Invert displacement measurement system and method for measuring invert displacement

Abstract

To provide an invert displacement measurement system capable of simultaneously measuring displacements at multiple points of an invert and calculating a vertical displacement distribution in the width direction of the invert.SOLUTION: An invert displacement measurement system 10 includes: an insertion pipe 20 embedded in backfill soil 3; a displacement measuring instrument 50 inserted into the insertion pipe 20; and a displacement calculation device 100. The displacement measuring instrument 50 includes a plurality of core members 51 arranged in the width direction of an invert 2, and acceleration sensors 52 attached to the core members 51, respectively. Two adjacent core members 51, 51 are tiltably connected to each other about a horizontal axis extending along the longitudinal direction of a tunnel 1. The displacement calculation device 100 calculates the vertical displacement of the invert 2 on the basis of acceleration data acquired from each acceleration sensor 52.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an invert displacement measurement system and an invert displacement measurement method. [Background technology]

[0002] In areas with poor geology, external pressure that exceeds the value assumed in the design may act on the tunnel invert, and this external pressure may cause the invert to rise. If the invert uplift continues, measures must be taken according to the severity of the uplift phenomenon. In addition, pouring the invert lining concrete is conditional on the convergence of the tunnel deformation, and since the tunnel deformation must be confirmed by displacement measurement, it is important to measure the displacement of the invert.

[0003] One measuring device for measuring invert displacement has a tube extending from a detector buried beneath the backfill soil (roadbed) to the inner surface of the invert (see, for example, Patent Documents 1 and 2). This measuring device is configured to measure the displacement of the invert based on the change in the height of the liquid surface in the detector when the position of the detector changes due to deformation of the invert. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7129240 [Patent Document 2] Patent No. 7284129 Summary of the Invention [Problem to be solved by the invention]

[0005] The conventional measuring device described above measures the displacement of a single point on the invert, and is unable to calculate the displacement distribution across the width of the invert, making it difficult to grasp the deformation of the entire bottom of the tunnel.

[0006] The present invention aims to solve the above-mentioned problems and to provide an invert displacement measurement system and an invert displacement measurement method that can simultaneously measure the displacement of multiple points on an invert and calculate the vertical displacement distribution in the width direction of the invert. [Means for solving the problem]

[0007] To solve the above problems, a first invention is an invert displacement measurement system for measuring the displacement of a tunnel invert, comprising an insertion pipe embedded in backfill soil provided on the inner surface of the invert while extending in the width direction of the invert, a displacement measuring instrument inserted into the insertion pipe, and a displacement calculation device. The displacement measuring instrument has a plurality of core members arranged in the width direction of the invert and a plurality of acceleration sensors attached to each of the core members. Two adjacent core members are connected so as to be tiltable at least around a horizontal axis along the extension direction of the tunnel. The displacement calculation device calculates the vertical displacement of the invert based on acceleration data acquired from each acceleration sensor.

[0008] In the invert displacement measurement system of the present invention, after the construction of the invert shotcrete or invert concrete, a displacement measuring device is inserted into an insertion pipe, allowing multiple acceleration sensors to be lined up in the backfill soil in the width direction of the invert. Then, based on the acceleration data (acceleration data correlated with gravitational acceleration) acquired from each acceleration sensor, vertical displacement at each of multiple points in the width direction of the invert can be measured simultaneously, allowing the vertical displacement distribution (uplift or subsidence) in the width direction of the invert to be calculated.

[0009] In the invert displacement measurement system of the present invention, when the displacement measuring instrument is inserted into the insertion tube, the two adjacent core materials bend along the curvature of the insertion tube, allowing the displacement measuring instrument to be inserted smoothly into the insertion tube. In the invert displacement measurement system of the present invention, after measuring the displacement of the invert, the displacement measuring instrument can be pulled out and recovered from the insertion tube, thereby reducing the cost required for measuring the displacement of the invert. The invert displacement measurement system of the present invention has a structure in which multiple core materials are connected, so the length of the displacement measuring device can be easily changed to match the width of the invert at each construction site.

[0010] In the above-described invertor displacement measurement system, it is preferable that the displacement calculation device calculates the displacement at predetermined time intervals to grasp the change over time in the vertical displacement distribution in the width direction of the invertor.

[0011] In the invert displacement measurement system, it is preferable that the end of the insertion pipe is placed on the upper surface of the backfill soil. In this configuration, the displacement measuring device can be inserted into the insertion pipe from the upper surface of the backfill soil, making the work easier.

