Composite loading device for civil engineering experiment

Abstract

The invention discloses a composite loading device for civil engineering experiments in the technical field of civil engineering, and the composite loading device comprises an experiment box body and a box door, a plurality of electric cylinders are fixedly connected to the inner top wall of the experiment box body, the output ends of the electric cylinders are fixedly connected with extrusion plates, and a hydraulic cylinder group is fixedly connected to the inner side wall of the experiment box body; the device is characterized in that the hydraulic cylinder set is provided with a multi-force socket, the output end of the hydraulic cylinder set is located in the multi-force socket, the multi-force socket is detachably connected with a plurality of linkage rods, the linkage rods are provided with a plurality of distance sockets, the distance sockets are detachably connected with a plurality of telescopic rods, and the telescopic rods are rotationally connected with extrusion rods used for adjusting the extrusion force direction. The experimental slicing device is scientific and reasonable, multiple samples are subjected to experimental slicing through the telescopic rod, the extrusion rods and the extrusion heads which are detachably arranged on the linkage rod, it is ensured that experimental conditions can be adjusted and controlled, and the experimental efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of civil engineering, in particular to a composite loading device for civil engineering experiments. Background Art

[0002] With the continuous development of civil engineering technology, the demand for research on the mechanical properties of structural parts under complex stress conditions is increasing. Traditional single loading methods such as vertical loading or lateral loading alone can no longer meet the needs of modern civil engineering experiments. Therefore, composite loading devices have emerged. This device can simulate multi-directional stress conditions in actual engineering by integrating multiple loading mechanisms, providing more comprehensive and accurate experimental data for the design, optimization and safety assessment of civil engineering structures.

[0003] By designing a reasonable loading mechanism, such as a hydraulic cylinder, a servo motor, etc., multi-directional loading of the test piece can be achieved. These loading mechanisms can work independently or collaboratively to simulate the complex stress state in actual engineering. Advanced control systems such as PLC and computer control are used to achieve precise control of the loading process. This includes precise adjustment of parameters such as loading speed, loading force value, and loading time to ensure the accuracy and reliability of the experimental results. Finally, various data during the experiment, such as loading force value, deformation, and stress distribution, are recorded in real time using sensors, data acquisition cards and other equipment. Subsequently, the data is processed and analyzed by professional data analysis software to evaluate the mechanical properties of the test piece. Although the composite loading device has broad application prospects and important research value in civil engineering experiments, there are still some problems in the actual application process. Since the composite loading experiment needs to simulate the multi-directional stress conditions in actual engineering, its experimental cycle is relatively long. This may lead to low experimental efficiency and fail to meet some urgent or rapid response research needs.

[0004] In summary, the low efficiency caused by the long experimental cycle of the composite loading device has become a problem that technicians in this field need to solve urgently. Therefore, it is necessary to propose a composite loading device for civil engineering experiments. Summary of the invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide a composite loading device for civil engineering experiments, which can perform experimental slicing on multiple samples through the detachable telescopic rod, extrusion rod and extrusion head on the linkage rod, and then through the coordinated action of the hydraulic cylinder group, electric cylinder, linear motor and rotary motor, it can ensure that the experimental conditions of multiple samples are adjustable, thereby increasing the experimental mode and efficiency.

[0006] In order to achieve the above-mentioned purpose, the technical scheme of the present invention is as follows: a composite loading device for civil engineering experiments, comprising an experimental box and a box door, the box door is hinged on one side of the outer wall of the experimental box, a plurality of electric cylinders are fixedly connected to the top wall of the experimental box, the output end of the electric cylinder is fixedly connected to an extrusion plate, and a hydraulic cylinder group is fixedly connected to the inner wall of the experimental box, characterized in that: a plurality of multi-force sockets are opened on the hydraulic cylinder group, the output ends of the hydraulic cylinder group are all located in the multi-force sockets, a plurality of linkage rods are detachably connected to the multi-force sockets, a plurality of distance sockets are opened on the linkage rods, a plurality of telescopic rods are detachably connected to the distance sockets, the telescopic rods are rotatably connected to an extrusion rod for adjusting the direction of the extrusion force, and the other end of the extrusion rod is detachably connected to an extrusion head for replacing different shapes.

