Evaluation device and method for testing early bonding performance of tunnel shotcrete

Abstract

The application provides an evaluation device and method for testing early bonding performance of tunnel sprayed concrete, and relates to the technical field of concrete testing. The evaluation device for testing early bonding performance of tunnel sprayed concrete simulates the tunnel inner wall structure through an arched wall surface, fixes the test mold at a preset position of the arched wall surface through a mold fixing mechanism to perform the test, drives the grinding ball assembly to insert into the test mold and drives the mold clamping jaw to clamp the test mold through a linear telescopic mechanism during the test, measures the pulling force value and displacement amount when the telescopic mechanism retracts through a pulling force detector, and finally calculates the adhesion energy between the coarse aggregate and the paste in the concrete sample and the adhesion energy between the paste through the measured pulling force value and displacement amount. Not only the labor and material consumption are reduced, the operation and test are facilitated, but also the problem that the existing test device and evaluation method are single is made up, the theoretical guidance for reducing the rebound of sprayed concrete is provided, and the construction quality is ensured.

Description

Technical Field

[0001] This application relates to the field of concrete testing technology, and more specifically, to an evaluation device and method for testing the early bond performance of tunnel shotcrete. Background Technology

[0002] With the rapid development of the social economy, railway construction has made significant progress, and the scale of tunnel engineering has continued to expand. Shotcrete is widely used in tunnel engineering, serving functions such as geological support, waterproofing, and maintaining the overall stability of the tunnel during construction and operation. This ensures the structural safety and operational reliability of the tunnel, while also improving its service life and sustainability. However, the rebound loss caused by the impact of shotcrete against the tunnel wall during construction has long been a problem. An excessively high rebound rate not only increases material and labor costs during construction, but also, due to the large proportion of coarse aggregate in the rebound material, it implicitly increases the amount of cementitious materials and sand ratio in the shotcrete, increasing the risk of shrinkage cracking and hindering the improvement of strength and durability. Therefore, reducing the rebound rate has become the primary goal of shotcrete development.

[0003] Studies have found that excessive rebound is largely due to insufficient interfacial adhesion between coarse aggregate and the paste, as well as insufficient cohesion within the paste. Adhesion and cohesion together determine the bonding performance of shotcrete, indicating that good bonding performance is beneficial for improving the rebound of shotcrete. Currently, the rebound rate is mainly measured manually on-site by weighing and calculating the amount of shotcrete used and the weight of the rebound material. This process is cumbersome and consumes a lot of manpower and resources. Furthermore, existing technologies do not disclose devices or methods for evaluating concrete bonding performance by measuring the interfacial adhesion between coarse aggregate and the paste, as well as the cohesion within the paste. Summary of the Invention

[0004] The purpose of this application is to provide an evaluation device and method for testing the early bond performance of shotcrete in tunnels, in order to overcome the shortcomings of the prior art.

[0005] To achieve the above objectives, in a first aspect, this application provides an evaluation device for testing the early bond performance of shotcrete in tunnels, comprising: The test chamber has arched walls that simulate a tunnel inside; The mold fixing module includes a mold fixing mechanism and a test mold. The mold fixing mechanism is disposed on the arched wall and is used to fix the test mold at a preset position on the arched wall. The test mold is used to fill the concrete sample to be tested. The testing module includes a linear telescopic mechanism and a mold gripper, a grinding ball assembly, a tension detector, and a displacement detector mounted on the linear telescopic mechanism. The linear telescopic mechanism is located on the side of the test chamber opposite to the arched wall. The linear telescopic mechanism drives the grinding ball assembly to insert into the test mold and drives the mold gripper to hold the test mold. The tension detector detects the tension value experienced by the telescopic mechanism during retraction, and the displacement detector measures the displacement of the telescopic mechanism during retraction. The control module is electrically connected to the tensile detector and the displacement detector, and is used to calculate the adhesion energy of the interface between coarse aggregate and paste in the concrete sample and the adhesion energy of the interface between pastes based on the tensile value and the displacement.

