support pattern set according to the strength of the ground, but excavation is generally performed with a span length of 1.0 to 2.0 m. After one span length has been excavated, the debris is removed (debris removal) using 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 as necessary, and steel supports are erected as necessary (depending on the support pattern), and the second concrete is sprayed, followed by the installation of rock bolts. The first and second concrete spraying is carried out over the entire span of the tunnel, i.e., on the inner surface of the unlined tunnel (the surface extending from the side walls to the top).

Stabilizing the tunnel face in NATM is extremely important in terms of safe construction, and auxiliary construction methods are used on the tunnel face depending on the strength of the ground, spring water, or the behavior of the tunnel face. For example, concrete spraying (mirror spraying) and rock bolts (mirror bolts) are used to stabilize the tunnel face, drainage boring is performed, and forepoling and long forepilling as pre-supporting work are performed. Of these, concrete spraying on the tunnel face is relatively easy to arrange and work, can suppress loosening of the tunnel face in the longitudinal direction (excavation direction), can prevent the skin from falling off the tunnel face, and can isolate the tunnel face from air and moisture in the case of expansive ground, making it a practical and effective auxiliary construction method.

NATM is also a so-called information-based construction method that uses measurement techniques (A and B measurements) in combination, and the excavation pattern is changed or auxiliary methods are adopted depending on the measurement results. Measurement techniques include internal displacement and top subsidence to measure the behavior of the surrounding ground, rock bolt axial force measurement to measure the axial force of the driven rock bolts, and face observation. This face observation is literally a measurement technique that observes the tunnel face, and considering that the information obtained from the tunnel face, where the ground is most exposed, is both effective and voluminous, it is one of the most important measurement techniques for proceeding with future excavation.

Traditionally, tunnel face observations were performed visually by humans, and the results were recorded by sketching in a field notebook or similar. In other words, the usefulness of tunnel face observations (the amount of useful information) was heavily dependent on the observer's experience and knowledge. However, the construction industry has been suffering from a chronic labor shortage for some time, and it is expected that securing skilled observers will become increasingly difficult in the future. In addition, although photos of tunnel faces are taken, they are often not clear or have a consistent color tone in situations where there is insufficient lighting (or the lighting conditions are not consistent), and as a result, a third party cannot verify and confirm the cracks and weathering of the tunnel face, the state of spring water, etc., as determined by the observer. In other words, it can be pointed out that there is a problem in that traceability cannot be ensured.

Therefore, various techniques have been proposed to objectively evaluate tunnel faces, relying as little as possible on the experience and knowledge of the observer. For example, Patent Document 1 proposes a tunnel face evaluation system that uses genetic programming to analyze the relationship between blast hole data and evaluation points after blasting, and calculates evaluation points from the blast hole data using a prediction formula obtained from this analysis.

JP 2018-71165 A

Patent Document 1 uses genetic programming, and by accumulating a large number of combinations of blast hole data and evaluation points, it is possible to obtain a highly accurate prediction formula, which is expected to have the effect of making it possible to appropriately consider excavation patterns and auxiliary construction methods. On the other hand, the evaluation points after blasting are still based on the observer's subjective opinion, so there is some room for improvement in terms of completely resolving problems such as the difficulty of securing skilled observers and ensuring traceability of the evaluation results.

The objective of the present invention is to solve the problems inherent in conventional technology, i.e. to provide technology that can objectively evaluate tunnel faces without relying on the experience or knowledge of the observer.

The present invention was developed with a focus on creating a normal image based on a three-dimensional model of the tunnel face and expressing the tunnel face condition using color information from this normal image, and is an invention based on an unprecedented idea.

The mobile measuring body of the present invention comprises a mobile body capable of moving within a tunnel, two or more image acquisition means, a spectral camera, a temperature distribution sensor, and a surveying target. The two or more image acquisition means, the spectral camera, and the temperature distribution sensor are mounted on the mobile body, and the three or more reflectors are mounted on the mobile body and arranged at three or more locations that are not aligned on a straight line. The image acquisition means acquires an image of the tunnel face, the spectral camera acquires spectral data of the tunnel face, and the temperature distribution of the tunnel face is acquired by the temperature distribution sensor. Furthermore, the attitude of the mobile body and its position within the tunnel are measured by a surveying instrument installed within the tunnel aiming at the surveying target.

The mobile measuring object of the present invention can be one in which the relative positions of various means with respect to the mobile body are grasped. That is, the relative positions of the image acquisition means, the spectral camera, and the temperature distribution sensor with respect to the mobile body are grasped, and the relative orientation with respect to the mobile body is grasped. Also, the position of the survey target with respect to the mobile body is grasped. In this case, by measuring the orientation and position of the mobile body, the orientation of the image acquisition means and its position within the tunnel are obtained, the orientation of the spectral camera and its position within the tunnel are obtained, the orientation of the temperature distribution sensor and its position within the tunnel are obtained, and the position of the survey target within the tunnel is obtained.

The mobile measuring body of the present invention may further include a lighting device that is mounted on the mobile body and can irradiate light onto the tunnel face.

