Method for measuring displacement of tunnel inner space

Abstract

To acquire inner space data in tunnel excavation safely and accurately, without using a reflector, from start of the excavation.SOLUTION: A non-prism total station that does not require a reflector is used to measure displacement of a tunnel cross section. A coordinate of an initial measurement position a0 of a displacement measurement point is measured, then after a predetermined time tn has elapsed, a direction of the initial measurement position a0 is measured, and thereby, a laser light irradiation position an is obtained and set as a measurement position an after tn. A difference (r0-rn) between a distance rn between a tunnel cross section arc center O2 that the laser light irradiation position an belongs to and the measurement position an after tn and a distance r0 between an initial measurement tunnel cross section arc center O1 and the initial measurement position a0 is set as a displacement magnitude, and thereby, displacement of a tunnel inner space can be measured by the non-prism total station.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for measuring displacement inside a tunnel using a non-prism total station, and more particularly to a method for measuring displacement of the ground on the inner wall of a tunnel during the period from when a tunnel face is excavated until when lining concrete is poured. [Background technology]

[0002] In mountain tunnels, etc., it is important to measure the displacement of the ground on the inner wall of the tunnel from the time the tunnel face is excavated until the lining concrete is poured, and to track its behavior thereafter, for example, in order to determine the safety of the tunnel and to form a stable tunnel lining. Usually, the displacement of the ground on the inner wall of the tunnel is measured, and the lining concrete is placed only after it is determined that the ground after excavation is stable.

[0003] In the conventional method of measuring the displacement of the ground on the inner wall of a tunnel, a number of targets are placed at predetermined positions on the inner wall of the tunnel covered with shotcrete after excavation, and these targets are sighted by a total station fixed to the shoulder of the tunnel at a position that does not interfere with the work, or a worker sights a total station installed on the roadbed inside the tunnel using a tripod for each measurement (see, for example, Patent Document 1). However, in this case, placing the targets on the inner wall of the tunnel immediately after excavation is difficult from the viewpoint of safety, and is not preferable for rapid construction progress. In addition, in the case of an automatic tracking total station, an expensive prism is usually used as the target, but there is a problem of the target falling off and being damaged due to the impact of blasting. In the case of a normal total station, there is no need to use an expensive prism, but the falling off and being damaged of the target are still a problem. Furthermore, although it is possible to obtain the displacement behavior at the location where the target is installed on the tunnel wall, it is not possible to grasp the displacement at the location where the target is not installed.

[0004] Meanwhile, there have been attempts to measure displacement using 3D laser scanners. 3D laser scanners can obtain the cross-sectional shape of a tunnel through automatic non-prism measurement, and the obtained data is point cloud data, which makes it possible to grasp the three-dimensional shape of the structure. However, although 3D laser scanners can grasp the current shape of the tunnel wall, they cannot measure the same location on the tunnel wall over time, so they cannot track the displacement of the same location. In addition, 3D laser scanners are expensive devices.

[0005] Patent Document 2 discloses a method for measuring the displacement inside a tunnel by combining a three-dimensional measuring device (total station) and a three-dimensional laser scanner. According to this disclosed technology, the displacement at any tunnel wall position in the cross-sectional shape of the inside of the tunnel can be grasped as the displacement amount. However, in order to do this, it is necessary to install multiple targets as reference points on the tunnel wall of the reference cross section in order to obtain the coordinates of each position. In this case, however, placing targets on the tunnel inner wall immediately after excavation is difficult from the viewpoint of safety, and is not preferable in terms of rapid construction progress. In addition, there is a problem of targets falling off and being damaged due to the impact of blasting.

[0006] A method for quickly measuring displacement inside a tunnel by combining a total station and a 3D laser scanner has been disclosed (Patent Document 3). The total station acquires the three-dimensional coordinates of a 3D laser scanner mounted on a mobile vehicle, and the 3D laser scanner scans the inner wall surface of the tunnel to obtain the three-dimensional coordinates of the point cloud data. However, this method requires an expensive 3D laser scanner in addition to the total station, which creates a problem in terms of cost. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 5-99670 [Patent Document 2] JP 2014-2027 A [Patent Document 3] JP 2018-163063 A Summary of the Invention [Problem to be solved by the invention]

[0008] Among the above-disclosed technologies, the technology using a total station has problems such as safety and delays in construction progress due to the need to place a target on the inner wall surface of the tunnel. In addition, the amount of displacement immediately after excavation is an important index for predicting the final amount of displacement, but for safety reasons, it is not possible to place a target on the inner wall surface of the tunnel immediately after excavation, so there is a problem that the amount of displacement immediately after excavation cannot be measured. The technology using a 3D laser scanner has a problem that it is not possible to track the displacement of the same location, or a target is required to avoid this, and the technology combining a total station and a 3D laser scanner has a problem in terms of cost.