[0006] As a further improvement to the above technical solution: In conjunction with the first aspect, in one possible implementation, the mold fixing mechanism includes: A slide is laid vertically on the arched wall, and the test mold is movably mounted on the slide. A first traction component is disposed at the upper end of the slide along the vertical direction and connected to the test mold, for traction of the test mold to move upward along the slide; A second traction component, disposed at the lower end of the slide along the vertical direction and connected to the test mold, is used to traction the test mold to move downward along the slide; and Multiple braking components are arranged at intervals along the vertical direction on the arched wall surface, and the braking components are used to stop the test mold at a preset position.

[0007] In conjunction with the first aspect, in one possible implementation, both the first traction assembly and the second traction assembly include: The traction controller is electrically connected to the control module; and The traction rope is connected at one end to the traction controller and at the other end to the test mold. The traction controller is used to drive the traction rope to retract and release the rope.

[0008] In conjunction with the first aspect, in one possible implementation, the braking assembly includes: A catapult is mounted on the arched wall and electrically connected to the control module; Braking divider plate, disposed on the catapult; and A position sensor is mounted on the catapult and electrically connected to the control module; When the test mold moves to a preset position and triggers the position sensor, the ejector drives the brake dividing plate to extend toward the test mold to restrict the movement of the test mold.

[0009] In conjunction with the first aspect, in one possible implementation, the test mold includes: The first mold body is movably mounted on the slide rail; and The second mold body is detachably disposed on the side of the first mold body away from the slide.

[0010] In conjunction with the first aspect, in one possible implementation, the detection module further includes an angle adjustment mechanism electrically connected to the control module. The angle adjustment mechanism is disposed on the side of the test chamber opposite to the arched wall. The linear telescopic mechanism is disposed on the angle adjustment mechanism, and the angle adjustment mechanism is used to adjust the angle between the linear telescopic mechanism and the horizontal plane.

[0011] In conjunction with the first aspect, in one possible implementation, the evaluation device for testing the early bonding performance of tunnel shotcrete further includes a temperature and humidity control module disposed on the test chamber, the temperature and humidity control module being electrically connected to the control module, and the temperature and humidity control module being used to control the temperature and humidity inside the test chamber.

[0012] In conjunction with the first aspect, in one possible implementation, the grinding ball assembly includes: A fixed rod is connected to the linear telescopic mechanism; and The grinding ball body is located at the end of the fixed rod away from the linear telescopic mechanism; The outer peripheral surface of the grinding ball body is a rough surface.

[0013] In conjunction with the first aspect, in one possible implementation, the test chamber is provided with an openable door, and the door is provided with a handle.

[0014] To achieve the above objectives, in a second aspect, this application also provides an evaluation method for testing the early bond performance of shotcrete in tunnels, utilizing the aforementioned evaluation device for testing the early bond performance of shotcrete in tunnels. The evaluation method for testing the early bond performance of shotcrete in tunnels includes: Prepare concrete samples for testing; The prepared concrete sample is filled into the test mold and the surface is smoothed. The test mold containing the concrete sample is fixed to a preset position on the arched wall using the mold fixing module. The grinding ball assembly is inserted into the test mold by driving the linear telescopic mechanism. After waiting for a preset time, the grinding ball assembly is retracted by driving the linear telescopic mechanism. The tension value F1 and displacement X1 of the linear telescopic mechanism are recorded during the retraction process, and the first curve of tension F1-displacement X1 is plotted. Remove the grinding ball assembly, drive the mold clamp to hold the test mold through the linear telescopic mechanism, and then drive the mold clamp to retract through the linear telescopic mechanism. Record the tension value F2 and displacement X2 of the linear telescopic mechanism during the retraction process, and plot the second curve of tension F2-displacement X2. The adhesion energy E between the coarse aggregate and the paste in the concrete sample was calculated based on the first curve and the second curve, respectively. a and the adhesion energy E at the interface between slurries c .