[0012] In the invert displacement measurement system, it is preferable that the two adjacent core members are connected so as to be tiltable only around a horizontal axis along the extension direction of the tunnel. In this configuration, when the invert deforms, the core tilts around a horizontal axis along the tunnel extension direction. In this way, when the tilting of the acceleration sensor is limited to one direction, measurement errors are reduced compared to when tilting in other directions, and the accuracy of invert displacement measurement can be improved.

[0013] In the above-mentioned invert displacement measurement system, a connecting shaft extending along a horizontal axis along the extension direction of the tunnel is provided at the connecting portion connecting two adjacent core materials, and the core materials are tilted around the axis of the connecting shaft, thereby limiting the tilting of the acceleration sensor to one direction.

[0014] In the above-described invert displacement measurement system, if the insertion tube is formed of a flexible tube body and is aligned along the inner surface of the invert, the displacement of the invert can be measured with high accuracy.

[0015] In the above-described inverted displacement measurement system, when the core material is inserted into the cylindrical body, the acceleration sensor attached to the core material can be prevented from coming into contact with the insertion tube and being damaged when the displacement measuring device is inserted into the insertion tube.

[0016] The invert displacement measurement system is provided with a shape-retaining tube for maintaining the inclination of the end portion of the insertion pipe relative to the inner surface of the invert. The shape-retaining tube is buried at the end of the backfill soil in the width direction, and is inclined so that the inclination changes from vertical to horizontal as it goes from the top to the bottom. It is preferable that the end portion of the insertion pipe is inserted into the shape-retaining tube, and the end portion of the insertion pipe is maintained in a state where it is tilted up obliquely relative to the inner surface of the bottom of the invert.

[0017] Furthermore, if there is a large gap between the inner peripheral surface of the insertion pipe and the outer surface of the displacement measuring instrument, deviations of the displacement measuring instrument due to ground behavior or vibrations during construction will affect the measurement results. In particular, when measuring displacement distribution based on accumulated displacement using the end of the displacement measuring instrument as a reference, as in the present invention, deviations of the displacement measuring instrument in each section will accumulate. For this reason, it is desirable to reduce the inner diameter of the insertion pipe to reduce the gap between the inner peripheral surface of the insertion pipe and the outer surface of the displacement measuring instrument. However, if the inner diameter of the insertion pipe is reduced, it becomes difficult to insert or remove the displacement measuring instrument from the end of the insertion pipe. Therefore, by maintaining the curved shape of the end of the insertion tube using the shape-retaining tube described above, the displacement measuring instrument can easily pass through the end of the insertion tube, making it easier to insert or retrieve the displacement measuring instrument even if the inner diameter of the insertion tube is reduced. As a result, the present invention can achieve measurement accuracy equivalent to that of conventional measuring devices (which measure the displacement of the invert based on the change in the liquid level in the detection unit when the position of the detection unit changes due to deformation of the invert).

[0018] In the invert displacement measurement system, the shape-retaining tube is supported on the inner surface of the invert by a support member. In this case, the support member is provided with a curved portion provided around the outer circumferential surface of the shape-retaining tube and a fixing portion fixed to the inner surface of the invert. In this way, it is preferable to reliably fix the shape-retaining tube to the inner surface of the invert.

[0019] In order to solve the above problem, the second invention is an invert displacement measurement method using the above-mentioned invert displacement measurement system, comprising a displacement measuring device inserting step of inserting the displacement measuring device into the insertion tube from the end of the insertion tube, a displacement measuring device fixing step of fixing the end of the displacement measuring device to the end of the insertion tube, and a displacement distribution calculation step of using the displacement calculation device to calculate the vertical displacement of the invert based on the acceleration data measured by each of the acceleration sensors.

[0020] In the invert displacement measurement method of the present invention, the two adjacent core members bend along the curve of the insertion pipe, allowing the displacement measuring device to be inserted smoothly into the insertion pipe. Then, by placing multiple acceleration sensors in the backfill soil, the vertical displacement distribution in the width direction of the invert can be calculated. In the present invention, the length of the displacement measuring device can be easily changed by changing the number of core materials to match the width of the invert at each construction site.

[0021] In the invert displacement measurement method described above, after the displacement distribution calculation step, a displacement measuring device recovery step can be performed in which the displacement measuring device in the insertion tube is pulled out from the end of the insertion tube and recovered. Since the recovered displacement measuring device can be used for other measurements, the cost required for invert displacement measurement can be reduced.