[0009] An object of the present invention is to provide a method for measuring displacement inside a tunnel which does not require measurement targets, enables rapid construction progress, enables fixed-point observation, and further enables cost reduction. [Means for solving the problem]

[0010] The aspects of the means for solving the above problems are as follows.

[0011] (First aspect) A process of acquiring three-dimensional coordinates of a plurality of adjacent points on the tunnel wall surface by a non-prism total station, acquiring the average coordinates thereof as the three-dimensional coordinates of a displacement measurement point on the initial measurement tunnel cross section arc, and setting the average coordinates as the initial measurement position a0; acquiring coordinates of an initial measurement tunnel cross section arc center O1 of the initial measurement tunnel cross section arc to which the initial measurement position a0 belongs; A step of calculating a distance r0 between the initial measurement tunnel cross section arc center O1 and the initial measurement position a0; After a predetermined time has elapsed, the laser beam of the total station is irradiated in the direction of the initial measurement position a0, so that the laser beam irradiation position a0 on the inner wall surface of the tunnel is measured. n acquiring three-dimensional coordinates of the The laser light irradiation position a n The tunnel cross section arc center O2 to which the laser beam irradiation position a belongs n Distance r from n and calculating The distance r0 and the distance r n and acquiring the difference as a displacement amount of the initial measurement position a0 after the predetermined period has elapsed; A line is formed on the line connecting the initial measurement tunnel cross section arc center O1 and the initial measurement position a0, and the distance from the initial measurement tunnel cross section arc center O1 is the distance r n And, point a in the direction of the initial measurement position a0 0n acquiring three-dimensional coordinates of the A method for measuring spatial displacement inside a tunnel.

[0012] (Action and effect) This invention uses a non-prism total station to measure the displacement inside a tunnel without installing a target on the tunnel inner wall. The non-prism type total station can measure in millimeters remotely without using a target.

[0013] In the present invention, a non-prism total station is used, the installation position of which is known (for example, the position information of the total station can be obtained by measuring a target whose installation position is known behind the tunnel). The non-prism total station makes it possible to obtain the three-dimensional coordinates of the target position without using a target, and it is possible to measure internal displacement with the same degree of accuracy and variance as a total station using a target. In addition, since there is no need to install a target, it is possible to safely and quickly grasp the internal displacement of the tunnel cross section immediately after excavation. Since the initial displacement reflects the nature of the ground, being able to obtain this at an early stage is also effective in terms of ensuring safety. Since the initial displacement is also correlated with the subsequent displacement progression, it is also effective in obtaining information on changes in displacement over time.

[0014] In addition, while a normal 3D laser scanner can perform measurements without requiring a target, it has problems such as the difficulty of acquiring fixed-point observation data and the high cost. The present invention, which uses a non-prism total station, makes it possible to acquire the three-dimensional coordinates of the target position without requiring a target, and makes it easy to measure the displacement inside a tunnel.

[0015] (Second aspect) The initial measurement tunnel cross section arc center O1 and the laser light irradiation position a n When the distance between the tunnel cross section arc center O2 and the laser beam irradiation position a exceeds a threshold value, the irradiation direction of the non-prism total station is changed, and the laser beam irradiation position a n re-measuring the position of A method for measuring displacement inside a tunnel according to claim 1.

[0016] (Action and effect) The tunnel inner wall surface covered with shotcrete has unevenness. If the laser beam is irradiated to the uneven surface, the correct position cannot be obtained, which may cause an error. In such a case, the initial measurement tunnel cross section arc center O1 and the laser beam irradiation position a nIn some cases, the distance between the tunnel cross-section arc center O2 to which O1 belongs may be larger than the actual value. On the other hand, from the viewpoint of measuring the displacement of the same point, it is preferable that the distance between O1 and O2 is small. In order to avoid the influence of such errors and to measure the displacement of points as close to the same point as possible, n If the distance of the tunnel cross section arc center O2 to which the belongs exceeds the threshold, the irradiation direction of the non-prism total station is changed and the measurement is performed again. This eliminates the influence of the above-mentioned unevenness and enables more accurate measurement.