[0015] Compared to existing technologies, the beneficial effects of this application are: This application provides an evaluation device and method for testing the early bond performance of shotcrete in tunnels. The evaluation device simulates the actual tunnel wall structure using an arched wall. A mold fixing mechanism secures the test mold at a preset position on the arched wall. During testing, a linear telescopic mechanism drives a grinding ball assembly to insert into the test mold and a mold clamp to hold the mold. A tension detector measures the tension and displacement when the telescopic mechanism retracts. Finally, based on the measured tension and displacement, the adhesion energy between the coarse aggregate and the paste in the concrete sample, as well as the adhesion energy between the paste interfaces, are calculated. Therefore, the evaluation device for testing the early bond performance of shotcrete in tunnels provided by this application eliminates the need for pre-testing spraying, using bond performance instead of rebound rate. This not only reduces manpower and material costs and facilitates operation and testing but also overcomes the limitations of existing testing devices and evaluation methods. Furthermore, based on the bond performance indicators of concrete, the mix proportions of shotcrete can be further optimized, providing theoretical guidance for reducing shotcrete rebound and ensuring construction quality.

[0016] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate this application and form part of the specification. They are used together with the following detailed description to explain this application. It should be understood that the following drawings only show some embodiments of this application and should not be considered as limiting the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort. In the drawings: Figure 1 This illustration shows a structural schematic diagram of an evaluation device for testing the early bond performance of shotcrete in tunnels, provided in an embodiment of this application. Figure 2 The diagram shows a schematic of the structure of the evaluation device for testing the early bonding performance of shotcrete in tunnels provided in this application, in an active state (a) and a fixed state (b) in which the test mold is fixed in a preset position. Figure 3 It shows Figure 1 A schematic diagram of the detection module in the evaluation device for testing the early bond performance of shotcrete in tunnels. Figure 4 This illustration shows a schematic diagram of the test state when the test mold is located at a first preset position on the arch wall in the evaluation device for testing the early bonding performance of shotcrete in tunnels provided in this application embodiment. Figure 5 This illustration shows a schematic diagram of the test state when the test mold is located at the second preset position on the arch wall in the evaluation device for testing the early bonding performance of shotcrete in tunnels provided in this application embodiment; Figure 6 The illustration shows two test states of the evaluation device for testing the early bonding performance of shotcrete in tunnels provided in this application: the grinding ball assembly is inserted into the test mold (a) and the mold clamps hold the test mold (b). Figure 7 This application illustrates a tension F-displacement X curve of an evaluation device for testing the early bond performance of tunnel shotcrete provided in an embodiment of this application.

[0018] Explanation of reference numerals in the attached figures: 100. Test chamber; 101. Arched wall; 110. Chamber door; 111. Handle; 200. Mold fixing module; 210. Mold fixing mechanism; 211. Slide rail; 212a. First traction assembly; 212b. Second traction assembly; 2120. Traction controller; 2121. Traction rope; 213. Braking assembly; 2130. Ejector; 2131. Braking divider plate; 2132. Position sensor; 220. Test mold; 221. First mold body; 222. Second mold body; 223. Roller; 300. Detection module; 310. Linear telescopic mechanism; 320. Mold gripper; 330. Grinding ball assembly; 331. Fixing rod; 332. Grinding ball body; 340. Tension detector; 350. Displacement detector; 360. Angle adjustment mechanism; 400. Control module; 500. Temperature and humidity control module; 510. Humidity controller; 520. Temperature controller; 600. Slurry collection box. Detailed Implementation

[0019] The specific implementation methods of the embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific implementation methods described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0021] In the embodiments of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0023] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0024] The present application will now be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0025] Example Please see Figure 1 This embodiment provides an evaluation device for testing the early bond performance of shotcrete in tunnels. It can be used to measure the early bond performance of concrete to provide technical guidance for actual operations (such as shotcrete construction in tunnels).

[0026] The evaluation device for testing the early bond performance of shotcrete in tunnels includes a test chamber 100, a mold fixing module 200, a detection module 300, and a control module 400. The test chamber 100 is a relatively enclosed space, and the interior of the test chamber 100 is equipped with an arched wall 101 simulating a tunnel.

[0027] Furthermore, the test chamber 100 is also equipped with an openable door 110, which has a handle 111. The handle 111 is convenient for operators to grip, thereby facilitating the opening and closing of the door 110.

[0028] The mold fixing module 200 includes a mold fixing mechanism 210 and a test mold 220. The mold fixing mechanism 210 is disposed on the arched wall 101 and is used to fix the test mold 220 at a preset position on the arched wall 101. The test mold 220 is used to fill the concrete sample to be tested. Therefore, it can be understood that the preset position on the arched wall 101 is set according to the testing requirements. This preset position can be any position on the arched wall 101 in the vertical direction, thereby improving the flexibility of the test and obtaining test data from different positions on the arched wall 101.