[0022] In the invert displacement measurement method described above, in the displacement measuring device insertion step, a shape-retaining tube is attached to the inner surface of the end of the invert in the width direction, the shape-retaining tube being inclined so that its inclination changes from vertical to horizontal as it moves from the top to the bottom, and the end-side portion of the insertion tube is inserted into the shape-retaining tube, thereby maintaining the inclination of the end-side portion of the insertion tube relative to the inner surface of the invert. [Effects of the Invention]

[0023] In this invention, even when the invert is covered with backfill soil, the displacement of multiple points along the width of the invert can be measured simultaneously and the vertical displacement distribution along the width of the invert can be calculated, thereby enabling accurate understanding of tunnel deformation. Furthermore, in this invention, the displacement measuring device can be smoothly inserted into the backfill soil and can be retrieved from the backfill soil after displacement measurement. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a side view showing an invert displacement measurement system according to an embodiment of the present invention. [Figure 2] FIG. 1 is a side view showing a displacement measuring instrument according to an embodiment of the present invention. [Figure 3] FIG. 1 is a plan view showing a displacement measuring instrument according to an embodiment of the present invention. [Figure 4] 4 is a cross-sectional view taken along line IV-IV in FIG. 3, showing the displacement measuring instrument according to the embodiment of the present invention. [Figure 5] FIG. 2 is a side view showing a core material according to an embodiment of the present invention. [Figure 6] 1 is a flowchart of an invert displacement measurement method according to an embodiment of the present invention. [Figure 7] FIG. 10 is a side view showing another form of a shape-retaining tube according to an embodiment of the present invention. [Figure 8] 10 is a side view showing an upper support member in another form of the shape-retaining tube according to the embodiment of the present invention. FIG. [Figure 9]10 is a side view showing a lower support member in another form of a shape-retaining tube according to another embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a side view showing an invert displacement measurement system according to an embodiment of the present invention. The invert displacement measurement system 10 of this embodiment measures the displacement of an invert 2 constructed at the bottom of a tunnel 1 shown in FIG. In this embodiment, the tunnel 1 is excavated to have a circular cross section. The invert 2 is a concrete portion covering the bottom surface of the excavated tunnel 1, which is excavated in an inverted arch shape. Furthermore, backfill soil 3 that forms the roadbed is provided on the inner surface of the invert 2 (the inner surface facing the inside of the tunnel 1).

[0026] The invert displacement measurement system 10 of this embodiment comprises an insertion pipe 20 and a shape-retaining pipe 30 buried in the backfill soil 3, a displacement measuring instrument 50 inserted into the insertion pipe 20, and a displacement calculation device 100. The insertion pipe 20 and the displacement measuring instrument 50 extend from one end to the other end in the width direction of the invert 2 (backfill soil 3).

[0027] The shape-retaining tube 30 is a hard tube. The shape-retaining tube 30 of this embodiment is a cylindrical hard polyvinyl chloride tube, and is formed with a straight portion and a curved portion. The shape-retaining pipes 30 are buried in the backfill soil 3. In this embodiment, two shape-retaining pipes 30 are buried at both ends of the backfill soil 3 in the width direction. The shape-retaining pipe 30 extends from the end in the width direction of the backfill soil 3 toward the center. The shape-retaining pipe 30 is inclined so that it changes from vertical to horizontal as it goes from the top to the bottom, and the entire shape-retaining pipe 30 is curved. The upper end of the shape-retaining pipe 30 protrudes from the top surface of the backfill soil 3.

[0028] The insertion tube 20 is a flexible tube. In this embodiment, the insertion tube 20 is a cylindrical corrugated hard polyethylene tube. The insertion pipe 20 is buried in the backfill soil 3. The end portion of the insertion pipe 20 is inserted into the shape-retaining pipe 30 and is inclined along the shape-retaining pipe 30. That is, the end portion of the insertion pipe 20 is curved and inclined toward the center in the width direction of the backfill soil 3 as it moves from the top to the bottom. In addition, the end portion of the insertion pipe 20 is fixed to the end portion of the shape-retaining pipe 30. The middle part of the insertion pipe 20 extends outward from the shape-retaining pipe 30 below the backfill soil 3, and extends in the width direction along the inner surface of the invert 2. The middle part of the insertion pipe 20 is curved to match the shape of the inner surface of the invert 2.

[0029] Fig. 2 is a side view showing a displacement measuring instrument according to an embodiment of the present invention, and Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 3 showing the displacement measuring instrument according to an embodiment of the present invention. As shown in Figure 2, the displacement measuring device 50 has a plurality of core materials 51 arranged in one direction, a plurality of acceleration sensors 52 attached to each core material 51, a plurality of cylindrical bodies 53 into which the core materials 51 are inserted, and a protective cylindrical body 54 into which the connecting portions 55 of adjacent cylindrical bodies 53, 53 are inserted. The core member 51 is a straight channel steel. As shown in Fig. 4, the core member 51 has side plates that rise vertically from both edges of the bottom plate.