The tunnel face condition display system includes a moving body, two or more image acquisition means mounted on the moving body, three or more reflectors mounted on the moving body, a surface inclination calculation means, a normal image creation means, a crack interval calculation means, and a crack evaluation point setting means. The surface inclination calculation means is a means for calculating the surface inclination angle in a three-dimensional space for each small area based on a three-dimensional model of the tunnel face composed of small areas (areas into which the tunnel face is divided). The normal image creation means is a means for creating a normal image of the tunnel face by setting color information for each small area based on the surface inclination angle. The crack interval calculation means is a means for extracting cracks by filtering the normal image and determining the crack interval. The crack evaluation point setting means is a means for setting a crack evaluation point of the tunnel face by comparing the crack interval determined by the crack interval calculation means with a preset crack interval threshold value. The image acquisition means is a means for determining the relative position and relative attitude of the image acquisition means with respect to the moving body in advance. In addition, a surveying instrument installed inside the tunnel aims at the reflector, obtaining the position and orientation of the image acquisition means inside the tunnel, and the three-dimensional model is assigned three-dimensional coordinates inside the tunnel. The normal image creation means sets color information according to the inclination angle and inclination direction of the surface inclination angle.

The tunnel face status display system sets a three-dimensional "color space" consisting of orthogonal R, G, and B axes, and can also set a "hue wheel" consisting of the six vertices that make up the color space. In this case, a reference vector is determined that points from the center of the hue wheel to one of the vertices. The normal image creation means also obtains a "rotation length" by multiplying the magnitude of the reference vector by an "orientation coefficient" that corresponds to the tilt orientation, and rotates a line segment of the rotation length by the tilt angle around the center of the hue wheel to obtain polar coordinates on the hue wheel. The normal image creation means then obtains RGB values by arranging the polar coordinates in the color space, and assigns RGB values to small regions.

The tunnel face status display system can also calculate the hue H based on the inclination angle and the saturation S according to the inclination direction, calculate the RGB value by converting the hue H, saturation S, and a preset brightness V into an HSV value, and assign the RGB value to a small area.

The tunnel face condition display system may further include a rock strength distribution map creation means and a crack distribution map creation means. The rock strength distribution map creation means is a means for estimating the rock strength of the tunnel face based on information from the time of blasting and drilling holes, and creating a rock strength distribution map of the tunnel face with coordinates assigned. The crack distribution map creation means is a means for creating a crack distribution map of the tunnel face with coordinates assigned, based on cracks extracted by the crack interval calculation means. In this case, the rock strength distribution map and the crack distribution map can be displayed superimposed.

The tunnel face condition display system may further include a rock strength evaluation point setting means and a rock weathering evaluation point setting means. The rock strength evaluation point setting means is a means for setting the rock strength evaluation point of the tunnel face based on a rock strength distribution map, and the overall evaluation point setting means is a means for setting the overall evaluation point of the tunnel face based on elements including the crack evaluation point and the rock strength evaluation point.

The tunnel face status display method is a method for displaying the state of a tunnel face using a tunnel face status display system, and includes an attitude acquisition process, an observation process, a face model creation process, and an image creation process. In the attitude acquisition process, a surveying instrument installed in the tunnel aims a reflector to acquire the position and attitude of the image acquisition means in the tunnel, and in the observation process, images of the tunnel face are acquired by two or more image acquisition means. In the face model creation process, a three-dimensional model of the tunnel face composed of small areas obtained by dividing the tunnel face is created based on the images acquired in the observation process, and in the image creation process, a normal image of the tunnel face is created by the tunnel face status display system. The three-dimensional model created in the face model creation process is assigned three-dimensional coordinates within the tunnel. In the image creation process, color information is set according to the inclination angle and inclination direction of the face inclination angle.

The tunnel face status display method can also be a method in which permanent lighting installed near the tunnel face is turned off, and an image of the tunnel face is acquired by an image acquisition means while lighting equipment mounted on a mobile measuring body projects light onto the tunnel face.

The mobile measuring body of the present invention has the following effects.
(1) It is possible to evaluate the condition of the tunnel face with higher accuracy than before. As a result, it is possible to select the optimal support pattern and auxiliary construction method, ensuring the quality of construction, and reducing construction costs and time.
(2) Since the condition of the tunnel face can be evaluated objectively, without being based on the observer's subjective judgment, the labor required for observation can be reduced and traceability of the evaluation can be ensured.
(3) In addition, since it does not depend on the experience or knowledge of the observer, the difficulty of securing a skilled observer can be avoided.
(4) The above effects can be achieved with little difference in work effort or time compared to conventional face observation.

FIG. 1 is a model diagram showing a schematic diagram of a tunnel face condition being observed by the mobile measuring body of the present invention. 1A is a side view showing a mobile measurement body of the present invention, and FIG. 1B is a front view showing the mobile measurement body of the present invention. FIG. 1 is a block diagram showing the main configuration of a tunnel face status display system. FIG. 2 is a flow chart showing the main processing flow of the spatial calculation means constituting the tunnel face status display system. A flow chart showing the process from creating a 3D model of the tunnel face to displaying a crack distribution map. FIG. 1A is a model diagram showing a three-dimensional space consisting of an R axis indicating red values, a G axis indicating green values, and a B axis indicating blue values, and FIG. 1B is a model diagram showing a hue wheel for determining color information. A flow chart showing the process of setting a rock strength evaluation score, a rock weathering evaluation score, a spring water condition evaluation score, and then setting an overall evaluation score. FIG. 2 is a flow chart showing the main steps of the tunnel face condition display method.

