Screw pile model horizontal bearing characteristic test device and use method

Abstract

The invention discloses a screw pile model horizontal bearing characteristic test device and a use method, and relates to the technical field of geotechnical engineering. Comprising a platform, the platform is provided with a model box, the model box is filled with transparent soil, a screw pile model is embedded in the transparent soil, and a strain gauge is preset in the screw pile model; the support is arranged on the platform, and a loading mechanism is arranged on the support; according to the acquisition system, a first laser group is connected to the platform through a test support, a first camera is connected to the platform through a fixing support, the fixing support and the test support are arranged outside the mutually perpendicular side walls of the model box respectively, a first displacement meter is connected to the support, and a strain gauge and the first displacement meter are electrically connected with an acquisition instrument. According to the device for testing the horizontal bearing characteristic of the screw pile model and the using method, observation of displacement of a soil body near the screw pile model can be achieved, and meanwhile research on the horizontal bearing characteristic of the screw pile model can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical engineering, and more particularly to a screw pile model horizontal bearing property test device and a use method thereof. Background Art

[0002] At present, pile foundation is one of the most widely used methods of foundation reinforcement in my country, and there are many forms of it. Among them, threaded piles have been widely used in China because of their high single pile bearing capacity, strong adaptability, wide application range, and environmental protection and economic benefits. As a new type of threaded pile, screw piles have a high single pile bearing capacity, but due to the complex structure, it brings about complex pile-soil interaction, which deserves further study.

[0003] Transparent soil technology is an advanced technology used to simulate and observe the internal structure and mechanical behavior of soil in a laboratory environment. It has shown broad application prospects in geotechnical engineering research. Its basic principle is to combine granular transparent soil materials with pore fluids of corresponding refractive indexes, and by matching the refractive index, the transparent soil can achieve a "transparent" effect under specific lighting conditions. The application of transparent soil technology is particularly important in pile foundation engineering. Traditional soil experiments make it difficult to accurately observe the subtle deformation of the soil around the pile foundation and the mechanical response at the pile-soil contact interface, and it is difficult to obtain the displacement field of the soil around the pile, especially for complex pile types, such as screw piles and other threaded pile types, which have complex pile-soil interactions. Conventional methods cannot observe the changes in the displacement field of the soil around the pile before and after a certain screw thread. Therefore, it is necessary to develop a test device that can measure the displacement strain of the pile body and observe the changes in the internal displacement field of the soil in multiple dimensions and sections. Summary of the invention

[0004] In view of this, the present invention provides a screw pile model horizontal bearing characteristic test device and use method, which can observe the changes in the displacement inside the soil in multiple dimensions and sections and measure the displacement strain of the pile body. In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0005] In one aspect, the present invention provides a screw pile model horizontal bearing property test device, comprising:

[0006] A platform, wherein a model box is arranged on the platform, the model box is filled with transparent soil, a screw pile model is buried in the transparent soil, a strain gauge is preset in the screw pile model, and a first threading hole and a second threading hole are respectively arranged on a pair of parallel side walls of the model box;

[0007] A bracket, wherein the bracket is arranged on the platform, a loading mechanism is arranged on the bracket, the loading mechanism is connected to the screw pile model, and the loading mechanism is used to apply a load to the screw pile model;

[0008] The acquisition system includes a first laser group, a first camera, a first displacement meter and an acquisition instrument, wherein the first laser group is connected to the platform through a test bracket, the first camera is connected to the platform through a fixed bracket, and the speckle of the screw pile model irradiated by the first laser group is photographed by the first camera, the fixed bracket and the test bracket are respectively arranged outside the mutually perpendicular side walls of the model box, the first displacement meter is connected to the bracket, the measuring end of the first displacement meter enters the model box through the first threading hole and is connected to the screw pile model, and the strain gauge and the first displacement meter are both electrically connected to the acquisition instrument.