[0030] FIG. 3 is a plan view showing a displacement measuring instrument according to an embodiment of the present invention. As shown in FIG. 3, two adjacent core members 51, 51 are connected via a connecting portion 55. The connecting portion 55 includes a first connecting member 55a provided on one core material 51, a second connecting member 55b provided on the other core material 51, and a connecting shaft 55c. The connecting portion 55 is a rotary joint (knuckle joint) in which a first connecting member 55a of one core material 51 and a second connecting member 55b of the other core material 51 are rotatably connected by a connecting shaft 55c.

[0031] A first connecting member 55a protrudes from one end of the core material 51, and a second connecting member 55b protrudes from the other end of the core material 51. The tip of the second connecting member 55b is divided into two parts spaced apart in the width direction of the core material 51. Mounting holes are formed at the tip of the first connecting member 55a and the tip of the second connecting member 55b. These mounting holes are perpendicular to the longitudinal direction of the core material 51 and penetrate the core material 51 in the lateral width direction (the width direction of the bottom plate of the core material 51). In the connecting portion 55, the tip end of the first connecting member 55a is sandwiched between the tip ends of the second connecting members 55b, and the mounting holes of the first connecting members 55a and the second connecting members 55b communicate with each other.

[0032] FIG. 5 is a side view showing a core material according to an embodiment of the present invention. A connecting shaft 55c is inserted through each mounting hole of the first connecting member 55a and the second connecting member 55b. In this manner, the first connecting member 55a and the second connecting member 55b are connected by the connecting shaft 55c. When the connecting shaft 55c is inserted through the mounting holes of the first connecting member 55a and the second connecting member 55b, the axis of the connecting shaft 55c is aligned in the width direction of the core material 51. As shown in FIG. 5, two adjacent core members 51, 51 are connected so as to be tiltable only around the axis of a connecting shaft 55c, and cannot tilt in the direction perpendicular to the plane of the paper in FIG.

[0033] As shown in FIG. 2, the cylindrical body 53 is a component into which the core material 51 is inserted. The cylindrical body 53 in this embodiment is a cylindrical stainless steel pipe (see FIG. 4). One core material 51 is inserted into one cylindrical body 53, and then adhesive is poured into the cylindrical body 53 to integrate the cylindrical body 53 and the core material 51. A first connecting member 55a and a second connecting member 55b protrude from both ends of the cylindrical body 53, respectively. As a result, a connecting portion 55 is disposed between two adjacent cylindrical bodies 53, 53.

[0034] The acceleration sensor 52 is a so-called inclinometer. The acceleration sensor 52 of this embodiment is made up of a three-axis MEMS sensor. As shown in FIG. 4, the acceleration sensor 52 is attached to the bottom plate of the core material 51, and is adjusted so that the output value of the acceleration data is zero when the core material 51 is placed horizontally, and is g (=gravitational acceleration) when the core material 51 is placed vertically. Therefore, the output value g1 of the acceleration data when the core material 51 is inclined at an angle θ1 with respect to the horizontal plane is g1=g·sinθ1, and the angle θ1 (=sin -1 (g1 / g) can be calculated.

[0035] As shown in FIG. 2 , the protective cylindrical body 54 is a component into which the connecting portion 55 is inserted, and in this embodiment, the protective cylindrical body 54 is a heat-shrinkable tube made of EPT (ethylene propylene rubber). After applying an adhesive to the outer peripheral surface of the end of the cylindrical body 53, the connecting portion 55 is inserted into the protective cylindrical body 54, and both ends of the protective cylindrical body 54 are placed over the ends of adjacent cylindrical bodies 53, 53. The protective cylindrical body 54 is then heated to shrink the protective cylindrical body 54, thereby adhering the protective cylindrical body 54 to the adjacent cylindrical bodies 53, 53. By accommodating the connecting portion 55 within the protective cylindrical body 54 in this manner, the acceleration sensor 52 and the connecting portion 55 can be protected from water and dust. In this embodiment, the connecting portion 55 is configured to be housed in the protective cylindrical body 54, but the connecting portion 55 and the entire cylindrical body 53 may also be housed in the protective cylindrical body 54.

[0036] The displacement calculation device 100 shown in Fig. 1 is a computer that calculates the displacement distribution in the width direction of the inverter 2. The displacement calculation device 100 is connected to each acceleration sensor 52 (see Fig. 2) of the displacement measuring device 50 by wire. Therefore, electric wires (not shown) pass through the connecting portion 55 of this embodiment. Note that the displacement calculation device 100 and the acceleration sensor 52 (see Fig. 2) are not limited to being connected by wire, and may be connected by various wireless means.