[0007] A linear motor group is fixedly connected to the bottom wall of the experimental box, and the output ends of the linear motor group are fixedly connected to the rotating motor. The output ends of the rotating motor are fixedly connected to a limit plate, and a limit slot is opened on the limit plate. Several samples are detachably connected in the limit slot. A controller is fixedly connected to the box door, and the electric cylinder, hydraulic cylinder group, linear motor and rotating motor are all connected to the controller signal.

[0008] The following principles and beneficial effects are achieved by adopting the above scheme:

[0009] Basic principle: The multi-force socket set on the hydraulic cylinder group allows multiple linkage rods to be detachably connected, which in turn can be connected to telescopic rods of different numbers and lengths. The design of the telescopic rod allows the experimenter to adjust the position and distance of the loading point as needed to adapt to samples of different sizes and experimental requirements. The other end of the telescopic rod is rotatably connected to the extrusion rod, which is detachably connected to the extrusion head of different shapes. This design allows the experimenter to replace the extrusion head of different shapes and sizes as needed to simulate different loading conditions and sample shapes.

[0010] The electric cylinder is fixed to the top wall of the test box and provides vertical loading through the extrusion plate at its output end. The hydraulic cylinder group realizes lateral or oblique loading of the sample through components such as linkage rods and telescopic rods to simulate the complex stress conditions in actual engineering. The linear motor group is responsible for moving the rotary motor and the sample connected to it in the horizontal direction, so that the sample can be adjusted in position in the test box. The rotary motor is responsible for driving the sample to rotate to simulate the rotational stress conditions in actual engineering or to perform specific mechanical property tests.

[0011] The controller fixed on the door is connected to the electric cylinder, hydraulic cylinder group, linear motor and rotary motor. Through the controller, the experimenter can accurately control the motion parameters of each loading mechanism, such as loading speed, loading force value, loading time, etc., as well as the position and rotation angle of the sample. The controller can also receive feedback signals from the sensor and monitor various data in the experiment in real time to ensure the accuracy and safety of the experiment.

[0012] Beneficial effects:

[0013] 1. The present invention realizes a modular design of the loading mechanism through the detachable connection of the linkage rod, telescopic rod, extrusion rod and extrusion head. This design allows the experimenter to quickly replace the extrusion head of different shapes and sizes according to the experimental requirements, and adjust the length and direction of the linkage rod and telescopic rod, so as to adapt to different experimental slicing conditions of the same sample.

[0014] 2. The present invention combines the synergistic effects of hydraulic cylinders, electric cylinders, linear motors and rotary motors to achieve multi-directional loading of samples. This loading method can more realistically simulate the complex stress conditions in actual engineering and provide more comprehensive and accurate experimental data for the design, optimization and safety assessment of civil engineering structures.

[0015] 3. The present invention realizes simultaneous experiments on multiple samples by placing multiple samples in the limiting grooves at the same time and using the controller to accurately control the loading mechanism and the sample positions. This not only shortens the experimental cycle, but also improves the experimental efficiency, allowing the experimenter to obtain more experimental data in a shorter time.

[0016] Furthermore, the samples are fixedly connected with eddy current sensors and piezoelectric accelerometers, and the eddy current sensors and piezoelectric accelerometers are connected with controller signals.

[0017] Beneficial effects: The eddy current sensor can accurately measure the tiny deformation of the sample during the experiment, while the piezoelectric accelerometer can accurately capture the vibration acceleration of the sample. These high-precision measurement data provide a strong guarantee for the accuracy of the experimental results. The signal connection between the sensor and the controller ensures the real-time transmission and processing of the experimental data. The experimenter can instantly obtain information such as the stress, strain and vibration acceleration of the sample, so as to adjust the experimental parameters or take corresponding measures in time to avoid potential risks during the experiment.

[0018] Furthermore, a plurality of cameras for photographing deformation images of the samples are fixedly connected to the inner side wall of the experimental box away from the box door.

[0019] Beneficial effects: The camera can capture and record the deformation of the sample during the experimental loading process in real time, including the size, direction and speed of the deformation. This intuitive visual record helps experimenters to more accurately observe and analyze the changes in the mechanical properties of the sample. Combined with the stress, strain and other experimental data collected by the sensor, the deformation images taken by the camera can provide more comprehensive information for data analysis. By comparing and analyzing the deformation images with the experimental data, experimenters can have a deeper understanding of the mechanical response characteristics of the sample under complex stress conditions.