An embodiment of the mobile measuring body of the present invention will be described with reference to the drawings.

1. Overall Overview Fig. 1 is a model diagram showing a state in which the state of a tunnel face is observed by a mobile measurement object 200 of the present invention. As shown in Fig. 2, this mobile measurement object 200 can be configured to include a mobile object 210, an image acquisition means 220, a spectral camera 230, a temperature distribution sensor 240, a reflector 250, and lighting equipment 260.

The mobile body 210 constituting the mobile measuring body 200 is a base machine that can move inside the tunnel with various measuring instruments mounted on it. As shown in FIG. 2, a tire-type ordinary car or a crawler-type car can be used. The image acquisition means 220 is a device that can acquire images of the tunnel face, such as a digital camera, a still camera, or a digital video camera. As described later, in order to create a three-dimensional model of the tunnel face (hereinafter simply referred to as a "face 3D model"), that is, to obtain stereo pair images, two or more image acquisition means 220 are provided. For example, in FIG. 2, three image acquisition means 220 are provided: a first image acquisition means 221 at the rear of the mobile body 210, a second image acquisition means 222 at the front right side of the mobile body 210, and a third image acquisition means 223 at the front left side of the mobile body 210.

The spectral camera 230 can acquire spectral data of the tunnel face, and the temperature distribution sensor 240 can acquire the temperature distribution of the tunnel face using a thermograph that acquires thermal infrared images. The reflector 250 is a target for a surveying instrument such as a total station, and a conventional surveying prism (also called a mirror or target) can be used. As described later, the reflectors 250 are arranged at three or more locations that are not aligned on the same line so that the position and attitude of the moving body 210 can be acquired. For example, in FIG. 2, three reflectors 250 are arranged: a first reflector 251 behind the moving body 210, a second reflector 252 on the front right side of the moving body 210, and a third reflector 253 on the front left side of the moving body 210.

The lighting equipment 260 can shine light on the tunnel face, and various lighting devices that have been used in the past can be used. The image acquisition means 220, the spectral camera 230, the temperature distribution sensor 240, the reflector 250, and the lighting equipment 260 are fixed to the moving body 210, and their relative positions with respect to the moving body 210 (i.e., where they are installed on the moving body 210) are known in advance. Furthermore, with regard to the image acquisition means 220, the spectral camera 230, and the temperature distribution sensor 240, their relative attitudes with respect to the moving body 210 (i.e., which direction they face with respect to the moving body 210) are also known in advance. The image acquisition means 220, the spectral camera 230, the temperature distribution sensor 240, the reflector 250, and the lighting equipment 260 can be installed on a frame FR fixed to the top of the moving body 210, as shown in FIG. 2.

As shown in FIG. 1, the mobile measuring body 200, which has stopped just before the tunnel face, illuminates the tunnel face with lighting equipment 260, then acquires an image (stereo pair image) of the tunnel face with image acquisition means 220, acquires spectral data of the tunnel face with spectral camera 230, and acquires the temperature distribution of the tunnel face with temperature distribution sensor 240. At this time, the position (hereinafter simply referred to as "inner tunnel position") and attitude of the mobile body 210 are measured by aiming the reflector 250 with a surveying instrument TS (e.g. a total station) installed in the tunnel, and further the inner tunnel position and attitude of the image acquisition means 220, the inner tunnel position and attitude of the spectral camera 230, and the inner tunnel position and attitude of the temperature distribution sensor 240 are obtained.

The tunnel face condition display system creates a 3D model of the tunnel face based on stereo pair images of the tunnel face acquired by the image acquisition means 220, and creates a "normal image" of the tunnel face from this 3D model. Furthermore, based on this normal image, it is possible to determine cracks and crack spacing at the tunnel face, calculate crack evaluation points, and create a crack distribution map. Since the position and attitude of the image acquisition means 220 inside the tunnel are obtained here, the crack distribution map can be given coordinates, and can be superimposed on a tunnel face photo with given coordinates or other tunnel face images (such as a rock weathering classification map or spring water distribution map).

The tunnel face condition display system can also create a rock weathering classification map based on the tunnel face spectral data acquired by the spectral camera 230 and set a rock weathering evaluation point from this rock weathering classification map, or create a spring water distribution map based on the temperature distribution of the tunnel face acquired by the temperature distribution sensor 240 and set a spring water condition evaluation point from this spring water distribution map. Since the positions and attitudes of the spectral camera 230 and the temperature distribution sensor 240 inside the tunnel are obtained, the rock weathering classification map and the spring water distribution map can be given coordinates, and can be superimposed on a tunnel face photograph or other tunnel face images (such as a crack distribution map) with given coordinates.