[0037] The displacement calculation device 100 acquires acceleration data from each acceleration sensor 52 (see FIG. 2) and calculates vertical displacement using the acceleration data. That is, if the length of one core material 51 (the distance from one connecting shaft 55c to the other connecting shaft 55c) is L, the output value of the acceleration data when the inclination of the core material 51 is θ1 is g1, and the output value of the acceleration data when the inclination of the core material 51 changes from θ1 to θ2 is g2 = g1 + Δg, the height difference (vertical displacement) d between one connecting shaft 55c and the other connecting shaft 55c when the inclination of the core material 51 changes from θ1 to θ2 is expressed by the following equation: d=L・sinθ2-L・sinθ1=L・sin(sin -1 (g2 / g))-L·sin(sin -1 (g1 / g) =L (g2 / g) - L (g1 / g) = L Δg / g Therefore, the length L of the nth core material 51 from one end n The acceleration change amount Δg in the acceleration sensor 52 attached to the n-th core material 51 n By multiplying by , the vertical displacement d of the nth core material 51 is obtained. n can be obtained.

[0038] The acceleration sensor 52 (see FIG. 2) is disposed on the inner surface of the invert 2 below the backfill soil 3, and therefore, when the invert 2 is displaced in the vertical direction, the acceleration sensor 52 is displaced in the vertical direction in accordance with the displacement of the invert 2. The displacement calculation device 100 calculates the vertical displacement of the invert 2. The displacement calculation device 100 then calculates the vertical displacement at each of multiple points within the inverter 2 (calculating the vertical displacement amount at each core material 51 (see Figure 2)), thereby calculating the vertical displacement distribution in the width direction of the inverter 2. The displacement calculation device 100 of this embodiment calculates the displacement of the inverter 2 at predetermined time intervals.

[0039] Next, an invert displacement measurement method using the invert displacement measurement system 10 of this embodiment will be described. 6 is a flowchart of an invert displacement measurement method according to an embodiment of the present invention. In the following description, the flowchart in FIG. 6 will be referred to as appropriate.

[0040] [Insertion pipe installation process] After constructing the invert 2 using shotcrete or invert concrete on the excavated bottom surface of the tunnel 1 shown in Fig. 1 (step S1), the insertion pipe 20 is placed along the inner surface of the invert 2. At this time, the end portion of the insertion pipe 20 is inserted into the shape-retaining pipe 30, and the shape-retaining pipe 30 is attached to the inner surface of the end portion in the width direction of the invert 2 together with the insertion pipe 20 (step S2). This allows the inclination of the end portion of the insertion tube 20 relative to the inner surface of the invert 2 to be maintained. In addition, by inserting the end portion of the insertion tube 20 into the shape-retaining tube 30 before placing the insertion tube 20 on the inner surface of the invert 2, the insertion tube 20 can be easily inserted into the curved shape-retaining tube 30. In addition, after attaching the shape-retaining tube 30 to the inner surface of the width-wise end of the invert 2, the insertion tube 20 may be placed on the inner surface of the invert 2 and the end portion of the insertion tube 20 may be inserted into the shape-retaining tube 30. Then, backfill soil 3 is applied to the inner surface of the invert 2, and the shape-retaining pipe 30 and the insertion pipe 20 are buried in the backfill soil 3 (step S3).

[0041] [Displacement measuring device insertion process] 2 are inserted in a connected state into the insertion pipe 20 from the top surface of the backfill soil 3. At this time, each core 51 is inserted into the insertion pipe 20 while tilting along the insertion pipe 20. In this way, when the entire displacement measuring device 50 is inserted into the insertion tube 20, each core material 51 is aligned in the width direction within the backfill soil 3 (see Figure 1), and multiple acceleration sensors 52 are arranged within the backfill soil 3 (see Figure 1) (step S4).

[0042] [Displacement measuring instrument fixing process] A connecting rod (not shown) extending along a horizontal axis along the extension direction (axial direction of tunnel 1) of tunnel 1 (see Figure 1) is inserted into the connecting holes formed at the ends of the insertion tube 20 and the shape-retaining tube 30 (see Figure 1) and into the mounting hole of the connecting portion 55 of the endmost core material 51. In this way, when the end of the displacement measuring device 50 is fixed to the insertion tube 20, the axis of the connecting shaft 55c of each connecting part 55 is aligned with the horizontal axis along the extension direction of the tunnel 1 (see FIG. 1). This allows each core material 51 to tilt freely only around the horizontal axis.

