Vibrating string force measuring structure, anchor rod detection device and detection method

Abstract

The application provides a vibrating string type force measuring structure, an anchor rod detection device and a detection method. A diameter of a force transmission cap of the vibrating string type force measuring structure ranges from 100 mm to 220 mm, and a height of the force transmission cap in an axial direction of the anchor rod ranges from one fourth to one half of the diameter. A template assembly is located in the force transmission cap and abuts against the force transmission cap and the supporting plate, respectively. A part of the template assembly can be deformed under the pressure of the force transmission cap. A steel string assembly is arranged on a side of the template assembly away from the anchor rod nut. A frequency detection element detects a dynamic frequency of the steel string assembly under the pressure. An information processing unit receives the dynamic frequency and calculates a stress value of the anchor rod based on an initial frequency of the steel string assembly to realize stress detection. By reasonably setting the size range of the force transmission cap, the mechanical impedance matching of the template assembly and the steel string assembly is optimized, so as to improve the stratum adaptability, measurement linearity and sensitivity of the entire vibrating string type force measuring structure.

Description

Technical Field

[0001] This application relates to the field of geotechnical stress detection technology, and in particular to a vibrating wire force measuring structure, an anchor bolt detection device, and a detection method. Background Technology

[0002] In the field of geotechnical engineering, stress detection and monitoring are core components for ensuring the safety of engineering structures and understanding the mechanical state of strata, and are of great significance for engineering design optimization, risk warning, and safe operation and maintenance. Currently, commonly used stress acquisition structures in geotechnical engineering mainly include resistance strain gauge sensors, piezoelectric sensors, fiber optic sensors, capacitive sensors, and vibrating wire sensors.

[0003] Specifically, the signal output by the vibrating wire sensor is the dynamic frequency of the steel wire, and the stress value of the anchor bolt can be obtained by calculating the dynamic frequency. Since the frequency value of the steel wire depends only on the physical properties of the steel wire itself and is not affected by external environmental parameters such as resistance, capacitance, temperature, and humidity, the vibrating wire sensor has excellent measurement performance and is suitable for complex detection environments such as underground mines.

[0004] However, when dealing with complex lithological formations, such as high-stress hard rock, high-stress soft rock, and fractured rock masses, existing vibrating wire sensors suffer from poor mechanical impedance matching between the steel wire and the working diaphragm. This results in an inability to accurately respond to dynamic stress changes in different lithological formations, leading to poor formation adaptability and inadequate measurement linearity and sensitivity. Summary of the Invention

[0005] The purpose of this application is to provide a vibrating wire force measuring structure, an anchor bolt detection device, and a detection method, aiming to solve the problems of improving the geological adaptability, measurement linearity, and sensitivity of the vibrating wire force measuring structure.

[0006] In a first aspect, embodiments of this application provide a vibrating wire force measuring structure, including: A hemispherical force-transmitting cap is used to be fitted onto the anchor bolt and abut against the anchor nut and the support plate on the anchor bolt; wherein the diameter of the side of the force-transmitting cap facing the support plate ranges from 100mm to 220mm, and the height of the force-transmitting cap along the axial direction of the anchor bolt ranges from one-quarter to one-half of the diameter of the side of the force-transmitting cap facing the support plate; A template assembly is located inside the force-transmitting cap and abuts against the force-transmitting cap and the support plate respectively. Part of the template assembly can be deformed under the pressure of the force-transmitting cap. A steel wire assembly is located on the side of the template assembly away from the anchor nut; A frequency detection element is disposed between the template assembly and the steel string assembly and is configured to detect and acquire the dynamic frequency of the steel string assembly under pressure. An information processing unit, electrically connected to the frequency detection element, is configured to receive the dynamic frequency and calculate the stress value borne by the anchor bolt in conjunction with the initial frequency of the steel string assembly; wherein the dynamic frequency and the stress value satisfy the following relationship: P=A(f 动 2 -f0 2 )-B(f 动 -f0); Where P is the stress value, A and B are curve constants, f0 is the initial frequency, and f 动 For dynamic frequency.

[0007] In some embodiments, when the anchor bolt is inserted into high-stress hard rock, the diameter of the side of the force transmission cap facing the support plate ranges from 100mm to 120mm, and the height of the force transmission cap along the axial direction of the anchor bolt ranges from one-third to one-half of the diameter of the side of the force transmission cap facing the support plate. And / or, when the anchor is inserted into high-stress soft rock, the diameter of the side of the force transmission cap facing the support plate is in the range of 180mm-220mm, and the height of the force transmission cap along the axial direction of the anchor is in the range of one-third to one-half of the diameter of the side of the force transmission cap facing the support plate. And / or, when the anchor bolt is inserted into the fractured rock mass, the diameter of the side of the force transmission cap facing the support plate ranges from 180mm to 220mm, and the height of the force transmission cap along the axial direction of the anchor bolt ranges from one-quarter to one-third of the diameter of the side of the force transmission cap facing the support plate.

[0008] In some embodiments, there are at least two template components, which are disposed on both sides of the anchor bolt. There are at least two steel wire components and at least two frequency detection elements, and each of the at least two steel wire components and at least two frequency detection elements corresponds to one of the at least two template components. All the frequency detection elements are electrically connected to the information processing unit. The information processing unit calculates at least two axial force values ​​based on the dynamic frequency and initial frequency of each steel string assembly, performs deviation verification on each axial force value, and obtains the stress value by arithmetic average or weighted average of the verified axial force values.

[0009] In some embodiments, each of the template components is provided with a pressure-transmitting plate on the side near the anchor nut, and a bearing plate is abutting between all the pressure-transmitting plates and the force-transmitting cap.

[0010] In some embodiments, the template assembly includes a deformable template and a support column. The deformable template abuts against the force-transmitting cap, and the support column is located on the side of the deformable template facing the tray and abuts against the tray. And / or, the frequency detection element includes a magnetic head; And / or, the information processing unit includes an information transmission element and an information processing display element electrically connected to the information transmission element, the information transmission element being electrically connected to the frequency detection element and configured to transmit the dynamic frequency to the information processing display element, the information processing display element being configured to receive the input initial frequency and dynamic frequency and calculate and display the stress value based on the dynamic frequency and the initial frequency; And / or, the steel string assembly includes at least two mounting posts disposed on the side of the template assembly away from the anchor nut and a steel string disposed between the mounting posts, and the frequency detection element is used to detect and acquire the dynamic frequency of the steel string.

[0011] Secondly, embodiments of this application provide an anchor bolt detection device, including an anchor bolt, an anchor bolt nut, a support plate, and a vibrating wire force measuring structure; One end of the anchor rod is inserted into the rock mass, and the other end of the anchor rod is located outside the rock mass. The anchor nut is located at the other end of the anchor rod, and the support plate is located at the other end of the anchor rod and on the side of the anchor nut closer to the end of the anchor rod.