Furthermore, the tunnel face condition display system can also create a rock strength distribution map based on information from the time of drilling for blasting one cycle ago (hereinafter referred to as "blasting drilling data"), and set a rock strength evaluation point from this rock strength distribution map. Blasting drilling data here includes the drilling position and drilling speed, and can also include rod feed pressure, impact pressure, rotation pressure, etc. Then, once the crack evaluation point, rock strength evaluation point, rock weathering evaluation point, and well water condition evaluation point are obtained, an overall evaluation point for the tunnel face can also be set based on these evaluation points.

2. Tunnel face status display system An example of a tunnel face status display system will be explained with reference to the diagram. Note that the tunnel face status display method is a method using the tunnel face status display system, so the tunnel face status display system will be explained first, and then the tunnel face status display method will be explained.

Figure 3 is a block diagram showing the main components of the tunnel face condition display system 100. As shown in this figure, the tunnel face condition display system 100 is configured to include a surface inclination calculation means 101 and a normal image creation means 102, and can also be configured to include a crack interval calculation means 103, a crack evaluation point setting means 104, a crack distribution map creation means 105, a rock strength distribution map creation means 106, a rock strength evaluation point setting means 107, a rock weathering classification map creation means 108, a rock weathering degree evaluation point setting means 109, a spring water distribution map creation means 110, a spring water condition evaluation point setting means 111, a total evaluation point setting means 112, a spatial calculation means 113, a 3D model creation means 114, a display means 115 such as a display, and a mobile measurement body 200.

Among the main components of the tunnel face condition display system 100, the surface inclination calculation means 101, normal image creation means 102, crack interval calculation means 103, crack evaluation point setting means 104, crack distribution map creation means 105, rock strength distribution map creation means 106, rock strength evaluation point setting means 107, rock weathering classification map creation means 108, rock weathering degree evaluation point setting means 109, spring water distribution map creation means 110, spring water condition evaluation point setting means 111, overall evaluation point setting means 112, spatial calculation means 113, and 3D model creation means 114 can be manufactured as dedicated devices, or general-purpose computer devices can be used. This computer device is equipped with a processor such as a CPU, memory such as ROM and RAM, input means such as a mouse and keyboard, and a display (display means 115), and can be configured by a personal computer (PC), a tablet PC such as an iPad (registered trademark), a mobile terminal including a smartphone, etc. When using a computer device, the computer device can be placed inside the mobile measuring body 200, or, particularly when a tablet PC or mobile terminal is used, the computer device can be carried by the worker, or can be installed in a location other than the mobile measuring body 200, such as an administrative office. When installing a computer device in an administrative office or the like, it is advisable to provide wireless communication (or wired communication) means so that the computer device can send and receive image data acquired by the image acquisition means 220, spectral data acquired by the spectral camera 230, temperature distribution data acquired by the temperature distribution sensor 240, and data on blasting and drilling by the drill jumbo.

(Spatial Operations)
FIG. 4 is a flow diagram showing the main processing flow of the spatial calculation means 113 constituting the tunnel face status display system 100. In this flow diagram, the action to be performed is shown in the center column, the things necessary for the action are shown in the left column, and the things resulting from the action are shown in the right column. As already described, the mobile measurement object 200 stopped in front of the tunnel face is collimated by the surveying instrument TS installed in the tunnel as shown in FIG. 1, and the coordinates of each reflector 250 are obtained. Then, the position and attitude of the mobile measurement object 200 in the tunnel are calculated from the coordinates of the reflector 250 (Step 11 in FIG. 4). At this time, since three or more reflectors 250 are arranged so as not to be on the same straight line, a three-dimensional plane is determined from the coordinates of these reflectors 250, and the attitude (pitch, roll, yaw) of the mobile measurement object 200 (i.e., the mobile object 210) can be calculated based on this three-dimensional plane. Furthermore, since the relative position of the reflector 250 with respect to the moving body 210 (i.e., where on the moving body 210 the reflector 250 is installed) is known in advance, the position of the entire moving measuring body 200 (i.e., the moving body 210) within the tunnel can be determined, i.e., the planar position of the moving measuring body 200 within the tunnel can be identified.

Once the position and attitude of the mobile measuring object 200 inside the tunnel is calculated, the position and attitude of the image acquisition means 220 inside the tunnel are calculated (Step 12 in FIG. 4), the position and attitude of the spectral camera 230 inside the tunnel are calculated (Step 13 in FIG. 4), and the position and attitude of the temperature distribution sensor 240 inside the tunnel are calculated (Step 14 in FIG. 4). As described above, the relative positions of the image acquisition means 220, the spectral camera 230, and the temperature distribution sensor 240 to the mobile object 210 (i.e., where they are installed on the mobile object 210) and their relative attitudes to the mobile object 210 (i.e., which direction they face with respect to the orientation of the mobile object 210) are known in advance, so once the position and attitude of the mobile object 210 inside the tunnel is determined, the position and attitude of the image acquisition means 220, the spectral camera 230, and the temperature distribution sensor 240 inside the tunnel can be calculated.

