Method for evaluating the tension of a ground anchor

Abstract

To easily measure the tension force of an anchor.SOLUTION: An evaluation method includes the steps for: acquiring detection data, from a sensor detecting elastic waves, which indicates the detection result of an elastic wave at the time of being input to an anchor and the detection result of an elastic wave reflected within the anchor and input to the sensor; calculating the velocity of the elastic wave propagating through the anchor on the basis of the detection data; and calculating a tension force pe occurring in the anchor on the basis of the following equation (1), where Vp0 is a reference velocity of the elastic wave propagating through the anchor measured in advance, Vpa is a calculated elastic wave velocity, and θ is a correlation coefficient.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] This disclosure relates to evaluation methods, programs, and evaluation apparatus. [Background technology]

[0002] Techniques for evaluating the integrity of ground anchors installed to prevent slope collapse are known. For example, Patent Document 1 discloses a technique for evaluating the integrity of a ground anchor based on the propagation speed of elastic waves transmitted through the anchor. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2007-322401 [Overview of the project] [Problems that the invention aims to solve]

[0004] Generally, the tension force acting on ground anchors is measured by a lift-off test. However, since lift-off tests are performed using test equipment such as hydraulic jacks, the process involves assembly, measurement, and disassembly of the test equipment, which presents a challenge in terms of time.

[0005] This disclosure aims to provide an evaluation method, program, and evaluation apparatus that can easily measure the tension force of a ground anchor. [Means for solving the problem]

[0006] The evaluation method of this disclosure includes the steps of: obtaining detection data from a sensor that detects elastic waves, showing the detection result of the elastic wave at the time it is input to the anchor and the detection result of the elastic wave reflected inside the anchor and input to the sensor; calculating the velocity of the elastic wave propagating through the anchor based on the detection data; and setting a reference velocity of the elastic wave propagating through the anchor that has been measured in advance to V p0 The calculated velocity of the elastic wave is V pa When the correlation coefficient is θ, the tension force p acting on the anchor is e This includes the step of calculating based on the following formula (1).

number

[0007] The program of this disclosure includes the steps of: obtaining detection data from a sensor that detects elastic waves, showing the detection result of the elastic wave at the time it is input to the anchor and the detection result of the elastic wave reflected inside the anchor and input to the sensor; calculating the velocity of the elastic wave propagating through the anchor based on the detection data; and setting a reference velocity of the elastic wave propagating through the anchor that has been measured in advance to V p0 The calculated velocity of the elastic wave is V pa When the correlation coefficient is θ, the tension force p acting on the anchor is e The steps involve calculating based on the following formula (1) and having the computer perform the following steps.

number

[0008] The evaluation apparatus of this disclosure includes: a detection data acquisition unit that acquires detection data from a sensor that detects elastic waves, showing the detection result of the elastic wave at the time it is input to the anchor and the detection result of the elastic wave reflected inside the anchor and input to the sensor; a velocity calculation unit that calculates the velocity of the elastic wave propagating through the anchor based on the detection data; and a V that sets the reference velocity of the elastic wave propagating through the anchor, which has been measured in advance. p0, the velocity V of the elastic wave calculated by the velocity calculation unit pa , when the correlation coefficient is θ, the tensile force p generated in the anchor e and a tensile force calculation unit that calculates based on the following formula (1).

Equation

Advantages of the Invention

[0009] According to the present disclosure, the tensile force of the anchor can be easily measured.