[0017] (Third embodiment) The time elapsed after excavation, the distance r0, and the distance r n The amount of internal displacement after a predetermined time is calculated using an approximation formula that represents the relationship between the difference between the 3. A method for measuring displacement inside a tunnel according to claim 1 or 2.

[0018] (Action and effect) By using the approximation curve, it is possible to reduce the influence of the variance in the measurement data and to predict a value closer to the actual displacement. It is also possible to predict the transition of the displacement amount over time. Effect of the Invention

[0019] According to the present invention, it is possible to quickly, easily and safely measure displacement within a tunnel immediately after excavation. [Brief description of the drawings]

[0020] [Figure 1] Measurement Schematic [Diagram 2] Grid-shaped measuring points [Diagram 3] Measurement procedure using a non-prism total station [Figure 4] Enlarged view of measurement points a0 and an [Diagram 5] Measurement procedure for crown subsidence [Figure 6A]Measurement procedure for internal displacement [Figure 6B] Measurement procedure for internal displacement [Figure 7] Schematic diagram of top subsidence measurement [Figure 8] Schematic diagram of inner space displacement measurement [Figure 9] Variation from the displacement approximation curve [Figure 10] Top subsidence data [Figure 11] Inner space displacement data

[0021] An embodiment of the present invention will be described with reference to the drawings.

[0022] First, the displacement measurement procedure will be described. Figure 1 shows an overview of measurement points inside a tunnel. Figure 3 shows a general procedure for measuring tunnel cross-sectional displacement using a non-prism total station. First, the non-prism total station TS is installed (S101) and its installation position is obtained. The installation position can be obtained by, for example, measuring a target whose installation position is known behind the tunnel, to obtain position information of the total station. In this case, the installation position is set to within 30 m of the initial measurement position a0 on the tunnel wall. Next, as shown in Figure 2, the positions of the nine target points a arranged in a grid pattern are measured by a non-prism total station TS (S102). The distance T between the grid points can be selected appropriately, but may be, for example, 10 mm, 20 mm, or 30 mm. The distance r from the center of the tunnel cross section arc to each of the nine measured points is calculated. The coordinates (x0, y0, z0) of the average position a0 of the nine points are obtained as the initial measurement position a0 (S103). The number of measurement points may be five or three.

[0023] Here, the tunnel inner wall surface covered with the shotcrete has unevenness. Therefore, the measurement values ​​of the nine target points may have abnormal values ​​due to the unevenness. Therefore, in order to eliminate the influence of abnormal values ​​due to the unevenness, the points whose measurement values ​​r are apart from the center of the tunnel cross-section arc by a certain value (e.g., 10 mm) or more from the average value of the distances r from the center of the tunnel cross-section arc of each of the nine measured points may be excluded as abnormal values, and the coordinates (x0, y0, z0) of the average position a0 of the initial measurement positions may be recalculated and acquired as the initial measurement position a0 (S102, S103). The tunnel cross-section arc to which the initial measurement position a0 belongs is defined as the initial measurement tunnel cross-section arc 1D.

[0024] The center of the tunnel cross section arc to which the initial measurement position a0 belongs is the initial measurement tunnel cross section arc center O1(x o ,y o ,z o ) (S103), and the distance between the initial measurement tunnel cross section arc center O1 and the initial measurement position a0 is set as r0 (S104). r0 is calculated by the following formula 1.

number

[0025] FIG. 1 also shows the initial measurement tunnel cross section arc 1D, a given time t n After the initial measurement, the tunnel cross section arc 1D is displaced, and the initial measurement tunnel cross section arc displacement 1H is n After the time has elapsed, the non-prism total station TS will measure t n Rear tunnel cross section arc 2H, t n The tunnel cross section arc 2D, which is the front tunnel cross section arc of the rear tunnel cross section arc 2H, and t n The center of the rear tunnel cross section arc 2H, t n The rear tunnel cross-section arc center O2 is shown.

