A built-in magnetic three-dimensional cohesive slip testing device and its installation testing method

Abstract

The application discloses a built-in magnetic three-dimensional bond-slip testing device and a mounting testing method thereof, which is used for testing the bond-slip and vertical peeling at the interface of a steel plate-concrete composite structure, is mounted on the inner side of the steel plate before pouring concrete, and comprises a steel shell and a core testing element in the steel shell, wherein the steel shell is magnetically sealed with the bottom of the steel plate; the core testing element comprises a hollow conduit, a sliding head, a pre-tightening spring and six arc-shaped steel belt strain gauges; the arc-shaped steel belt strain gauge comprises a pre-tightening arc-shaped steel belt and a resistance strain gauge attached to the pre-tightening arc-shaped steel belt, and six arc-shaped steel belt strain gauges are arranged in two groups along X, Y and Z directions, respectively, and are used for testing the slip amount along the X and Y directions and the peeling amount along the Z direction between the steel plate and the concrete. The application breaks through the defects of single testing direction and low testing dimension of the existing bond-slip testing, and significantly improves the feasibility of long-term monitoring of the interface damage of the composite structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of interface damage monitoring of steel plate-concrete composite structure, and particularly relates to a built-in magnetic three-dimensional bond-slip testing device and a mounting and testing method thereof. BACKGROUND

[0002] At present, composite structures are widely used as main load-bearing components of large-scale infrastructures. The effective bond between steel and concrete can make full use of the material mechanical properties of steel and concrete, and is widely used in large bridges and super high-rise buildings as main load-bearing components. Steel has high tensile strength and is prone to instability under compression; concrete has good compressive performance and is prone to cracking under tension. Due to the difference in mechanical parameters of the two materials, the steel plate-concrete interface is prone to shear cracking, and the buckling of the steel plate in the compression zone is prone to cause separation of the steel plate and the concrete. When interface slip or interface peeling damage occurs, the cooperative load-bearing mechanism of the steel plate and the concrete is destroyed, significantly reducing the load-bearing capacity of the component. In addition, cracks between the steel plate and the concrete are prone to corrosion caused by rainwater, further reducing the durability of the composite structure.

[0003] Many scholars have carried out related damage tests based on the method of presetting different forms of interface defects, such as knocking method, ultrasonic detection, etc. However, there are technical problems of low precision, inaccurate measurement or inability to measure for the current interface void test. The commonly used testing methods are mainly direct testing methods based on relative displacement difference and strain difference, which test the relative displacement of the steel plate and the concrete part through the LVDT displacement sensor, or arrange strain gauges in the steel plate and the concrete respectively, and calculate the difference between the strain gauges. The above testing methods cannot effectively test the bond-slip.

[0004] Patent CN2551971Y provides an embedded steel-concrete electronic slip sensor, patent CN207215011U provides a sensor for measuring the bond-slip between the steel plate and the concrete, and patent CN110208182 provides a measuring sensor for measuring the bond-slip at the interface between the shaped steel and the concrete. However, the above patents can only carry out one-way testing and cannot realize three-dimensional bond-slip testing. In the aspect of vertical peeling monitoring, there is no relevant literature reported at present. SUMMARY

[0005] The application aims to provide a magnetic built-in three-dimensional adhesive slip testing device and a mounting testing method thereof, which realizes slip testing on the X and Y horizontal planes and Z direction peeling testing through built-in X, Y and Z direction sensing elements.

[0006] To solve the above technical problems, embodiments of the application provide the following solutions:

[0007] In one aspect, a magnetic built-in three-dimensional adhesive slip testing device is provided, which is used for testing adhesive slip and vertical peeling at the interface of a steel plate-concrete combined structure, and is mounted on the inner side of the steel plate before pouring concrete, and comprises a steel shell and a core testing element located in the steel shell, wherein the steel shell is magnetically sealed with the bottom of the steel plate.