Brief Description of the Drawings

[0010] [Figure 1] Figure 1 is a schematic diagram of a ground anchor according to the first embodiment. [Figure 2] Figure 2 is a diagram for explaining a method of detecting an elastic wave according to the first embodiment. [Figure 3] Figure 3 is a block diagram showing a configuration example of an evaluation device according to the first embodiment. [Figure 4] Figure 4 is a diagram for explaining a method of calculating the velocity of an elastic wave according to the first embodiment. [Figure 5] Figure 5 is a diagram for explaining a method of deriving a correlation formula between the tensile force and the velocity of an elastic wave according to the first embodiment. [Figure 6] Figure 6 is a flowchart showing the flow of a tensile force calculation method according to the first embodiment. [Figure 7] Figure 7 is a block diagram showing a configuration example of an evaluation device according to the second embodiment. [Figure 8] Figure 8 is a flowchart showing the flow of a soundness evaluation method according to the second embodiment. [Figure 9] Figure 9 is a diagram for explaining an anchor evaluation method according to the third embodiment. [Figure 10] Figure 10 is a flowchart showing the flow of a soundness evaluation method according to the third embodiment. [Figure 11]Figure 11 is a diagram illustrating the method of inputting elastic waves to an anchor according to the fourth embodiment. [Figure 12] Figure 12 is a block diagram showing an example configuration of a striking device according to the fourth embodiment. [Figure 13] Figure 13 is a flowchart showing the flow of the tension force calculation method according to the fourth embodiment. [Modes for carrying out the invention]

[0011] Embodiments relating to this disclosure will be described in detail below with reference to the attached drawings. However, this embodiment does not limit the disclosure, and in the following embodiments, the same parts are denoted by the same reference numerals to avoid redundant explanations.

[0012] [First Embodiment] (Schematic diagram of a ground anchor) The general outline of the ground anchor according to the first embodiment will be explained using Figure 1. Figure 1 is a schematic diagram of the ground anchor according to the first embodiment. Hereafter, the ground anchor will simply be referred to as an anchor.

[0013] Anchor 10 is composed of PC steel strands, multi-layer PC steel strands, PC steel bars, continuous fiber reinforcement, etc. Anchor 10 is installed on slopes such as cut slopes and fill slopes. Anchor 10 stabilizes the slope by using tension force by connecting one end to the slope and the other end to stable ground, thereby preventing the slope from collapsing. The total length of anchor 10 is assumed to be L1 [m].

[0014] The anchor 10 has a free length portion 12 and a restrained length portion 14. The restrained length portion 14 is formed, for example, by injecting grout into stable ground underground. One end of the free length portion 12 is fixed to the stable ground underground by the restrained length portion 14. The other end of the free length portion 12 is exposed above ground level. The other end of the free length portion 12 is fixed to a structure 18 provided on the ground surface by an anchor head 16. The structure 18 is, for example, a concrete structure. The anchor head 16 and the structure 18 are fixed together, for example, with fasteners such as nuts. Since one end of the free length portion 12 is fixed to the restrained length portion 14, tension can be applied to the free length portion 12 by pulling on the other end of the free length portion 12. The anchor head 16 maintains the tension applied to the free length portion 12 by fixing the other end of the free length portion 12 to the structure 18 while tension is applied to the free length portion 12. The excess length portion 12a is the portion of the free length portion 12 that is exposed to the ground. The length of the free length portion 12 is assumed to be L2 [m].

[0015] Sensor 20 is provided at the tip of the excess length portion 12a. Sensor 20 is a sensor that detects elastic waves incident from one end of anchor 10 and elastic waves reflected from the other end of anchor 10. Specifically, elastic waves are incident from one end of the free length portion 12 of anchor 10 and reflected from the other end of the free length portion 12. Sensor 20 is, for example, a piezoelectric sensor, but is not limited to this.

[0016] The evaluation device 100 is connected to the sensor 20 via a wired or wireless network for communication. Based on the detection results of elastic waves detected by the sensor 20, the evaluation device 100 calculates the velocity of elastic waves propagating through the free length portion 12 of the anchor 10. Based on the calculated velocity of elastic waves, the evaluation device 100 calculates the tension force generated in the free length portion 12 of the anchor 10.

[0017] (Method for detecting elastic waves) The elastic wave detection method according to the first embodiment will be explained using Figure 2. Figure 2 is a diagram illustrating the elastic wave detection method according to the first embodiment.