[0029] Please see Figure 1 , Figure 2 and Figure 3 The testing module 300 includes a linear telescopic mechanism 310, a mold gripper 320, a grinding ball assembly 330, a tension detector 340, and a displacement detector 350. The linear telescopic mechanism 310 is located on the side of the test chamber 100 opposite to the arched wall 101. The mold gripper 320, grinding ball assembly 330, tension detector 340, and displacement detector 350 are all mounted on the linear telescopic mechanism 310. The linear telescopic mechanism 310 drives the grinding ball assembly 330 to insert into the test mold 220 and drives the mold gripper 320 to hold the test mold 220. The tension detector 340 detects the tension value experienced by the telescopic mechanism during retraction, and the displacement detector 350 measures the displacement amount during retraction.

[0030] The control module 400 is electrically connected to the tensile detector 340 and the displacement detector 350, and is used to calculate the adhesion energy of the interface between coarse aggregate and paste in the concrete sample and the adhesion energy of the interface between pastes based on the tensile force value and the displacement.

[0031] Furthermore, the mold fixing mechanism 210 includes a slide 211, a first traction component 212a, a second traction component 212b, and multiple braking components 213. The slide 211 is laid vertically on the arched wall 101, and the test mold 220 is movably disposed on the slide 211; wherein, the test mold 220 and the slide can be in a sliding engagement or a rolling engagement.

[0032] The first traction component 212a is vertically disposed at the upper end of the slide 211 and connected to the test mold 220, for pulling the test mold 220 upward along the slide 211. The second traction component 212b is vertically disposed at the lower end of the slide 211 and connected to the test mold 220, for pulling the test mold 220 downward along the slide 211. Thus, through the cooperation between the first traction component 212a and the second traction component 212b, the test mold 220 can be driven to move up and down along the slide 211, thereby driving the test mold 220 to move to a preset position on the arched wall 101 for testing.

[0033] Multiple braking components 213 are arranged vertically at intervals on the arched wall 101. The braking components 213 are used to stop the test mold 220 at a preset position. Optionally, the multiple braking components 213 are evenly spaced on the arched wall 101.

[0034] In this embodiment, the first traction component 212a and the second traction component 212b have identical structures. Both the first traction component 212a and the second traction component 212b include a traction controller 2120 and a traction rope 2121. The traction controller 2120 can be disposed on the side wall of the test chamber 100 and electrically connected to the control module 400. One end of the traction rope 2121 is connected to the traction controller 2120, and the other end of the traction rope 2121 is connected to the test mold 220. The control module 400 can control the operation of the traction controller 2120 according to the requirements of the test position. The traction controller 2120 drives the traction rope 2121 to retract and release the rope.

[0035] Please refer to the diagram as well. Figure 4 and Figure 5 Understandably, when the traction controller 2120 in the first traction assembly 212a retracts the rope, the traction controller 2120 in the second traction assembly 212b simultaneously releases the rope, at which point the test mold 220 moves upward along the slide rail 211; when the traction controller 2120 in the second traction assembly 212b retracts the rope, the traction controller 2120 in the first traction assembly 212a simultaneously releases the rope, at which point the test mold 220 moves downward along the slide rail 211. This achieves the movement of the test mold 220 along the slide rail.

[0036] Optionally, the traction controller 2120 is similar to a winch mechanism, driven by a motor to rotate the winding wheel, thereby enabling the winding and unwinding of the traction rope 2121.

[0037] Please see Figure 1 and Figure 2The aforementioned braking assembly 213 includes a catapult 2130, a braking dividing plate 2131, and a position sensor 2132. The catapult 2130 is mounted on the arched wall 101 and electrically connected to the control module 400. The braking dividing plate 2131 is mounted on the catapult 2130. The position sensor 2132 is mounted on the catapult 2130 and electrically connected to the control module 400. When the test mold 220 moves to a preset position and triggers the corresponding position sensor 2132, the catapult 2130 drives the braking dividing plate 2131 to extend towards the test mold 220. Specifically, the braking dividing plate 2131 is inserted into the slide rail 211 to restrict the movement of the test mold 220 on the slide rail 211, thereby stopping the test mold 220 at the preset test position. When the test is completed and the test mold 220 needs to be moved to the next preset position, the ejector 2130 drives the brake dividing plate 2131 to reset, thereby releasing the restriction on the movement of the test mold 220.