[0020] Furthermore, the controller is provided with a display screen, and the sample deformation image taken by the camera is transmitted to the controller. The edge detection, deformation variable calculation and dynamic analysis are performed through the preset image processing algorithm, and the deformation of multiple samples under different loading conditions is monitored in real time. The analysis results are displayed in the form of graphics on the controller's display screen.

[0021] Beneficial effects: Traditional deformation monitoring methods often require experimenters to manually measure and record data, which is not only time-consuming and labor-intensive, but also prone to human errors. However, through real-time monitoring with cameras and image processing algorithms, experimenters can instantly obtain deformation information of samples, greatly improving experimental efficiency.

[0022] Furthermore, the eddy current sensor and the piezoelectric accelerometer obtain experimental data and transmit them to the controller by real-time collecting the stress, strain and vibration acceleration experimental data during the experiment, and converting the experimental data into digital signals and transmitting them to the controller. The controller uses a preset data analysis algorithm to filter, denoise and perform statistical analysis on the experimental data to obtain the mechanical response characteristics of the sample such as the stress-strain curve and vibration frequency.

[0023] Beneficial effects: The controller uses a preset data analysis algorithm to filter, denoise and perform statistical analysis on the experimental data, effectively eliminating noise and interference in the data and improving the accuracy and efficiency of data analysis. At the same time, by obtaining the mechanical response characteristics of the sample, including stress-strain curves and vibration frequencies, it provides more comprehensive and in-depth data support for experimenters. Traditional data analysis methods often require manual processing of large amounts of data, which is not only time-consuming and labor-intensive, but also prone to human errors. By automatically performing data analysis and processing through the controller, experimenters can obtain experimental results more quickly, greatly improving experimental efficiency.

[0024] Furthermore, the limiting grooves are respectively slidably fitted with fixing plates and detachably connected with clamping blocks.

[0025] Beneficial effects: The fixing plate can slide in the limit slot, allowing the experimenter to adjust its position according to the size and shape of the sample, thereby ensuring that the sample can be firmly fixed. The detachable design of the card block allows the experimenter to choose whether to use the card block as needed, and adjust the position and number of the card block to accommodate samples of different shapes and sizes. By sliding the fixing plate and fixing it with the card block, the sample can be effectively prevented from moving or deforming during the experiment, thereby ensuring the accuracy of the experimental results.

[0026] Furthermore, a tempered glass layer is fixedly connected to the outer wall of the camera.

[0027] Beneficial effects: During the experiment, the deformation or breakage of the sample may generate flying fragments, and the tempered glass layer can effectively block these fragments and protect the camera from damage. This ensures that the camera can continuously and stably capture the sample deformation image, providing a guarantee for the accuracy and integrity of the experimental data.

[0028] Furthermore, pressure sensors are fixedly connected to the bottom of the extrusion plate and the bottom wall of the limiting groove, and the pressure sensors are connected to the controller signals.

[0029] Beneficial effects: By monitoring pressure changes in real time, experimenters can more accurately control sample consistency and experimental conditions, including sample length, weight, loading speed, and loading force, to ensure the accuracy and reliability of experimental results. This helps reduce experimental errors and improve experimental accuracy.

[0030] Furthermore, the experimental box, the limit plate, the limit groove, the multi-force socket and the bottom of the distance socket are all fixedly connected with a friction layer.

[0031] Beneficial effects: The friction layer can increase the friction between the contact surfaces, thereby preventing the loosening or displacement of components due to vibration or external force during the experiment. It helps to ensure the overall stability of the experimental device and ensure the accuracy and reliability of the experimental results.

[0032] Furthermore, a transparent explosion-proof observation window is provided on the box door.

[0033] Beneficial effects: The transparent explosion-proof observation window allows the experimenter to observe the changes in the sample and the operation of the experimental equipment in real time during the experiment. This helps the experimenter to promptly discover abnormal conditions in the experiment, such as sample rupture, equipment failure, etc., so as to take prompt measures to ensure the safety and smooth progress of the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is an axonometric diagram of an embodiment of the present invention.