(Creating legal images)
Figure 5 is a flow diagram showing a series of processes from the creation of a 3D model of the tunnel face to the display of a crack distribution map. As in Figure 4, this flow diagram also shows the action to be performed in the center column, the left column shows what is necessary for the action, and the right column shows what results from the action. When two or more tunnel face images (stereo pair images) are acquired by the image acquisition means 220 and the position and attitude of the image acquisition means 220 inside the tunnel are calculated by the spatial calculation means 113, the 3D model creation means 114 creates a 3D model of the tunnel face (Step 21 in Figure 5). More specifically, the three-dimensional coordinates of multiple points on the tunnel face are obtained by conventional stereo photography technology, and a 3D model of the tunnel face is created from these point cloud coordinates. The 3D tunnel face model is a model in which three-dimensional coordinates are assigned to each of the so-called meshes (hereinafter referred to as "small regions") obtained by dividing the tunnel face into a plurality of parts. For example, a method using a triangulated irregular network (TIN) that determines the height using an irregular triangular mesh formed from random data (point cloud coordinates), a method using the nearest neighbor method that uses the nearest laser measurement point 4, and various other methods such as the inverse distance weighting method (IWD), the Kriging method, and the average method can be adopted. The 3D tunnel face model is preferably set using three-dimensional coordinate axes consisting of two axes (e.g., the X-axis and the Y-axis) that constitute a vertical plane (hereinafter referred to as the "face reference plane") that is approximately parallel (including parallel) to the tunnel face, and an axis (e.g., the Z-axis) that is perpendicular to the face reference plane.

When the face 3D model is created, the face inclination calculation means 101 calculates the face inclination angle for each small area (Step 22 in Figure 5). This face inclination is a value that indicates the attitude of the small area, and is a value consisting of the angle with respect to the horizontal plane (or face reference plane) (hereinafter referred to as the "depression angle") and the direction of the intersection line between the small area and the horizontal plane or the direction perpendicular to that (hereinafter referred to as the "azimuth"). Note that the face inclination can be calculated using various conventional methods, such as calculation using the three-dimensional coordinates of eight small areas surrounding the small area of interest.

Once the surface inclination angle is calculated for each small region, the normal image creation means 102 creates a normal image of the tunnel face (Step 23 in Figure 5). This normal image is sometimes called a normal map, and is an image to which color information corresponding to the spatial information (coordinates and orientation) of the target object is added. The surface inclination calculation means 101 of the tunnel face status display system 100 then creates a normal image of the tunnel face by adding color information corresponding to the surface inclination angle (depression angle and azimuth) of the small region. The procedure for creating a normal image of the tunnel face is explained in detail below.

First, as shown in Figure 6(a), a three-dimensional space (hereafter referred to as "color space") is set up, consisting of an R axis indicating the red value, a G axis indicating the green value, and a B axis indicating the blue value. Points placed in this color space can be expressed in three-dimensional coordinates, and these coordinate values are directly used as color information (i.e., RGB). For example, in the case of Figure 6(a), the origin RGB(0,0,0) is displayed as "black", RGB(255,0,0) is displayed as "red", RGB(0,255,0) is displayed as "green", RGB(0,0,255) is displayed as "blue", and RGB(255,255,255) is displayed as "white".

Next, focusing on six vertices of the cube shown in Figure 6 (a), namely, vertex PT11 (255,0,0), vertex PT21 (0,255,0), vertex PT31 (0,0,255), vertex PT41 (255,255,0), vertex PT51 (0,255,255), and vertex PT61 (255,0,255), consider a regular hexagon on a plane as shown in Figure 6 (b), namely, a regular hexagon consisting of six vertices, namely, vertex PT12 corresponding to vertex PT11, vertex PT42 corresponding to vertex PT41, vertex PT22 corresponding to vertex PT21, vertex PT52 corresponding to vertex PT51, vertex PT32 corresponding to vertex PT31, and vertex PT62 corresponding to vertex PT61, and with its center O being the center point of the cube shown in Figure 6 (a). For convenience, the regular hexagon shown in Figure 6(b) will be referred to as the "hue wheel."

Once the hue circle is set, the small area is positioned (plotted) on the hue circle according to the surface inclination angle of the small area. Specifically, a reference vector is determined from the center O toward the vertex PT12, and a coefficient (hereafter referred to as the "orientation coefficient") according to the orientation of the small area is set. The length (hereafter referred to as the "rotation length") is set by multiplying the magnitude (length) of the reference vector by the orientation coefficient. The orientation coefficient can be calculated as the ratio of the orientation to a predetermined reference angle (e.g., 180° or 360°). The point (i.e., the polar coordinates obtained from the rotation length and the depression angle) obtained by rotating this rotation length (i.e., the radius) around the center O from the direction of the reference vector by the depression angle of the small area is set as the position (coordinates) of the small area on the hue circle.