[0008] The core testing element comprises a hollow conduit, a sliding head, a pre-tightening spring and six arc-shaped steel belt strain gauges; the hollow conduit is vertically arranged in the middle of the steel shell, the upper end penetrates through a positioning hole in the top of the steel plate, and the lower end can freely slide on the bottom contact surface of the steel shell; the sliding head is sleeved on the outside of the hollow conduit and can slide up and down along the hollow conduit; the pre-tightening spring is located below the sliding head, the upper end is connected with the sliding head, and the lower end is in contact with the bottom of the steel shell, and the pre-tightening spring provides a pre-tightening force to make the sliding head in contact with the top of the steel plate.

[0009] The arc-shaped steel belt strain gauge comprises a pre-tightening arc-shaped steel belt and a resistance strain gauge attached to the pre-tightening arc-shaped steel belt, and six arc-shaped steel belt strain gauges are arranged in two groups along the X, Y and Z directions, respectively, and are used for testing the slip amount in the X and Y directions and the peeling amount in the Z direction between the steel plate and the concrete, one end of the pre-tightening arc-shaped steel belt is connected with the sliding head, and the other end is connected with the steel shell.

[0010] Preferably, the steel shell is a square shell with an open top, the inner side of the steel shell is bonded with the bottom of the steel plate by using a ring-shaped high-strength magnet, the adsorption force of the ring-shaped high-strength magnet is greater than the gravity of the device, thereby providing effective bonding; the outer side of the steel shell is packaged with the bottom of the steel plate by a sealing rubber ring to avoid water intrusion before the concrete hardens.

[0011] Preferably, a plurality of studs are arranged on the outer side and the bottom of the steel shell to enhance the linkage with the concrete, avoid separation of the concrete from the steel shell due to shrinkage of the concrete, and enhance the integrity between the two.

[0012] Preferably, the middle part of the sliding head is provided with a cylindrical through hole with a diameter consistent with the outer wall diameter of the hollow conduit, so that the freedom degrees in X and Y directions are consistent, and the sliding head is guaranteed to slide freely in Z direction.

[0013] Preferably, the six resistance strain gauges on the six pre-tightening arc-shaped steel belts are respectively a first X-direction resistance strain gauge, a second X-direction resistance strain gauge, a first Y-direction resistance strain gauge, a second Y-direction resistance strain gauge, a first Z-direction resistance strain gauge and a second Z-direction resistance strain gauge.

[0014] The first X-direction resistance strain gauge and the second X-direction resistance strain gauge are symmetrically arranged, and the measurement results of the two are averaged as the test results of the X-direction slip; the first Y-direction resistance strain gauge and the second Y-direction resistance strain gauge are symmetrically arranged, and the measurement results of the two are averaged as the test results of the Y-direction slip; the first Z-direction resistance strain gauge and the second Z-direction resistance strain gauge are symmetrically arranged, and the measurement results of the two are averaged as the test results of the Z-direction separation; avoiding the phenomenon that a single resistance strain gauge is arranged in a single direction, and the test data is not accurate due to the failure of a single resistance strain gauge.

[0015] Preferably, the first X-direction resistance strain gauge, the second X-direction resistance strain gauge, the first Y-direction resistance strain gauge, the second Y-direction resistance strain gauge, the first Z-direction resistance strain gauge and the second Z-direction resistance strain gauge are respectively attached to the arc-shaped top of the corresponding pre-tightening arc-shaped steel belt, one end of the pre-tightening arc-shaped steel belt is hinged to the sliding head, and the other end is hinged to the steel shell.

[0016] Preferably, a wire groove is arranged on the sliding head, a wire inlet hole and a wire outlet hole are arranged on the hollow conduit, and the wires of the resistance strain gauges are led out of the device outside in sequence along the wire groove, the wire inlet hole and the wire outlet hole.

[0017] Preferably, after the wires of the six resistance strain gauges are led out of the device outside, the wires are connected to a multi-channel strain acquisition box, and the multi-channel strain acquisition box is connected to a computer terminal.