[0038] Optionally, the position sensor 2132 may be selected as any one of a pressure sensor, limit switch, proximity sensor, photoelectric sensor or metal sensor.

[0039] Please see Figure 1 and Figure 2 In this embodiment, the test mold 220 includes a first mold body 221 and a second mold body 222. The first mold body 221 is movably disposed on the slide rail 211; the second mold body 222 is detachably disposed on the side of the first mold body 221 away from the slide rail 211. The first mold body 221 and the second mold body 222 are interconnected to form a mold cavity for filling concrete samples.

[0040] Please refer to the following: Figure 3 and Figure 6 Understandably, when the linear telescopic mechanism 310 drives the grinding ball assembly 330 to insert into the test mold 220, the grinding ball assembly 330 is inserted into the concrete sample in the mold cavity from the side of the second mold body 222 away from the first mold body 221. Then, the linear telescopic mechanism 310 drives it to retract and pull out the grinding ball assembly 330, completing the test. During this process, the second mold body 222 and the first mold body 221 remain connected. When the linear telescopic mechanism 310 drives the mold gripper 320 to clamp the test mold 220, the mold gripper 320 clamps the outer peripheral surface of the second mold body 222. Then, the connection between the second mold body 222 and the first mold body 221 is released, and then the linear telescopic mechanism 310 drives it to retract until the second mold body 222 and the first mold body 221 separate, completing the test.

[0041] Optionally, the first mold body 221 and the second mold body 222 are connected by bolts or snap-fit.

[0042] Optionally, the first mold body 221 is provided with rollers 223 that roll in cooperation with the slide 211.

[0043] Optionally, the linear telescopic mechanism 310 can be selected as a hydraulic cylinder, pneumatic cylinder, electric push rod, electric cylinder or lead screw motor.

[0044] Optionally, the mold gripper 320 can be a pneumatic gripper, driven by a cylinder to grip the second mold body 222.

[0045] The grinding ball assembly 330 includes a fixed rod 331 and a grinding ball body 332. The fixed rod 331 is connected to the linear telescopic mechanism 310. The grinding ball body 332 is located at the end of the fixed rod 331 away from the linear telescopic mechanism 310. The outer circumferential surface of the grinding ball body 332 is roughened to simulate coarse aggregates of the same size and roughness in a concrete sample, thereby improving the accuracy of the test.

[0046] Please see Figure 1 , Figure 3 , Figure 4 and Figure 5 Furthermore, the detection module 300 also includes an angle adjustment mechanism 360 electrically connected to the control module 400. The angle adjustment mechanism 360 is located on the side of the test chamber 100 opposite to the arched wall 101. A linear telescopic mechanism 310 is located on the angle adjustment mechanism 360. The angle adjustment mechanism 360 is used to adjust the angle between the linear telescopic mechanism 310 and the horizontal plane to adapt to the test mold 220 fixed at different positions on the arched wall 101.

[0047] In some embodiments, the angle adjustment mechanism 360 may be optionally driven by a motor to rotate a gear, which then meshes with a sector gear provided on the linear telescopic mechanism 310. The motor is electrically connected to the control module 400, thereby enabling the motor to operate according to control information issued by the control module 400, so that the rotation angle of the linear telescopic mechanism 310 matches the test mold 220 at the current position.

[0048] Optionally, the motor can be selected as a stepper motor or a servo motor to further improve control precision.

[0049] In other embodiments, the angle adjustment mechanism 360 may be configured as a rotatable adjustment knob. Turning the adjustment knob adjusts the rotation angle of the linear telescopic mechanism 310 to match the current position of the test mold 220.

