Anchor rod stress measuring device

Abstract

The invention relates to the field of anchor rod stress measurement, and particularly discloses an anchor rod stress measurement device which comprises a tensile stress measurement mechanism. The tensile stress measuring mechanism comprises a first piston cylinder assembly, a piston on one side of the first piston cylinder assembly is connected with a first piston assembly, the outer side of the first piston cylinder assembly is connected with a second piston cylinder assembly through a hydraulic oil pipeline, and a piston on one side of the second piston cylinder assembly is connected with a second piston assembly; according to the invention, the thrust of the second piston assembly is measured by using the force sensor, so that the pressure change in the hydraulic system can be accurately converted into the value of the tensile stress of the anchor rod, and the measurement error caused by environmental factors and mechanical wear in the traditional measurement method is avoided through the measurement mode; and the accuracy of measuring the tensile stress of the anchor rod is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the field of bolt stress measurement, and specifically relates to a bolt stress measurement device. Background Art

[0002] A bolt is a tension member that penetrates deep into the ground and is widely used in engineering fields such as mines, tunnels, slopes, and dams. Its basic structure consists of a rod body, an anchorage section, and a free section. The function of the bolt is to overcome the defect of low tensile strength of rock and soil masses through the longitudinal tensile force of the rod body, and enhance the stability and bearing capacity of rock and soil masses. Its working principle is to connect one end of the bolt to an engineering structure and the other end to penetrate deep into the ground, and utilize the bonding and frictional action between the anchor body and the soil layer to transfer the tension of the free section to the deep part of the soil body.

[0003] In the conventional method of bolt stress measurement, traditional operations usually require first finely grinding the surface of the bolt to ensure surface flatness and cleanliness, and then accurately attaching a strain rosette to the ground bolt surface after grinding. This treatment method aims to avoid direct contact between the strain rosette and the external environment through physical isolation means, thereby reducing the interference of external factors on the measurement data and ensuring the accuracy of the measurement results.

[0004] However, before attaching the strain rosette, multiple processes such as grinding and cleaning the bolt surface are required, and the operation process is cumbersome and time-consuming. In addition, the manual attachment process is easily affected by factors such as the technical level of the operator and the environmental temperature and humidity, resulting in deviation in the attachment position of the strain rosette or uneven attachment quality, thereby introducing measurement errors. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a bolt stress measurement device to solve the problems of numerous processes in the strain rosette attachment work in the prior art and being easily affected by the outside.

[0006] A bolt stress measurement device includes a tensile stress measurement mechanism; The tensile stress measurement mechanism includes a first piston cylinder assembly, one side piston of the first piston cylinder assembly is connected to a first piston assembly, the outside of the first piston cylinder assembly is connected to a second piston cylinder assembly through a hydraulic oil pipeline, and one side piston of the second piston cylinder assembly is connected to a second piston assembly; A force sensor for measuring the thrust magnitude of the second piston assembly is further installed on the second piston cylinder assembly; Rotate and snap the first piston assembly onto the outside of the bolt, and then fix the first piston cylinder assembly to the rock mass; When the anchor bolt is subjected to tensile stress in the direction of the rock mass, the first piston assembly moves along with the anchor bolt, causing the hydraulic oil to move along the hydraulic oil pipeline and pushing the second piston assembly to extend out of the second piston cylinder assembly. The force sensor measures the magnitude of the thrust generated by the second piston assembly, thereby measuring the magnitude of the tensile stress of the anchor bolt.

[0007] Preferably, the first piston cylinder assembly includes a cylindrical fixing frame, and a plurality of positioning rods are fixedly installed on one side of the cylindrical fixing frame; A plurality of the positioning rods are clamped in the reserved holes in the rock mass and fixed by chemical potions; The anchor bolt is located on the center line of the cylindrical fixing frame and keeps a distance.

[0008] Preferably, the first piston assembly includes an annular bracket, a limiting ring is fixedly installed on the outer side of the annular bracket, a thread groove matching the threaded end of the anchor bolt is formed in the middle of the annular bracket, and a plurality of first piston bodies are fixedly connected to one side of the annular bracket through a piston rod; A plurality of first piston cylinder bodies are fixed inside the cylindrical fixing frame; The limiting ring is slidably clamped inside the cylindrical fixing frame in a limiting manner, and a plurality of the first piston bodies are piston-connected to the first piston cylinder bodies.

[0009] Preferably, the second piston cylinder assembly includes a second piston cylinder body; The second piston assembly includes a second piston body that is slidably clamped inside the second piston cylinder body in a limiting manner, and a second piston rod is fixedly installed on the outer side of the second piston body; The force sensor is installed on the second piston cylinder body through a bracket and monitors the thrust of the second piston rod.

