A visual test device for simulating the complex load transfer law of piles

Abstract

The present invention discloses a visualization test device for simulating the complex load transfer law of piles, which mainly includes a calibration device and an experimental device. When working, first, a small ball of equal mass is placed in the pipe mouth and allowed to fall at the same height, and the data of impact force intensity and fluorescence intensity are collected at the same time, and a relationship diagram of force-luminescence intensity is drawn. Then, the model box is filled with suitable soil particles in layers, the model pile and the first force-induced fluorescent material are placed, the loading module is adjusted, and a single pile load or multiple load coupling is applied to the pile foundation, and the camera module is adjusted so that it can fully observe all the first force-induced fluorescent materials. Then, a slow-maintained load method is adopted, and the next level of load is applied after the soil is stable, and the luminous image is collected in real time. Finally, the experimental images collected in real time are analyzed and processed, and the photometric changes are used to obtain the performance characteristics of the side friction and end friction of a single pile or a group of piles, and the pile load transfer law and the change in the influence range are further analyzed.

Description

Technical Field

[0001] The invention relates to the field of visualization test devices, in particular to a visualization test device for simulating complex load transfer rules of piles. Background Art

[0002] Under the action of complex loads, the pile is transferred to the soil layer through the pile side and pile bottom, and the load is borne by both. Therefore, how to consider the interaction between the pile and soil interface has always been the focus of geotechnical engineers. The bearing capacity Q of a single pile under load is u The lateral friction Q su and pile tip resistance Q pu Composition, can be expressed as:

[0003] Q u =Q su +Q pu =∑U i L i q sui +A p p pu

[0004] Where: L i ,U i : The thickness of the i-th layer of soil around the pile and the corresponding pile perimeter;

[0005] q sui ,q pu : the lateral friction resistance of the i-th soil layer and the end resistance of the bearing layer;

[0006] A P : Cross-sectional area of ​​pile end.

[0007] Although the commonly used computational models have clear mechanical concepts and simple calculations and are widely used in geotechnical engineering design, their calculation parameters are often difficult to obtain accurately considering the complexity of geotechnical materials. Therefore, field tests and indoor model tests are still an indispensable research method for researchers.

[0008] In order to clearly understand the time course of load transfer of pile foundations under complex loads, a large number of scholars have buried earth pressure boxes and strain gauges in indoor model tests. However, due to the large size and few points of the earth pressure box, a stress field will be generated around it, and the earth pressure cannot be accurately obtained. The newly improved earth pressure membrane FSR (Force sensel resistance), although it reduces the volume of the test element, is still a contact test method and cannot observe the change law of earth pressure very intuitively.

[0009] However, photoelastic experiments often require laser transmitters and polarizers, and the test instruments are bulky, and the photoelastic particles are large. In order to simulate rock and soil materials more realistically, conveniently, clearly and intuitively observe the time-course changes of pile side friction and pile end friction of different pile foundations under complex continuous loads, and directly display images and data of pile side friction and end resistance, the present invention introduces a simple visualized indoor test device to further explore the intrinsic mechanism of pile-soil interaction. Summary of the invention

[0010] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a visual test device for simulating the complex load transfer law of piles.

[0011] The purpose of the present invention is achieved through the following technical solutions:

[0012] A visualization test device for simulating the complex load transfer law of piles mainly includes a calibration device for calibrating mechanoluminescent materials and an experimental device for applying a single pile load or multiple load couplings to a pile foundation. The impact force intensity and fluorescence intensity data collected by the calibration device are used for analysis and processing by the experimental device.

[0013] Specifically, the experimental device mainly includes a first dark box, a guide rail, a model box, a simulation pile, a first loading module, a second loading module, a camera module, a signal generator, and a computer. The model box is arranged in the first dark box and fixedly connected to the first dark box. The simulation pile is arranged in the model box. The guide rail is horizontally arranged on the first dark box. The first loading module and the second loading module are both arranged on the guide rail, and their loading ends are in contact with the model box. The camera module is arranged in the first dark box and is respectively connected to the signal generator and the computer through wires.

[0014] Specifically, the model box is filled with a first force-induced fluorescent material and soil particles. The first force-induced fluorescent material wraps the simulated pile. The soil particles are filled between the first force-induced fluorescent material and the model box. A rubber film for wrapping the first force-induced fluorescent material is also provided between the first force-induced fluorescent material and the soil particles.

[0015] Specifically, the first loading module mainly includes a first mounting seat, a motor, a first jack, a wheel, a first displacement meter, and a shock-absorbing spring. The motor is mounted on the guide rail through the first mounting seat and can slide along the guide rail. The output end of the motor is connected to the wheel and drives the wheel to rotate. The first jack is arranged on the first mounting seat, and its output end is connected to the wheel and drives the wheel to apply pressure downward. The shock-absorbing spring is sleeved on the output end of the first jack and connected to the wheel. The first displacement meter is arranged on the first mounting seat, and its measuring end is connected to the wheel.