[0026] Next, at a given time t nAfter that, the direction of the initial measurement position a0 (x0, y0, z0) is measured by the non-prism total station TS (S105). When the tunnel wall is displaced, it is usually displaced downward, so as shown in Figures 1 and 4, the tunnel wall surface where the laser light is irradiated, that is, the irradiation position a n is the displacement of the tunnel cross section arc 2D on the total station side from the initial measurement tunnel cross section arc 1D where the initial measurement position a0 was measured, t n Therefore, when the initial measurement position a0 direction is measured using the non-prism total station TS, the laser beam irradiation position a n (x n ,y n ,z n The coordinates of the laser beam irradiation position a are obtained. n A n Rear measurement position a n (S106). Next, t n Rear measurement position a n belongs to t n The center of the rear tunnel cross section arc 2H, t n Then, the position of the tunnel cross section arc center O2 is obtained (S106).

[0027] The laser beam irradiation position is t n Rear measurement position a n And, t n The distance between the tunnel cross section arc center O2 and the n (S107). Here, the tunnel inner wall surface covered with the shotcrete has unevenness, which may cause errors. Initial measurement tunnel cross section arc center O1 and t nIdeally, the distance of the rear tunnel cross section arc center O2 is 0, but in consideration of the time required for measurement, if it exceeds a certain threshold, the irradiation direction is slightly changed and measurement is performed again (S110). The threshold can be determined appropriately. The threshold is, for example, 50 mm, preferably 30 mm, more preferably 5 mm, and particularly preferably 1 mm. If it exceeds this, it is considered to be due to the influence of errors caused by the unevenness of the tunnel inner wall surface, and the irradiation direction of the non-prism total station TS is changed and a similar measurement is performed (S110). The change in the irradiation direction can be determined appropriately, but for example, it may be sufficient that the irradiation position on the wall surface changes by 10 mm to 30 mm, or 20 mm to 30 mm.

[0028] Δr = (r0 -r n ) at the initial measurement position a0 at time t n The amount of displacement after the initial measurement is regarded as the amount of displacement after the initial measurement (S107). n At point a in the direction of the initial measurement position a0 0n The initial measurement position a0 is the initial measurement position, and the displacement position a 0n (S108, S109).

[0029] (Measurement of nadir N) The measurement of the top subsidence N using the above displacement measurement procedure will now be described. The measurement procedure is shown in Fig. 5, and a schematic diagram of the measurement is shown in Fig. 7. First, the non-prism total station TS is installed (S201), and its installation position is acquired. The installation position can be acquired, for example, by measuring a target whose installation position is known behind the tunnel, to acquire the position information of the total station. At this time, the installation position is set to within 30 m of the initial measurement position a0 on the tunnel wall. Next, the positions of nine target points a arranged in a grid pattern on the tunnel wall vertically above the center of the tunnel cross-section arc are measured by a non-prism total station TS (S202). The distance T between the points arranged in a grid pattern can be selected appropriately, but may be 30 mm, for example. The distance r from the center of the tunnel cross-section arc to each of the nine measured points is calculated. The coordinates (x0, y0, z0) of the average position a0 of the nine points are also obtained as the initial measurement position a0 (S203).

[0030] Here, the tunnel inner wall surface covered with the shotcrete has unevenness. Therefore, the measurement values ​​of the nine target points may have abnormal values ​​due to the unevenness. Therefore, in order to eliminate the influence of abnormal values ​​due to the unevenness, the points whose measurement values ​​r are apart from the center of the tunnel cross-section arc by a certain value (e.g., 10 mm) or more from the average value of the distances r of the nine measured points from the center of the tunnel cross-section arc may be excluded as abnormal values, and the coordinates (x0, y0, z0) of the average position a0 of the initial measurement positions may be recalculated and acquired as the initial measurement position a0 (S202, S203). The tunnel cross-section arc to which the initial measurement position a0 belongs is defined as the initial measurement tunnel cross-section arc 1D.

[0031] The center of the tunnel cross section arc to which the initial measurement position a0 belongs is the initial measurement tunnel cross section arc center O1(x o ,y o ,z o ) (S203), and the distance between the initial measurement tunnel cross section arc center O1 and the initial measurement position a0 is set as r0 (S204). r0 is calculated using the above formula 1.