[0012] In some embodiments, when the rock mass is high-stress hard rock, the length of the support plate ranges from 100mm to 200mm, the width of the support plate ranges from 100mm to 200mm, and the thickness of the support plate ranges from 10mm to 15mm. And / or, when the rock mass is high-stress soft rock, the length of the support plate ranges from 200mm to 300mm, the width of the support plate ranges from 200mm to 300mm, and the thickness of the support plate ranges from 10mm to 15mm. And / or, when the rock mass is a fractured rock mass, the length of the pallet ranges from 200mm to 300mm, the width of the pallet ranges from 200mm to 300mm, and the thickness of the pallet ranges from 10mm to 15mm.

[0013] Thirdly, embodiments of this application provide a method for detecting the force on an anchor bolt using an anchor bolt detection device, comprising: Step S1: Install the anchor bolt detection device on the preset rock mass; Step S2: Detect and obtain the dynamic frequency of the steel string assembly using a frequency detection element; Step S3: Receive the dynamic frequency through the information processing unit, and calculate the stress value borne by the anchor rod based on the dynamic frequency and the initial frequency of the steel string assembly.

[0014] In some embodiments, step S1 includes: Drill holes in the pre-defined rock mass and clean the holes. One end of the anchor rod is inserted into the borehole, and an anchoring agent is injected into the borehole. After the anchoring agent has cured, the anchor rod is fixed in the borehole. Install the support plate and vibrating wire force measuring structure sequentially on the other end of the anchor rod, and install the anchor rod nut on the other end of the anchor rod for fastening; And / or, prior to step S1, the detection method further includes: The vibrating wire force measuring structure is subjected to rigid loading calibration to obtain curve constant A1 and curve constant B1; The vibrating wire force measuring structure is calibrated by flexible loading to obtain curve constant A2 and curve constant B2; The curve constant A is obtained by taking the average of A1 and A2, and the curve constant B is obtained by taking the average of B1 and B2.

[0015] In some embodiments, when the template assembly, the steel wire assembly, and the frequency detection element all include at least two, step S3 includes: The information processing unit receives the dynamic frequency and initial frequency of each steel string assembly and calculates at least two axial force values. All the axial force values ​​are checked for deviation, and the stress value is obtained by arithmetic average or weighted average of the axial force values ​​that pass the check.

[0016] In some embodiments, the method of verifying the deviation of all the axial force values ​​and obtaining the stress value by arithmetic average or weighted average of the verified axial force values ​​includes: The relative deviation rate is obtained by calculating the deviation between any two axial force values ​​and then compared with a preset deviation rate threshold. If the relative deviation rate is less than the lower limit of the preset deviation rate threshold, the verification is deemed qualified and the stress value is obtained by taking the average value of the axial force value. If the relative deviation rate is within the range of the preset deviation rate threshold, the verification is deemed qualified and the stress value is obtained by weighted averaging of the axial force value. If the relative deviation rate is greater than the upper limit of the preset deviation rate threshold, the verification is deemed unqualified and the axial force value is invalid.

[0017] The beneficial effects of this invention are: This application provides a vibrating wire force measuring structure, an anchor bolt detection device, and a detection method. The vibrating wire force measuring structure includes a hemispherical force-transmitting cap, a template assembly, a steel wire assembly, a frequency detection element, and an information processing unit. The hemispherical force-transmitting cap is fitted onto the anchor bolt and abuts against the anchor nut and the support plate. The diameter of the side of the force-transmitting cap facing the support plate ranges from 100mm to 220mm, and the height of the force-transmitting cap along the axial direction of the anchor bolt ranges from one-quarter to one-half of the diameter of the side of the force-transmitting cap facing the support plate. The template assembly is located inside the force-transmitting cap and abuts against both the force-transmitting cap and the support plate. Part of the template assembly can deform under the pressure of the force-transmitting cap. The steel wire assembly is located on the side of the template assembly away from the anchor nut. The frequency detection element is located between the template assembly and the steel string assembly and is configured to detect and acquire the dynamic frequency of the steel string assembly under pressure. The information processing unit is electrically connected to the frequency detection element and is configured to receive the dynamic frequency and calculate the stress value of the anchor bolt based on the initial frequency of the steel string assembly, thereby realizing the accurate detection of the stress of the anchor bolt.

[0018] Meanwhile, by reasonably setting the size range of the force transmission cap, this application allows for reasonable size setting based on the lithology of the rock mass supported by the anchor bolt, thereby adjusting the overall stiffness and stress transmission characteristics of the entire vibrating wire force measurement structure. This optimizes the mechanical impedance matching between the template assembly and the steel wire assembly, thereby improving the geological adaptability, measurement linearity, and sensitivity of the entire vibrating wire force measurement structure. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the anchor bolt detection device shown in the embodiment of this application; Figure 2 This is a schematic diagram of the anchor bolt detection device shown in the embodiment of this application after removing the force transmission cap. Figure 1 ; Figure 3 This is a schematic diagram of the anchor bolt detection device shown in the embodiment of this application after removing the force transmission cap. Figure 2 ; Figure 4 This is a schematic diagram of the anchor bolt detection device shown in the embodiment of this application after removing the force transmission cap and the pressure plate; Figure 5This is a schematic diagram of the pressure plate, template assembly, and steel wire assembly of the vibrating wire force measuring structure shown in the embodiments of this application. Figure 1 ; Figure 6 This is a schematic diagram of the pressure plate, template assembly, and steel wire assembly of the vibrating wire force measuring structure shown in the embodiments of this application. Figure 2 ; Figure 7 This is a schematic diagram of the pressure plate, template assembly, and steel wire assembly of the vibrating wire force measuring structure shown in the embodiments of this application. Figure 3 ; Figure 8 This is a schematic diagram of the template assembly and steel wire assembly of the vibrating wire force measuring structure shown in the embodiments of this application; Figure 9 This is a schematic diagram of the detection method shown in the embodiments of this application.

[0021] Figure label: 100. Force transmission cap; 200. Anchor bolt; 210. Anchor bolt nut; 220. Support plate; 300. Template assembly; 310. Deformable template; 320. Bearing column; 400. Steel string assembly; 410. Installation column; 420. Steel string; 430. Clamping component; 500. Frequency detection element; 600. Information processing unit; 610. Information transmission element; 620. Information processing display element; 700. Pressure plate; 800. Pressure bearing plate. Detailed Implementation

[0022] In the embodiments of this application, the terms "first," "second," "third," "fourth," "fifth," and "sixth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," "third," "fourth," "fifth," and "sixth" may explicitly or implicitly include one or more of that feature.

[0023] In embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0024] Reference Figures 1 to 8As shown, this embodiment provides a vibrating wire force measuring structure, including a hemispherical force transmission cap 100, a template assembly 300, a steel wire assembly 400, a frequency detection element 500, and an information processing unit 600.

[0025] The force transmission cap 100 is used to be sleeved on the anchor rod 200 and abuts against the anchor nut 210 and the support plate 220 on the anchor rod 200; wherein, the diameter of the side of the force transmission cap 100 facing the support plate 220 is in the range of 100mm-220mm, and the height of the force transmission cap 100 along the axial direction of the anchor rod 200 is in the range of one-quarter to one-half of the diameter of the side of the force transmission cap 100 facing the support plate 220.

[0026] The template assembly 300 is located inside the force transmission cap 100 and abuts against both the force transmission cap 100 and the support plate 220. Part of the template assembly 300 can deform under the pressure of the force transmission cap 100. The steel wire assembly 400 is located on the side of the template assembly 300 away from the anchor nut 210.