[0009] Furthermore, the first laser group includes two first lasers, and the two first lasers are respectively arranged outside two parallel side walls of the model box through two test brackets, so as to irradiate speckles on both sides of the screw pile model.

[0010] Furthermore, the acquisition system also includes a second laser and a second camera, the second laser is arranged on the fixed bracket, the second camera is arranged above the screw pile model and connected to the bracket, and the second camera is used to capture the speckle on the surface of the screw pile model irradiated by the second laser.

[0011] Furthermore, a slide groove is provided at the bottom end of the test bracket, and a slide rail is provided on the platform, and the sliding of the test bracket on the platform is achieved through the cooperation of the slide groove and the slide rail.

[0012] Furthermore, a vertical slide rail and a vertical slider are provided on the fixed bracket, and the second laser and the first camera are slidably connected to the fixed bracket via the vertical slider respectively.

[0013] Furthermore, the loading mechanism includes a pulley, a load wire and a weight hook, the pulley is fixed on the bracket, one end of the load wire enters the model box through the second threading hole and is connected to the screw pile model, the other end of the load wire is connected to the weight hook and is suspended in the air, and the load is applied to the screw pile model through the weight.

[0014] Furthermore, a crossbeam for preventing the model box from sliding is arranged on the bracket, and the crossbeam is arranged between the model box and the pulley.

[0015] Furthermore, the acquisition system also includes a second displacement meter, one end of which is fixed to the bracket, the other end of which is connected to the upper end of the screw pile model, and the second displacement meter is electrically connected to the acquisition instrument.

[0016] On the other hand, the present invention provides a method for using a screw pile model horizontal bearing characteristic test device, the method using the screw pile model horizontal bearing characteristic test device comprising the following steps:

[0017] S10: Divide the screw pile model into two halves and use 3D printing to polish the inside of the screw pile model, draw lines at the locations where strain gauges need to be attached and attach strain gauges, glue the two half-split piles together, and spray matte black paint on the outer surface of the glued screw pile model;

[0018] S20: connecting one end of the first displacement meter to the screw pile model through the first threading hole;

[0019] S30: Filling the model box with transparent soil, and burying the screw pile model during the filling process;

[0020] S40: connecting one end of the loading mechanism to the screw pile model through the second threading hole;

[0021] S50: connecting the strain gauge and the first displacement meter to the acquisition instrument through a line;

[0022] S60: turning on the acquisition instrument, recording the data of the first displacement meter and the strain gauge, turning on the first laser group and the first camera, photographing the speckle field of the vertical section, and turning off the first laser group and the first camera;

[0023] S70: turning on the second laser and the second camera to capture a single speckle field of a horizontal section, and turning off the second laser and the second camera;

[0024] S80: Start the loading mechanism, start to apply the load, turn on the first laser group and the first camera, the first laser group irradiates the axis of the pile body, shoots the vertical section speckle field, increases the load, and shoots the vertical section speckle field again, and repeats this process to record the displacement field changes of the screw pile model at different stages during the entire horizontal load application process;

[0025] S90: Organize the data and analyze the moment distribution of the screw pile model under different levels of horizontal loads.

[0026] It can be known from the above technical scheme that, compared with the prior art, the present invention discloses a screw pile model horizontal bearing characteristic test device, which applies load to the screw pile model through a loading device, irradiates speckles on the side of the screw pile model through a first laser group, records the speckles irradiated by the first laser group through a first camera, applies load to the screw pile model step by step through a loading device, and records the changes of the screw pile model during the loading process through a data acquisition instrument. The test device can realize the observation of soil displacement near the screw pile model, and at the same time can realize the study of the horizontal characteristics of the screw pile model. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0028] Figure 1 A schematic diagram of the structure of a screw pile model horizontal bearing characteristic test device provided by the present invention;

[0029] Figure 2 A schematic diagram of the structure of the screw pile model provided by the present invention;

[0030] Figure 3 A schematic diagram of the structure inside the model box provided by the present invention;

[0031] Figure 4 It is a schematic diagram of the structure of part A of the present invention;

[0032] Figure 5 A partial flow chart of a method for using the screw pile model horizontal bearing characteristic test device provided by the present invention;

[0033] Figure 6 Another partial flow chart of the method for using the screw pile model horizontal bearing property test device provided by the present invention.