[0032] FIG. 7 also shows the initial measurement tunnel cross section arc 1D, the predetermined time t n After the initial measurement, the tunnel cross section arc 1D is displaced, and the initial measurement tunnel cross section arc displacement 1H is n After the time has elapsed, the non-prism total station TS will measure t n Rear tunnel cross section arc 2H, t n The tunnel cross section arc 2D, which is the front tunnel cross section arc of the rear tunnel cross section arc 2H, and t n The center of the rear tunnel cross section arc 2H, tn The rear tunnel cross-section arc center O2 is shown.

[0033] Next, at a given time t n After that, the direction of the initial measurement position a0 (x0, y0, z0) is measured by the non-prism total station TS (S205). At this time, the position irradiated with the laser light is called a n When the tunnel wall is displaced, it is usually displaced downward, so as shown in Figs. 1, 4 and 7, the laser beam irradiation position a n is the distance from the tunnel cross-section arc 1D where the initial measurement position a0 was measured to the non-prism total station TS side, t n It is on the rear tunnel cross section arc 2H. Therefore, when the direction of the initial measurement position a0 is measured using the non-prism total station TS, the laser beam irradiation position a0 is not the initial measurement position a0 but the direction of the n The coordinates of the laser beam irradiation position a are obtained. n A n Rear measurement position a n Next, t n Rear measurement position a n belongs to t n The center of the rear tunnel cross section arc 2H, t n Then, the position of the tunnel cross section arc center O2 is obtained (S206).

[0034] The laser beam irradiation position is t n Rear measurement position a n And, t n The distance between the tunnel cross section arc center O2 and the n (S207). Here, the tunnel inner wall surface covered with the shotcrete has unevenness, which may cause errors. Initial measurement tunnel cross section arc center O1 and t nIdeally, the distance of the rear tunnel cross section arc center O2 is 0, but taking into consideration the time required for measurement, if it exceeds a certain threshold, the irradiation direction is slightly changed and measurement is performed again (S211). The threshold can be determined appropriately. The threshold is, for example, 50 mm, preferably 30 mm, more preferably 5 mm, and particularly preferably 1 mm. If it exceeds this, it is considered to be due to the influence of errors caused by unevenness of the tunnel inner wall surface, and the irradiation direction of the non-prism total station TS is changed and a similar measurement is performed (S211). The change in the irradiation direction can be determined appropriately, but for example, it may be sufficient that the irradiation position on the wall surface changes by 10 mm to 30 mm, or 20 mm to 30 mm. Δr = (r0 -r n ) is regarded as the amount of crown settlement (S207, S210), and the distance r from the initial measurement tunnel cross section arc center O1 on the straight line connecting the initial measurement tunnel cross section arc center O1 and the initial measurement position a0 is n At the initial measurement position a0, the initial measurement position displacement position a 0n is regarded as the top subsidence position (S208, S209).

[0035] By the above procedure, the top subsidence amount Δr and the initial measurement position displacement position a, which is the top subsidence position, were measured using the non-prism total station TS. 0n It becomes possible to measure.

[0036] (Measurement of internal displacement S) Next, the measurement of the internal displacement S will be explained. The measurement procedure is shown in Fig. 6, and a schematic diagram is shown in Fig. 8. First, the non-prism total station TS is installed (S301), and its installation position is acquired. The installation position can be acquired, for example, by measuring a target whose installation position is known behind the tunnel, to acquire the position information of the total station. At this time, the installation position is set to within 30 m of the initial measurement position a0 on the tunnel wall. Next, the positions of nine target points a arranged in a grid pattern at a height of R from the tunnel bottom on the left side of the non-prism total station TS are measured by the non-prism total station TS (S302). The distance T between the grid points can be selected appropriately, but may be 30 mm, for example. The distance r from the center of the tunnel cross section arc to each of the nine measured points is calculated. The average position a0 (x0, y0, z0) of the nine points is obtained as the initial measurement position a0 (S303).

[0037] Here, the tunnel inner wall surface covered with the shotcrete has unevenness. Therefore, the measurement values ​​of the nine target points may have abnormal values ​​due to the unevenness. Therefore, in order to eliminate the influence of abnormal values ​​due to the unevenness, the points whose measurement values ​​r are apart from the center of the tunnel cross-section arc by a certain value (for example, 10 mm) or more from the average value of the distances r of the nine measured points from the center of the tunnel cross-section arc may be excluded as abnormal values, and the coordinates (x0, y0, z0) of the average position a0 of the initial measurement positions may be recalculated and acquired as the initial measurement position a0 (S302, S303). The tunnel cross-section arc to which the initial measurement position a0 belongs is defined as the initial measurement tunnel cross-section arc 1D.