[0027] A frequency detection element 500 is disposed on the template assembly 300 and configured to detect and acquire the dynamic frequency of the steel string assembly 400 under pressure. An information processing unit 600 is electrically connected to the frequency detection element 500 and configured to receive the dynamic frequency and calculate the stress value borne by the anchor bolt 200 based on the initial frequency of the steel string assembly 400; wherein the dynamic frequency and stress value satisfy the following relationship: P = A(f 动 2 -f0 2 )-B(f 动 -f0); where P is the stress value, A and B are curve constants, f0 is the initial frequency, and f 动 For dynamic frequency.

[0028] In this embodiment, a force-transmitting cap 100 is provided to uniformly transmit stress. The tensile stress borne by the anchor rod 200 is converted into compressive stress by the anchor nut 210 and then transmitted to the force-transmitting cap 100. The force-transmitting cap 100 uniformly transmits the compressive stress to the support plate 220 and the template assembly 300, thereby avoiding stress concentration that could cause non-uniform deformation of the template assembly 300, so as to facilitate good mechanical impedance matching between the steel string assembly 400 and the template assembly 300.

[0029] For example, the diameter of the force transmission cap 100 is set to 100mm-220mm and the height is set to 1 / 4 to 1 / 2 of the diameter. This allows for flexible setting of the size of the force transmission cap 100 according to the mechanical characteristics of different lithological strata, thereby changing the overall stiffness and stress transmission characteristics of the entire vibrating wire force measurement structure. This, in turn, optimizes the mechanical impedance matching between the template assembly 300 and the steel wire assembly 400, thereby improving the stratum adaptability, measurement linearity, and sensitivity of the entire vibrating wire force measurement structure.

[0030] For example, for rock masses with high hardness and stress, a small-diameter, moderately high force-transmitting cap 100 can be selected to increase stress concentration and thus enhance high-frequency dynamic stress response; for rock masses with high stress but low hardness, a large-diameter, moderately high force-transmitting cap 100 can be selected to increase the bearing area of ​​the support plate 220 and optimize measurement linearity; for fractured rock masses, a large-diameter, low-height force-transmitting cap 100 can be selected to improve the installation stability and anti-eccentric load capacity of the entire vibrating wire force measuring structure, so as to fully adapt to different lithological strata.

[0031] Furthermore, the template assembly 300 is located inside the force transmission cap 100 and abuts against the force transmission cap 100 and the support plate 220 respectively. Part of the template assembly 300 can deform under the pressure of the force transmission cap 100, that is, to bear the stress of the anchor rod 200 transmitted by the force transmission cap 100, so that the vibration frequency of the steel string assembly 400 can change with the deformation of the template assembly 300.

[0032] A frequency detection element 500 is disposed in the template assembly 300, specifically between the template assembly 300 and the steel string assembly 400, and is used to detect the dynamic frequency of the steel string assembly 400 as the template assembly 300 deforms. An information processing unit 600 is electrically connected to the frequency detection element 500 and is used to receive the dynamic frequency and calculate the stress value borne by the anchor bolt 200 based on the dynamic frequency and a pre-input initial frequency.

[0033] It should be noted that the template assembly 300 will undergo slight bending deformation under the pressure transmitted from the force-transmitting cap 100, and the amount of deformation is related to the magnitude of the compressive stress, as detailed in formula (1) below. The deflection of the template assembly 300 will change the tensile stress of the steel string assembly 400 connected to it. The natural frequency of the steel string assembly 400 is: (1) In the formula: f is the natural frequency; L is the chord length of the steel string assembly 400; ρ is the material density of the steel string assembly 400; σ is the tensile stress of the steel string assembly 400.

[0034] Based on this, the relationship between the stress value P and the natural frequency of the steel string assembly 400 can be derived, and thus the formula for calculating the stress value can be obtained: P = A(f 动 2 -f0 2 )-B(f 动 -f0). Where A and B are curve constants, f0 is the initial frequency, and f 动 For dynamic frequency.

[0035] In summary, the vibrating wire force measuring structure of this embodiment, by reasonably setting the size range of the force transmission cap 100, can adjust the size according to the lithology of the rock mass supported by the anchor rod 200, thereby adjusting the overall stiffness and stress transmission characteristics of the entire vibrating wire force measuring structure. This optimizes the mechanical impedance matching between the template assembly 300 and the steel wire assembly 400, thereby improving the geological adaptability, measurement linearity, and sensitivity of the entire vibrating wire force measuring structure.

[0036] It should be noted that the force-transmitting cap 100 in this embodiment acts as a mechanical adapter. By changing its size, the pressure-displacement conversion coefficient transmitted to the template assembly 300 can be adjusted. When the conversion coefficient matches the optimal working range of the tension-frequency characteristic curve of the steel string assembly 400, good mechanical impedance matching can be achieved, thereby maximizing sensitivity, optimizing linearity, and achieving optimal dynamic response.

[0037] In one embodiment, when the anchor bolt 200 is inserted into high-stress hard rock, the diameter of the side of the force transmission cap 100 facing the support plate 220 is in the range of 100mm-120mm, and the height of the force transmission cap 100 along the axial direction of the anchor bolt 200 is in the range of one-third to one-half of the diameter of the side of the force transmission cap 100 facing the support plate 220.

[0038] It should be noted that, due to the high overall stiffness and extremely small deformation of high-stress hard rock, it is prone to high-frequency, small-amplitude, and rapid dynamic stress fluctuations, and may even be accompanied by instantaneous stress changes caused by rock bursts and rock bursts. Therefore, the sensitivity and high-frequency dynamic response capability of the vibrating wire force measuring structure are required to be extremely high.

[0039] Therefore, the diameter of the force transmission cap 100 can be set to be smaller to reduce the pressure-bearing contact area of ​​the force transmission cap 100, thereby increasing the stress concentration. This allows small stress changes in the surrounding rock to produce significant deformation on the template component 300, which is then efficiently converted into frequency changes in the steel string component 400. This significantly improves the sensitivity of the vibrating wire force measuring structure to capturing high-frequency small-amplitude dynamic stress.

[0040] At the same time, the height of the force transmission cap 100 is selected to be moderate, which can optimize the overall force transmission path stiffness while ensuring the structural strength of the force transmission cap 100, avoid stress attenuation caused by excessive rigidity, and accurately match the high stiffness characteristics of high-stress hard rock. This allows the template component 300 and the steel string component 400 to achieve optimal mechanical impedance matching, so as to ensure that the measurement structure under high-frequency dynamic stress is not distorted.

[0041] For example, when the anchor bolt 200 is inserted into high-stress hard rock, the diameter of the side of the force transmission cap 100 facing the support plate 220 can be 100mm, 110mm, or 120mm. The height of the force transmission cap 100 along the axial direction of the anchor bolt 200 can be one-third or one-half of the diameter of the side of the force transmission cap 100 facing the support plate 220.