[0018] As shown in Figure 2, in this disclosure, when calculating the tension force generated in the free length portion 12 of the anchor 10, a sensor 20 is attached to the end of the excess length portion 12a. The sensor 20 is connected to the evaluation device 100 by a cable 22. To calculate the tension force of the anchor 10, elastic waves are input to the anchor 10. In this disclosure, elastic waves are input to the anchor 10 by applying an impact to the sensor 20. For example, an operator can input elastic waves to the anchor 10 by applying an impact to the head of the sensor 20 with a hammer 30 or the like. In this case, the impact applied to the sensor 20 may be a light impact, such as just touching the sensor 20. For example, the impact applied to the sensor 20 may be an impact that does not damage the sensor 20. The sensor 20 detects the elastic waves input to the anchor 10 at the timing when an impact is applied by the hammer 30. The input elastic waves travel along the free length portion 12 and are reflected at the other end of the free length portion 12. The elastic wave reflected at the other end of the free length portion 12 travels along the free length portion 12 of the anchor 10 and is input to the sensor 20. As a result, the sensor 20 detects the elastic wave reflected at the other end of the free length portion 12. In this disclosure, by applying an impact to the sensor 20 to input the elastic wave to the anchor 10, the input point of the elastic wave and the detection point of the reflected elastic wave coincide, thereby improving the detection accuracy of the elastic wave by the sensor 20.

[0019] (Evaluation device) An example of the configuration of the evaluation apparatus according to the first embodiment will be described using Figure 3. Figure 3 is a block diagram showing an example of the configuration of the evaluation apparatus according to the first embodiment.

[0020] The evaluation device 100 includes a communication unit 102, a storage unit 104, an input unit 106, an output unit 108, and a control unit 110.

[0021] The communication unit 102 is connected to the sensor 20 via a wired or wireless network in a communicative manner. The communication unit 102 receives detection data from the sensor 20 indicating the detection result of elastic waves.

[0022] The memory unit 104 stores various types of information. For example, the memory unit 104 stores velocity information relating to the reference velocity of elastic waves propagating along the free length portion 12 of the anchor 10. The reference velocity of the elastic waves is, for example, a velocity calculated in advance using a model that simulates the anchor 10. The reference velocity of the elastic waves is, for example, a velocity calculated when the anchor 10 is installed on a slope or the like. The memory unit 104 stores, for example, a model equation for calculating the tension force generated in the anchor. The memory unit 104 stores the calculation contents of the control unit 110 and information such as programs. The memory unit 104 includes, for example, at least one of the following: RAM (Random Access Memory), main memory such as ROM (Read Only Memory), and external memory such as HDD (Hard Disk Drive).

[0023] The input unit 106 receives various input operations for the evaluation device 100. The input unit 106 outputs an operation signal to the control unit 110 corresponding to the received input operation. The input unit 106 includes, for example, switches, buttons, keyboards, mice, touch panels, etc. When a touch panel is used as the input unit 106, the input unit 106 is located on the output unit 108.

[0024] The output unit 108 displays various types of images. The output unit 108 is a display including, for example, a liquid crystal display or an organic EL (Electro-Luminescence) display. The output unit 108 may also include a speaker for outputting sound.

[0025] The control unit 110 controls each part of the evaluation device 100. The control unit 110 includes, for example, an information processing device such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), and a storage device such as RAM or ROM. The control unit 110 executes a program that controls the operation of the evaluation device 100 according to the present invention. The control unit 110 may be implemented by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control unit 110 may be implemented by a combination of hardware and software.

[0026] The control unit 110 includes a data acquisition unit 120, a speed calculation unit 122, a tension force calculation unit 124, and an output control unit 126.

[0027] The data acquisition unit 120 acquires detection data of elastic waves detected by the sensor 20 from the sensor 20 via the communication unit 102. Specifically, the data acquisition unit 120 acquires detection data related to the detection results of elastic waves input from one end of the free length portion 12 of the anchor 10 and elastic waves reflected from the other end of the free length portion 12 of the anchor 10, as detected by the sensor 20.