[0038] The center of the tunnel cross section arc to which the initial measurement position a0 belongs is the initial measurement tunnel cross section arc center O1(x o ,y o ,z o ) (S303), and the distance between the initial measurement tunnel cross section arc center O1 and the initial measurement position a0 is set as r0 (S304). r0 is calculated using the above formula 1.

[0039] FIG. 8 also shows the initial measurement tunnel cross section arc 1D, the predetermined time t n After the initial measurement, the tunnel cross section arc 1D is displaced, and the initial measurement tunnel cross section arc displacement 1H is n After the time has elapsed, the non-prism total station TS will measure t n Rear tunnel cross section arc 2H, t n The tunnel cross section arc 2D, which is the front tunnel cross section arc of the rear tunnel cross section arc 2H, and the tunnel cross section arc 2D or tn After passing, the center of the tunnel cross section arc 2H, t n The rear tunnel cross-section arc center O2 is shown.

[0040] Next, the positions of nine target points a arranged in a grid pattern at a height of R from the tunnel bottom on the right side of the non-prism total station TS are measured by the non-prism total station TS (S305). The distance T between the grid points can be selected appropriately, but may be 30 mm, for example. The distance r from the center of the tunnel cross section arc to each of the nine measured points is calculated. The average position a'0 (x'0, y'0, z'0) of the nine points is obtained as the initial measurement position a'0 (S306).

[0041] Here, the tunnel inner wall surface covered with the shotcrete has unevenness. Therefore, the measurement values ​​of the nine target points may have abnormal values ​​due to the unevenness. Therefore, in order to eliminate the influence of abnormal values ​​due to the unevenness, points where the measurement value r is away from the center of the tunnel cross section arc by a certain value (for example, 10 mm) or more from the average value of the distance r of each of the nine measured points from the center of the tunnel cross section arc may be excluded as abnormal values, and the average position a'0 (x'0, y'0, z'0) of the initial measurement positions may be obtained as the initial measurement position a'0 (S305, S306).

[0042] The initial measurement position a'0 is located near the tunnel wall at a height of R from the tunnel bottom on the right side of the initial measurement tunnel cross section arc 1D as seen from the non-prism total station TS. The distance between the initial measurement tunnel cross section arc center O1 and the initial measurement position a'0 is set to r'0 (S306). r'0 is calculated using the above formula 1.

[0043] Next, at a given time t n After that, the direction of the initial measurement position a0 (x0, y0, z0) is measured by the non-prism total station TS (S307). At this time, the position irradiated with the laser light is called a n When the tunnel wall is displaced, it is usually displaced downward, so as shown in Figs. 1, 4 and 8, the laser beam irradiation position an is the distance from the non-prism total station TS side to the initial measurement tunnel cross section arc 1D where the initial measurement position a0 was measured. n After passing through, it is on the tunnel cross section arc 2H. Therefore, when measuring the direction of the initial measurement position a0 using the non-prism total station TS, the laser beam irradiation position a0 is not the initial measurement position a0 but the n The coordinates of the laser beam irradiation position a are obtained. n A n Rear measurement position a n Next, t n Rear measurement position a n belongs to t n The center of the rear tunnel cross section arc 2H, t n Then, the position of the tunnel cross section arc center O2 is obtained (S308).

[0044] The laser beam irradiation position is t n Rear measurement position a n And, t n The distance between the tunnel cross section arc center O2 and the n (S309). Here, the tunnel inner wall surface covered with the shotcrete has unevenness, which may cause errors. Initial measurement tunnel cross section arc center O1 and t n Ideally, the distance of the tunnel cross section arc center O2 is 0, but in consideration of the time required for measurement, if it exceeds a certain threshold, the irradiation direction is slightly changed and measurement is performed again (S318). The threshold can be determined appropriately. The threshold is, for example, 50 mm, preferably 30 mm, more preferably 5 mm, and particularly preferably 1 mm. If it exceeds this, it is considered to be due to the influence of errors caused by unevenness of the tunnel inner wall surface, and the irradiation direction of the non-prism total station TS is changed and a similar measurement is performed (S318). The change in the irradiation direction can be determined appropriately, but for example, it may be sufficient that the irradiation position on the wall surface changes by 10 mm to 30 mm, or 20 mm to 30 mm. Δr = (r0 -r n ) at the initial measurement position a0 at time t nThe amount of displacement after the initial measurement is regarded as the amount of displacement after the initial measurement (S309). n At the initial measurement position a0, point a 0n The initial measurement position a0 is the initial measurement position, and the displacement position a 0n (S310, S311).