[0010] Preferably, a fixing plate is fixedly installed on the outer side of the second piston cylinder body, and the fixing plate is fixedly installed on the rock mass.

[0011] Preferably, a hollow tube is further fixedly installed on one side of the cylindrical fixing frame away from the annular bracket; A plurality of pressure sensors are fixedly installed in a ring shape on the outer side of the hollow tube; The detection ends of a plurality of the pressure sensors are attached to the anchor bolt; Both the hollow tube and the cylindrical fixing frame are of hollow structures and keep a distance from the anchor bolt.

[0012] Preferably, a threaded retaining ring is further provided at one end of the hollow tube away from the cylindrical fixing frame, and the threaded retaining ring is rotatably clamped on the outer side of the anchor bolt; The threaded retaining ring seals the hollow tube.

[0013] Preferably, a pressure gauge is fixedly installed on the second piston cylinder assembly.

[0014] Compared with the prior art, the present invention has the following beneficial effects: By using a force sensor to measure the thrust of the second piston assembly, the pressure change in the hydraulic system can be accurately converted into the value of the bolt tensile stress. This measurement method avoids many problems existing when attaching strain gauges and improves work efficiency. The entire tensile stress measurement mechanism is composed of simple components such as a first piston cylinder assembly, a first piston assembly, a hydraulic oil pipeline, a second piston cylinder assembly, and a second piston assembly. It has a compact structure and is easy to install and maintain. By providing a hollow tube on the cylindrical fixing frame and installing a plurality of pressure sensors outside the hollow tube, the measurement of the bolt shear stress is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is an exploded schematic diagram of the present invention; Figure 3 is a schematic diagram of the structure of the tensile stress measurement mechanism of the present invention; Figure 4 is a sectional view of the tensile stress measurement mechanism of the present invention; Figure 5 is an application schematic diagram of the present invention.

[0016] In the figure: 1, tensile stress measurement mechanism; 11, first piston cylinder assembly; 111, cylindrical fixing frame; 112, positioning rod; 113, first piston cylinder body; 114, hollow tube; 12, first piston assembly; 121, annular bracket; 122, limiting ring; 123, thread groove; 124, first piston body; 13, hydraulic oil pipeline; 14, second piston cylinder assembly; 141, second piston cylinder body; 142, fixing plate; 15, second piston assembly; 151, second piston body; 152, second piston rod; 16, pressure gauge; 2, pressure sensor; 3, threaded retaining ring. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0018] Such as Figure 1 、 2 and Figure 5As shown in the following: Embodiment 1: The present invention provides an anchor bolt stress measurement device, including a tensile stress measurement mechanism 1; The tensile stress measurement mechanism 1 includes a first piston cylinder assembly 11. One side piston of the first piston cylinder assembly 11 is connected to a first piston assembly 12. The outside of the first piston cylinder assembly 11 is connected to a second piston cylinder assembly 14 through a hydraulic oil pipeline 13. One side piston of the second piston cylinder assembly 14 is connected to a second piston assembly 15; A force sensor for measuring the thrust magnitude of the second piston assembly 15 is also installed on the second piston cylinder assembly 14; Rotate and snap the first piston assembly 12 on the outside of the anchor bolt, and then fix the first piston cylinder assembly 11 on the rock mass; When the anchor bolt is subjected to a tensile stress in the direction of the rock mass, the first piston assembly 12 moves along with the anchor bolt, causing the hydraulic oil to move along the hydraulic oil pipeline 13 and push the second piston assembly 15 to extend out of the second piston cylinder assembly 14. The force sensor measures the magnitude of the thrust generated by the second piston assembly 15, thereby measuring the tensile stress magnitude of the anchor bolt.

[0019] As can be seen from the above, when the anchor bolt is subjected to a tensile stress in the direction of the rock mass, the first piston assembly 12 moves along with the anchor bolt, pushing the hydraulic oil in the first piston cylinder assembly 11 to move along the hydraulic oil pipeline 13, and then pushing the second piston assembly 15 to extend out of the second piston cylinder assembly 14. The force sensor measures the magnitude of the thrust of the second piston assembly 15 to measure the tensile stress of the anchor bolt; The calculation method is as follows: According to the piston area ratio of the first piston assembly 12 and the second piston assembly 15, combined with Pascal's law that the pressure in a closed liquid can be transmitted in all directions without change, the relationship between the tensile stress of the anchor bolt and the measured value of the force sensor can be deduced, and then the calculation of the tensile stress of the anchor bolt can be completed.

[0020] Let the piston area of the first piston assembly 12 be , and the piston area of the second piston assembly 15 be , the tensile stress received by the anchor bolt be , and the magnitude of the thrust generated by the second piston assembly 15 measured by the force sensor be .