[0028] The velocity calculation unit 122 calculates the velocity of the elastic wave propagating through the free length section 12. The velocity calculation unit 122 calculates the velocity of the elastic wave based on the elastic wave detection data acquired by the data acquisition unit 120. Figure 4 is a diagram illustrating the method for calculating the velocity of the elastic wave according to the first embodiment. In Figure 4, the horizontal axis represents time [ms (milliseconds)] and the vertical axis represents signal strength [mV]. Waveform 41 shows the detection result of the elastic wave input from one end of the free length section 12. Waveform 42 shows the detection result of the elastic wave reflected at the other end of the free length section 12. In the example shown in Figure 4, the elastic wave input to one end of the free length section 12 is detected by the sensor 20 at timing t1. The elastic wave is reflected at the other end of the free length section 12 at timing t2. The elastic wave reflected at the other end of the free length section 12 is detected by the sensor 20 at timing t3. The velocity calculation unit 122 calculates the time from timing t1 to timing t2, which is the time it takes for an elastic wave incident on one end of the free length section 12 to reach the other end of the free length section 12, based on timing t1 and timing t3. The time from timing t1 to timing t2 is half the time from timing t1 to timing t3. Let the time from timing t1 to timing t2 be Δt [ms]. Since the total length of the free length section 12 is L2 [m], the velocity calculation unit 122 calculates the velocity V of the elastic wave. pa V pa The calculation is as follows: =L2 / Δt[km / s].

[0029] The tension calculation unit 124 calculates the tension force acting on the anchor 10. The tension calculation unit 124 calculates the tension force acting on the anchor 10 based on the velocity of the elastic wave calculated by the velocity calculation unit 122.

[0030] In this disclosure, anchor model experiments using a model simulating anchor 10 revealed that the velocity of elastic waves differs between the free length section 12 and the constrained length section 14. The anchor model experiments also revealed that when anchor 10 is made of PC steel strands, the velocity decreases slightly as the tension increases. Based on these findings, a correlation equation (model equation) between the velocity of elastic waves propagating through the free length section 12 and the tension was derived. Figure 5 illustrates the method for deriving the correlation equation between tension and elastic wave velocity according to the first embodiment. In Figure 5, the horizontal axis represents tension [kN] and the vertical axis represents elastic wave velocity [km / s]. In Figure 5, the white triangle marks represent the correlation between tension and elastic wave velocity in the anchor model experiments. The white circle marks represent the correlation between tension and elastic wave velocity in an actual anchor in a field. As indicated by the white triangle and white circle marks, the velocity of elastic waves decreases as the tension increases. Regression line 43 is a regression line derived based on the correlation between tension force and elastic wave velocity in the anchor model experiment. Regression line 44 is a regression line derived based on the correlation between tension force and elastic wave velocity at the anchor 10 in the actual field. Regression line 43 and regression line 44 are in close agreement. Therefore, based on the elastic wave velocity calculated in the actual field, the tension force occurring at the anchor 10 can be calculated using the correlation formula derived based on the correlation between tension force and elastic wave velocity in the anchor model experiment. Tension force p e V is the reference velocity of elastic waves propagating through anchor 10, which was measured in advance by an anchor model experiment. p0 The velocity of the elastic wave calculated by the velocity calculation unit 122 is V pa When the correlation coefficient is θ, it can be calculated using the correlation equation shown in equation (1) below.

[0031]

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[0032] The tension force calculation unit 124 substitutes the velocity of the elastic wave calculated by the velocity calculation unit 122 into equation (1) above to calculate the tension force generated in the anchor 10.

[0033] The output control unit 126 controls the output unit 108. The output control unit 126 controls the output unit 108 to output the tension calculation result from the tension calculation unit 124.

[0034] (Tension force calculation method) The flow of the tension calculation method according to the first embodiment will be explained using Figure 6. Figure 6 is a flowchart showing the flow of the tension calculation method according to the first embodiment.

[0035] The data acquisition unit 120 acquires detection data of elastic waves input to the anchor 10 via the communication unit 102 (step S10). Specifically, the data acquisition unit 120 acquires detection data of elastic waves incident from one end of the free length portion 12 and elastic waves reflected from the other end of the free length portion 12. Then, the process proceeds to step S12.

[0036] The velocity calculation unit 122 calculates the velocity of the elastic wave propagating through the free length section 12 based on the detection data acquired by the data acquisition unit 120 (step S12). Then, the process proceeds to step S14.

[0037] The tension calculation unit 124 calculates the tension force generated in the free length section 12 based on the velocity of the elastic wave calculated by the velocity calculation unit 122 (step S14). Then, the process proceeds to step S16.

[0038] The output control unit 126 controls the output unit 108 to output the tension calculation result (step S16). Then, the process shown in Figure 6 is completed.