[0043] [Displacement distribution calculation process] 1 acquires acceleration data measured by each acceleration sensor 52 (see FIG. 2), and calculates vertical displacement from the amount of change in the acceleration data. In this way, the displacement calculation device 100 calculates the vertical displacement at each of the multiple points in the inverter 2, and calculates the vertical displacement distribution in the width direction of the inverter 2 (step S5). Furthermore, the displacement calculation device 100 calculates the displacement of the inverter 2 at predetermined time intervals, and calculates the vertical displacement distribution of the inverter 2 in the width direction. In this embodiment, the acceleration sensor 52 (see FIG. 2) disposed inside the shape-retaining tube 30 is outside the range of measurement of the vertical displacement distribution because there is a risk that its movement may be hindered by the shape-retaining tube 30. Therefore, it is desirable to place the shape-retaining tube 30 as close to the inner surface of the inverter 2 as possible.

[0044] [Displacement measuring instrument recovery process] After the measurement of the displacement of the invert 2 is completed, the displacement measuring device 50 in the insertion pipe 20 is pulled out from the end of the insertion pipe 20 on the upper surface of the backfill soil 3 and collected (step S6).

[0045] In the invert displacement measurement system 10 and invert displacement measurement method described above, as shown in Figure 1, a displacement measuring instrument 50 can be inserted into an insertion pipe 20 buried in backfill soil 3. Then, based on acceleration data acquired from each acceleration sensor 52 (see Figure 2) of the displacement measuring instrument 50, vertical displacement at each of multiple points in the width direction of the invert 2 can be measured simultaneously, and the vertical displacement distribution (uplift or subsidence) in the width direction of the invert 2 can be calculated. Furthermore, in the inverter displacement measurement system 10 of this embodiment, the tilting of the acceleration sensor 52 (see FIG. 1) is limited to one direction, and measurement errors are small, so the accuracy of displacement measurement of the inverter 2 can be improved. In the invert displacement measurement system 10 of this embodiment, the vertical displacement distribution in the width direction of the invert 2 is calculated at predetermined time intervals, thereby making it possible to grasp the deformation of the tunnel 1 with high accuracy.

[0046] In the invert displacement measurement system 10 of this embodiment, when the displacement measuring device 50 is inserted into the insertion tube 20, the two adjacent core materials 51, 51 (see Figure 5) bend along the curvature of the insertion tube 20, so that the displacement measuring device 50 can be inserted smoothly into the insertion tube 20. Furthermore, in the invert displacement measurement system 10 of this embodiment, as shown in FIG. 2, the core material 51 is inserted into the cylindrical body 53, so that when the displacement measuring device 50 is inserted into the insertion tube 20, the acceleration sensor 52 attached to the core material 51 can be prevented from coming into contact with the insertion tube 20 and being damaged. Furthermore, in the invert displacement measurement system 10 of this embodiment, the connecting portion 55 is housed in the protective cylinder 54, so that the acceleration sensor 52, connecting portion 55, and electric wires (not shown) can be protected from water and dust.

[0047] 1, in the invert displacement measurement system 10 of this embodiment, the end of the insertion pipe 20 can be kept inclined along the shape-retaining pipe 30 by inserting the insertion pipe 20 into the shape-retaining pipe 30 that extends downward from the upper surface of the backfill soil 3. This allows the insertion pipe 20 to be reliably buried beneath the backfill soil 3, so that the displacement measuring device 50 can be extended below the backfill soil 3, which is susceptible to the influence of the displacement of the invert 2.

[0048] Furthermore, by using the shape-retaining tube 30 to maintain the curved shape of the end of the insertion tube 20, the displacement measuring device 50 can easily pass through the end of the insertion tube 20, making it easier to insert or retrieve the displacement measuring device 50 even if the inner diameter of the insertion tube 20 is reduced. Furthermore, by reducing the inner diameter of the insertion tube 20 and preventing the displacement measuring device 50 from shifting inside the insertion tube 20, it is possible to improve measurement accuracy.

[0049] In the invert displacement measurement system 10 and invert displacement measurement method of this embodiment, after measuring the displacement of the invert 2, the displacement measuring instrument 50 can be pulled out and recovered from the insertion tube 20, and the recovered displacement measuring instrument 50 can be used for other measurements, thereby reducing the cost required for measuring the displacement of the invert 2. In the invert displacement measurement system 10 and invert displacement measurement method of this embodiment, the length of the displacement measuring device 50 can be easily changed by changing the number of core materials 51 (see Figure 2) to match the width of the invert 2 for each construction site.

[0050] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate within the scope of the invention. 4, the core material 51 of the invert displacement measurement system 10 of this embodiment uses a channel steel, but the shape of the core material 51 is not limited thereto, and the core material 51 may be formed of a flat plate or a cylindrical member. For example, if the core material 51 is formed of a cylindrical member and the acceleration sensor 52 is housed inside the cylindrical member, the cylindrical body 53 may not be provided.