[0021] Since the hydraulic oil transmits pressure in a closed system, according to Pascal's law, the pressure generated at the first piston assembly 12, the pressure generated at the second piston assembly 15, and .

[0022] Then , from which the tensile stress of the anchor bolt can be deduced.

[0023] Therefore, by measuring the thrust of the second piston assembly 15 , and the piston areas of the known first piston assembly 12 and second piston assembly 15 , , the tensile stress of the anchor rod can be calculated according to the above formula .

[0024] As Figure 3 and Figure 4 shown: Embodiment 2: This embodiment is basically the same as the previous one, except that the first piston cylinder assembly 11 includes a cylindrical fixing frame 111, and a plurality of positioning rods 112 are fixedly installed on one side of the cylindrical fixing frame 111; A plurality of positioning rods 112 are clamped in the reserved holes in the rock mass and fixed by chemical potions; The anchor rod is located on the center line of the cylindrical fixing frame 111 and keeps a distance.

[0025] Specifically, the first piston assembly 12 includes an annular bracket 121, a limiting ring 122 is fixedly installed on the outer side of the annular bracket 121, a threaded groove 123 matching the threaded end of the anchor rod is opened in the middle of the annular bracket 121, and a plurality of first piston bodies 124 are fixedly connected to one side of the annular bracket 121 through a piston rod; A plurality of first piston cylinder bodies 113 are fixed inside the cylindrical fixing frame 111; The limiting ring 122 is slidably clamped inside the cylindrical fixing frame 111, and a plurality of first piston bodies 124 are piston-connected to the first piston cylinder bodies 113.

[0026] Specifically, the second piston cylinder assembly 14 includes a second piston cylinder body 141; The second piston assembly 15 includes a second piston body 151 that is slidably clamped inside the second piston cylinder body 141, and a second piston rod 152 is fixedly installed on the outer side of the second piston body 151; The force sensor is installed on the second piston cylinder body 141 through a bracket and monitors the thrust of the second piston rod 152.

[0027] Specifically, a fixing plate 142 is fixedly installed on the outer side of the second piston cylinder body 141, and the fixing plate 142 is fixedly installed on the rock mass.

[0028] As described above, during operation, the anchor bolt is subjected to tensile stress in the direction of the rock mass. Since the annular support 121 is connected to the threaded end of the anchor bolt through the threaded groove 123, it drives the annular support 121 to move, thereby causing the limit ring 122 to slide within the cylindrical fixing frame 111 in a limited manner. At the same time, several first piston bodies 124 move within the first piston barrel body 113, pushing the hydraulic oil to transfer along the hydraulic oil pipeline 13 to the second piston barrel body 141, and then pushing the second piston body 151 to extend out of the second piston barrel body 141. The second piston rod 152 moves accordingly, and the force sensor monitors the thrust of the second piston rod 152, thereby measuring the tensile stress of the anchor bolt.

[0029] As Figure 1 , 2 , 4 and Figure 5 shown: Embodiment 3: This embodiment is basically the same as the previous embodiment, except that a hollow tube 114 is fixedly installed on the side of the cylindrical fixing frame 111 away from the annular support 121; A number of pressure sensors 2 are fixedly installed in a ring shape on the outer side of the hollow tube 114; The detection ends of the number of pressure sensors 2 are attached to the anchor bolt; Both the hollow tube 114 and the cylindrical fixing frame 111 are of hollow structures and are kept at a distance from the anchor bolt.

[0030] Specifically, a threaded retaining ring 3 is further provided at one end of the hollow tube 114 away from the cylindrical fixing frame 111, and the threaded retaining ring 3 is rotationally clamped on the outer side of the anchor bolt; The threaded retaining ring 3 seals the hollow tube 114.

[0031] Specifically, a pressure gauge 16 is further fixedly installed on the second piston barrel assembly 14.

[0032] As described above, during operation, when the anchor bolt is subjected to shear stress, since the pressure sensor 2 is attached to the anchor bolt, when the anchor bolt deforms under force, the pressure sensor 2 can detect the change in the surface pressure of the anchor bolt, and then obtain the shear strain at the current detection position . At this time, according to Hooke's law of elasticity in three dimensions: ; wherein, is the shear modulus of the material; Therefore, by measuring the shear strain , the shear stress can be calculated; The pressure gauge 16 displays the pressure inside the second piston barrel assembly 14; The threaded retaining ring 3 is rotationally clamped on the outer side of the anchor bolt and seals the hollow tube 114, thereby preventing rock and soil from entering the hollow tube 114 and affecting the reading of the pressure sensor 2; The hollow tube 114 and the cylindrical fixing bracket 111 are kept at a certain distance from the anchor rod, thereby avoiding the anchor rod directly applying tensile stress to the cylindrical fixing bracket 111.