[0034] In the figure: 1. model box; 2. fixed support rod; 3. support; 4. first camera; 5. first displacement meter; 6. weight hook; 7. weight; 8. crossbeam; 9. pulley support; 10. test support rod; 11. support; 12. screw pile model; 13. line; 14. strain gauge; 15. first threading hole; 16. second threading hole; 17. transparent soil; 18. first displacement meter wire; 19. load wire; 20. pulley; 21. first laser; 22. second laser; 23. slide rail; 24. fixed support; 25. platform; 26. slide trough; 27. vertical slider; 28. second displacement meter; 29. ​​second displacement meter wire; 30. connecting plate; 31. second camera. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] See also Figure 1-6On the one hand, the embodiment of the present invention discloses a screw pile model horizontal bearing property test device, comprising:

[0037] A platform 25 is provided on the platform 25. A model box 1 is filled with transparent soil 17. A screw pile model 12 is buried in the transparent soil 17. A strain gauge 14 is preset in the screw pile model 12. A pair of parallel side walls of the model box 1 are respectively provided with a first threading hole 15 and a second threading hole 16.

[0038] A bracket 3, the bracket 3 is arranged on the platform 25, a loading mechanism is arranged on the bracket 3, the loading mechanism is connected to the screw pile model 12, and the loading mechanism is used to apply a load to the screw pile model 12;

[0039] The acquisition system includes a first laser group, a first camera 4, a first displacement meter 5 and an acquisition instrument. The first laser group is connected to the platform 25 through a test support rod 10, and the first camera 4 is connected to the platform 25 through a fixed bracket 24. The first camera 4 shoots the speckle of the screw pile model 12 irradiated by the first laser group. The fixed bracket 24 and the test support rod 10 are respectively arranged outside the mutually perpendicular side walls of the model box 1. The first displacement meter 5 is connected to the bracket 3. The measuring end of the first displacement meter 5 enters the model box 1 through the first threading hole 15 and is connected to the screw pile model 12. The strain gauge 14 and the first displacement meter 5 are both electrically connected to the acquisition instrument.

[0040] By filling the model box 1 with transparent soil 17 , the change of the displacement field of the soil around the screw pile model 12 during the loading process can be obtained.

[0041] A load is applied to the screw pile model 12 through a loading mechanism, the deformation of the screw pile model 12 is measured by the strain gauge 14 and the first displacement meter 5, and the data measured by the first displacement meter 5 and the strain gauge 14 are recorded by a data acquisition instrument, so as to measure the horizontal bearing capacity of the screw pile model 12 during the loading process, and at the same time, the horizontal characteristics of the screw pile model 12 can be studied.

[0042] In some embodiments, the fixing bracket 24 is fixed to the platform 25 via a connecting plate 30 .

[0043] In some embodiments, the first displacement meter wire 18 enters the model box 1 through the first threading hole 15 and is connected to the screw pile model 12 .

[0044] In some embodiments, the first laser group includes two first lasers 21 , which are respectively arranged outside two parallel side walls of the model box 1 through two test support rods 10 to irradiate speckles on both sides of the screw pile model 12 .

[0045] The two first lasers 21 emit vertical lasers toward the axis of the screw pile model 12 , thereby irradiating speckles on the tensile and compressive surfaces of the screw pile model 12 , and the first camera 4 captures and records the speckles on the tensile and compressive surfaces of the screw pile model 12 .