[0045] Next, the direction of the initial measurement position a'0 (x'0, y'0, z'0) is measured by the non-prism total station TS (S312). At this time, the position irradiated with the laser light is referred to as a' n When the tunnel wall is displaced, it usually displaces downward, so as shown in Figs. 1, 4, and 8, the laser beam is irradiated at position a'. n is the distance t from the non-prism total station TS side to the initial measurement tunnel cross section arc 1D where the initial measurement position a'0 was measured. n It is on the rear tunnel cross section arc 3H. n Rear measurement position a n The same operation as when measuring the laser beam irradiation position a' was performed. n A n Rear measurement position a' n Toshi (S313), t n Rear measurement position a' n belongs to t n Rear tunnel cross section arc center O'2 and time t n Rear measurement position a' n The distance between n (S314). Δr'=(r'0-r' n ) at the initial measurement position a'0, time t n The amount of displacement after the initial measurement is regarded as the amount of displacement after the initial measurement (S314). n At the initial measurement position a'0, point a' 0n The initial measurement position a'0 is the initial measurement position displacement position a' 0n (S315, S316).

[0046] The distance S1 between the initial measurement position a0 and the initial measurement position a'0 and the initial measurement position displacement position a 0n and initial measurement position displacement position a' 0n The difference between the distances S2 is set as the amount of internal displacement S (S317). EXAMPLES

[0047] To confirm the effectiveness of the present invention, a comparison was made with measurements using a total station equipped with a reflector (1-inch prism). However, because the reflector cannot be installed immediately after excavation for safety reasons, measurements using the total station equipped with the reflector were carried out 1.5 days after excavation. The reflector was also installed 4 m into the tunnel from the measurement point using the non-prism total station.

[0048] Example 1 In order to confirm the effectiveness of the present invention, the degree of error in measuring the displacement of a cross section inside a tunnel according to the present invention was confirmed. 9 shows the displacement measurement values ​​and their approximation curves according to the present invention. The deviation from the approximation curve was calculated using the following formula.

number

number

number

[0049] Table 1 shows a comparison of measurements for test sections 1 to 4 using a non-prism total station and a total station equipped with a reflector. The final value of the top settlement N measured using the non-prism total station and the total station equipped with a reflector differed by 2.0 mm, showing good agreement. In addition, the difference in the variability of the displacement measurement values ​​calculated from the above formulas 2 and 3 between the measurements using the non-prism total station and the total station equipped with a reflector was 0.5 mm or less for each test cross section, and the average value of the variability for the four test cross sections was 0.1 mm. The variability of the data was also almost the same as the measurements using the total station equipped with a reflector. [Table 1]

[0050] The final value of the internal space displacement S measured using the non-prism total station and the total station with the reflector installed had a difference of 3.4 mm, showing good agreement. In addition, the difference in the variability of the displacement measurement values ​​calculated from the above formulas 2 and 3 between the measurements using the non-prism total station and the total station equipped with a reflector was 1.2 mm or less at each test cross section, and the average value of the variability at the four test cross sections was 0.7 mm. The variability of the data was also almost the same as the measurements using the total station equipped with a reflector.

[0051] Example 2 Figure 10 shows the time-dependent change in the crest settlement N data for test section 4. The results of measurements using the non-prism total station TS and measurements using a total station equipped with a reflector are compared. For measurements using the total station equipped with a reflector, measurements were started 1.5 days after excavation because the reflector could not be installed immediately after excavation for safety reasons. The amount of initial settlement up to 1.5 days after excavation was 2.1 mm. The amount of initial settlement is an important indicator for predicting subsequent settlement behavior, but during this period, measurements using a total station equipped with a reflector were not possible, demonstrating the effectiveness of measurements using the non-prism total station TS. Furthermore, the results of measurements using the non-prism total station TS and the total station TS equipped with a reflector showed similar trends, demonstrating the effectiveness of measurements using the non-prism total station TS.

