A mechanical property testing device and testing method for anchor cable and inner anchor head

Abstract

The invention discloses a mechanical property testing device for an anchor cable and an inner anchor head and a testing method thereof, comprising an environmental simulation component, wherein an anchor cable anchor head simulation component and a stress deformation monitoring component are arranged in the environmental simulation component, wherein the environmental simulation component comprises a box body, wherein the box body is filled with simulated mortar and simulated surrounding rock, wherein the anchor cable anchor head simulation component is arranged in the simulated surrounding rock; the testing method comprises the following steps: S1, making simulated surrounding rock representing different strengths, and setting a pressure box for monitoring the internal stress of the surrounding rock mortar; S2, setting anchor cable axial force monitoring sensors at both ends of the simulated anchor cable, and connecting the two ends of the simulated inner anchor head with the simulated anchor cable and a jack respectively; S3, performing grouting operation in the box body and setting a pressure box for monitoring the internal stress of the surrounding rock mortar; S4, drawing auxiliary lines for monitoring deformation of the surrounding rock mortar, and installing a video monitor; S5, controlling the jack to perform simulation, and recording the data changes of each instrument during the tensioning process in real time.

Description

Technical Field

[0001] The invention relates to the field of geotechnical engineering, and in particular to a device and a method for testing the mechanical properties of an anchor cable and an inner anchor head. Background Art

[0002] Anchor cables are one of the most common and effective reinforcement measures for slope reinforcement. As the core component of the anchoring section of the anchor cable, the mechanical characteristics of the inner anchor head determine the maximum pullout resistance that the anchor cable can provide. Therefore, the structural design and optimization of the inner anchor head are effective means to improve the characteristics of the anchor cable. However, since both the anchor cable and the inner anchor head are in the surrounding rock and mortar, it is not easy to test their mechanical properties during tensioning. At present, there is a lack of effective indoor test equipment and methods for testing the mechanical properties of anchor cables and inner anchor heads, which has caused certain obstacles to the development of geotechnical engineering. Summary of the invention

[0003] The object of the present invention is to provide a device and method for testing the mechanical properties of an anchor cable and an inner anchor head which has a simple structure and is easy to operate in order to solve the above problems.

[0004] In order to achieve the above object, the technical solution of the present invention is:

[0005] A device for testing the mechanical properties of an anchor cable and an inner anchor head, comprising an environmental simulation component, wherein an anchor cable anchor head simulation component and a stress deformation monitoring component are arranged in the environmental simulation component, wherein the environmental simulation component comprises a box, a cover plate, simulated mortar, and simulated surrounding rock, wherein the top of the box is open and the top of the box is connected to the cover plate, the cover plate is made of a transparent material, the box is filled with simulated mortar and simulated surrounding rock, the simulated surrounding rock is located in the middle of the simulated mortar, and an anchor cable anchor head simulation component is arranged in the simulated surrounding rock; the anchor cable anchor head simulation component comprises a simulated anchor cable, a simulated inner anchor head, and a jack, wherein the volume of the simulated inner anchor head is half of the actual anchor head volume divided along the axis, the simulated inner anchor head is placed in the simulated surrounding rock, and one end of the simulated inner anchor head is aligned with one end of the simulated anchor cable The simulated anchor cable is connected to each other, and the other end of the simulated anchor cable passes through the simulated surrounding rock and the side wall of the box in turn and is connected to the jack; the stress and deformation monitoring component includes an anchor cable axial force monitoring sensor, a surrounding rock mortar deformation monitoring auxiliary line, a surrounding rock mortar internal stress monitoring pressure box, a video monitoring frame, and a video monitor; the anchor cable axial force monitoring sensor is arranged at both ends of the simulated anchor cable, the surrounding rock mortar deformation monitoring auxiliary line is arranged on the upper end surface of the cover plate outside the simulated internal anchor head, there are several surrounding rock mortar internal stress monitoring pressure boxes and they are arranged at equal intervals in the simulated mortar and the simulated surrounding rock, the bottom end of the video monitoring frame is fixedly connected to the box or the ground, the top end of the video monitoring frame is fixedly connected to the video monitor, and the camera of the video monitor faces the surrounding rock mortar deformation monitoring auxiliary line.