[0039] As described above, in the first embodiment, the velocity of the elastic wave is calculated from the detection result of the elastic wave input to one end of the free length portion of the anchor and the detection result of the elastic wave reflected at the other end of the free length portion of the anchor, and the tension force acting on the anchor can be calculated based on the calculated velocity. As a result, the first embodiment can easily evaluate the tension force acting on an anchor installed on a slope.

[0040] [Second Embodiment] (Evaluation device) An example of the configuration of the evaluation apparatus according to the second embodiment will be described using Figure 7. Figure 7 is a block diagram showing an example of the configuration of the evaluation apparatus according to the second embodiment.

[0041] As shown in Figure 7, the evaluation device 100A differs from the evaluation device 100 shown in Figure 3 in that the control unit 110A includes a soundness evaluation unit 128.

[0042] The integrity evaluation unit 128 evaluates the integrity of the anchor 10. The integrity evaluation unit 128 evaluates the integrity of the anchor 10 based on the tension force calculated by the tension force calculation unit 124, the yield tensile force of the anchor 10, and the ultimate tensile force of the anchor 10. Information regarding the yield tensile force of the anchor 10 and the ultimate tensile force of the anchor 10 is preferably stored in the memory unit 104.

[0043] (Methods for assessing soundness) The flow of the soundness evaluation method according to the second embodiment will be explained using Figure 8. Figure 8 is a flowchart showing the flow of the soundness evaluation method according to the second embodiment.

[0044] The processes from steps S20 to S24 are the same as the processes from steps S10 to S14 shown in Figure 6, so their explanation will be omitted.

[0045] The integrity evaluation unit 128 evaluates the integrity of the anchor 10 (step S26). Specifically, it evaluates the ultimate tensile force of the anchor 10 T us The yield tensile force of anchor 10 is T ysThe soundness evaluation unit 128 determines that the tension force in the free length portion 12 is 0.1T. us If the value is less than 0.1T, the anchor 10 is determined to be non-functional. The integrity evaluation unit 128 determines that the tension force in the free length portion 12 is 0.1T. us More than 0.3T us If the value is less than 0.3T, it is determined that the integrity of anchor 10 is declining. The integrity evaluation unit 128 determines that the tension force generated in the free length portion 12 is 0.3T. us More than 0.6T us If the value is less than 0.6T, the anchor 10 is determined to be sound. The soundness evaluation unit 128 determines that the tension force present in the free length portion 12 is 0.6T. us Above 0.65T us If the value is less than 0.65T, the integrity of anchor 10 is determined to be declining. The integrity evaluation unit 128 determines that the tension force generated in the free length portion 12 is 0.65T. us Above 0.9T ys If the value is less than 0.9T, the anchor 10 is determined to be in a dangerous condition. The integrity assessment unit 128 determines that the tension force in the free length portion 12 is 0.9T. ys Therefore, it is determined that anchor 10 is at risk of fracture. Then, proceed to step S28.

[0046] The output control unit 126 controls the output unit 108 to output the tension calculation result and the soundness evaluation result (step S28). Then, the process shown in Figure 8 is completed.

[0047] As described above, in the second embodiment, the value can be calculated based on the tension force acting on the anchor. This allows the first embodiment to easily evaluate the soundness of the anchor installed on the slope.

[0048] [Third Embodiment] The anchor evaluation method according to the third embodiment will be explained using Figure 9. Figure 9 is a diagram illustrating the anchor evaluation method according to the third embodiment. The evaluation apparatus according to the third embodiment is the same as the evaluation apparatus 100A shown in Figure 7, so its explanation will be omitted.

[0049] As shown in Figure 9, multiple anchors 10 are installed along the slope 50. Conventionally, the anchors 10 were evaluated by lift-off tests. Because lift-off tests are expensive and time-consuming, only anchors 10 selected by the worker were evaluated for tension and integrity. As a result, only a few percent of the multiple anchors 10 installed on the slope 50 were evaluated. Therefore, for example, if the integrity of one anchor 10 was evaluated poorly and it needed to be replaced, the surrounding anchors 10 also had to be replaced, which could result in unnecessary costs and effort.