[0050] Please see Figure 1In this example, the evaluation device for testing the early bonding performance of tunnel shotcrete also includes a temperature and humidity control module 500 installed on the test chamber 100. The temperature and humidity control module 500 is electrically connected to the control module 400. The temperature and humidity control module 500 is used to control the temperature and humidity inside the test chamber 100, thereby simulating real working conditions. It can also be understood that by controlling the temperature and humidity inside the test chamber 100 through the temperature and humidity control module 500, different environmental conditions can be simulated, and test data under different environmental conditions can be obtained.

[0051] The aforementioned temperature and humidity control module 500 includes a humidity controller 510 and a temperature controller 520, both electrically connected to the control module 400. The humidity controller 510 has a humidifier and a humidification head, with the humidifier connected to the humidification head. Water vapor is generated by the humidifier and then passes through the humidification head to humidify the test chamber 100. Furthermore, the humidity controller 510 incorporates a humidity sensor. When the humidity reaches a preset value, the control module 400 controls the humidifier to stop humidifying, thereby achieving humidity control within the test chamber 100.

[0052] The temperature controller 520 includes a heating element and a fan. The fan exchanges heat with the heating element through the airflow within the circulating test chamber 100. Understandably, the temperature controller 520 also includes a temperature sensor, which monitors the temperature of the test chamber 100 in real time. When the temperature within the test chamber 100 reaches the preset requirement, the control module 400 controls the heating element and fan to stop working, thereby achieving the purpose of temperature regulation within the test chamber 100.

[0053] Optionally, the heating element may be a heating plate, an electric heating wire, or an electric heating lamp, etc.

[0054] Please see Figure 1 , Figure 4 and Figure 5 In some embodiments, the test chamber 100 is further provided with a slurry collection box 600 at the bottom, which is used to collect fallen concrete and waste material in the test mold 220.

[0055] Please see Figures 1 to 7 Furthermore, this embodiment also provides an evaluation method for testing the early bond performance of shotcrete in tunnels, utilizing the aforementioned evaluation device for testing the early bond performance of shotcrete in tunnels. The evaluation method for testing the early bond performance of shotcrete in tunnels includes the following steps: S100: Prepare concrete samples for testing.

[0056] S200: The prepared concrete sample is filled into the test mold 220 and the surface is smoothed. During the filling operation, the temperature and humidity inside the test chamber 100 can be pre-controlled by the temperature and humidity control module 500 so that the temperature and humidity inside the test chamber 100 reach the preset values ​​before the test.

[0057] S300: The test mold 220 containing the concrete sample is fixed to the preset position on the arched wall 101 by the mold fixing module 200.

[0058] S400: The grinding ball assembly 330 is inserted into the test mold 220 via the linear telescopic mechanism 310. After a preset time, the grinding ball assembly 330 is retracted via the linear telescopic mechanism 310. The tension value F1 and displacement X1 of the linear telescopic mechanism 310 during the retraction process are recorded, and the first curve of tension F1-displacement X1 is plotted. Please refer to... Figure 6 As shown in (a), during this process, the mold gripper 320 does not participate in the work, that is, the mold gripper 320 does not hold the test mold 220. The preset waiting time is set according to the on-site conditions, for example, the preset time can be set to 7s~20s, preferably 10s.

[0059] S500: Remove the grinding ball assembly 330, and use the linear telescopic mechanism 310 to drive the mold gripper 320 to clamp the test mold 220 (see [link]). Figure 6 As shown in (b), the mold gripper 320 is then driven to retract by the linear telescopic mechanism 310. The tension value F2 and displacement X2 of the linear telescopic mechanism 310 during the retraction process are recorded, and the second curve of tension F2-displacement X2 is plotted.

[0060] S600: Calculate the adhesion energy E between the coarse aggregate and paste interface in the corresponding concrete sample based on the first and second curves. a and the adhesion energy E at the interface between slurries c .

[0061] Specifically, in step S600 above, the adhesion energy Ea of the interface between coarse aggregate and paste and the adhesion energy E of the interface between pastes in the corresponding concrete sample are calculated by integrating the first curve and the second curve respectively. c Among them, E a and E c The calculation formulas are shown in (1) and (2): (1) (2) The above E a J;E represents the adhesion energy between coarse aggregate and slurry. cF1(X) is the adhesion energy between the slurry, in J; F2(X) is the real-time tensile force curve function between the coarse aggregate and the slurry; X1 and X2 are the intersection points of the F1(X) and F2(X) curves with the horizontal displacement axis, respectively, in mm.