[0018] On the one hand, a mounting test method based on the magnetic attraction built-in three-dimensional cohesive slip test device is provided, which includes the following steps:

[0019] Processing and manufacturing a steel shell;

[0020] Welding a plurality of pegs on the outer wall of the steel shell;

[0021] Installing a pre-tightening spring at the bottom of the steel shell;

[0022] Installing a sliding head above the pre-tightening spring;

[0023] A hollow conduit is installed in the middle of the sliding head;

[0024] Six pre-tightening arc-shaped steel belts are installed, two in each of the X, Y and Z directions.

[0025] Resistance strain gauges are attached to the six pre-tightening arc-shaped steel belts respectively, and left to stand for more than 24 hours.

[0026] The wires of the resistance strain gauges are led out through the sliding head and the hollow conduit.

[0027] A ring-shaped high-strength magnet is arranged on the inner side of the steel shell and magnetically bonded to the bottom of the steel plate.

[0028] The outer side of the steel shell and the bottom of the steel plate are packaged by a sealing rubber ring and left to stand for more than 24 hours.

[0029] Concrete is poured and cured for 28 days.

[0030] The wires of the resistance strain gauges are connected to a multi-channel strain acquisition box, and the multi-channel strain acquisition box is connected to a computer terminal.

[0031] Load and perform calibration test.

[0032] After completing the calibration test in the X, Y and Z directions, it is used for actual test.

[0033] The technical scheme provided by the embodiment of the present application has at least the following beneficial effects:

[0034] The embodiment of the present application is based on a new internal structure, and six resistance strain gauges attached to the pre-tightening arc-shaped steel belts are symmetrically arranged in the X, Y and Z directions as sensing elements, which can simultaneously realize the bonding and sliding test in the X and Y directions and the vertical peeling test in the Z direction of the steel plate-concrete interface, break through the drawbacks of single test direction, low strain gauge test error and low test dimension of the existing bonding and sliding test, and significantly improve the feasibility of long-term monitoring of the damage of the combined structure interface. In addition, the device installs the sensor based on magnetic adsorption, has the characteristics of convenient installation, high test precision and stable performance, and can be widely applied to the health monitoring and loading experiment of the steel plate-concrete combined structure. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0036] Figure 1 is a 3D perspective view of the magnetic built-in three-dimensional cohesive slip testing device provided by the embodiment of the present application;

[0037] Figure 2 is an isometric side sectional view of the magnetic built-in three-dimensional cohesive slip testing device provided by the embodiment of the present application;

[0038] Figure 3 is a longitudinal sectional view of the magnetic built-in three-dimensional cohesive slip testing device provided by the embodiment of the present application;

[0039] Figure 4 is a transverse sectional view of the magnetic built-in three-dimensional cohesive slip testing device provided by the embodiment of the present application;

[0040] Figure 5 is a 3D side view of the magnetic built-in three-dimensional cohesive slip testing device provided by the embodiment of the present application;

[0041] Figure 6 is a top view of the magnetic built-in three-dimensional cohesive slip testing device provided by the embodiment of the present application after assembly;

[0042] Figure 7 is a side view of the magnetic built-in three-dimensional cohesive slip testing device provided by the embodiment of the present application after assembly;

[0043] Figure 8 is a schematic view of the pre-tightened arc-shaped steel belt provided by the embodiment of the present application with a resistance strain gauge;

[0044] Figure 9 is a structural schematic view of the annular high-strength magnet provided by the embodiment of the present application;

[0045] Figure 10 is a structural schematic view of the sealing rubber ring provided by the embodiment of the present application;

[0046] Figure 11 is a structural schematic view of the steel shell provided by the embodiment of the present application;

[0047] Figure 12 is a structural schematic view of the hollow catheter provided by the embodiment of the present application;

[0048] Figure 13 is a structural schematic view of the top positioning hole of the combined structure steel plate provided by the embodiment of the present application;

[0049] Figure 14 is a structural schematic view of the sliding head and the pre-tightened spring provided by the embodiment of the present application;

[0050] Figure 15 is a structural schematic view of the core testing element provided by the embodiment of the present application;

[0051] Figure 16 is a sectional view of a core test element provided by an embodiment of the present application;

[0052] Figure 17 is a structural schematic diagram of a test system provided by an embodiment of the present application;

[0053] Figure 18 is a schematic diagram of a mounting test process of a magnetic built-in three-dimensional bond slip test device provided by an embodiment of the present application.