[0042] In another embodiment, if the anchor 200 is inserted into high-stress soft rock, the diameter of the side of the force transmission cap 100 facing the support plate 220 is in the range of 180mm-220mm, and the height of the force transmission cap 100 along the axial direction of the anchor 200 is in the range of one-third to one-half of the diameter of the side of the force transmission cap 100 facing the support plate 220.

[0043] It should be noted that high-stress soft rock has low rock mass strength and high elastic modulus. The surrounding rock undergoes long-term large deformation, with gradual stress changes and a large measurement range requirement. Therefore, vibrating wire force measurement structures are prone to problems such as uneven stress transmission and poor measurement linearity.

[0044] Therefore, in this embodiment, a large-diameter force-transmitting cap 100 is selected to increase the bearing area of ​​the force-transmitting cap 100 and reduce the bearing stress per unit area. This allows the deformation pressure of the surrounding rock to be slowly and evenly transferred to the template assembly 300 over a wide range to avoid local stress overload. This enables the wide-range detection requirements under large deformation of high-stress soft rock to be adapted to.

[0045] At the same time, selecting a force transmission cap 100 of appropriate height can maintain stable stress transmission stiffness, balance the pressure-bearing stability and deformation transmission efficiency of the force transmission cap 100, and ensure a good linear relationship between the deformation of the template component 300 and the frequency change of the steel string component 400, so as to take into account both measurement sensitivity and linearity, and effectively solve the problems of monitoring data drift and nonlinear deviation in soft rock formations.

[0046] For example, when the anchor bolt 200 is inserted into high-stress soft rock, the diameter of the side of the force transmission cap 100 facing the support plate 220 can be 180mm, 200mm, or 220mm. The height of the force transmission cap 100 along the axial direction of the anchor bolt 200 is one-third or one-half of the diameter of the side of the force transmission cap 100 facing the support plate 220.

[0047] In another embodiment, when the anchor 200 is inserted into the fractured rock mass, the diameter of the side of the force transmission cap 100 facing the support plate 220 ranges from 180mm to 220mm, and the height of the force transmission cap 100 along the axial direction of the anchor 200 ranges from one-quarter to one-third of the diameter of the side of the force transmission cap 100 facing the support plate 220.

[0048] It should be noted that the fractured rock mass has well-developed fissures and uneven rock walls, making the anchor bolt 200 prone to uneven loading and stress eccentricity. This can easily cause non-uniform deformation of the template assembly 300, disrupting the mechanical impedance matching between the steel string assembly 400 and the template assembly 300, and consequently leading to measurement failure.

[0049] Therefore, this embodiment selects a large-diameter force-transmitting cap 100 to expand the pressure-bearing contact range of the force-transmitting cap 100, so as to adapt to the uneven rock wall shape of the fractured rock mass, thereby dispersing the local stress at the surrounding rock fissures and reducing the probability of stress eccentricity.

[0050] Meanwhile, a lower-height force transmission cap 100 is selected to reduce the overall structural height of the force transmission cap 100, decrease the center of gravity of the vibrating wire force measuring structure, thereby improving the installation fit and structural stability; at the same time, it can reduce the axial stiffness of the force transmission cap 100, weaken the influence of eccentric load stress on the torsional deformation of the template assembly 300, enhance the resistance to eccentric load, ensure the stable mechanical impedance matching between the template assembly 300 and the steel wire assembly 400 under complex stress, and avoid measurement failure.

[0051] For example, when the anchor bolt 200 is inserted into the fractured rock mass, the diameter of the side of the force transmission cap 100 facing the support plate 220 can be 180mm, 200mm, or 220mm. The height of the force transmission cap 100 along the axial direction of the anchor bolt 200 is one-quarter or one-third of the diameter of the side of the force transmission cap 100 facing the support plate 220.

[0052] Reference Figures 2 to 6 As shown, in some embodiments, there are at least two template components 300, and at least two template components 300 are arranged on both sides of the anchor rod 200. There are at least two steel wire components 400 and at least two frequency detection elements 500, and each of the at least two steel wire components 400 and at least two frequency detection elements 500 corresponds to at least two template components 300.

[0053] All frequency detection elements 500 are electrically connected to the information processing unit 600. The information processing unit 600 calculates at least two axial force values ​​based on the dynamic frequency and initial frequency of each steel string assembly 400, performs deviation verification on each axial force value, and obtains the stress value by arithmetic average or weighted average of the verified axial force values.

[0054] In practice, in deep geotechnical engineering, the anchor bolt 200 is prone to uneven rock walls, eccentric installation, and uneven stress on the surrounding rock, resulting in eccentric loading and eccentric stress, which in turn leads to abnormal deformation of the template component 300 and affects the accuracy of the final stress value detection.

[0055] To this end, this embodiment arranges at least two sets of template assemblies 300, steel wire assemblies 400, and frequency detection elements 500 outside the anchor bolt 200 to achieve synchronous acquisition of stress values ​​at different locations of the anchor bolt 200. Specifically, the information processing unit 600 performs deviation verification on multiple axial force values, and outputs the final stress value by applying an arithmetic average or weighted average algorithm to the axial force values ​​that pass the verification. For specific deviation verification methods, please refer to the relevant description in the detection method section below.

[0056] In this embodiment, by setting multiple steel string assemblies 400, template assemblies 300, and frequency detection elements 500, the measurement deviation caused by unilateral load and local stress concentration that is easily caused by setting only one steel string assembly can be offset. In turn, invalid data introduced by improper installation and abnormal local stress of surrounding rock can be effectively eliminated, which greatly improves the accuracy and stability of stress detection results, so as to adapt to complex working conditions such as fractured rock mass and uneven rock wall that are prone to eccentric load.

[0057] For example, refer to Figures 2 to 6 As shown, in this embodiment, the template component 300, the steel string component 400, and the frequency detection element 500 can all be set as two symmetrically arranged components. Alternatively, in other embodiments, they can be set as three or more circumferentially spaced components.

[0058] Reference Figures 3 to 7 As shown, in some embodiments, each template assembly 300 is provided with a pressure transmission plate 700 on the side near the anchor nut 210, and a bearing plate 800 is provided between all pressure transmission plates 700 and force transmission cap 100.

[0059] In practice, when the preload applied by the anchor nut 210 and the pressure transmitted by the surrounding rock are transmitted through the force transmission cap 100, uneven stress distribution and local stress concentration are likely to occur. When these stresses are directly applied to the template assembly 300, they will cause non-uniform deformation of the template assembly 300, which will disrupt the mechanical impedance matching between the steel string assembly 400 and the template assembly 300, thereby affecting the measurement linearity and sensitivity.

[0060] Therefore, the pressure transmission plate 700 added in this embodiment serves as a stress transition component, which can uniformly diffuse and regulate the pressure received by the force transmission cap 100 and then transmit it to the template assembly 300, thereby achieving uniform and planar transmission of pressure, avoiding local stress concentration, ensuring that the template assembly 300 is subjected to uniform and controllable force, and further ensuring the stability of mechanical impedance matching effect under different lithological strata.

[0061] For example, the pressure plate 700 can be presented as follows: Figure 3 The structure shown is crescent-shaped, or it could be a cone-shaped structure.