[0052] Example 3 Figure 11 shows the time-dependent change in the data of the internal displacement S at test section 4. The results of measurements using a non-prism total station TS and a total station TS equipped with a reflector are compared. The initial displacement up to 1.5 days after excavation was 5.1 mm, which was larger than the initial settlement. During this period, measurements using a total station TS equipped with a reflector were not possible, demonstrating the effectiveness of measurements using a non-prism total station TS. Measurements using a total station TS equipped with a reflector showed that the displacement was almost stable from three days after excavation, and measurements using the non-prism total station TS showed a similar trend, demonstrating the effectiveness of measurements using the non-prism total station TS.

[0053] The non-prism total station TS has been shown to be highly accurate and practical for measuring internal displacement within a tunnel. Furthermore, when using a total station TS equipped with a reflector, for safety reasons the reflector cannot be installed immediately after excavation. On the other hand, when a non-prism total station TS is used, measurements can be taken immediately after excavation. This makes it possible to obtain the amount of initial displacement, which is also useful for understanding subsequent displacement trends. In addition, since there is no need to install reflectors, work can be done safely and there are no problems such as reflectors falling off or being damaged due to the impact of blasting, making this an extremely useful measurement method.

[0054] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. [Explanation of symbols]

[0055] 1...Tunnel, 1D...Initial measurement tunnel cross section arc, 1H...Initial measurement tunnel cross section arc displacement, 2D...Tunnel cross section arc, 2H...t n Rear tunnel cross section arc, 3D...Tunnel cross section arc, 3H...t n Rear tunnel cross section arc, a0...initial measurement position, a n …t n Rear measurement position, a 0n …Initial measurement position, displacement position, O1…Initial measurement tunnel cross section arc center, O2…t n Rear tunnel cross section arc center, O'2...t n Rear tunnel cross section arc center, a... measurement point, a'0... initial measurement position, a' n …t n Rear measurement position, a' 0n …Initial measurement position displacement position, TS…Non-prism total station, S1…Distance between initial measurement position a0 and initial measurement position a'0, S2…Initial measurement position displacement position a 0n and initial measurement position displacement position a' 0n Distance

Claims

1. The three-dimensional coordinates of a plurality of adjacent points on the tunnel wall are acquired by the non-prism total station, and the average coordinates are acquired as the three-dimensional coordinates of the displacement measurement point on the initial measurement tunnel cross section arc, and the initial measurement position a ０ and The initial measurement position a ０ The initial measurement tunnel cross-sectional arc center O of the initial measurement tunnel cross-sectional arc to which １ acquiring coordinates of The initial measurement tunnel cross section arc center O １ and the initial measurement position a ０ Distance r ０ and calculating After a predetermined time has elapsed, the initial measurement position a ０ By irradiating the laser beam of the total station in the direction of the laser beam, the laser beam irradiation position a on the inner wall surface of the tunnel is ｎ acquiring three-dimensional coordinates of the The laser light irradiation position a ｎ The center of the tunnel cross section arc O ２ and the laser light irradiation position a ｎ Distance r from ｎ and calculating The distance r ０ and the distance r ｎ The difference between the initial measurement position a after the predetermined period has elapsed is calculated. ０ and acquiring the displacement of the The initial measurement tunnel cross section arc center O １ and the initial measurement position a ０ on the straight line connecting the initial measurement tunnel cross section arc center O １ The distance from ｎ and the initial measurement position a ０ Point a in the direction ０ｎ acquiring three-dimensional coordinates of the A method for measuring spatial displacement inside a tunnel.

2. The initial measurement tunnel cross section arc center O １ and the laser light irradiation position a ｎ The center of the tunnel cross section arc O ２ When the distance between the laser beam irradiation position a and the non-prism total station exceeds a threshold value, the irradiation direction of the non-prism total station is changed, and the laser beam irradiation position a ｎ re-measuring the position of A method for measuring displacement inside a tunnel according to claim 1.

3. The time elapsed after excavation and the distance r ０ and the distance r ｎ The estimated amount of internal displacement after a predetermined time is calculated using an approximate equation that represents the relationship between the difference between the 3. A method for measuring displacement inside a tunnel according to claim 1 or 2.

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