[0006] Furthermore, the box body includes a bottom plate, a front side plate, a rear side plate, a left side plate, and a right side plate, and the bottom plate, the front side plate, the rear side plate, the left side plate, and the right side plate are welded into a rectangular box body in a sealed state.

[0007] Furthermore, one end of the jack is in contact with the left side plate, and the other end is connected to one end of the simulated anchor cable.

[0008] Furthermore, the cross-section of the simulated surrounding rock is semicircular, and anchor holes for simulating the passage of anchor cables are provided in the simulated surrounding rock.

[0009] Furthermore, one end of the anchor cable is connected to one end of the anchor head close to the right side plate, and the other end of the anchor cable passes through the anchor head, simulated surrounding rock, and the side wall of the box in sequence and is connected to the jack.

[0010] Furthermore, the surrounding rock mortar deformation monitoring auxiliary lines are two groups of scale lines engraved on the end surface of the cover plate and perpendicular to each other, and each group of scale lines has two scale lines that are parallel to each other.

[0011] Furthermore, the surrounding rock mortar internal stress monitoring pressure boxes are arranged side by side at the front and rear sides below the anchor cable.

[0012] Furthermore, the simulated anchor cable is a steel strand.

[0013] A testing method for a mechanical property testing device of an anchor cable and an inner anchor head, characterized in that it comprises the following steps:

[0014] S1. By adjusting the concrete mix ratio, simulated surrounding rocks with different strengths are made, and anchor holes with different diameters and pressure boxes for monitoring the internal stress of the surrounding rock mortar are set in the simulated surrounding rocks;

[0015] S2. Different types of simulated inner anchor heads and simulated anchor cables are made by 3D printing or steel casting. The simulated inner anchor heads are placed in the simulated surrounding rock. Anchor cable axial force monitoring sensors are set at both ends of the simulated anchor cable. The simulated inner anchor head is connected to one end of the simulated anchor cable. The other end of the simulated anchor cable passes through the anchor hole and the left side plate and a jack is installed.

[0016] S3, adjusting the cement mortar ratio, making simulated mortars of different strengths, performing grouting operations in the box, and setting a pressure box for monitoring the internal stress of the surrounding rock mortar in the simulated mortar;

[0017] S4. Draw auxiliary lines for monitoring deformation of surrounding rock mortar on the end surface of the cover plate, and install a full video monitoring frame and a video monitor;

[0018] S5. The anchor cable tensioning process under different conditions is simulated by controlling the jack, and the data changes of the anchor cable axial force monitoring sensor and the anchor cable axial force monitoring sensor during the tensioning process as well as the deformation data of the simulated mortar and the simulated surrounding rock are recorded in real time, so as to obtain the mechanical properties of the simulated anchor cable and the simulated inner anchor head.

[0019] Compared with the prior art, the present invention has the following advantages and positive effects:

[0020] The present invention can simulate the existence environments of different surrounding rocks, mortars, anchor holes, etc. through the environmental simulation component, providing basic conditions for the mechanical property test of anchor cables and inner anchor heads; the tensioning process simulation of different inner anchor heads and anchor cables can be realized through the anchor cable anchor head simulation component; the whole process of deformation and destruction of mortar and surrounding rocks during the tensioning of anchor cables and stress-deformation data information can be realized through the stress-deformation monitoring component. Through the coordinated work of the three components, the tensioning process of anchor cables under different conditions can be simulated and accurate stress-deformation test data can be obtained, which provides a research basis for the mechanical property test of anchor cables and inner anchor heads and brings convenience to the research work in the geotechnical field. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 It is a structural schematic diagram of the present invention;

[0023] Figure 2 for Figure 1 AA section view;

[0024] Figure 3 for Figure 1 BB cross-sectional view. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work, any modifications, equivalent substitutions, improvements, etc., should be included in the protection scope of the present invention.

[0026] like Figure 1 , Figure 2 and Figure 3As shown, a test device suitable for testing the mechanical properties of anchor cables and inner anchor heads comprises an environmental simulation component 1, an anchor cable and inner anchor head simulation component 2, and a stress and deformation monitoring component 3.