[0046] In some embodiments, the acquisition system also includes a second laser 22 and a second camera 31. The second laser 22 is disposed on a fixed bracket 24, and the second camera 31 is disposed above the screw pile model 12 and connected to the bracket 3. The second camera 31 is used to capture the speckle on the surface of the screw pile model 12 irradiated by the second laser 22.

[0047] In some embodiments, the screw pile model 12 is connected to the bracket 3 via a fixing support rod 2 .

[0048] In some embodiments, two second lasers 22 are provided, and the two second lasers 22 are respectively arranged outside two parallel side walls of the model box 1 through two fixing brackets 24 .

[0049] The second laser 22 emits horizontal laser light toward the screw pile model 12 , thereby irradiating speckles around the screw pile model 12 at the same depth. The speckles irradiated by the second laser 22 are recorded by the second camera 31 .

[0050] In some embodiments, a slide groove 26 is disposed at the bottom end of the test support rod 10 , and a slide rail 23 is disposed on the platform 25 , and the slide groove 26 and the slide rail 23 cooperate to enable the test support rod 10 to slide on the platform 25 .

[0051] By cooperating the slide groove 26 and the slide rail 23 to change the position of the test support rod 10, the position of the first laser 21 is changed, and the position of the first laser 21 irradiating the screw pile model 12 is changed, so that the first camera 4 can record the vertical speckle of the screw pile model 12 at different angles.

[0052] In some embodiments, a vertical slide rail and a vertical slider 27 are provided on the fixed bracket 24 , and the second laser 22 and the first camera 4 are slidably connected to the fixed bracket 24 via the vertical slider 27 .

[0053] Through the cooperation of the vertical slide rail and the vertical slider 27, the second laser 22 can move in the vertical direction, so that the horizontal laser emitted by the second laser 22 can irradiate different heights of the screw pile model 12, and the second camera 31 can record the circumferential speckle at different heights of the screw pile model 12.

[0054] In some embodiments, the loading mechanism includes a pulley 20, a load wire 19 and a weight hook 6. The pulley 20 is fixed on the bracket 3. One end of the load wire 19 enters the model box 1 through the second threading hole 16 and is connected to the screw pile model 12. The other end of the load wire 19 is connected to the weight hook 6 and is suspended in the air. The load is applied to the screw pile model 12 through the weight 7.

[0055] In some embodiments, the pulley 20 is fixed to the bracket 3 via the pulley bracket 9 .

[0056] In some embodiments, a crossbeam 8 is disposed on the bracket 3 to prevent the model box 1 from sliding, and the crossbeam 8 is disposed between the model box 1 and the pulley 20 .

[0057] The crossbeam 8 blocks the sliding of the model box 1 , thereby preventing the model box 1 from sliding off the platform 25 .

[0058] In some embodiments, the acquisition system further includes a second displacement meter 28, one end of which is fixed to the bracket 3, the other end of which is connected to the upper end of the screw pile model 12, and the second displacement meter 28 is electrically connected to the acquisition instrument.

[0059] The second displacement device 28 detects the change of the upper end of the screw pile model 12 during the loading process.

[0060] In some embodiments, the second displacement meter 28 is connected to the upper end of the screw pile model 12 via a second displacement meter wire 29 .

[0061] In some embodiments, the first displacement meter 5 and the second displacement meter 28 are fixed on the bracket 3 via a support 11 .

[0062] The change of the top end of the screw pile model 12 during the loading process is recorded by the second displacement meter 28 .

[0063] In some embodiments, the first displacement meter 5 , the second displacement meter 28 , and the strain gauge 14 are electrically connected to the acquisition instrument through the line 13 .

[0064] The speckle field on the side of the screw pile model 12 during the loading process is obtained by the first camera 4, the speckle field in the circumferential direction of the screw pile model 12 during the loading process is obtained by the second camera 31, and the displacement strain of the pile body of the screw pile model 12 during the loading process is obtained by the first displacement meter 5 and the second displacement meter 28. The load-displacement response, pile head rotation angle, pile body bending moment response, pile body deformation response, the relationship curve between the lateral reaction force of the soil and the lateral displacement of the screw pile model, the front displacement of the soil around the pile, and the top surface displacement of the soil around the pile are analyzed to obtain the screw pile model 12.