[0054] As shown in the drawings, in order to clearly realize the structure of the embodiments of the present application, specific structures and devices are marked in the drawings, but this is only for the need of illustration, and is not intended to limit the present application to the specific structures, devices and environments, and those skilled in the art can adjust or modify these devices and environments according to specific needs, and the adjustments or modifications still fall within the protection scope of the present application. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0056] The embodiments of the present application provide a magnetic built-in three-dimensional bond slip test device, Figures 1-7 respectively, are a 3D perspective view, an isometric sectional view, a longitudinal sectional view, a transverse sectional view, a 3D side view, an assembled top view and an assembled side view of the magnetic built-in three-dimensional bond slip test device.

[0057] The device is used for testing the bond slip and vertical peeling at the interface of a steel plate-concrete composite structure, is installed on the inner side of the steel plate before pouring concrete, and comprises a steel shell 1 and a core test element 2 located in the steel shell 1, wherein the steel shell 1 is magnetically sealed with the bottom of the steel plate.

[0058] The core test element 2 comprises a hollow conduit 21, a sliding head 22, a pre-tightening spring 23 and six arc-shaped steel belt strain gauges 24; the hollow conduit 21 is vertically arranged in the middle of the steel shell 1, the upper end penetrates through a positioning hole in the top of the steel plate, and the lower end can freely slide on the bottom contact surface of the steel shell 1; the sliding head 22 is sleeved outside the hollow conduit 21 and can slide up and down along the hollow conduit 21; the pre-tightening spring 23 is located below the sliding head 22, the upper end is connected with the sliding head 22, and the lower end is in contact with the bottom of the steel shell 1; the pre-tightening spring 23 provides a pre-tightening force to make the sliding head 22 in contact with the top of the steel plate.

[0059] In the embodiment of the present application, the structure of the arc-shaped steel band strain gauge 24 is shown in Figure 8 The arc-shaped steel band strain gauge 24 comprises a pre-tightened arc-shaped steel band 241 and a resistance strain gauge 242 attached to the pre-tightened arc-shaped steel band 241. Six arc-shaped steel band strain gauges 24 are arranged in the X, Y and Z directions respectively, two in each direction, for testing the slip amount in the X and Y directions and the peeling amount in the Z direction between the steel plate and the concrete. One end of the pre-tightened arc-shaped steel band 241 is connected to the sliding head 22, and the other end is connected to the steel shell 1.

[0060] The pre-tightened arc-shaped steel band 241 is pre-tightened from a flat steel band into an arc shape. When the three-dimensional slip between the steel plate and the concrete in the combined structure occurs, the corresponding pre-tightened arc-shaped steel band 241 in the X, Y and Z directions is deformed, which in turn causes the strain value of the resistance strain gauge to change, thereby realizing the testing of the slip amount and the peeling amount.

[0061] As a specific embodiment of the present application, as shown in Figures 9-11 The steel shell 1 is a square shell with an open top. The inner side of the steel shell 1 is bonded to the bottom of the steel plate by using a ring-shaped high-strength magnet 3. The adsorption force of the ring-shaped high-strength magnet 3 is greater than the weight of the device, thereby providing effective bonding. The outer side of the steel shell 1 is packaged with the bottom of the steel plate by using a sealing rubber ring 4 to avoid moisture intrusion before the concrete hardens.

[0062] In order to enhance the reliable bonding between the testing device and the concrete, a plurality of pegs 5 are arranged on the outer side and the bottom of the steel shell 1 to enhance the linkage with the concrete, avoid the separation between the steel shell 1 and the concrete caused by the shrinkage of the concrete, eliminate the gap between them, enhance the integrity between them, ensure the close connection between the testing device and the concrete, keep the slip amount in the slip direction highly consistent, and improve the accuracy of the test.