[0027] The environmental simulation component 1 includes a rectangular parallelepiped frame consisting of a bottom plate 101, a left side plate 105, a right side plate 104, a rear side plate 102, a front side plate 103, and a transparent observation cover plate 106. The frame size can be determined according to the simulated environment. The left side plate 105 plays the role of loading reaction force, and its rigidity is required to be higher. In the present invention, the left side plate 105 is designed to be a 30mm thick steel plate; in order to facilitate the observation of the deformation characteristics of the surrounding rock and mortar materials during the test, the top plate adopts a transparent observation cover plate 106. The simulated mortar 107 and the simulated surrounding rock 108 are both realized by on-site casting. During the casting process, according to the characteristics of the axisymmetric model, half of the actual situation is taken as the research object. It is feasible to simulate the actual conditions through half of the rock mass and mortar according to the characteristics of the axisymmetric object.

[0028] The anchor cable and anchor head simulation component 2 includes a simulated inner anchor head 201, a simulated anchor cable 202 and a loading jack 203. For slope observation, the simulated inner anchor head 201 is half of the actual model. According to the characteristics of an axisymmetric object, it is feasible to pass through the actual conditions of half of the anchor head. The simulated inner anchor head 201 can be made by 3D printing or steel casting according to the design drawings; the simulated anchor cable 202 is the steel strand used in the actual anchor cable, so the actual simulation is the anchor cable tensioning condition of two axisymmetric steel strands; the loading jack 203 is a hydraulic servo-controlled jack, which is convenient for tensioning load control during the test.

[0029] The stress deformation monitoring system 3 includes an anchor cable axial force monitoring sensor 301, a surrounding rock mortar deformation monitoring auxiliary line 302, a surrounding rock mortar internal stress monitoring pressure box 303, a video monitoring frame 304 and a video monitoring device 305. The surrounding rock mortar deformation monitoring auxiliary line 302 is two sets of mutually perpendicular auxiliary lines with scales artificially drawn near the simulated inner anchor head 201. Through video monitoring, the whole process of surrounding rock and mortar deformation during the anchor cable tensioning process can be obtained.

[0030] The test steps of the test device are as follows:

[0031] S1. By adjusting the concrete mix ratio, simulated surrounding rocks 108 representing different strengths are produced. During the production process, prefabricated round holes 109 are used to simulate anchor holes of different diameters.

[0032] S2. Different types of simulated inner anchor heads 201 are made by 3D printing or steel casting technology, the simulated inner anchor heads 201 are connected to the steel strands by conventional anchor cable fixing equipment, and hydraulic servo jacks 203 are installed to realize servo control of anchor cable tensioning to realize different loading modes;

[0033] S3, by adjusting the cement mortar ratio, making simulated mortars 107 of different strengths, using the simulated mortar 107 to truly simulate the grouting process in the project;

[0034] S4. During the process of S1 to S3, the anchor cable axial force sensor 301, the pressure box 303 for burying the surrounding rock mortar stress test, the auxiliary line 302 for monitoring the deformation of the surrounding rock mortar, the video monitoring frame 304 and the video monitoring equipment 305 are installed at the corresponding positions;

[0035] S5. The servo jack is controlled to simulate the tensioning process of anchor cables under different conditions, and the stress and deformation characteristics of anchor cables, surrounding rocks and mortar are recorded in real time during the tensioning process, providing basic conditions for testing the mechanical properties of anchor heads in anchor cables.