[0051] As shown in FIG. 3, the invert displacement measurement system 10 of this embodiment is provided with a connecting portion 55 that connects a first connecting member 55a and a second connecting member 55b via a connecting shaft 55c, but the structure of the connecting portion is not limited, and various types of joints can be used.

[0052] The two adjacent core members 51, 51 may be connected so as to be tiltable at least around a horizontal axis. That is, the two adjacent core members 51, 51 may be configured to tilt in a direction other than around the horizontal axis. In this case, it is preferable to form a guide surface on the inner surface of the insertion tube 20 to regulate the tilting direction of the two core members 51, 51 so that the two core members 51, 51 inserted into the insertion tube 20 tilt around the horizontal axis.

[0053] In this embodiment, as shown in Fig. 1, the end of the insertion pipe 20 is disposed on the upper surface of the backfill soil 3, but the position of the end of the insertion pipe 20 is not limited. For example, the end of the insertion pipe 20 may be disposed within the backfill soil 3 without protruding from the upper surface.

[0054] In the invert displacement measurement system 10 of this embodiment, a shape retention tube 30 is provided as shown in Figure 1, but for example, if the inclination angle of the end portion of the insertion tube 20 relative to the inner surface of the invert 2 is small, the shape retention tube 30 does not need to maintain the inclination of the insertion tube 20.

[0055] Next, other embodiments of the shape-retaining tube 30 will be described. FIG. 7 is a side view showing another form of the shape-retaining tube according to the embodiment of the present invention. 7 is supported on the inner surface of the invert 2 by an upper support member 31. In addition, the lower part of the shape-retaining tube 30 is supported on the inner surface of the invert 2 by two lower support members 32, 32. The upper part of the shape-retaining pipe 30 is raised obliquely relative to the inner surface of the invert 2 and is spaced apart from the inner surface of the invert 2. In addition, the upper end of the shape-retaining pipe 30 protrudes from the upper surface of the backfill soil 3.

[0056] FIG. 8 is a side view showing an upper support member in another form of the shape-retaining tube according to the embodiment of the present invention. As shown in FIG. 8, the upper support member 31 includes a curved portion 31a provided around the outer circumferential surface of the shape-retaining tube 30, and a fixed portion 31b fixed to the inner surface of the inverter 2.

[0057] The fixing portion 31b is a flat plate that is laid on the inner surface of the invert 2. Mounting holes 31c, 31c are formed at both ends of the fixing portion 31b in the longitudinal direction (extension direction of the tunnel 1). The fixing portion 31b is fixed to the inner surface of the invert 2 by inserting an anchor bolt (not shown) protruding from the inner surface of the invert 2 into the mounting hole 31c and screwing a nut onto the anchor bolt on the surface side of the fixing portion 31b. The curved portion 31a of the upper support member 31 is formed in a cylindrical shape. The curved portion 31a includes two semicircular members. The shape-retaining tube 30 is inserted into the curved portion 31a by sandwiching the shape-retaining tube 30 between the pair of semicircular members.

[0058] Two support bolts 31d, 31d are erected on the fixed portion 31b of the upper support member 31. The support bolts 31d, 31d are arranged on both sides of the curved portion 31a. Both sides of the curved portion 31a are attached to the tips of the support bolts 31d, 31d. The curved portion 31a of the upper support member 31 is supported at a position separated from the fixed portion 32b by both support bolts 31d, 31d. 7, the upper part of the shape-retaining tube 30 is supported by the upper support member 31 and is positioned at a position away from the inner surface of the inverter 2. This allows the upper part of the shape-retaining tube 30 to be raised up close to vertical.

[0059] FIG. 9 is a side view showing a lower support member in another form of a shape-retaining tube according to another embodiment of the present invention. As shown in FIG. 9, the lower support member 32 includes a curved portion 32a provided around the outer circumferential surface of the shape-retaining tube 30, and two fixing portions 32b, 32b fixed to the inner surface of the inverter 2.

[0060] The curved portion 32a of the lower support member 32 is bent into a U-shape. The arc portion of the curved portion 32a is superimposed on the outer peripheral surface. Fixing portions 32b, 32b are formed at both ends (lower ends) of curved portion 32a. Fixing portion 32b is a portion that is to be superimposed on the inner surface of inverter 2. Fixing portion 32b has mounting hole 32c formed therein. An anchor bolt (not shown) protruding from the inner surface of inverter 2 is inserted into mounting hole 32c, and a nut is screwed onto the anchor bolt on the surface side of fixing portion 32b, thereby fixing fixing portion 32b to the inner surface of inverter 2.