[0063] Further, as shown in Figures 12-14 A positioning hole 8 is arranged on the steel plate, and a cylindrical through hole is arranged in the middle of the sliding head 22. The hollow conduit 21 passes through the positioning hole 8 and the cylindrical through hole at one time. The diameter of the cylindrical through hole is consistent with the outer wall diameter of the hollow conduit 21, so that the degrees of freedom in the X and Y directions of the two are consistent, and the sliding head 22 is ensured to slide freely in the Z direction. The hollow conduit 21 can slide freely on the contact surface at the bottom of the steel shell 1, thereby realizing the test of the slip in the X and Y directions. At the same time, the hollow conduit 21 and the sliding head 22 remain parallel in the Z direction. When vertical peeling occurs, the sliding head 22 can move vertically along the hollow conduit 21 under the pre-tightening force of the pre-tightening spring 23, thereby realizing the test of the peeling in the Z direction.

[0064] Further, as shown in Figures 15-16As shown, the six resistance strain gauges 242 on the six pre-tightening arc-shaped steel belts 241 are respectively a first X-direction resistance strain gauge, a second X-direction resistance strain gauge, a first Y-direction resistance strain gauge, a second Y-direction resistance strain gauge, a first Z-direction resistance strain gauge and a second Z-direction resistance strain gauge.

[0065] The first X-direction resistance strain gauge and the second X-direction resistance strain gauge are symmetrically arranged, and the measurement results of the two are averaged as the test result of the X-direction slip amount.

[0066] In the embodiment of the application, the first X-direction resistance strain gauge, the second X-direction resistance strain gauge, the first Y-direction resistance strain gauge, the second Y-direction resistance strain gauge, the first Z-direction resistance strain gauge and the second Z-direction resistance strain gauge are respectively attached to the arc-shaped top of the corresponding pre-tightening arc-shaped steel belt 241.

[0067] Further, the sliding head 22 is provided with a wire groove 221, and the hollow conduit 21 is provided with a wire inlet hole 211 and a wire outlet hole 212.

[0068] As shown in the figure, Figure 17 After the wires 243 of the six resistance strain gauges 242 are led out of the device, they are connected to a multi-channel strain acquisition box 6, and the multi-channel strain acquisition box 6 is connected to a computer terminal 7.

[0069] Correspondingly, the embodiment of the application also provides an installation test method based on the magnetic attraction built-in three-dimensional bond slip test device. Figure 18 As shown in the figure, the method comprises the following steps:

[0070] Processing and manufacturing a steel shell;

[0071] Welding a plurality of studs on the outer wall of the steel shell;

[0072] Installing a pre-tightening spring at the bottom of the steel shell;

[0073] Install the sliding head above the pre-tightening spring;

[0074] Install the hollow conduit in the middle of the sliding head;

[0075] Install six pre-tightening arc-shaped steel belts, two in each of the X, Y and Z directions;

[0076] Paste resistance strain gauges on the six pre-tightening arc-shaped steel belts respectively, and stand for more than 24 hours;

[0077] Lead the wires of the resistance strain gauges out through the sliding head and the hollow conduit;

[0078] Set annular high-strength magnets on the inner side of the steel shell, and bond with the bottom of the steel plate through magnetic attraction;

[0079] Seal the outer side of the steel shell and the bottom of the steel plate with a sealing rubber ring, and stand for more than 24 hours;

[0080] Pour concrete and maintain for 28 days;

[0081] Connect the wires of the resistance strain gauges with a multi-channel strain acquisition box, and connect the multi-channel strain acquisition box with a computer terminal;

[0082] Load and perform calibration test;

[0083] After completing the calibration test in the X, Y and Z directions, use for actual test.

[0084] The embodiment of the application is based on a new internal structure, and six resistance strain gauges attached to pre-tightening arc-shaped steel belts are symmetrically arranged in the X, Y and Z directions as sensing elements, which can simultaneously realize the bonding and sliding test in the X and Y directions and the vertical peeling test in the Z direction of the steel plate-concrete interface, break through the defects of single test direction, low strain test error and test dimension of the existing bonding and sliding test, and significantly improve the feasibility of long-term monitoring of the damage of the combined structure interface.