[0065] On the other hand, a method for using a screw pile model horizontal bearing characteristic test device is provided. The method for using the screw pile model horizontal bearing characteristic test device comprises the following steps:

[0066] S100: making a screw pile model 12;

[0067] S101: dividing the screw pile model 12 into two halves and printing them through 3D aluminum alloy;

[0068] S102: polishing the inside of the screw pile model 12 to be smooth, marking the position where the strain gauge 14 needs to be attached, and attaching the strain gauge 14;

[0069] S103: bonding two half-split piles;

[0070] S104: Spray matte black paint on the outer surface of the bonded screw pile model 12;

[0071] S200: making a model box 1;

[0072] S201: Design the size of model box 1;

[0073] S202: Processing the first threading hole 15 and the second threading hole 16 of the model box 1, connecting the first displacement meter 5, the second displacement meter 28 and the load wire 19 to the screw pile model 12;

[0074] S203: configuring transparent soil 17 in proportion;

[0075] S300: configuring transparent soil 17;

[0076] S301: Put the transparent soil 17 into the model box 1, and when it is about to be filled, seal the first threading hole 15 and the second threading hole 16 on the model box 1;

[0077] S302: Use hammering method to control the height and relative density of transparent soil;

[0078] S400: Install the loading device, the first laser 21, the second laser 22, the first camera 4 and the second camera 31;

[0079] S500: Turn on the data collector to record the data measured by the first displacement meter 5, the second displacement meter 28 and the strain gauge 14;

[0080] S600: Shoot the speckle field before loading, move and shoot multiple sections, and close after completion;

[0081] S601: moving the test bracket 10, using the first camera 4 to photograph the speckle emitted by the first laser 21 before loading, photographing multiple cross sections, and turning off the first camera 4 and the first laser 21;

[0082] S602: Move the second laser 22, use the second camera 31 to photograph the speckle emitted by the second laser 22 before loading, photograph multiple cross sections, and turn off the second camera 31 and the second laser 22;

[0083] S700: start the first laser 21 and the first camera 4 again, so that the laser emitted by the first laser 21 remains at the position of the pile shaft axis;

[0084] S800: Apply horizontal load;

[0085] S900: After the displacement curve is stable for a period of time, the first laser 21 and the first camera 4 are turned off;

[0086] S901: moving the test support 10, changing the position of the first laser 21, using the first camera 4 to capture speckles of the screw pile model 12 on multiple cross sections, and turning off the first laser 21 and the first camera 4;

[0087] S1000: Turn on the second laser 22 and the second camera 31, move the vertical pulley to take pictures of multiple sections, and turn them off after completion;

[0088] S1001: moving the second laser 22, the second camera 31 photographs circumferential speckles at different heights on the screw pile model 12, and turning off the second camera 31 and the second laser 22;

[0089] S1100: Determine whether the stop requirement is met;

[0090] S1101: does not meet the requirements, repeat S700-S1000;

[0091] S1200: Meets the requirements, end the test.

[0092] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0093] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A screw pile model horizontal bearing characteristics test device, characterized in that: include: A platform, wherein a model box is arranged on the platform, the model box is filled with transparent soil, a screw pile model is buried in the transparent soil, a strain gauge is preset in the screw pile model, and a first threading hole and a second threading hole are respectively arranged on a pair of parallel side walls of the model box; A bracket, wherein the bracket is arranged on the platform, a loading mechanism is arranged on the bracket, the loading mechanism is connected to the screw pile model, and the loading mechanism is used to apply a load to the screw pile model; The acquisition system includes a first laser group, a first camera, a first displacement meter and an acquisition instrument, wherein the first laser group is connected to the platform through a test bracket, the first camera is connected to the platform through a fixed bracket, and the speckle of the screw pile model irradiated by the first laser group is photographed by the first camera, the fixed bracket and the test bracket are respectively arranged outside the mutually perpendicular side walls of the model box, the first displacement meter is connected to the bracket, the measuring end of the first displacement meter enters the model box through the first threading hole and is connected to the screw pile model, and the strain gauge and the first displacement meter are both electrically connected to the acquisition instrument.