[0061] 7, the lower portion of the shape-retaining tube 30 supported by the two lower support members 32, 32 is disposed in contact with the inner surface of the invert 2. As a result, the lower portion of the shape-retaining tube 30 is inclined along the inner surface of the invert 2. [Explanation of symbols]

[0062] 1. Tunnel 2 Invert 3 Backfill soil 10 Invert Displacement Measurement System 20 Insertion tube 30 Shape-retaining tube 31 Upper support member 31a Curved section 31b Fixed part 31c Mounting hole 31d Support bolt 32 Lower support member 32a Curved section 32b Fixed part 32c Mounting hole 50 Displacement measuring instrument 51 Core material 52 Acceleration sensor 53 Cylinder 54 Protective barrel 55 Connecting part 55a First connecting member 55b Second connecting member 55c connection shaft 100 Displacement calculation device

Claims

1. An invert displacement measurement system for measuring the displacement of a tunnel invert, An insertion pipe that is buried in backfill soil provided on the inner surface of the invert while extending in the width direction of the invert; a displacement measuring device inserted into the insertion tube; a displacement calculation device, The displacement measuring instrument is A plurality of core materials arranged in the width direction of the invert; a plurality of acceleration sensors attached to each of the core materials, The two adjacent core members are connected to each other so as to be tiltable at least around a horizontal axis along the extension direction of the tunnel, The displacement calculation device An invert displacement measurement system characterized by calculating the vertical displacement of the invert based on acceleration data acquired from each of the acceleration sensors.

2. 2. The invert displacement measurement system according to claim 1, The invertor displacement measurement system is characterized in that the displacement calculation device calculates the displacement at predetermined time intervals.

3. 2. The invert displacement measurement system according to claim 1, An invert displacement measurement system characterized in that the end of the insertion pipe is positioned on the top surface of the backfill soil.

4. 2. The invert displacement measurement system according to claim 1, An invert displacement measurement system characterized in that two adjacent core members are connected so as to be able to tilt freely only around a horizontal axis along the extension direction of the tunnel.

5. 5. The invert displacement measurement system according to claim 4, The connecting portion connecting two adjacent core materials has: a connecting shaft extending along a horizontal axis along the extension direction of the tunnel; An invert displacement measurement system characterized in that the core material is freely tiltable around the axis of the connecting shaft.

6. 2. The invert displacement measurement system according to claim 1, An invert displacement measurement system, wherein the insertion pipe is a flexible pipe body.

7. 2. The invert displacement measurement system according to claim 1, An invert displacement measurement system characterized in that the core material is inserted into a cylindrical body.

8. 2. The invert displacement measurement system according to claim 1, a shape-retaining tube for maintaining an inclined state of a portion of the end side of the insertion tube relative to the inner surface of the invert; The shape-retaining pipe is buried in the end of the backfill soil in the width direction, and is inclined so as to change from a vertical direction to a horizontal direction as it goes from the top to the bottom, An invert displacement measurement system characterized in that an end portion of the insertion tube is inserted into the shape-retaining tube.

9. 9. The invert displacement measurement system according to claim 8, The shape-retaining tube is supported on the inner surface of the invert by a support member, The support member is a curved portion provided around the outer peripheral surface of the shape-retaining tube; An invert displacement measurement system characterized by comprising a fixed portion fixed to the inner surface of the invert.

10. 2. An invert displacement measurement method using the invert displacement measurement system according to claim 1, comprising: a displacement measuring device inserting step of inserting the displacement measuring device into the insertion tube from an end of the insertion tube; a displacement measuring device fixing step of fixing an end of the displacement measuring device to an end of the insertion tube; An invert displacement measurement method characterized by comprising a displacement distribution calculation process in which the displacement calculation device calculates the vertical displacement of the invert based on the acceleration data measured by each acceleration sensor.

11. 11. The invert displacement measurement method according to claim 10, After the displacement distribution calculation step, An invert displacement measuring method comprising a displacement measuring device recovery step of pulling out and recovering the displacement measuring device in the insertion tube from the end of the insertion tube.

12. 11. The invert displacement measurement method according to claim 10, In the displacement measuring device insertion step, An invert displacement measurement method characterized by attaching a shape-retaining tube that is inclined so that it changes from vertical to horizontal as it moves from the top to the bottom to the inner surface of the invert's width-wise end, and inserting the end portion of the insertion tube into the shape-retaining tube, thereby maintaining the inclined state of the end portion of the insertion tube relative to the inner surface of the invert.

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