[0035] Figure 2 It is a front cross-sectional view of an embodiment of the present invention.

[0036] Figure 3 It is a top sectional view of an embodiment of the present invention.

[0037] The figure marks in the drawings of the specification include: 1. experimental box; 2. box door; 3. display screen; 4. controller; 5. transparent explosion-proof observation window; 6. linkage rod; 7. electric cylinder; 8. extrusion plate; 9. sample; 10. hydraulic cylinder group; 11. distance socket; 12. telescopic rod; 13. extrusion rod; 14. multi-force socket; 15. limit plate; 16. linear motor group; 17. limit slot; 18. rotary motor; 19. pressure sensor; 20. extrusion head; 21. camera; 22. fixing plate; 23. block. DETAILED DESCRIPTION

[0038] The following is further described in detail through specific implementation methods:

[0039] Example 1

[0040] Basically as attached Figure 1-Figure 3 As shown: A composite loading device for civil engineering experiments, including an experimental box 1 and a box door 2, the box door 2 is hinged to one side of the outer wall of the experimental box 1, and a transparent explosion-proof observation window 5 is opened on the box door 2. A plurality of electric cylinders 7 are fixedly connected to the top wall of the experimental box 1 by bolts, and the output end of the electric cylinder 7 is fixedly connected to the extrusion plate 8 by bolts, and a hydraulic cylinder group 10 is fixedly connected to the inner wall of the experimental box 1 by bolts, characterized in that: a plurality of multi-force sockets 14 are opened on the hydraulic cylinder group 10, and the output ends of the hydraulic cylinder group 10 are all located in the multi-force sockets 14, and a plurality of linkage rods 6 are detachably connected to the multi-force sockets 14, and a plurality of distance sockets 11 are opened on the linkage rod 6, and a plurality of telescopic rods 12 are detachably connected to the distance sockets 11, and the telescopic rods 12 are all rotatably connected to the extrusion rods 13 for adjusting the direction of the extrusion force, and the other end of the extrusion rod 13 is detachably connected to the extrusion head 20 for replacing different shapes.

[0041] The bottom wall of the experimental box 1 is fixedly connected with a linear motor group 16 by bolts, and the output end of the linear motor group 16 is fixedly connected with a rotary motor 18 by bolts, and the output end of the rotary motor 18 is fixedly connected with a limit plate 15 by bolts, and a limit slot 17 is opened on the limit plate 15, and a number of samples 9 are detachably connected in the limit slot 17, and a fixed plate 22 and a detachably connected block 23 are respectively slidably matched in the limit slot 17. Eddy current sensors and piezoelectric accelerometers are bonded to the samples 9. The box door 2 is fixedly connected with a controller 4 by bolts, and the eddy current sensor, piezoelectric accelerometer, electric cylinder 7, hydraulic cylinder group 10, linear motor and rotary motor 18 are all connected to the controller 4 signal. The bottom of the experimental box 1, the limit plate 15, the limit slot 17, the multi-force socket 14 and the distance socket 11 are all integrally formed with a friction layer.

[0042] The eddy current sensor and the piezoelectric accelerometer obtain experimental data and transmit them to the controller 4 by real-time acquisition of stress, strain and vibration acceleration experimental data during the experiment, and after converting the experimental data into digital signals, transmit them to the controller 4. The controller 4 uses a preset data analysis algorithm to filter, denoise and perform statistical analysis on the experimental data to obtain the mechanical response characteristics of the sample 9 including the stress-strain curve and the vibration frequency.

[0043] Specific implementation steps:

[0044] First, multiple identical samples 9 are placed in the limiting grooves 17 in the experimental box 1 to ensure that each sample 9 is firmly clamped by the fixing plate 22 and the clamping block 23. Eddy current sensors and piezoelectric accelerometers are bonded to each sample 9 to collect stress, strain and vibration acceleration data in real time during the experiment.

[0045] Connect the electric cylinder 7, hydraulic cylinder group 10, linear motor and rotary motor 18 and other loading devices with the controller 4 to ensure the accuracy and real-time performance of data transmission. Check whether the friction layer of the experimental box 1, limit plate 15, limit slot 17, multi-force socket 14 and distance socket 11 are intact to ensure stability and safety during the experiment.