[0062] Furthermore, since there are at least two pressure transmission plates 700, in order to ensure that the compressive stress borne by the force transmission cap 100 can be evenly transmitted to each pressure transmission plate 700, a bearing plate 800 can be provided on the pressure transmission plate 700 and the force transmission cap 100, so that the pressure transmitted to the force transmission cap 100 can be evenly transmitted to each pressure transmission plate 700 through the bearing plate 800.

[0063] Reference Figures 4 to 8 As shown, the template assembly 300 includes a deformable template 310 and a support column 320. The deformable template 310 abuts against the force transmission cap 100, and the support column 320 is located on the side of the deformable template 310 facing the support plate 220 and abuts against the support plate 220.

[0064] In practice, the deformable template 310 bears the pressure and undergoes elastic deformation, thereby accurately converting stress into deformation to drive the steel string assembly 400 to vibrate and change frequency. The bearing column 320 serves as a rigid support member, connecting the deformable template 310 and the support plate 220 to form a stable load-bearing support structure.

[0065] For example, the frequency detection element 500 includes a magnetic head. The magnetic head acquires the vibration frequency of the steel string assembly 400 based on the principle of electromagnetic induction, achieving zero mechanical contact loss. This results in advantages such as resistance to moisture, dust, and electromagnetic interference, long lifespan, and high stability, making it suitable for long-term online monitoring needs in deep underground engineering. Simultaneously, the magnetic head can accurately capture minute vibration signals from the steel string assembly 400, ensuring effective acquisition of high-frequency dynamic stress and small-amplitude stress fluctuations.

[0066] In this embodiment, the information processing unit 600 includes an information transmission element 610 and an information processing display element 620 electrically connected to the information transmission element 610. The information transmission element 610 is electrically connected to the frequency detection element 500 and is configured to transmit the dynamic frequency to the information processing display element 620. The information processing display element 620 is configured to receive the input initial frequency and dynamic frequency, and calculate and display the stress value based on the dynamic frequency and the initial frequency.

[0067] In a specific implementation, the information transmission element 610 is responsible for the stable transmission of dynamic frequency signals. For example, the information transmission element 610 can be a transmission cable.

[0068] Specifically, the information processing display element 620 is configured to support manual input of the initial frequency, thereby flexibly setting the parameters and formulas in the stress value formula. This allows for automatic calculation of the stress value based on the formula and visual output, enabling operators to obtain stress information promptly. Furthermore, the slim display element 620 can also store data.

[0069] It should be noted that the initial frequency of the steel string assembly 400 can be detected by the frequency detection element 500 or by additional frequency detection modules.

[0070] Reference Figures 4 to 8 As shown, the steel string assembly 400 includes at least two mounting posts 410 disposed on the side of the template assembly 300 away from the anchor nut 210 and a steel string 420 disposed between the mounting posts 410. The frequency detection element 500 is used to detect and acquire the dynamic frequency of the steel string 420.

[0071] In practice, the mounting column 410 can provide a stable mounting carrier for the steel string 420, ensuring the accuracy of the installation position of the steel string 420.

[0072] Reference Figure 7 , Figure 8 As shown, furthermore, a clamping member 430 is provided on the mounting column 410, which presses against the steel wire 420 to clamp and fix the steel wire 420. For example, the clamping member 430 can be a pressure cap or a pressure plate. Alternatively, in other implementations, the clamping member 430 can be a clamping nut, allowing the initial tension of the steel wire 420 to be adjusted by rotating the clamping nut to adapt to different monitoring range requirements.

[0073] Furthermore, the frequency detection element 500 can be disposed between the deformable template 310 and the steel string 420, and is used to detect the dynamic frequency of the steel string 420 as it deforms with the deformable template 310. The information processing unit 600 is electrically connected to the frequency detection element 500, and is used to receive the dynamic frequency and, based on the dynamic frequency and a pre-input initial frequency, calculate the frequency using the formula P=A(f 动 2 -f0 2 )-B(f 动 (-f0) Calculate the stress value borne by anchor bolt 200.

[0074] Furthermore, it should be noted that the ground pressure of the rock mass is divided into generalized ground pressure and narrow ground pressure. Generalized ground pressure generally refers to the force exerted by the rock mass on the surrounding rock, while narrow ground pressure refers to the pressure exerted by the surrounding rock on the support plate 220. When the anchor bolt 200 is a fully bonded anchor bolt, the final measured stress value only characterizes the axial force experienced by the anchor bolt 200 during the support process. When the anchor bolt 200 is a prestressed anchor bolt, the anchor bolt 200 penetrates deep into the surrounding rock, passing through the plastic failure zone, and its end is firmly fixed in the rock mass. In this case, the final calculated stress value can be characterized as the pressure of the surrounding rock on the rock wall, i.e., the rock wall pressure that the support plate 220 needs to bear.

[0075] Reference Figures 1 to 8 As shown in the figure, this application provides an anchor bolt detection device, including an anchor bolt 200, an anchor bolt nut 210, a support plate 220, and a vibrating wire force measuring structure.

[0076] The specific structure and implementation principle of the vibrating wire force measuring structure in this embodiment are the same as those of the vibrating wire force measuring structure provided in the above embodiments, and can bring the same or similar technical effects. They will not be described in detail here, but can be referred to the description of the above embodiments.

[0077] Specifically, one end of the anchor bolt 200 is inserted into the rock mass and the other end of the anchor bolt 200 is located outside the rock mass. The anchor bolt nut 210 is located at the other end of the anchor bolt 200. The support plate 220 is located at the other end of the anchor bolt 200, on the side of the anchor bolt nut 210 closer to the end of the anchor bolt 200. The support plate 220 abuts against the rock mass to support the rock mass.

[0078] In one embodiment, when the rock mass is high-stress hard rock, the length of the support plate 220 ranges from 100mm to 200mm, the width of the support plate 220 ranges from 100mm to 200mm, and the thickness of the support plate 220 ranges from 10mm to 15mm.

[0079] It should be noted that high-stress hard rock exhibits stress concentration and high transmission efficiency, thus requiring no excessively large support plate 220 to achieve uniform stress distribution and transmission. Specifically, if the length and width of the support plate 220 are too large, it will increase the installation difficulty. Furthermore, given the flat surface of hard rock, an excessively large support plate 220 may lead to uneven stress transmission due to installation deviations. Therefore, the length and width of the support plate 220 are set within the range of 100mm-200mm. This not only matches the size of the force transmission cap 100 of the vibrating wire force measuring structure, ensuring that the stress transmitted by the force transmission cap 100 can be stably fed back to the rock mass through the support plate 220, but also avoids localized stress overload caused by an excessively small contact area between the support plate 220 and the rock mass, thereby protecting the rock surface from damage.

[0080] Furthermore, the stress amplitude and instantaneous impact of high-stress hard rock are large, requiring the support plate 220 to have sufficient rigidity to resist stress impact and prevent deformation that could lead to stress transmission distortion. A thickness of 10mm-15mm ensures that the support plate 220 does not undergo plastic deformation under high-frequency impact stress, while also maintaining a lightweight structure. This prevents the support plate 220 from increasing the end load on the anchor bolt 200 due to excessive weight, ensuring the stability of the anchor bolt 200 after installation. It also works in synergy with the rigidity of the force transmission cap 100 to optimize the mechanical impedance matching effect between the steel wire assembly 400 and the template assembly 300.