[0050] In contrast, as described in the first and second embodiments, this disclosure allows for easy evaluation of the tension force and integrity of the anchor 10, making it possible to evaluate all anchors 10 installed on the slope 50. That is, in the third embodiment, the evaluation of multiple anchors 10 installed on the slope 50 can be performed spatially. By evaluating multiple anchors 10 spatially, for example, map information can be generated that shows the evaluation results of tension force or integrity for each anchor 10 installed on the slope 50. The map information is, for example, information that associates the location where the anchor 10 is installed with the evaluation results of tension force or integrity. By checking the map information, workers can easily understand the locations where anchors 10 with good tension force or integrity evaluation results and anchors 10 with poor tension force or integrity are installed. Note that when evaluating the integrity of anchors 10 spatially, it is not necessarily required to evaluate all anchors 10. For example, the integrity of all anchors 10 installed on the slope 50 may be evaluated every other anchor.

[0051] (Methods for assessing soundness) The flow of the soundness evaluation method according to the third embodiment will be explained using Figure 10. Figure 10 is a flowchart showing the flow of the soundness evaluation method according to the third embodiment.

[0052] The processes from step S30 to step S36 are the same as the processes from step S26 to step S28 shown in Figure 8, so their explanation will be omitted.

[0053] The control unit 110A determines whether the evaluation of the integrity of all anchors 10 installed on the slope 50 has been completed (step S38). Specifically, if the input unit 106 receives input indicating that the evaluation of all anchors 10 has been completed, it determines that the evaluation of the integrity of all anchors 10 has been completed. If it is determined that the evaluation of the integrity of all anchors 10 has been completed (step S38; Yes), the process proceeds to step S40. If it is not determined that the evaluation of the integrity of all anchors 10 has been completed (step S38; No), the process in step S38 is repeated.

[0054] If the result in step S38 is Yes, the soundness evaluation unit 128 generates soundness map information for all anchors 10 installed on the slope 50 based on the soundness evaluation results of all anchors 10 (step S40). Then, the process proceeds to step S42.

[0055] The structural integrity evaluation unit 128 controls the output unit 108 to output the generated structural integrity map information (step S42). By referring to the map information, the worker can appropriately and easily grasp the status of all anchors 10 installed on the slope. Then the process shown in Figure 10 is completed.

[0056] In step S40, the tension force calculation unit 124 may generate tension force map information for all anchors 10 installed on the slope 50. In this case, in step S42, the tension force calculation unit 124 may control the output unit 108 to output the generated tension force map information.

[0057] As described above, in the third embodiment, by evaluating the anchors installed on the slope surface in a surface manner, the condition of all anchors installed on the slope surface can be appropriately and easily grasped. As a result, the third embodiment can appropriately identify which of the multiple anchors need to be replaced and which need maintenance, thereby suppressing the occurrence of unnecessary costs and effort.

[0058] [Fourth Embodiment] The method of inputting elastic waves to an anchor according to the fourth embodiment will be explained using Figure 11. Figure 11 is a diagram illustrating the method of inputting elastic waves to an anchor according to the fourth embodiment.

[0059] As shown in Figure 11, the fourth embodiment differs from the first embodiment shown in Figure 1 in that a striking device 200 is provided at the tip of the excess length portion 12a.

[0060] (Impact device) An example of the configuration of the striking device according to the fourth embodiment will be described using Figure 12. Figure 12 is a block diagram showing an example of the configuration of the striking device according to the fourth embodiment.

[0061] As shown in Figure 12, the striking device 200 comprises a sensor 20, a striking unit 202, and a drive unit 204. The striking device 200 is a device that can input elastic waves to the anchor 10 by having the striking unit 202 strike the sensor 20.

[0062] The striking unit 202 directly strikes the sensor 20 when driven by the drive unit 204. The striking unit 202 is, for example, a hammer, but is not limited to that.

[0063] The drive unit 204 is a drive mechanism that includes a motor and gears. For example, when the drive unit 204 is driven and the driving force is transmitted to the striking unit 202, the striking unit 202 directly strikes the sensor 20. As a result, elastic waves are input to the anchor 10.