[0062] Finally, based on the actual rebound effect of shotcrete with the same mix proportion, a bond performance-rebound rate curve was plotted to further optimize the mix proportion design of shotcrete and reduce rebound.

[0063] In this embodiment, the control module 400 can be selected as a PLC controller, industrial computer, or industrial control computer, etc. It should be understood that the above is only an example and is not intended to limit the scope of protection of this application.

[0064] Compared to existing technologies, the evaluation device and method for testing the early bond performance of shotcrete in tunnels provided in this embodiment simulate a real arched tunnel structure using an arched wall 101 within a test chamber 100. A mold fixing mechanism 210 fixes the test mold 220 at a preset position on the arched wall 101 for testing. During testing, a linear telescopic mechanism 310 drives the grinding ball assembly 330 to insert into the test mold 220 and drives the mold clamps 320 to hold the test mold 220. A tensile detector 340 measures the tensile force and displacement when the telescopic mechanism retracts. Finally, the adhesion energy E between the coarse aggregate and the paste interface in the concrete sample is calculated based on the measured tensile force and displacement. a and the adhesion energy E at the interface between slurries c Therefore, the evaluation device for testing the early bond performance of shotcrete in tunnels provided in this application eliminates the need for pre-testing spraying, using bond performance instead of rebound rate as the indicator. This not only reduces manpower and material costs and facilitates operation and testing, but also overcomes the limitations of existing testing devices and evaluation methods. Furthermore, based on the bond performance indicators of concrete, the mix proportions of shotcrete can be further optimized, providing theoretical guidance for reducing shotcrete rebound and ensuring construction quality.

[0065] Furthermore, the temperature and humidity inside the test chamber 100 are regulated by the temperature and humidity control module 400 to reduce test errors caused by environmental influences.

[0066] The optional embodiments of the present application have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present application are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present application, various simple modifications can be made to the technical solutions of the embodiments of the present application, and these simple modifications all fall within the protection scope of the embodiments of the present application.

[0067] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, the embodiments of this application will not describe the various possible combinations separately.

[0068] Furthermore, various different implementation methods of the embodiments of this application can be combined arbitrarily, as long as they do not violate the spirit of the embodiments of this application, they should also be regarded as the content disclosed in the embodiments of this application.

Claims

1. An evaluation device for testing the early bond performance of shotcrete in tunnels, characterized in that, include: The test chamber (100) has an arched wall (101) inside that simulates a tunnel. The mold fixing module (200) includes a mold fixing mechanism (210) and a test mold (220). The mold fixing mechanism (210) is disposed on the arched wall (101) and is used to fix the test mold (220) at a preset position on the arched wall (101), fill the prepared concrete sample into the test mold (220) and smooth the surface. The detection module (300) includes a linear telescopic mechanism (310) and a mold gripper (320), a grinding ball assembly (330), a tension detector (340), and a displacement detector (350) disposed on the linear telescopic mechanism (310). The linear telescopic mechanism (310) is disposed on the side of the test chamber (100) opposite to the arched wall (101). The linear telescopic mechanism (310) is used to drive the grinding ball assembly (330) to insert into the test mold (220) and to drive the mold gripper (320) to clamp the test mold (220). The tension detector (340) is used to detect the tension value of the telescopic mechanism during the retraction process. The displacement detector (350) is used to measure the displacement of the telescopic mechanism during the retraction process. The control module (400) is electrically connected to the tensile detector (340) and the displacement detector (350) and is used to calculate the adhesion energy of the interface between coarse aggregate and paste and the adhesion energy of the interface between pastes in the concrete sample based on the tensile value and the displacement. The mold fixing mechanism (210) includes: The slide (211) is laid vertically on the arched wall (101), and the test mold (220) is movably mounted on the slide (211); The first traction component (212a) is disposed at the upper end of the slide (211) along the vertical direction and connected to the test mold (220), for traction of the test mold (220) to move upward along the slide (211); The second traction component (212b) is disposed at the lower end of the slide (211) along the vertical direction and connected to the test mold (220), for traction of the test mold (220) to move downward along the slide (211); Multiple braking components (213) are arranged at intervals along the vertical direction on the arched wall (101), and the braking components (213) are used to stop the test mold (220) at a preset position; The detection module (300) further includes an angle adjustment mechanism (360) electrically connected to the control module (400). The angle adjustment mechanism (360) is located on the side of the test chamber (100) opposite to the arched wall (101). The linear telescopic mechanism (310) is located on the angle adjustment mechanism (360). The angle adjustment mechanism (360) is used to adjust the angle between the linear telescopic mechanism (310) and the horizontal plane.