[0081] For example, when the anchor bolt 200 is inserted into high-stress hard rock, the length of the support plate 220 can be 100mm, 150mm or 200mm, the width of the support plate 220 can be 100mm, 150mm or 200mm, and the thickness of the support plate 220 can be 10mm, 12mm or 15mm.

[0082] In another embodiment, when the rock mass is high-stress soft rock, the length of the support plate 220 ranges from 200mm to 300mm, the width of the support plate 220 ranges from 200mm to 300mm, and the thickness of the support plate 220 ranges from 10mm to 15mm.

[0083] It should be noted that, compared with high-stress hard rock, high-stress soft rock has a weaker bearing capacity. Enlarging the length and width of the support plate 220 can significantly increase the contact area between the support plate 220 and the rock mass, thereby dispersing the concentrated stress borne by the anchor bolt 200 to a larger area of ​​the rock mass surface, reducing the bearing stress per unit area, preventing the support plate 220 from embedding into the soft rock due to excessive stress, and alleviating the problem of uneven stress caused by large deformation of soft rock.

[0084] In addition, the length and width of the support plate 220 are compatible with the size of the force transmission cap 100 corresponding to high-stress soft rock, ensuring that the pressure transmitted by the force transmission cap 100 can be evenly transmitted to the rock mass through the support plate 220, avoiding stress concentration at the contact point between the support plate 220 and the force transmission cap 100, so as to ensure the accuracy of stress acquisition of the vibrating wire force measuring structure.

[0085] Furthermore, while the stress changes in high-stress soft rock are gradual, long-term large deformations can exert continuous compressive forces on the support plate 220. Therefore, the support plate 220 needs to possess sufficient structural strength to resist long-term fatigue deformation. A thickness of 10mm-15mm ensures that the support plate 220 does not warp or deform under long-term compression, while avoiding excessive thickness that would increase the weight of the support plate 220. This ensures that the support plate 220 is always in close contact with the rock mass, thereby providing a stable support foundation for the vibrating wire force measuring structure and guaranteeing its good measurement linearity.

[0086] For example, when the anchor bolt 200 is inserted into high-stress soft rock, the length of the support plate 220 can be 200mm, 250mm or 300mm, the width of the support plate 220 can be 300mm, 350mm or 300mm, and the thickness of the support plate 220 can be 10mm, 12mm or 15mm.

[0087] In other embodiments, when the rock mass is fractured rock mass, the length of the pallet 220 ranges from 200mm to 300mm, the width of the pallet 220 ranges from 200mm to 300mm, and the thickness of the pallet 220 ranges from 10mm to 15mm.

[0088] It should be noted that, for fractured rock masses, increasing the length and width of the support plate 220 allows it to adapt to the uneven rock face, increasing the contact points between the support plate 220 and the rock mass, reducing localized suspension, and improving the stability of the support plate 220 installation. Simultaneously, the larger contact area can disperse localized stress in the fractured rock mass, preventing stress concentration caused by rock fissures and preventing the support plate 220 from damaging the rock mass or fracturing itself.

[0089] In addition, the length and width dimensions of the support plate 220 are coordinated with the dimensions of the force transmission cap 100 corresponding to the fractured rock mass, which can effectively offset the stress deviation caused by the off-center load, ensure that the stress signal received by the vibrating wire force measuring structure is true and reliable, and avoid measurement distortion caused by off-center load.

[0090] In addition, the fractured rock mass is subjected to complex stresses and instantaneous impact stresses, such as the impact from rock collapse. The support plate 220 needs to have sufficient rigidity and impact resistance. A thickness of 10mm-15mm can ensure that the support plate 220 does not undergo plastic deformation or breakage under eccentric loading and impact stress. At the same time, it takes into account structural flexibility, so that the support plate 220 can fit into the uneven rock wall, thereby further improving the installation stability and providing stable force support for the vibrating wire force measurement structure, thus ensuring the reliability of long-term monitoring.

[0091] For example, when the anchor bolt 200 is inserted into the fractured rock mass, the length of the support plate 220 can be 200mm, 250mm or 300mm, the width of the support plate 220 can be 300mm, 350mm or 300mm, and the thickness of the support plate 220 can be 10mm, 12mm or 15mm.

[0092] In summary, the deformation capacity of different lithological strata varies. Under the action of surrounding rock pressure, the dynamic response of the internal stress of the anchor bolt 200 has a significant impact on the matching quality between the steel wire 420 and the deformable diaphragm 310. Since the support structure of the anchor bolt detection device includes the force transmission cap 100 and the bearing column 320, the pressure state of the vibrating wire force measuring structure can be adjusted by adjusting the size of the force transmission cap 100, thereby reducing the influence of the surrounding rock conditions on the matching quality between the steel wire 420 and the deformable diaphragm 310. Furthermore, when characterizing the rock wall pressure with prestressed anchor bolts, the differences in monitoring data caused by the deformation of different strata can also be adjusted by adjusting the size of the support plate 220.

[0093] Reference Figure 9 As shown, this embodiment provides a method for detecting the force on an anchor bolt 200 using an anchor bolt detection device, including: Step S1: Install the anchor bolt detection device on the preset rock mass; Step S2: Detect and obtain the dynamic frequency of the steel string assembly 400 by the frequency detection element 500; Step S3: Receive the dynamic frequency through the information processing unit 600, and calculate the stress value borne by the anchor rod 200 based on the dynamic frequency and the initial frequency of the steel string assembly 400.

[0094] The specific structure and implementation principle of the anchor bolt detection device in this embodiment are the same as those of the anchor bolt detection device provided in the above embodiments, and can bring the same or similar technical effects. They will not be described in detail here, but can be referred to the description of the above embodiments.

[0095] In practice, step S1 is the installation step before testing. The specific installation steps include assembling the anchor bolt 200, support plate 220, vibrating wire force measuring structure, and anchor bolt nut 210 according to the specifications to ensure that the support plate 220 is tightly against the rock mass and the vibrating wire force measuring structure is firmly installed to ensure the subsequent acquisition of dynamic frequency and calculation of stress value.

[0096] In step S2, the dynamic frequency of the steel wire assembly 400 is captured in real time by the frequency detection element 500. This dynamic frequency is directly related to the tension of the steel wire 420 of the steel wire assembly 400. The tension of the steel wire 420 is determined by the stress transmitted by the anchor rod 200. Therefore, the dynamic frequency can directly reflect the stress state of the anchor rod 200.

[0097] Specifically, during the testing process, the frequency detection element 500 continuously collects signals to ensure that frequency changes under different operating conditions are captured, thus guaranteeing the comprehensiveness of signal acquisition.

[0098] In step S3, the information processing unit 600 receives the dynamic frequency and calculates the stress value borne by the anchor rod 200 based on the dynamic frequency and the initial frequency of the steel string assembly 400. Specifically, the information processing unit 600 receives the dynamic frequency transmitted by the frequency detection element 500, combines it with the pre-input initial frequency of the steel string 420 of the steel string assembly 400, and calculates the stress value using the preset stress calculation formula: P=A(f 动 2 -f0 2 )-B(f 动 The calculation is performed using -f0) to obtain the final stress value, providing engineers with clear monitoring data.