[0046] Experimental parameters such as loading speed, loading force, and loading direction are set through the controller 4. The electric cylinder 7 is started so that its output end pushes the extrusion plate 8 to perform preliminary extrusion on the sample 9 to simulate the static load in the actual project. At the same time, the hydraulic cylinder group 10 is started, and the loading force is transmitted to the telescopic rod 12 through the multi-force socket 14 and the linkage rod 6, and then the sample 9 is loaded at multiple points and in multiple directions through the extrusion rod 13 and the extrusion head 20 to simulate the mechanical response under complex load conditions. At the same time, on different samples 9 of the same linkage rod 6, it is selected whether to insert the telescopic rod 12 and the extrusion rod 13 to realize experimental slicing. The linear motor group 16 is started to drive the rotary motor 18 and the limit plate 15 to rotate, thereby changing the force direction and angle of the sample 9, further simulating the dynamic load in the actual project.

[0047] During the experiment, the eddy current sensor and the piezoelectric accelerometer collect the stress, strain and vibration acceleration data of the sample 9 in real time, and convert these data into digital signals and transmit them to the controller 4. The controller 4 uses a preset data analysis algorithm to filter, denoise and perform statistical analysis on the experimental data to obtain the mechanical response characteristics of the sample 9, such as the stress-strain curve and vibration frequency. Through the transparent explosion-proof observation window 5, the experimenter can observe the changes of the sample 9 in real time during the experiment, such as crack extension, deformation degree, etc., so as to adjust the experimental parameters or record key experimental phenomena in time.

[0048] When the experiment reaches the preset termination conditions, such as sample 9 is damaged or the loading force reaches the maximum value, stop all loading devices and turn off the controller 4. Take out sample 9 and perform necessary subsequent processing, such as observing the damage morphology. According to the experimental data stored in the controller 4, further data analysis and processing are performed to draw more in-depth conclusions and rules. Organize the experimental report, record the experimental process, experimental results and experimental analysis, etc., to provide reference for subsequent research and engineering applications.

[0049] Example 2

[0050] Basically as attached Figure 2 and Figure 3 As shown: The difference from the above embodiment is that a plurality of cameras 21 for photographing deformation images of the sample 9 are fixedly connected by bolts on the inner wall of the experimental box body 1 away from the box door 2. The outer wall of the camera 21 is integrally formed with a tempered glass layer. The controller 4 is provided with a display screen 3, and the deformation image of the sample 9 photographed by the camera 21 is transmitted to the controller 4. The edge detection, deformation amount calculation and dynamic analysis are performed through the preset image processing algorithm, and the deformation of multiple samples 9 under different loading conditions is monitored in real time, and the analysis results are displayed on the display screen 3 of the controller 4 in the form of graphics.

[0051] Specific implementation steps:

[0052] During the experiment, the eddy current sensor and the piezoelectric accelerometer collect the stress, strain and vibration acceleration data of the sample 9 in real time, and convert these data into digital signals and transmit them to the controller 4. At the same time, the camera 21 starts to shoot the deformation images of the sample 9 during the experiment, and transmits these images to the controller 4 in real time. The controller 4 uses a preset data analysis algorithm to filter, denoise and perform statistical analysis on the experimental data, and uses an image processing algorithm to perform edge detection, deformation calculation and dynamic analysis on the images taken by the camera 21.

[0053] The controller 4 displays the analysis results in the form of graphs on the display screen 3, including the stress-strain curve, vibration frequency, and analysis results of the deformation image of the sample 9. The experimenter can monitor the deformation of multiple samples 9 under different loading conditions and their mechanical response characteristics in real time by observing the graphs and data on the display screen 3.

[0054] Example 3

[0055] Basically as attached Figure 2 As shown: The difference from the above embodiment is that pressure sensors 19 are embedded in the bottom of the extrusion plate 8 and the inner bottom wall of the limiting groove 17, and the pressure sensors 19 are connected to the controller 4 by signal.

[0056] Specific implementation steps:

[0057] The pressure sensors 19 at the bottom of the extrusion plate 8 and the inner bottom wall of the limiting groove 17 monitor the stress of the sample 9 in real time during the experiment, and transmit the stress data to the controller 4 in real time. During the installation of the sample 9, the camera 21 cooperates with the collected sample 9 shape, size and quality to ensure the consistency of multiple samples 9.