[0064] The striking device 200 may have a configuration in which the striking section 202 strikes the sensor 20 according to the operator's operation. The striking device 200 may also have a configuration in which the striking section 202 strikes the sensor 20 according to the control of the evaluation device 100.

[0065] (Tension force calculation method) The flow of the tension calculation method according to the fourth embodiment will be explained using Figure 13. Figure 13 is a flowchart showing the flow of the tension calculation method according to the fourth embodiment.

[0066] The control unit 110 controls the drive unit 204 of the striking device 200 to cause the striking unit 202 to directly strike the sensor 20 (step S50). Then, the process proceeds to step S52.

[0067] The processes from steps S52 to S58 are the same as the processes from steps S10 to S16 shown in Figure 6, so their explanation will be omitted.

[0068] As described above, in the fourth embodiment, elastic waves can be input to the anchor using a striking device. This allows the fourth embodiment to input elastic waves of a certain intensity to the anchor, thereby improving the accuracy of anchor evaluation.

[0069] [Other embodiments] In the embodiments described above, the anchor 10 was described as being installed on a slope, but the disclosure is not limited thereto. The anchor 10 may also connect a building on the ground to stable ground underground.

[0070] (effect) The evaluation method according to the first aspect of this disclosure includes the steps of: acquiring detection data from a sensor 20 that detects elastic waves, showing the detection result of the elastic wave at the time it was input to the anchor 10 and the detection result of the elastic wave that was reflected inside the anchor 10 and input to the sensor 20; calculating the velocity of the elastic wave propagating through the anchor 10 based on the detection data; and setting a reference velocity of the elastic wave propagating through the anchor 10 that has been measured in advance to V p0The calculated velocity of the elastic wave is V pa When the correlation coefficient is θ, the tension force p acting on anchor 10 is e The procedure includes the step of calculating based on the following equation (1). This makes it easy to evaluate the tension force generated in the anchor 10 based on the velocity of the elastic wave input to the anchor 10.

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[0071] The evaluation method according to the second aspect of this disclosure is the evaluation method according to the first aspect, wherein the sensor 20 is provided at the tip of the anchor 10, and the elastic wave is input to the anchor 10 by directly striking the sensor 20. As a result, the point at which the elastic wave is input and the point at which it is reflected inside the anchor 10 and input to the sensor 20 coincide, thereby improving the accuracy of the evaluation of the tension force of the anchor 10.

[0072] The evaluation method relating to the third aspect of this disclosure is the evaluation method relating to the first or second aspect, wherein the calculated tension force p e This includes a step to assess the integrity of the anchor based on the above. This allows for an assessment of the tension present in the anchor.

[0073] The evaluation method relating to the fourth aspect of this disclosure is an evaluation method relating to any of the first to third aspects, wherein the anchor 10 is installed along the slope 50. This makes it possible to evaluate the anchor 10 installed on the slope.

[0074] The evaluation method according to the fifth aspect of this disclosure is the evaluation method according to the fourth aspect, wherein multiple anchors 10 are installed along the slope 50, and includes the steps of evaluating the tension force of the multiple anchors 10 in a surface manner and generating map information showing the evaluation results of the tension force of the multiple anchors 10. This makes it possible to evaluate the multiple anchors 10 installed on the slope 50 in a surface manner.

[0075] The evaluation method according to the sixth aspect of this disclosure is an evaluation method according to any of the first to fifth aspects, wherein the sensor 20 is integrally configured with a striking part 202 that strikes the sensor and a drive part 204 that drives the striking part 202, the sensor 20 is provided at the tip of the anchor 10, and the method includes the step of controlling the drive part 204 to cause the striking part 202 to directly strike the sensor 20 and input elastic waves to the anchor 10. This makes it possible to input elastic waves of a certain intensity to the anchor 10, thereby improving the evaluation accuracy.

[0076] A program according to the seventh aspect of this disclosure includes the steps of: obtaining detection data from a sensor 20 that detects elastic waves, showing the detection result of the elastic wave at the time it was input to the anchor and the detection result of the elastic wave that was reflected inside the anchor 10 and input to the sensor 20; calculating the velocity of the elastic wave propagating through the anchor based on the detection data; and setting a reference velocity of the elastic wave propagating through the anchor 10 that has been measured in advance to V p0 The calculated velocity of the elastic wave is V pa When the correlation coefficient is θ, the tension force p acting on anchor 10 is e The process involves the steps of calculating based on the following equation (1) and having a computer perform the calculation. This makes it easy to evaluate the tension force acting on the anchor 10 based on the velocity of the elastic wave input to the anchor 10.