[0016] Specifically, the second loading module mainly includes a second mounting seat, a second jack, and a second displacement meter. The second mounting seat is arranged on a guide rail and can slide along the guide rail. The second jack is arranged on the second mounting seat, and its output end is pressed downward toward the model box. The second displacement meter is arranged on the second mounting seat, and its measuring end is connected to the output end of the second jack.

[0017] As a preferred solution of the present invention, the camera module adopts an array camera setting.

[0018] Specifically, the calibration device mainly includes a second dark box, a second force-induced fluorescent material, a pressure sensing film, a pipe, a high-speed camera, and a ball. The second force-induced fluorescent material is arranged at the bottom of the second dark box. The pressure sensing film covers the second force-induced fluorescent material and is connected to a computer. The high-speed camera is arranged in the second dark box and is connected to a computer, with its shooting end facing the second force-induced fluorescent material. The pipe is vertically inserted into the second dark box. The ball is arranged in the pipe and falls from the pipe to the bottom of the second dark box.

[0019] Specifically, the calibration device further includes a support and a lifting platform. The second dark box is arranged on the lifting platform, and the second dark box is driven to rise and fall vertically by the lifting platform. The support is arranged on one side of the lifting platform, and its upper end is fixedly connected to the pipeline and the high-speed camera respectively through a connecting rod.

[0020] As a preferred solution of the present invention, both the first dark box and the second dark box are made of opaque plates.

[0021] As a preferred solution of the present invention, the camera module uses a CCD camera, and each camera module includes no less than 3 cameras.

[0022] As a preferred solution of the present invention, the first mesoluminescent material and the second mesoluminescent material are both in powder form, and the luminescent material can be ZnS:Mn 2+ or SrAl2O4:Eu 2+ Material.

[0023] The working process and principle of the present invention are as follows: first, the force-induced fluorescent material is calibrated: a small ball of equal mass is placed in the pipe port of the calibration device, and it is allowed to fall at the same height, and the data of the impact force intensity and the fluorescence intensity are collected at the same time, and a force-luminescence intensity relationship diagram is drawn in a computer. Then, according to the geological conditions of the actual project, the model box of the experimental device is filled with suitable soil particles, a model pile, and the first force-induced fluorescent material in layers and filled, and the first loading module and the second loading module are adjusted. According to the actual situation, a single pile load or multiple load coupling is applied to the pile foundation, and the camera module is adjusted to ensure that the camera module can fully observe all the first force-induced fluorescent materials. Then, a slow-maintained load method is adopted, and the next level of load is applied after the soil body is stable. During the loading process, the luminous image of the force-induced material is collected in real time. Finally, the experimental images collected in real time are analyzed and processed, and the performance characteristics of the side friction resistance and end friction resistance of a single pile or a group of piles are obtained according to the photometric changes of the first force-induced fluorescent material, and the pile load transfer law and the change of the influence range are further analyzed. The experimental data can provide an important reference basis for actual engineering. The invention also has the advantages of simple structure, convenient operation and easy implementation.

[0024] Compared with the prior art, the present invention also has the following advantages:

[0025] (1) The present invention provides a visualized indoor test simulation device for simulating the time-course variation of load transfer under complex loads on a pile. By simulating the pile foundation indoors under continuous complex loads, real-time simulation and collection of experimental images and data are performed, which is beneficial for targeted maintenance of pile foundation reinforcement under long-term complex loads, and can also provide experimental data support for pile foundation design according to different on-site conditions.

[0026] (2) The mechanoluminescent material provided by the present invention is in powder form, which is similar to the particle size of soil particles. It can more realistically simulate rock and soil materials and reflect the mechanical properties of soil particles. The characteristics of the mechanoluminescent material can be used to directly observe the characteristics and failure mechanism of pile side resistance and pile end resistance.

[0027] (3) By changing the number of model piles in the model box, the present invention can directly observe the influence and development law of the pile group effect on the pile foundation; by changing the loading method, the influence of the loading method on the pile-soil interaction force transmission law and the change of the influence range can be explored. By filling the model box with different types of soil particles to simulate different soil layers, the vertical load transmission law of the simulated pile under the geological conditions can be quickly and accurately observed.

[0028] (4) The present invention can apply load to the sample without a reaction frame, which greatly reduces the space occupied by the loading device. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1It is a structural schematic diagram of an experimental device in a visual test device for simulating the complex load transfer law of piles provided by the present invention.

[0030] Figure 2 It is a side view of an experimental device in a visual test device for simulating the complex load transfer law of piles provided by the present invention.

[0031] Figure 3 It is a structural schematic diagram of a calibration device in a visualization test device for simulating the complex load transfer law of a pile provided by the present invention.