[0099] In some embodiments, step S1 includes: Drill holes in the pre-defined rock mass and clean the holes. Insert one end of the anchor rod 200 into the borehole and inject anchoring agent into the borehole. After the anchoring agent has cured, fix the anchor rod 200 in the borehole. Install the support plate 220 and the vibrating wire force measuring structure on the other end of the anchor rod 200 in sequence, and install the anchor nut 210 on the other end of the anchor rod 200 for fastening.

[0100] In practice, step S1 includes the following steps: Step 1: Drilling and Hole Cleaning: On the pre-set rock mass, drill suitable holes according to the size of the anchor rod 200 and monitoring requirements. After drilling, clean the rock cuttings and debris in the hole to achieve hole cleaning operation, so as to avoid impurities affecting the bonding effect between the anchoring agent and the rock mass and the anchor rod 200, and ensure that the anchor rod 200 is more firmly fixed in the hole, laying the foundation for subsequent force transmission and detection.

[0101] Step 2: Anchor bolt 200 fixing: Insert one end of anchor bolt 200 into the borehole, inject anchoring agent into the borehole, and after the anchoring agent has cured, firmly bond anchor bolt 200 to the rock mass to ensure that anchor bolt 200 can effectively bear the stress of the surrounding rock and transmit it to the support plate 220 and the vibrating wire force measuring structure.

[0102] Step 3: Component Assembly and Fastening: Install the support plate 220 and the vibrating wire force measuring structure sequentially at the end of the anchor rod 200 located outside the rock mass, and then fasten them with the anchor nut 210. If it is a prestressed anchor rod, sufficient preload must be applied to compress the surrounding rock before tightening the anchor nut 210 to ensure that the support plate 220 is tightly fitted to the rock mass and that the vibrating wire force measuring structure is subjected to uniform force, thus avoiding measurement errors caused by loose installation.

[0103] Furthermore, prior to step S1, the detection method also includes: Rigid loading calibration was performed on the vibrating wire force measurement structure to obtain curve constants A1 and B1. The vibrating wire force measurement structure was calibrated by flexible loading to obtain curve constants A2 and B2. The curve constant A is obtained by taking the average of A1 and A2, and the curve constant B is obtained by taking the average of B1 and B2.

[0104] In practice, the rigid loading calibration process is as follows: A press is used to directly calibrate the vibrating wire force measuring structure. A range matching the actual monitoring scenario is set, and the actual pressure value can be calculated based on the shape and size of the pressure plate 700. Pressure is applied to the vibrating wire force measuring structure in ascending order to obtain the frequency change of the steel wire assembly 400. The calibration is performed at least three times. The calibration data are then fitted using the stress calculation formula and software developed using the least squares method to obtain curve constants A1 and B1.

[0105] The specific process of flexible loading calibration is as follows: a press is used to perform loading calibration on the force transmission cap 100 and the bearing column 320 of the vibrating wire force measuring structure. The appropriate range is also set. The pressure value borne by the force transmission cap 100 is calculated according to the size of the force transmission cap 100 and the support plate 220. The pressure is applied in order from small to large, and the calibration is performed no less than 3 times. The curve constants A2 and B2 are obtained by fitting the calibration data.

[0106] Finally, the average values ​​of A1 and B1 obtained from rigid loading calibration and A2 and B2 obtained from flexible loading calibration are taken to obtain the final curve constants A and B. This optimization method can offset the systematic error of a single calibration method, ensure the accuracy of the stress calculation formula, and further improve the reliability of the test data.

[0107] In some embodiments, when the template assembly 300, the steel wire assembly 400, and the frequency detection element 500 all include at least two, step S3 includes: The information processing unit 600 receives the dynamic frequency and initial frequency of each steel string assembly 400 and calculates at least two axial force values. All axial force values ​​are checked for deviation, and the stress values ​​are obtained by arithmetic average or weighted average of the qualified axial force values.

[0108] In specific implementation, when at least two template components 300, steel string components 400, and frequency detection elements 500 are all set, the information processing unit 600 receives the dynamic frequency and initial frequency of the corresponding steel string component 400 transmitted by each frequency detection element 500. Using a preset stress value calculation formula, it calculates the axial force value corresponding to each steel string component 400, forming multiple sets of axial force data. Then, it performs deviation verification on all axial force values. Valid axial force values ​​are deemed effective, and finally, the effective axial force values ​​are averaged or weighted averaged to obtain the final stress value.

[0109] In some embodiments, the method of verifying the deviation of all axial force values ​​and obtaining the stress value by arithmetic average or weighted average of the verified axial force values ​​includes: The relative deviation rate is obtained by calculating the deviation between any two axial force values ​​and then compared with a preset deviation rate threshold. If the relative deviation rate is less than the lower limit of the preset deviation rate threshold, the verification is deemed qualified and the stress value is obtained by averaging all axial force values. If the relative deviation rate is within the preset deviation rate threshold range, the verification is deemed qualified and the stress value is obtained by weighted averaging of all axial force values. If the relative deviation rate is greater than the upper limit of the preset deviation rate threshold, the verification is deemed unqualified and the axial force value is invalid.

[0110] The specific method for calculating the relative deviation rate is as follows: For example, taking steel string assembly 400 as an example, we finally obtain two axial force values ​​F1 and F2, and then the relative deviation rate is... The calculation is based on the following formula:

[0111] The above calculation formula is valid when F1 and F2 have the same sign, i.e., both are tensile or compressive stresses. If one is tensile and the other is compressive, it indicates a severe off-center load, which is directly judged as unacceptable.

[0112] For example, the range of the preset deviation rate threshold can be 0.5% to 15%.

[0113] If the relative deviation rate of the two axial force values ​​is less than 0.5%, it indicates that the installation quality is good and there is no obvious off-center load. The anchor rod 200 is approximately concentric under force. In this case, the arithmetic mean of the two axial force values ​​can be taken to obtain the final stress value. If the relative deviation rate is within the range of the preset deviation rate threshold, i.e., 5% ≤ relative deviation rate < 15%, it indicates that there is a significant off-center load but it does not affect the validity of the data. The two axial force values ​​are weighted and the weight can be allocated according to the uniformity of the force corresponding to each axial force value to compensate for the error caused by the off-center load and obtain the final stress value. If the relative deviation rate is ≥ 15%, it indicates that there is a serious off-center load. The template component 300 may produce non-uniform deformation, causing the frequency and stress correspondence of the steel wire 420 to deviate from the calibration curve. In this case, the two axial force values ​​are deemed invalid and the device installation needs to be readjusted, such as adjusting the fit of the support plate 220 and the position of the vibrating wire force measuring structure, until the deviation rate is ≤ 0.5%, and then the test is repeated.