Claims

1. A mechanical property testing device for an anchor cable and an inner anchor head, comprising an environmental simulation component, wherein an anchor cable and an inner anchor head simulation component and a stress and deformation monitoring component are arranged in the environmental simulation component, characterized in that: The environmental simulation component includes a box body, a cover plate, simulated mortar, and simulated surrounding rock. The top of the box body is open and the top of the box body is connected to the cover plate, which is made of transparent material. The box body is filled with simulated mortar and simulated surrounding rock. The simulated surrounding rock is located in the middle of the simulated mortar. An anchor cable and anchor head simulation component is arranged in the simulated surrounding rock. The anchor cable and anchor head simulation component includes a simulated anchor cable, a simulated inner anchor head, and a jack. The volume of the simulated inner anchor head is half of the volume of the actual anchor head divided along the axis. The simulated inner anchor head is placed in the simulated surrounding rock. One end of the simulated inner anchor head is connected to one end of the simulated anchor cable. The other end of the simulated anchor cable passes through the simulated surrounding rock and the side wall of the box body in sequence and then connects to the surrounding rock. The jack is connected; the stress and deformation monitoring component includes an anchor cable axial force monitoring sensor, a surrounding rock mortar deformation monitoring auxiliary line, a surrounding rock mortar internal stress monitoring pressure box, a video monitoring frame, and a video monitor; the anchor cable axial force monitoring sensor is arranged at both ends of the simulated anchor cable, the surrounding rock mortar deformation monitoring auxiliary line is arranged on the upper end surface of the cover plate outside the simulated internal anchor head, there are several surrounding rock mortar internal stress monitoring pressure boxes and they are arranged at equal intervals in the simulated mortar and simulated surrounding rock, the bottom end of the video monitoring frame is fixedly connected to the box or the ground, the top end of the video monitoring frame is fixedly connected to the video monitor, and the camera of the video monitor faces the surrounding rock mortar deformation monitoring auxiliary line.

2. The mechanical property testing device for anchor cable and inner anchor head according to claim 1, characterized in that: The box body comprises a bottom plate, a front side plate, a rear side plate, a left side plate and a right side plate, which are welded into a rectangular box body in a sealed state.

3. The mechanical property testing device for anchor cable and inner anchor head according to claim 2, characterized in that: One end of the jack is in contact with the left side plate, and the other end is connected with one end of the simulated anchor cable.

4. The mechanical property testing device for anchor cable and inner anchor head according to claim 3, characterized in that: The cross section of the simulated surrounding rock is semicircular, and anchor holes for simulating the passage of anchor cables are arranged in the simulated surrounding rock.

5. The mechanical property testing device for anchor cable and inner anchor head according to claim 4, characterized in that: One end of the anchor cable is connected to an end of the anchor head close to the right side plate, and the other end of the anchor cable passes through the anchor head, the simulated surrounding rock, and the side wall of the box in sequence and is connected to the jack.

6. The mechanical property testing device for anchor cable and inner anchor head according to claim 5, characterized in that: The surrounding rock mortar deformation monitoring auxiliary lines are two groups of scale lines engraved on the end surface of the cover plate and perpendicular to each other, and each group of scale lines has two scale lines that are parallel to each other.

7. The mechanical property testing device for anchor cable and inner anchor head according to claim 6, characterized in that: The surrounding rock mortar internal stress monitoring pressure boxes are arranged side by side at the front and rear sides below the anchor cable.

8. The mechanical property testing device for anchor cable and inner anchor head according to claim 7, characterized in that: The simulated anchor cable is a steel strand.

9. A testing method for the mechanical property testing device of the anchor cable and the inner anchor head as claimed in claim 8, characterized in that: The following steps are involved: S1. By adjusting the concrete mix ratio, simulated surrounding rocks with different strengths are made, and anchor holes with different diameters and pressure boxes for monitoring the internal stress of the surrounding rock mortar are set in the simulated surrounding rocks; S2. Different types of simulated inner anchor heads and simulated anchor cables are made by 3D printing or steel casting. The simulated inner anchor heads are placed in the simulated surrounding rock. Anchor cable axial force monitoring sensors are set at both ends of the simulated anchor cable. The simulated inner anchor head is connected to one end of the simulated anchor cable. The other end of the simulated anchor cable passes through the anchor hole and the left side plate and a jack is installed. S3, adjusting the cement mortar ratio, making simulated mortars of different strengths, performing grouting operations in the box, and setting a pressure box for monitoring the internal stress of the surrounding rock mortar in the simulated mortar; S4. Draw auxiliary lines for monitoring deformation of surrounding rock mortar on the end surface of the cover plate, and install a full video monitoring frame and a video monitor; S5. The anchor cable tensioning process under different conditions is simulated by controlling the jack, and the data changes of the anchor cable axial force monitoring sensor and the anchor cable axial force monitoring sensor during the tensioning process as well as the deformation data of the simulated mortar and the simulated surrounding rock are recorded in real time, so as to obtain the mechanical properties of the simulated anchor cable and the simulated inner anchor head.

Images