[0032] Description of the reference numerals in the above drawings:

[0033] 1-first loading module, 2-second loading module, 3-motor, 4-first jack, 5-wheel, 6-first displacement meter, 7-guide rail, 8-first dark box, 9-simulation pile, 10-first force-induced fluorescent material, 11-soil particles, 12-model box, 13-shock-absorbing spring, 14-rubber membrane, 15-computer, 16-second dark box, 17-camera module, 18-signal generator, 19-pipeline, 20-high-speed camera, 21-second force-induced fluorescent material, 22-pressure sensing membrane, 23-lifting platform, 24-support. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clear and explicit, the present invention is further described below with reference to the accompanying drawings and embodiments.

[0035] Embodiment 1:

[0036] like Figures 1 to 3 As shown, this embodiment discloses a visualization test device for simulating the complex load transfer law of piles, which mainly includes a calibration device for calibrating the mechanoluminescent material and an experimental device for applying a single pile load or multiple load coupling to the pile foundation. The impact force intensity and fluorescence intensity data collected by the calibration device are used for analysis and processing by the experimental device.

[0037] Specifically, the experimental device mainly includes a first dark box 8, a guide rail 7, a model box 12, a simulation pile 9, a first loading module 1, a second loading module 2, a camera module 17, a signal generator 18, and a computer 15. The model box 12 is arranged in the first dark box 8 and is fixedly connected to the first dark box 8. The simulation pile 9 is arranged in the model box 12. The guide rail 7 is horizontally arranged on the first dark box 8. The first loading module 1 and the second loading module 2 are both arranged on the guide rail 7, and their loading ends are in contact with the model box 12. The camera module 17 is arranged in the first dark box 8, and is respectively connected to the signal generator 18 and the computer 15 through wires.

[0038] Specifically, the model box 12 is filled with a first force-induced fluorescent material 10 and soil particles 11. The first force-induced fluorescent material 10 wraps the simulated pile 9. The soil particles 11 are filled between the first force-induced fluorescent material 10 and the model box 12. A rubber film 14 for wrapping the first force-induced fluorescent material 10 is also provided between the first force-induced fluorescent material 10 and the soil particles 11.

[0039] Specifically, the first loading module 1 mainly includes a first mounting seat, a motor 3, a first jack 4, a wheel 5, a first displacement meter 6, and a shock-absorbing spring 13. The motor 3 is mounted on the guide rail 7 through the first mounting seat and can slide along the guide rail 7. The output end of the motor 3 is connected to the wheel 5 and drives the wheel 5 to rotate. The first jack 4 is arranged on the first mounting seat, and its output end is connected to the wheel 5 and drives the wheel 5 to apply pressure downward. The shock-absorbing spring 13 is sleeved on the output end of the first jack 4 and connected to the wheel 5. The first displacement meter 6 is arranged on the first mounting seat, and its measuring end is connected to the wheel 5.

[0040] Specifically, the second loading module 2 mainly includes a second mounting seat, a second jack, and a second displacement meter. The second mounting seat is arranged on the guide rail 7 and can slide along the guide rail 7. The second jack is arranged on the second mounting seat, and its output end is pressed downward toward the model box 12. The second displacement meter is arranged on the second mounting seat, and its measuring end is connected to the output end of the second jack.

[0041] As a preferred solution of the present invention, the camera module 17 adopts an array camera configuration.

[0042] Specifically, the calibration device mainly includes a second dark box 16, a second force-induced fluorescent material 21, a pressure sensing film 22, a pipe 19, a high-speed camera 20, and a ball. The second force-induced fluorescent material 21 is arranged at the bottom of the second dark box 16. The pressure sensing film 22 covers the second force-induced fluorescent material 21 and is connected to the computer 15. The high-speed camera 20 is arranged in the second dark box 16, connected to the computer 15, and its shooting end faces the second force-induced fluorescent material 21. The pipe 19 is vertically inserted into the second dark box 16. The ball is arranged in the pipe 19 and falls from the pipe 19 to the bottom of the second dark box 16.

[0043] Specifically, the calibration device further includes a support 24 and a lifting platform 23. The second dark box 16 is arranged on the lifting platform 23, and the second dark box 16 is driven to vertically lift by the lifting platform 23. The support 24 is arranged on one side of the lifting platform 23, and its upper end is fixedly connected to the pipeline 19 and the high-speed camera 20 respectively through a connecting rod.

[0044] As a preferred solution of the present invention, the first dark box 8 and the second dark box 16 are both made of opaque plates.

[0045] As a preferred solution of the present invention, the camera module 17 uses a CCD camera, and each camera module 17 includes no less than 3 cameras.

[0046] As a preferred solution of the present invention, the first mesoluminescent material 10 and the second mesoluminescent material 21 are both in powder form, and the luminescent material can be ZnS:Mn 2+ or SrAl2O4:Eu 2+ Material.