Once the location (coordinates) of the small area on the hue circle is obtained, the coordinate values (RGB) in the color space shown in Figure 6(a) are found based on those coordinates. For example, in the case of Figure 6(b), the intersection point a between the straight line passing through point p and center O on the hue circle and vertex PT12-vertex PT42 (line segment) is found, and the internal division point b between vertex PT11-vertex PT41 (line segment) in Figure 6(a) is found so that it is the same as the internal division ratio of point a between vertex PT12-vertex PT42 (line segment). Furthermore, the internal division point between the center point-intersection point b (line segment) of the cube shown in Figure 6(a) is found so that it is the same as the internal division ratio of point p between center O-intersection point a (line segment), and this internal division point is set as the coordinate value (RGB) of the small area in the color space.

Instead of the method of converting coordinate values on the hue wheel into coordinate values in color space as described above, a method of calculating RGB values based on an HSV model consisting of hue H, saturation S, and value of brightness V can be used. Specifically, as shown in FIG. 6(b), the hue H is calculated by taking the depression angle of the small area as the rotation angle from the reference vector (i.e., the R axis), and the saturation S is calculated according to the orientation coefficient, and the HSV is determined by the preset brightness V. Then, RGB is calculated from the HSV value using a conventional conversion formula.

In this way, the surface inclination angle (depression angle and direction) is calculated for each small area, and color information according to the surface inclination angle is assigned, thereby creating a normal image of the tunnel face. It is also possible to calculate the distance from a specified reference point (e.g., image acquisition means 220) for each small area (i.e., unevenness relative to the face reference surface), and create a distance image with color information (e.g., grayscale) assigned according to that distance.

When the normal image of the tunnel face is created, the crack interval calculation means 103 extracts the cracks of the tunnel face (Step 24 in FIG. 5) and calculates the crack interval based on the arrangement of the cracks (Step 25 in FIG. 5). In order to extract the cracks of the tunnel face, it is advisable to apply a filter (such as a Sobel filter) to the normal image of the tunnel face. For example, the normal image is binarized by the filter process, and the range where a certain number of white pixels (above a threshold) are collected is extracted as a crack. Alternatively, the normal image can be grayscaled by the filter process, and the range where a certain value or more of the pixels are collected or the range where the gradient (differential value) of the grayscale is above a threshold can be extracted as a crack. Then, when the cracks can be extracted, the distance between the cracks is calculated as the crack interval. It is also possible to assign the crack interval consisting of these cracks to small areas between the cracks, and to obtain the crack interval for each small area.

After the cracks in the tunnel face are extracted and the crack intervals are calculated, the crack evaluation point setting means 104 sets a crack evaluation point (Step 26 in Figure 5). Specifically, the crack intervals are divided and set in advance into multiple ranges, and scores are assigned to each range. Based on the crack intervals obtained by the crack interval calculation means 103, a crack interval range is set for each small area, and a score is assigned to each range. Then, a statistical value (average, median, mode, etc.) is calculated based on the scores of all small areas (or some of the small areas), and this is set as the crack evaluation point of the tunnel face.

When cracks at the tunnel face are extracted, the crack distribution map creation means 105 creates a crack distribution map (Step 27 in Figure 5). The cracks extracted by the crack spacing calculation means 103 are based on a 3D model of the face, so they are assigned coordinates; that is, the crack distribution map is assigned coordinates. Therefore, the crack distribution map can be superimposed on other face images, such as a photograph (e.g., an orthophoto) of the tunnel face with coordinates assigned, a rock weathering classification map, or a spring water distribution map (Step 28 in Figure 5).

(Setting the overall evaluation score)
FIG. 7 is a flow diagram showing a series of processing steps from setting a rock strength evaluation point, a rock weathering evaluation point, and a spring water state evaluation point to setting a total evaluation point. In this flow diagram, as in FIG. 4 and FIG. 5, the action to be performed is shown in the center column, the left column shows what is necessary for the action, and the right column shows what results from the action. As shown in this figure, when the blasting drilling data is obtained, the rock strength distribution map creation means 106 creates a rock strength distribution map (Step 31 in FIG. 7). Since the blasting drilling data includes the drilling position, it is possible to create a rock strength distribution map by showing the rock strength for each drilling position. The rock strength for each drilling position can be set based on the drilling speed, or based on the drilling speed and the feed pressure, impact pressure, rotation pressure, etc. of the rod. When the rock strength distribution map is created, the rock strength evaluation point setting means 107 sets the rock strength evaluation point (Step 32 in FIG. 7). Specifically, the rock strength is divided into multiple ranges in advance, and each range is assigned a score, and a range of rock strength is set for each small area based on the obtained rock strength, and a score is assigned to each range. Then, a statistical value (average, median, mode, etc.) is calculated based on the scores for all drilling positions (or some of the drilling positions), and this is set as the rock strength evaluation score for the tunnel face.