[0058] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A composite loading device for civil engineering experiments, comprising an experimental box (1) and a box door (2), wherein the box door (2) is hinged to one side of the outer wall of the experimental box (1), a plurality of electric cylinders (7) are fixedly connected to the inner top wall of the experimental box (1), an extrusion plate (8) is fixedly connected to the output end of the electric cylinder (7), and a hydraulic cylinder group (10) is fixedly connected to the inner side wall of the experimental box (1), characterized in that: The hydraulic cylinder group (10) is provided with a plurality of multi-force sockets (14), the output ends of the hydraulic cylinder group (10) are all located in the multi-force sockets (14), the multi-force sockets (14) are detachably connected with a plurality of linkage rods (6), the linkage rods (6) are provided with a plurality of distance sockets (11), the distance sockets (11) are detachably connected with a plurality of telescopic rods (12), the telescopic rods (12) are rotatably connected with an extrusion rod (13) for adjusting the direction of the extrusion force, and the other end of the extrusion rod (13) is detachably connected with an extrusion head (20) for replacing different shapes; A linear motor group (16) is fixedly connected to the bottom wall of the experimental box (1), the output end of the linear motor group (16) is fixedly connected to a rotary motor (18), the output end of the rotary motor (18) is fixedly connected to a limit plate (15), a limit groove (17) is formed on the limit plate (15), a plurality of samples (9) are detachably connected in the limit groove (17), a controller (4) is fixedly connected to the box door (2), and the electric cylinder (7), the hydraulic cylinder group (10), the linear motor and the rotary motor (18) are all connected to the controller (4) for signal.

2. The composite loading device for civil engineering experiments according to claim 1, characterized in that: The samples (9) are fixedly connected with an eddy current sensor and a piezoelectric accelerometer, and the eddy current sensor and the piezoelectric accelerometer are both connected to the controller (4) for signal transmission.

3. The composite loading device for civil engineering experiments according to claim 2, characterized in that: A plurality of cameras (21) for photographing deformation images of the sample (9) are fixedly connected to the inner side wall of the experimental box (1) away from the box door (2).

4. The composite loading device for civil engineering experiments according to claim 3 is characterized in that: The controller (4) is provided with a display screen (3). The deformation image of the sample (9) captured by the camera (21) is transmitted to the controller (4). The edge detection, deformation amount calculation and dynamic analysis are performed through a preset image processing algorithm. The deformation of multiple samples (9) under different loading conditions is monitored in real time, and the analysis results are displayed in the form of a graph on the display screen (3) of the controller (4).

5. The composite loading device for civil engineering experiments according to claim 4 is characterized in that: The eddy current sensor and the piezoelectric accelerometer obtain experimental data and transmit them to the controller (4). The stress, strain and vibration acceleration experimental data in the experimental process are collected in real time, and the experimental data are converted into digital signals and then transmitted to the controller (4). The controller (4) uses a preset data analysis algorithm to filter, remove noise and perform statistical analysis on the experimental data to obtain the mechanical response characteristics of the sample (9), including the stress-strain curve and the vibration frequency.

6. The composite loading device for civil engineering experiments according to claim 5, characterized in that: A fixing plate (22) and a clamping block (23) are detachably connected and slidably matched in the limiting groove (17).

7. The composite loading device for civil engineering experiments according to claim 6, characterized in that: A tempered glass layer is fixedly connected to the outer wall of the camera (21).

8. The composite loading device for civil engineering experiments according to claim 7, characterized in that: The bottom of the extrusion plate (8) and the inner bottom wall of the limiting groove (17) are both fixedly connected with a pressure sensor (19), and the pressure sensor (19) is connected to the controller (4) for signal transmission.

9. The composite loading device for civil engineering experiments according to claim 8, characterized in that: The experimental box (1), the limiting plate (15), the limiting groove (17), the multi-force socket (14) and the bottom of the distance socket (11) are all fixedly connected with a friction layer.

10. The composite loading device for civil engineering experiments according to claim 9, characterized in that: A transparent explosion-proof observation window (5) is provided on the box door (2).

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