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[0077] The program according to the eighth aspect of this disclosure includes a data acquisition unit 120 that acquires detection data from a sensor 20 that detects elastic waves, showing the detection result of the elastic wave at the time it was input to the anchor 10 and the detection result of the elastic wave that was reflected inside the anchor 10 and input to the sensor 20; a velocity calculation unit 122 that calculates the velocity of the elastic wave propagating through the anchor 10 based on the detection data; and a V that sets a reference velocity of the elastic wave propagating through the anchor 10 that has been measured in advance. p0 The velocity of the elastic wave calculated by the velocity calculation unit 122 is V pa When the correlation coefficient is θ, the tension force p acting on anchor 10 ise The evaluation device includes a tension force calculation unit 124 that calculates the tension force based on the following equation (1). This makes it possible to easily evaluate the tension force generated in the anchor 10 based on the velocity of the elastic wave input to the anchor 10.

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[0078] Each component of the illustrated device is a functional concept and does not necessarily have to be physically configured as shown. In other words, the specific forms of distribution and integration of each device are not limited to those shown, and all or part of them can be functionally or physically distributed and integrated in any unit according to various loads and usage conditions. Furthermore, this distribution and integration configuration may be performed dynamically.

[0079] While embodiments of the present disclosure have been described above, the present disclosure is not limited by the content of these embodiments. Furthermore, the aforementioned components include those that are readily conceivable to those skilled in the art, those that are substantially identical, and those that fall within the so-called equivalent range. Moreover, the aforementioned components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the embodiments described above. [Explanation of symbols]

[0080] 10 Anchors 12 Free length section 12a Extra length 14 Restraint Length 16 Anchor heads 18 Structures 20 sensors 100, 100A evaluation device 102 Communications Department 104 Storage section 106 Input section 108 Output section 110, 110A Control Unit 120 Data Acquisition Unit 122 Speed ​​calculation section 124 Tension force calculation section 126 Output Control Unit 128 Health Assessment Department 200 Impact device 202 Batting Department 204 Drive Unit

Claims

1. A step of obtaining detection data from a sensor that detects elastic waves provided at one end of the free length portion of the anchor, which includes the detection result of the elastic wave at the time it was input to one end of the free length portion of the anchor, and the detection result of the elastic wave that was reflected at the other end of the free length portion of the anchor and input to the sensor, A step of calculating the velocity of the elastic wave propagating through the free length portion of the anchor based on the detection data, The reference velocity of the elastic wave propagating through the free length portion of the anchor, which has been measured in advance, is V. ｐ０ The calculated velocity of the elastic wave is V ｐａ When the correlation coefficient is θ, the tension force p acting on the anchor is ｅ The steps are to calculate based on the following formula (1), A method for evaluating the tension force of a ground anchor, including the method described above. [Math 1]

2. The sensor is provided at the tip of the anchor, The elastic wave is input to the anchor by directly striking the sensor. A method for evaluating the tension force of a ground anchor according to claim 1.

3. The process includes a step of evaluating the integrity of the anchor based on the calculated tension force pe, A method for evaluating the tension force of a ground anchor according to claim 1 or 2.

4. The aforementioned anchor is installed along the slope. A method for evaluating the tension force of a ground anchor according to claim 1 or 2.

5. The sensor is configured integrally with a striking part that strikes the sensor and a driving part that drives the striking part, and the sensor is provided at the tip of the anchor. The step includes controlling the drive unit to cause the striking unit to directly strike the sensor and input elastic waves to the anchor, A method for evaluating the tension force of a ground anchor according to claim 1.

6. A step of generating map information showing the evaluation result of the tension force p e for each of the plurality of anchors installed along the slope, The step includes the step of outputting the aforementioned map information from the output unit, The method for evaluating the tension force of a ground anchor according to claim 4.

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