When the spectral data of the tunnel face is obtained by the spectral camera 230, the rock weathering classification map creation means 108 creates a rock weathering classification map (Step 41 in FIG. 7). Since the position and attitude of the spectral camera 230 inside the tunnel are obtained by the spatial calculation means 113, the acquired spectral data can be associated with the position of the tunnel face, that is, a rock weathering classification map with coordinates can be created. In creating a rock weathering classification map, it is necessary to set the degree of rock weathering (hereinafter referred to as "rock weathering degree") according to the acquired spectral data. For this, it is recommended to use a rock weathering degree table showing the relationship between the rock weathering degree and the spectral data. This rock weathering degree table is based on the actual value of the spectral data acquired for rocks with known rock weathering degrees, and shows the relationship between multiple rock weathering degrees and the corresponding spectral data. It is recommended to prepare a rock weathering degree table for each type of rock, such as sandstone and granite. Once the rock weathering classification map is created, the rock weathering evaluation point setting means 109 sets the rock weathering evaluation point (Step 42 in FIG. 7). Specifically, a score is assigned to each stage of rock weathering in advance, and a score is assigned to each small area based on the obtained rock weathering. Then, a statistical value (average value, median value, mode value, etc.) is calculated based on the scores in all small areas (or some of the small areas), and this is set as the rock weathering evaluation point for the tunnel face.

When the temperature distribution of the tunnel face is obtained by the temperature distribution sensor 240, the spring water distribution map creation means 110 creates a spring water distribution map (Step 51 in FIG. 7). Since the position and attitude of the temperature distribution sensor 240 inside the tunnel are obtained by the spatial calculation means 113, the acquired temperature distribution can be associated with the position of the tunnel face, that is, a spring water distribution map with coordinates can be created. When creating a spring water distribution map, it is necessary to set the degree of spring water (hereinafter referred to as "spring water level") according to the temperature data acquired by the temperature distribution sensor 240. For this purpose, it is advisable to use a spring water level table that shows the relationship between the spring water level set in stages in advance and the temperature data by the temperature distribution sensor 240. This spring water level table is based on the actual value of the temperature data acquired for a rock mass with a known spring water level, and shows the relationship between multiple spring water levels and the corresponding temperature data. When the spring water distribution map is created, the spring water condition evaluation point setting means 111 sets the spring water condition evaluation point (Step 52 in FIG. 7). Specifically, a score is assigned to each spring water level in advance, and a score is assigned to each small area based on the obtained spring water level. A statistical value (average, median, mode, etc.) is then calculated based on the scores for all small areas (or some of the small areas), and this is set as the spring water condition evaluation score for the tunnel face.

Once the crack evaluation score, rock strength evaluation score, rock weathering evaluation score, and spring water condition evaluation score have been set, the overall evaluation score setting means 112 sets an overall evaluation score for the tunnel face (Step 60 in FIG. 7). Specifically, a statistical value such as a total value, or a weighted total value, average value, or weighted average value, consisting of the crack evaluation score, rock strength evaluation score, rock weathering evaluation score, and spring water condition evaluation score is calculated, and this is set as the overall evaluation score for the tunnel face.

3. Tunnel Face Status Display Method Next, the tunnel face status display method will be described with reference to Fig. 8. Note that the tunnel face status display method is a method using the tunnel face status display system 100 described so far, and therefore, explanations that overlap with the contents explained in the tunnel face status display system 100 will be avoided, and only the contents unique to the tunnel face status display method will be explained. In other words, the contents not described here are the same as those explained in "2. Tunnel Face Status Display System".

Figure 8 is a flow diagram showing the main steps of the tunnel face status display method. After one cycle of blasting excavation (or mechanical excavation) is performed and the debris is removed by a dump truck (or rail construction method) while removing loose stones and the like (Step 101), that is, at the timing when conventional visual observation of the face is performed, the mobile measurement body 200 approaches the vicinity of the face (Step 102). When the mobile measurement body 200 stops, the surveying instrument TS measures the coordinates of the reflector 250 mounted on the mobile measurement body 200 (mobile body 210) as shown in Figure 1 (Step 103). The results measured here (i.e., the coordinates of the reflector 250) are transmitted to the spatial calculation means 113 using wireless communication (or wired communication) means or the like.

Images of the tunnel face are acquired by the image acquisition means 220 (Step 105), but it is advisable to switch the lighting beforehand (Step 104). Specifically, the permanent lighting (mercury lamps, fluorescent lights, etc.) installed near the tunnel face is turned off, and the tunnel face is illuminated by the lighting device 260 mounted on the mobile measuring body 200. While the illuminance of construction lighting (permanently installed lighting) tends to be relatively unstable, the illuminance of the lighting device 260 is generally stable, so images can be acquired under similar conditions at each tunnel face.

After the lighting is switched, the observation process (Step 105 to Step 107) is performed. Specifically, an image of the tunnel face is acquired by the image acquisition means 220 (Step 105), spectral data of the tunnel face is acquired by the spectral camera 230 (Step 106), and the temperature distribution of the tunnel face is acquired by the temperature distribution sensor 240 (Step 107). The order of performing the process of acquiring an image of the tunnel face (Step 105), the process of acquiring spectral data of the tunnel face (Step 106), and the process of acquiring the temperature distribution of the tunnel face (Step 107) can be selected as appropriate, and the order of performing the coordinate acquisition process (Step 103) by the surveying instrument TS and the observation process can also be selected as appropriate, and the coordinate acquisition process and the observation process can also be performed in parallel. The image of the tunnel face acquired here is sent to the 3D model creation means 114, the spectral data of the tunnel face to the rock weathering classification map creation means 108, and the temperature distribution of the tunnel face to the spring water distribution map creation means 110, each of which is sent using wireless communication (or wired communication) means.