[0085] In addition, the device is based on the form of magnetic attraction for installing sensors, has the advantages of convenient installation, high test precision, stable performance and the like, and can be widely applied to the health monitoring and loading experiment of the steel plate-concrete combined structure.

[0086] It has to be understood that the terms "including", "containing", or any other similar term are intended to be inclusive in a manner similar to the term "comprising", such that a process, method, article, or apparatus that includes a list of elements is not necessarily limited to those elements but can include other elements not expressly listed, or can include elements inherent in such process, method, article, or apparatus. An element proceeded by "comprises a", "has", "has a", "includes", or "includes a", does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0087] Reference throughout this specification to "one embodiment", "an embodiment", "exemplary embodiment", "some embodiments", and so on means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

[0088] In general, the terminology or nomenclature used herein is understood in at least part from the context in which it is used. For example, the terminology "one or more" as used herein can be used to describe any feature, structure, or characteristic in the singular or can be used to describe combinations of features, structures, or characteristics in the plural, depending at least in part on the context in which the terminology is used. Additionally, the terminology "based on" is understood as not necessarily being confined to factors that are strictly technological in nature, but alternatively, at least in part, can rest on design choices that are at least in part outside of strictly technological considerations.

[0089] It is to be understood that the terms "on", "over", and "above" in the present disclosure are to be interpreted in the broadest possible way, such that "on" not only means "directly on" but also includes the meaning of "on" with intervening features or layers therebetween, and "over" or "above" not only means "over" or "above" but also can include the meaning of "over" or "above" with no intervening features or layers therebetween.

[0090] Furthermore, spatially relative terms, such as "beneath", "below", "lower", "above", "upper", and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. The devices can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein can likewise be interpreted accordingly.

[0091] The present application encompasses any alternatives, modifications, equivalent methods and solutions made to the spirit and scope of the present application. In order to make the public have a thorough understanding of the present application, specific details are described in the following preferred embodiments of the present application, and the present application can be fully understood without the description of these details by those skilled in the art. In addition, in order to avoid unnecessary confusion to the essence of the present application, well-known methods, processes, procedures, elements and circuits, etc. are not described in detail.

[0092] Those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment methods can be completed by programs instructing the relevant hardware, and the programs can be stored in computer-readable storage media, such as ROM / RAM, magnetic discs, optical discs, etc.

[0093] The above description is only the preferred embodiment of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A magnetic built-in type three-dimensional cohesive slip test device, characterized by, The device is used for testing the bond slip and vertical debonding at the interface of steel plate-concrete composite structure, and is installed in the inside of the steel plate before pouring concrete, comprising a steel shell and a core test element in the steel shell, and the steel shell is magnetically sealed with the bottom of the steel plate; The core test element comprises a hollow conduit, a sliding head, a pre-tightening spring and six arc-shaped steel band strain gauges; the hollow conduit is vertically arranged in the middle of the steel shell, the upper end penetrates through the positioning hole in the top of the steel plate, and the lower end can freely slide on the bottom contact surface of the steel shell; the sliding head is sleeved on the outside of the hollow conduit and can slide up and down along the hollow conduit; the pre-tightening spring is arranged below the sliding head, the upper end is connected with the sliding head, and the lower end is in contact with the bottom of the steel shell, and the pre-tightening spring provides a pre-tightening force to make the sliding head in contact with the top of the steel plate; The arc-shaped steel band strain gauge comprises a pre-tightening arc-shaped steel band and a resistance strain gauge attached to the pre-tightening arc-shaped steel band, and six arc-shaped steel band strain gauges are arranged in two in each of X, Y and Z directions, respectively, for testing the slip amount in the X and Y directions and the debonding amount in the Z direction between the steel plate and the concrete, one end of the pre-tightening arc-shaped steel band is connected with the sliding head, and the other end is connected with the steel shell.

2. The magnetic built-in type three-dimensional cohesive slip test device according to claim 1, wherein The steel shell is a square shell with an open top, the inside of the steel shell is bonded with the bottom of the steel plate by using a ring-shaped high-strength magnet, and the adsorption force of the ring-shaped high-strength magnet is greater than the gravity of the device, thereby providing effective bonding; the outside of the steel shell is packaged with the bottom of the steel plate by using a sealing rubber ring to avoid moisture intrusion before the concrete hardens.