2. The screw pile model horizontal bearing characteristics test device according to claim 1 is characterized in that: The first laser group includes two first lasers, which are respectively arranged outside two mutually parallel side walls of the model box through two test brackets, and are used to irradiate speckles on both sides of the screw pile model.

3. The screw pile model horizontal bearing characteristic test device according to claim 1 is characterized in that: The acquisition system also includes a second laser and a second camera, wherein the second laser is disposed on the fixed bracket, and the second camera is disposed above the screw pile model and connected to the bracket, and the second camera is used to photograph the speckle on the surface of the screw pile model irradiated by the second laser.

4. The screw pile model horizontal bearing characteristics test device according to claim 1, characterized in that: A slide groove is arranged at the bottom end of the test bracket, and a slide rail is arranged on the platform. The slide groove and the slide rail cooperate to realize the sliding of the test bracket on the platform.

5. The screw pile model horizontal bearing characteristic test device according to claim 3 is characterized in that: The fixed bracket is provided with a vertical slide rail and a vertical slider, and the second laser and the first camera are respectively slidably connected to the fixed bracket through the vertical slider.

6. The screw pile model horizontal bearing characteristic test device according to claim 1, characterized in that: The loading mechanism includes a pulley, a load wire and a weight hook, the pulley is fixed on the bracket, one end of the load wire enters the model box through the second threading hole and is connected to the screw pile model, the other end of the load wire is connected to the weight hook and is suspended in the air, and the load is applied to the screw pile model through the weight.

7. The screw pile model horizontal bearing characteristic test device according to claim 6, characterized in that: The bracket is provided with a crossbeam for preventing the model box from sliding, and the crossbeam is arranged between the model box and the pulley.

8. The screw pile model horizontal bearing characteristic test device according to claim 1, characterized in that: The acquisition system further includes a second displacement meter, one end of which is fixed on the bracket, the other end of which is connected to the upper end of the screw pile model, and the second displacement meter is electrically connected to the acquisition instrument.

9. A method for using a screw pile model horizontal bearing characteristic test device, characterized in that: The method of use uses the screw pile model horizontal bearing property test device according to any one of claims 1 to 8, comprising the following steps: S10: Divide the screw pile model into two halves and use 3D printing to polish the inside of the screw pile model, draw lines at the locations where strain gauges need to be attached and attach strain gauges, glue the two half-split piles together, and spray matte black paint on the outer surface of the glued screw pile model; S20: connecting one end of the first displacement meter to the screw pile model through the first threading hole; S30: Filling the model box with transparent soil, and burying the screw pile model during the filling process; S40: connecting one end of the loading mechanism to the screw pile model through the second threading hole; S50: connecting the strain gauge and the first displacement meter to the acquisition instrument through a line; S60: Turn on the acquisition instrument, record the data of the first displacement meter and the strain gauge, turn on the first laser group and the first camera, shoot the speckle field of the vertical section, and turn off the first laser group and the first camera; S70: turning on the second laser and the second camera to capture a single speckle field of a horizontal section, and turning off the second laser and the second camera; S80: Start the loading mechanism, start to apply the load, turn on the first laser group and the first camera, the first laser group irradiates the axis of the pile body, shoots the vertical section speckle field, increases the load, and shoots the vertical section speckle field again, and repeats this process to record the displacement field changes of the screw pile model at different stages during the entire horizontal load application process; S90: Organize data and analyze the bending moment distribution of screw piles under different levels of horizontal loads.

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