When the image, spectrum data, and temperature distribution of the tunnel face are obtained by the observation process, various images are created (Step 201). Specifically, the rock strength distribution map creation means 106 creates a rock strength distribution map based on the blasting hole drilling data, the rock weathering classification map creation means 108 creates a rock weathering classification map based on the spectrum data of the tunnel face, and the spring water distribution map creation means 110 creates a spring water distribution map based on the temperature distribution of the tunnel face. In addition, the 3D model creation means 114 creates a face 3D model based on the image (stereo pair image) of the tunnel face, the face inclination calculation means 101 calculates the face inclination based on the face 3D model, the normal image creation means 102 creates a normal image based on the face inclination, and the crack interval calculation means 103 extracts cracks, and then the crack distribution map creation means 105 creates a crack distribution map. Furthermore, because the crack distribution map, rock mass strength distribution map, rock mass weathering classification map, and spring water distribution map are each assigned coordinates, these images can be superimposed on each other, or superimposed on a photograph of the tunnel face, which also has coordinates (Step 202).

After the crack distribution map, rock strength distribution map, rock weathering classification map, and spring water distribution map are created, various evaluation points for the tunnel face are set (Step 203). Specifically, the crack evaluation point setting means 104 sets the crack evaluation point for the tunnel face based on the crack interval, the rock strength evaluation point setting means 107 sets the rock strength evaluation point for the tunnel face based on the rock strength distribution map, the rock weathering evaluation point setting means 109 sets the rock weathering evaluation point for the tunnel face based on the rock weathering classification map, and the spring water condition evaluation point setting means 111 sets the spring water condition evaluation point for the tunnel face based on the spring water distribution map. Then, the overall evaluation point setting means 112 sets the overall evaluation point for the tunnel face based on the rock strength evaluation point, the crack evaluation point, the rock weathering evaluation point, and the spring water condition evaluation point (Step 204).

The mobile measuring body of the present invention can be used in the excavation of various tunnels, such as road tunnels, railway tunnels, pedestrian tunnels, etc. 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 shared quickly. Considering that construction can be performed while ensuring the safety of workers, this invention can be expected to not only be used industrially, but also to make a great contribution to society.

100 Tunnel face condition display system 101 (Tunnel face condition display system) Face inclination degree calculation means 102 (Tunnel face condition display system) Normal image creation means 103 (Tunnel face condition display system) Crack interval calculation means 104 (Tunnel face condition display system) Crack evaluation point setting means 105 (Tunnel face condition display system) Crack distribution map creation means 106 (Tunnel face condition display system) Rock strength distribution map creation means 107 (Tunnel face condition display system) Rock strength evaluation point setting means 108 (Tunnel face condition display system) Rock weathering classification map creation means 109 (Tunnel face condition display system) Rock weathering degree evaluation point setting means 110 (Tunnel face condition display system) Spring water distribution map creation means 111 (Tunnel face condition display system) Spring water condition evaluation point setting means 112 (Tunnel face condition display system) Overall evaluation point setting means 113 Spatial calculation means (of tunnel face status display system) 114 3D model creation means (of tunnel face status display system) 115 Display means (of tunnel face status display system) 200 Mobile measuring body (of tunnel face status display system) 210 Mobile body (of mobile measuring body) 220 Image acquisition means (of mobile measuring body) 230 Spectral camera (of mobile measuring body) 240 Temperature distribution sensor (of mobile measuring body) 250 Reflector (of mobile measuring body) 260 Lighting equipment (of mobile measuring body) TS Surveying equipment (of tunnel face status display system)

Claims (3)

a mobile object capable of moving within the tunnel;
Two or more image acquisition means mounted on the moving object;
A spectral camera mounted on the moving object;
A temperature distribution sensor mounted on the moving body;
A survey target is provided on the moving body and is arranged at three or more locations that are not aligned on a straight line,
The image capturing means captures an image of the tunnel face,
The spectral camera acquires spectral data of the tunnel face;
The temperature distribution of the tunnel face is acquired by the temperature distribution sensor,
A surveying instrument installed in the tunnel is sighted on the survey target, thereby measuring the attitude of the moving body and its position within the tunnel.
A moving measuring body characterized by: the image acquisition means, the spectral camera, and the temperature distribution sensor are each capable of grasping a relative position and a relative attitude with respect to the moving body;
The position of the survey target relative to the moving body is grasped,
By measuring the attitude and position of the moving body, the attitude of the image acquisition means and its position within the tunnel are obtained, the attitude of the spectral camera and its position within the tunnel are obtained, the attitude of the temperature distribution sensor and its position within the tunnel are obtained, and the position of the survey target within the tunnel is obtained.
2. The mobile measuring body according to claim 1. Further comprising a lighting device mounted on the moving body and capable of shining light on the tunnel face;
3. The mobile measuring body according to claim 1 or 2.

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