[0047] The working process and principle of the present invention are as follows: first, the force-induced fluorescent material is calibrated: a small ball of equal mass is placed in the pipe 19 of the calibration device, and it is allowed to fall at the same height, and the data of the impact force intensity and the fluorescence intensity are collected at the same time, and a force-luminescence intensity relationship diagram is drawn in the computer 15. Then, according to the geological conditions of the actual project, the model box 12 of the experimental device is filled with suitable soil particles 11, the model pile is placed, and the first force-induced fluorescent material 10 is filled and filled, and the first loading module 1 and the second loading module 2 are adjusted, and a single pile load or multiple load coupling is applied to the pile foundation according to the actual situation, and the camera module 17 is adjusted to ensure that the camera module 17 can fully observe all the first force-induced fluorescent materials 10. Then, the slow maintenance load method is adopted, and the next level of load is applied after the soil is stable. During the loading process, the luminescence image of the force-induced material is collected in real time. Finally, the experimental images collected in real time are analyzed and processed, and the performance characteristics of the side friction and end friction of a single pile or a pile group are obtained according to the luminosity change of the first mechanoluminescent material 10, and the pile load transfer law and the change of the influence range are further analyzed. The experimental data can provide an important reference basis for actual engineering. The present invention also has the advantages of simple structure, convenient operation and easy implementation.

[0048] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A visual test device for simulating the complex load transfer law of piles, characterized in that: It includes a calibration device for calibrating the mechanoluminescent material, and an experimental device for applying a single pile load or a plurality of load couplings to the pile foundation; the impact force intensity and fluorescence intensity data collected by the calibration device are used for analysis and processing by the experimental device; The experimental device comprises a first dark box, a guide rail, a model box, a simulation pile, a first loading module, a second loading module, a camera module, a signal generator, and a computer; the model box is arranged in the first dark box and fixedly connected to the first dark box; the simulation pile is arranged in the model box; the guide rail is horizontally arranged on the first dark box; the first loading module and the second loading module are both arranged on the guide rail, and their loading ends are both in contact with the model box; the camera module is arranged in the first dark box and is respectively connected to the signal generator and the computer through wires; The model box is filled with a first force-induced fluorescent material and soil particles; the first force-induced fluorescent material wraps the simulated pile; the soil particles are filled between the first force-induced fluorescent material and the model box; a rubber film for wrapping the first force-induced fluorescent material is also provided between the first force-induced fluorescent material and the soil particles; The first loading module includes a first mounting seat, a motor, a first jack, a wheel, a first displacement meter, and a shock absorbing spring; the motor is mounted on the guide rail through the first mounting seat and can slide along the guide rail; the output end of the motor is connected to the wheel and drives the wheel to rotate; the first jack is arranged on the first mounting seat, and its output end is connected to the wheel and drives the wheel to apply pressure downward; the shock absorbing spring is sleeved on the output end of the first jack and connected to the wheel, and the first displacement meter is arranged on the first mounting seat, and its measuring end is connected to the wheel; The calibration device includes a second dark box, a second force-induced fluorescent material, a pressure sensing film, a pipe, a high-speed camera, and a sphere; the second force-induced fluorescent material is arranged at the bottom of the second dark box; the pressure sensing film covers the second force-induced fluorescent material and is connected to a computer; the high-speed camera is arranged in the second dark box, is connected to a computer, and its shooting end faces the second force-induced fluorescent material; the pipe is vertically inserted into the second dark box; the sphere is arranged in the pipe and falls from the pipe to the bottom of the second dark box.

2. The visualization test device for simulating the complex load transfer law of piles according to claim 1 is characterized in that: The second loading module includes a second mounting seat, a second jack, and a second displacement meter; the second mounting seat is arranged on the guide rail and can slide along the guide rail; the second jack is arranged on the second mounting seat, and its output end is pressed downward toward the model box; the second displacement meter is arranged on the second mounting seat, and its measuring end is connected to the output end of the second jack.

3. The visualization test device for simulating the complex load transfer law of piles according to claim 1 is characterized in that: The camera module adopts an array camera configuration.

4. The visualization test device for simulating the complex load transfer law of piles according to claim 1 is characterized in that: The calibration device also includes a support and a lifting platform; the second dark box is arranged on the lifting platform, and the lifting platform drives the second dark box to rise and fall vertically; the support is arranged on one side of the lifting platform, and its upper end is fixedly connected to the pipeline and the high-speed camera respectively through a connecting rod.

5. The visualization test device for simulating the complex load transfer law of piles according to claim 1 is characterized in that: The first dark box and the second dark box are both made of opaque plates.

6. The visualization test device for simulating the complex load transfer law of piles according to claim 1 is characterized in that: The camera module uses a CCD camera, and each camera module includes no less than 3 cameras.

Images