3. The magnetic built-in type three-dimensional cohesive slip test device according to claim 2, wherein Multiple pegs are arranged on the outside and bottom of the steel shell to enhance the connection with the concrete, avoid separation between the concrete and the steel shell due to concrete shrinkage, and enhance the integrity between the two.

4. The magnetic built-in type three-dimensional cohesive slip test device according to claim 3, wherein A cylindrical through hole is arranged in the middle of the sliding head, the diameter of the cylindrical through hole is consistent with the diameter of the outer wall of the hollow conduit, so that the degrees of freedom in the X and Y directions of the two are consistent, and the sliding head is ensured to freely slide in the Z direction.

5. The magnetic built-in type three-dimensional cohesive slip test device according to claim 4, wherein The six resistance strain gauges on the six pre-tightening arc-shaped steel bands are respectively a first X-direction resistance strain gauge, a second X-direction resistance strain gauge, a first Y-direction resistance strain gauge, a second Y-direction resistance strain gauge, a first Z-direction resistance strain gauge and a second Z-direction resistance strain gauge; The first X-direction resistance strain gauge and the second X-direction resistance strain gauge are symmetrically arranged, the measurement results of the two are averaged, and the average value is taken as the test result of the X-direction slip amount; the first Y-direction resistance strain gauge and the second Y-direction resistance strain gauge are symmetrically arranged, the measurement results of the two are averaged, and the average value is taken as the test result of the Y-direction slip amount; the first Z-direction resistance strain gauge and the second Z-direction resistance strain gauge are symmetrically arranged, the measurement results of the two are averaged, and the average value is taken as the test result of the Z-direction debonding amount.

6. The magnetic built-in type three-dimensional cohesive slip test device according to claim 5, wherein The first X-direction resistive strain gauge, the second X-direction resistive strain gauge, the first Y-direction resistive strain gauge, the second Y-direction resistive strain gauge, the first Z-direction resistive strain gauge and the second Z-direction resistive strain gauge are respectively attached to the arc-shaped top of the corresponding pre-tightening arc-shaped steel belt, one end of the pre-tightening arc-shaped steel belt is hinged to the sliding head, and the other end is hinged to the steel shell.

7. The magnetic built-in type three-dimensional cohesive slip test device according to claim 6, wherein The sliding head is provided with a wire slot, the hollow conduit is provided with a wire inlet hole and a wire outlet hole, and the wires of the resistive strain gauges are led out of the device outside in sequence along the wire slot, the wire inlet hole and the wire outlet hole.

8. The magnetic built-in type three-dimensional cohesive slip test device according to claim 7, wherein The wires of the six resistive strain gauges are connected to a multi-channel strain acquisition box after being led out of the device outside, and the multi-channel strain acquisition box is connected to a computer terminal.

9. A method of installing a test based on the magnetic built-in three-dimensional cohesive slip test device according to claim 8, characterized by, The method comprises the following steps: processing and manufacturing a steel shell; welding a plurality of pegs on the outer wall of the steel shell; installing a pre-tightening spring at the bottom of the steel shell; installing a sliding head above the pre-tightening spring; installing a hollow conduit in the middle of the sliding head; installing six pre-tightening arc-shaped steel belts, two in each of the X, Y and Z directions; attaching resistive strain gauges to the six pre-tightening arc-shaped steel belts respectively and standing for more than 24 hours; leading the wires of the resistive strain gauges out through the sliding head and the hollow conduit; arranging annular high-strength magnets on the inner side of the steel shell and magnetically bonding them to the bottom of the steel plate; sealing the outer side of the steel shell and the bottom of the steel plate with a sealing rubber ring and standing for more than 24 hours; pouring concrete and curing for 28 days; connecting the wires of the resistive strain gauges to a multi-channel strain acquisition box, and connecting the multi-channel strain acquisition box to a computer terminal; loading and performing calibration test; after completing the calibration test in the X, Y and Z directions, the method is used for actual test.

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