[0033] The standard parts used in the present invention can all be purchased from the market. The special-shaped parts can be customized according to the description in the specification and the drawings. The specific connection methods of each part all adopt conventional means such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts, and equipment all adopt conventional models in the prior art. Coupled with the circuit connection adopting the conventional connection method in the prior art, details are not described herein. The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0034] In the description of the present invention, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. The meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0035] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over", and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below", and "beneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0037] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0038] In the drawings of the disclosed embodiments of the present invention, only the structures related to the disclosed embodiments are involved. For other structures, reference can be made to the general design. Without conflict, the same embodiment and different embodiments of the present invention can be combined with each other.

[0039] Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An anchor stress measuring device, characterized in that: It comprises a tensile stress measuring mechanism (1); The tensile stress measuring mechanism (1) comprises a first piston cylinder assembly (11), a piston on one side of the first piston cylinder assembly (11) is connected to a first piston assembly (12), the outer side of the first piston cylinder assembly (11) is connected to a second piston cylinder assembly (14) via a hydraulic oil pipeline (13), and a piston on one side of the second piston cylinder assembly (14) is connected to a second piston assembly (15); The second piston cylinder assembly (14) is also equipped with a force sensor for measuring the thrust of the second piston assembly (15); The first piston assembly (12) is rotated and embedded on the outer side of the anchor rod, and the first piston cylinder assembly (11) is then fixed on the rock mass; When the anchor rod is subjected to tensile stress in the direction of the rock mass, the first piston assembly (12) moves along with the anchor rod, thereby causing the hydraulic oil to move along the hydraulic oil pipeline (13) and push the second piston assembly (15) to extend out of the second piston cylinder assembly (14). The force sensor measures the magnitude of the thrust generated by the second piston assembly (15), thereby measuring the magnitude of the tensile stress of the anchor rod.

2. An anchor stress measuring device as claimed in claim 1, characterized in that: The first piston cylinder assembly (11) comprises a cylindrical fixing frame (111), and a plurality of positioning rods (112) are fixedly mounted on one side of the cylindrical fixing frame (111); A plurality of positioning rods (112) are embedded in the reserved holes in the rock mass and fixed by chemical solution; The anchor rod is located on the center line of the cylindrical fixing frame (111) and keeps a distance therefrom.

3. An anchor stress measuring device as claimed in claim 2, characterized in that: The first piston assembly (12) comprises an annular bracket (121), a limiting ring (122) is fixedly mounted on the outer side of the annular bracket (121), a thread groove (123) matching the threaded end of the anchor rod is provided in the middle of the annular bracket (121), and one side of the annular bracket (121) is also fixedly connected to a plurality of first piston bodies (124) via a piston rod; A plurality of first piston cylinder bodies (113) are fixed inside the cylindrical fixing frame (111); The limiting ring (122) is limitedly slidably embedded in the interior of the cylindrical fixing frame (111), and a plurality of the first piston bodies (124) and the first piston cylinder body (113) are piston-connected.

4. An anchor stress measuring device as claimed in claim 3, characterized in that: The second piston cylinder assembly (14) comprises a second piston cylinder body (141); The second piston assembly (15) comprises a second piston body (151) which is limitedly slidably embedded in the interior of the second piston cylinder body (141); the outer side of the second piston body (151) is also fixedly mounted on the second piston rod (152); The force sensor is mounted on the second piston cylinder body (141) via a bracket, and monitors the thrust of the second piston rod (152).

5. An anchor stress measuring device as claimed in claim 4, characterized in that: A fixing plate (142) is fixedly mounted on the outer side of the second piston cylinder body (141), and the fixing plate (142) is fixedly mounted on the rock mass.

6. An anchor stress measuring device as claimed in claim 4, characterized in that: A hollow tube (114) is also fixedly mounted on a side of the cylindrical fixing frame (111) away from the annular support (121); A plurality of pressure sensors (2) are fixedly mounted in a ring shape on the outer side of the hollow tube (114); The detection ends of a plurality of the pressure sensors (2) are attached to the anchor rod; The hollow tube (114) and the cylindrical fixing frame (111) are both hollow structures and are spaced apart from the anchor rod.

7. An anchor stress measuring device as claimed in claim 6, characterized in that: A threaded retaining ring (3) is also provided on one end of the hollow tube (114) away from the cylindrical fixing frame (111), and the threaded retaining ring (3) is rotatably engaged with the outer side of the anchor rod; The threaded retaining ring (3) seals the hollow tube (114).

8. An anchor stress measuring device as claimed in claim 1, characterized in that: A pressure gauge (16) is also fixedly mounted on the second piston cylinder assembly (14).

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