[0114] In the description of the embodiments of this application, specific features, structures, materials or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0115] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A vibrating wire force measuring structure, characterized in that, include: A hemispherical force-transmitting cap is used to be fitted onto the anchor bolt and abut against the anchor nut and the support plate on the anchor bolt; wherein the diameter of the side of the force-transmitting cap facing the support plate ranges from 100mm to 220mm, and the height of the force-transmitting cap along the axial direction of the anchor bolt ranges from one-quarter to one-half of the diameter of the side of the force-transmitting cap facing the support plate; A template assembly is located inside the force-transmitting cap and abuts against the force-transmitting cap and the support plate respectively. Part of the template assembly can be deformed under the pressure of the force-transmitting cap. A steel wire assembly is located on the side of the template assembly away from the anchor nut; A frequency detection element is disposed on the template assembly and configured to detect and acquire the dynamic frequency of the steel string assembly under pressure. An information processing unit, electrically connected to the frequency detection element, is configured to receive the dynamic frequency and calculate the stress value borne by the anchor bolt in conjunction with the initial frequency of the steel string assembly; wherein the dynamic frequency and the stress value satisfy: P=A(f 动 2 -f0 2 )-B(f 动 -f0); Where P is the stress value, A and B are curve constants, f0 is the initial frequency, and f 动 For dynamic frequency.

2. The vibrating wire force measuring structure according to claim 1, characterized in that, When the anchor is inserted into high-stress hard rock, the diameter of the side of the force transmission cap facing the support plate is in the range of 100mm-120mm, and the height of the force transmission cap along the axial direction of the anchor is in the range of one-third to one-half of the diameter of the side of the force transmission cap facing the support plate. And / or, when the anchor is inserted into high-stress soft rock, the diameter of the side of the force transmission cap facing the support plate is in the range of 180mm-220mm, and the height of the force transmission cap along the axial direction of the anchor is in the range of one-third to one-half of the diameter of the side of the force transmission cap facing the support plate. And / or, when the anchor bolt is inserted into the fractured rock mass, the diameter of the side of the force transmission cap facing the support plate ranges from 180mm to 220mm, and the height of the force transmission cap along the axial direction of the anchor bolt ranges from one-quarter to one-third of the diameter of the side of the force transmission cap facing the support plate.

3. The vibrating wire force measuring structure according to claim 1, characterized in that, The template assembly comprises at least two, and the at least two template assemblies are respectively disposed on both sides of the anchor rod. The steel string assembly and the frequency detection element each comprise at least two, and the at least two steel string assemblies and the at least two frequency detection elements each correspond one-to-one with the at least two template assemblies. All the frequency detection elements are electrically connected to the information processing unit. The information processing unit calculates at least two axial force values ​​based on the dynamic frequency and initial frequency of each steel string assembly, performs deviation verification on each axial force value, and obtains the stress value by arithmetic average or weighted average of the verified axial force values.

4. The vibrating wire force measuring structure according to claim 3, characterized in that, Each of the template components is provided with a pressure-transmitting plate on the side near the anchor nut, and a bearing plate is provided between all the pressure-transmitting plates and the force-transmitting cap.

5. The vibrating wire force measuring structure according to any one of claims 1 to 4, characterized in that, The template assembly includes a deformable template and a support column. The deformable template abuts against the force-transmitting cap, and the support column is located on the side of the deformable template facing the support plate and abuts against the support plate. And / or, the frequency detection element includes a magnetic head; And / or, the information processing unit includes an information transmission element and an information processing display element electrically connected to the information transmission element, the information transmission element being electrically connected to the frequency detection element and configured to transmit the dynamic frequency to the information processing display element, the information processing display element being configured to receive the input initial frequency and dynamic frequency and calculate and display the stress value based on the dynamic frequency and the initial frequency; And / or, the steel string assembly includes at least two mounting posts disposed on the side of the template assembly away from the anchor nut and a steel string disposed between the mounting posts, and the frequency detection element is used to detect and acquire the dynamic frequency of the steel string.

6. An anchor bolt detection device, characterized in that, Includes anchor bolts, anchor bolt nuts, support plates, and vibrating wire force measuring structures as described in any one of claims 1 to 5; One end of the anchor rod is inserted into the rock mass, and the other end of the anchor rod is located outside the rock mass. The anchor nut is located at the other end of the anchor rod, and the support plate is located at the other end of the anchor rod and on the side of the anchor nut closer to the end of the anchor rod.

7. The anchor bolt detection device according to claim 6, characterized in that, When the rock mass is high-stress hard rock, the length of the support plate ranges from 100mm to 200mm, the width of the support plate ranges from 100mm to 200mm, and the thickness of the support plate ranges from 10mm to 15mm. And / or, when the rock mass is high-stress soft rock, the length of the support plate ranges from 200mm to 300mm, the width of the support plate ranges from 200mm to 300mm, and the thickness of the support plate ranges from 10mm to 15mm. And / or, when the rock mass is a fractured rock mass, the length of the pallet ranges from 200mm to 300mm, the width of the pallet ranges from 200mm to 300mm, and the thickness of the pallet ranges from 10mm to 15mm.

8. A method for detecting the stress on an anchor bolt using the anchor bolt detection device according to claim 6 or 7, characterized in that, include: Step S1: Install the anchor bolt detection device on the preset rock mass; Step S2: Detect and obtain the dynamic frequency of the steel string assembly using a frequency detection element; Step S3: Receive the dynamic frequency through the information processing unit, and calculate the stress value borne by the anchor rod based on the dynamic frequency and the initial frequency of the steel string assembly.

9. The detection method according to claim 8, characterized in that, Step S1 includes: Drill holes in the pre-defined rock mass and clean the holes. One end of the anchor rod is inserted into the borehole, and an anchoring agent is injected into the borehole. After the anchoring agent has cured, the anchor rod is fixed in the borehole. Install the support plate and vibrating wire force measuring structure sequentially on the other end of the anchor rod, and install the anchor rod nut on the other end of the anchor rod for fastening; And / or, prior to step S1, the detection method further includes: The vibrating wire force measuring structure is subjected to rigid loading calibration to obtain curve constant A1 and curve constant B1; The vibrating wire force measuring structure is calibrated by flexible loading to obtain curve constants A2 and B2; The curve constant A is obtained by taking the average of A1 and A2, and the curve constant B is obtained by taking the average of B1 and B2.

10. The detection method according to claim 8, characterized in that, When the template assembly, the steel string assembly, and the frequency detection element are all configured to include at least two components, step S3 includes: The information processing unit receives the dynamic frequency and initial frequency of each steel string assembly and calculates at least two axial force values. All the axial force values ​​are checked for deviation, and the stress value is obtained by arithmetic average or weighted average of the axial force values ​​that pass the check.

11. The detection method according to claim 10, characterized in that, The method for verifying the deviation of all the axial force values ​​and obtaining the stress value by arithmetic average or weighted average of the verified axial force values ​​includes: The relative deviation rate is obtained by calculating the deviation between any two axial force values ​​and then compared with a preset deviation rate threshold. If the relative deviation rate is less than the lower limit of the preset deviation rate threshold, the verification is deemed qualified and the stress value is obtained by taking the average value of the axial force value. If the relative deviation rate is within the range of the preset deviation rate threshold, the verification is deemed qualified and the stress value is obtained by weighted averaging of the axial force value. If the relative deviation rate is greater than the upper limit of the preset deviation rate threshold, the verification is deemed unqualified and the axial force value is invalid.

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