2. The evaluation device for testing the early bond performance of shotcrete in tunnels according to claim 1, characterized in that, Both the first traction assembly (212a) and the second traction assembly (212b) include: The traction controller (2120) is electrically connected to the control module (400); The traction rope (2121) is connected at one end to the traction controller (2120) and at the other end to the test mold (220). The traction controller (2120) is used to drive the traction rope (2121) to retract and release the rope.

3. The evaluation device for testing the early bond performance of shotcrete in tunnels according to claim 1, characterized in that, The braking assembly (213) includes: A catapult (2130) is disposed on the arched wall (101) and electrically connected to the control module (400); A brake divider plate (2131) is disposed on the catapult (2130); A position sensor (2132) is disposed on the catapult (2130) and electrically connected to the control module (400); When the test mold (220) moves to a preset position and triggers the position sensor (2132), the ejector (2130) drives the brake dividing plate (2131) to extend toward the test mold (220) to restrict the movement of the test mold (220).

4. The evaluation device for testing the early bond performance of shotcrete in tunnels according to claim 1, characterized in that, The test mold (220) includes: The first mold body (221) is movably disposed on the slide (211); The second mold body (222) is detachably disposed on the side of the first mold body (221) away from the slide (211).

5. The evaluation device for testing the early bond performance of shotcrete in tunnels according to claim 1, characterized in that, The evaluation device for testing the early bonding performance of tunnel shotcrete also includes a temperature and humidity control module (500) installed on the test chamber (100). The temperature and humidity control module (500) is electrically connected to the control module (400) and is used to control the temperature and humidity inside the test chamber (100).

6. The evaluation device for testing the early bond performance of shotcrete in tunnels according to claim 1, characterized in that, The grinding ball assembly (330) includes: A fixed rod (331) is connected to the linear telescopic mechanism (310); The grinding ball body (332) is located at the end of the fixed rod (331) away from the linear telescopic mechanism (310); The outer peripheral surface of the grinding ball body (332) is a rough surface.

7. The evaluation device for testing the early bond performance of shotcrete in tunnels according to claim 1, characterized in that, The test chamber (100) is provided with an openable door (110), and the door (110) is provided with a handle (111).

8. A method for evaluating the early bond performance of shotcrete in tunnels, characterized in that, The evaluation apparatus for testing the early bond performance of shotcrete in tunnels according to any one of claims 1-7, and the evaluation method for testing the early bond performance of shotcrete in tunnels, include: Prepare concrete samples for testing; The prepared concrete sample is filled into the test mold (220) and the surface is smoothed. The test mold (220) containing the concrete sample is fixed to a preset position on the arched wall (101) by means of the mold fixing module (200); The grinding ball assembly (330) is driven by the linear telescopic mechanism (310) to be inserted into the test mold (220). After waiting for a preset time, the grinding ball assembly (330) is driven to retract by the linear telescopic mechanism (310). The tension value F1 and displacement X1 of the linear telescopic mechanism (310) during the retraction process are recorded, and the first curve of tension F1-displacement X1 is plotted. Remove the grinding ball assembly (330), drive the mold gripper (320) to clamp the test mold (220) through the linear telescopic mechanism (310), and then drive the mold gripper (320) to retract through the linear telescopic mechanism (310). Record the tension value F2 and displacement X2 of the linear telescopic mechanism (310) during the retraction process, and plot the second curve of tension F2-displacement X2. The adhesion energy E between the coarse aggregate and the paste in the concrete sample was calculated based on the first curve and the second curve, respectively. a and the adhesion energy E at the interface between slurries c .

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