Sandy soil liquefaction test vibration table

Abstract

The utility model relates to a sand liquefaction test vibration table, which comprises a base, a side rocking jack, a mechanical spring, a table top, a positioning steel plate, a model box, a motor, an eccentric wheel, a frequency converter and an automatic cycle timing controller, the upper side of the table top is connected with a model box, two parallel positioning steel plates are vertically welded on the lower side of the table top and used for fixedly mounting a motor; bolt holes are preset in the positioning steel plate in the horizontal direction, the vertical direction and the clockwise 45-degree direction, and the motor and the positioning steel plate can be fixedly connected in the horizontal direction, the vertical direction and the clockwise 45-degree direction through bolts. Three vibration modes of vertical vibration, horizontal vibration and horizontal and vertical simultaneous vibration can be respectively realized. Compared with the prior art, the device has the advantages of simple structure, stable operation, adjustable vibration direction and frequency, controllable vibration duration, observable displacement and deformation of a test material and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of earthquake mold sand liquefaction test, in particular to a sand liquefaction test vibration table. Background Art

[0002] Sand liquefaction refers to the process in which the pore water pressure of saturated sand increases under vibration, the effective stress decreases to zero, the sand loses its shear strength, and changes from a solid state to a liquid state. Sand liquefaction can cause a series of hazards such as ground subsidence, surface collapse, loss of foundation bearing capacity, and ground slide. When an earthquake occurs, the strong ground vibration not only directly destroys surface buildings, but also causes the shallow saturated sand to liquefy, further expanding the disaster.

[0003] Among the many methods for studying sand liquefaction, the small shaking table model test is one of the most common and effective methods. During the test, the model box is fixed on the shaking table, and the saturated sand sample is prepared by the sand falling method in water. Sensors such as water pressure gauges and earth pressure boxes are buried in the sand sample. After applying vibration, the change law of parameters such as pore water pressure and earth pressure is observed, and the liquefaction characteristics of saturated sand can be obtained.

[0004] Chinese patents CN202351181U, CN216209166U and CN219935633U disclose some sand liquefaction test vibration tables, but they have the following disadvantages:

[0005] 1. The circular motion is converted into linear repetitive motion by using many parts such as wheels and rods, which results in complex structure, high maintenance difficulty and low overall reliability;

[0006] 2. It can only realize horizontal vibration alone, but cannot realize vertical vibration or simultaneous vibration in vertical and horizontal directions alone, and cannot control the duration of vibration, and cannot better simulate real earthquake conditions. Utility Model Content

[0007] The purpose of the utility model is to provide a sand liquefaction test vibration table in order to overcome the defects of the above-mentioned prior art, which has simple structure, stable operation, adjustable vibration direction and frequency, controllable vibration duration, and observable displacement and deformation of test materials.

[0008] The purpose of the utility model can be achieved through the following technical solutions:

[0009] The utility model provides a sand liquefaction test vibration table, comprising: a base, a side rocking jack, a mechanical spring, a table top, a positioning steel plate, a model box, a motor, an eccentric wheel, a frequency converter, and an automatic cycle timing controller;

[0010] A limited position block is welded on the top of the base, the upper side of the table is connected to the model box, and a positioning steel plate is vertically welded on the lower side of the table. The positioning steel plate is used to fix the motor. There are two positioning steel plates, which are parallel to each other. Limited position blocks are welded on the bottom surface of the table and the corresponding positions of the base. The corresponding limit blocks of the table and the base are connected by mechanical springs.

[0011] The transmission shaft of the motor is fixedly connected to the eccentric wheel; the eccentric wheel rotates under the driving of the transmission shaft of the motor to generate exciting force, thereby causing the table to vibrate; the frequency converter is wired to the motor, and the automatic cycle timing controller is wired to the frequency converter.

[0012] The positioning steel plate is preset with bolt holes in the horizontal direction, vertical direction and 45 degrees clockwise direction. The motor and the positioning steel plate can be fixedly connected in three directions: horizontal direction, vertical direction and 45 degrees clockwise direction through bolts. Three vibration modes, namely vertical vibration, horizontal vibration and simultaneous horizontal and vertical vibration, can be achieved respectively to simulate different earthquake conditions.

[0013] The automatic cycle timing controller controls the power-on time of the entire circuit, thereby controlling the vibration time of the motor and protecting the circuit; the frequency converter can adjust the speed of the motor before or during operation, thereby controlling the vibration frequency and protecting the motor from overcurrent, overload, short circuit and overheating.

[0014] Furthermore, the four legs of the base are fixedly installed with a side-shaking jack, and the output end of the side-shaking jack is fixedly installed with a universal pulley; the telescopic rod of the side-shaking jack is engraved with a scale, and the telescopic length can be read. The entire vibration table can be moved after the four universal pulleys are evenly stressed in a horizontal plane through the side-shaking jack.

[0015] Furthermore, the length, width and height of the inner net dimensions of the model box are 80 cm, 40 cm and 50 cm respectively, and the length and width of the bottom plate and the table top of the model box are consistent, both of which are 100 cm×100 cm.

[0016] Furthermore, the model box material is made of 2cm thick polyvinyl chloride plastic board. The model box has high strength and high transparency. When conducting sand liquefaction test, the deformation, displacement and other parameters of the sand inside the model box can be recorded and observed by high-speed cameras and other equipment; the bottom plate of the model box is cantilevered, and high-speed cameras and other equipment can be installed on the bottom plate.

[0017] Furthermore, the power of the motor is 3HP (2.238kW), the transmission shaft of the motor is stepped, the transmission shaft of the motor is connected to the eccentric wheel through a flat key, a transmission shaft radial bolt and a transmission shaft axial bolt, and a high-strength gasket with a diameter larger than the transmission shaft is installed between the axial bolt and the eccentric wheel. This connection method can prevent the eccentric wheel from loosening radially and axially, ensuring that the power of the motor is smoothly transmitted to the eccentric wheel.

[0018] Furthermore, a protective cover is installed on the outside of the eccentric wheel to further ensure safety.

[0019] Furthermore, four limit blocks are welded on the bottom surface of the table and the corresponding positions of the base. The limit blocks have a diameter of 10 cm and a height of 5 cm. The height of the mechanical spring is 15 cm, the wire diameter is 2 cm, and the inner diameter is 10 cm. After the model box is filled with sand samples and the motor is installed, the corresponding limit blocks are not in contact with each other, which can provide vertical support force and constrain horizontal movement.

[0020] Furthermore, the base is a base welded from square steel.

[0021] Furthermore, the table top is preset with bolt holes, and the table top and the model box are connected through the bolt holes and bolts arranged in the bolt holes.

[0022] Furthermore, lubricating oil or grease is applied at the connection between the transmission shaft of the motor and the eccentric wheel and at the connection between the limit block and the mechanical spring to reduce friction.

[0023] Compared with the prior art, the utility model has the following advantages:

[0024] (1) The motor can be fixed in three directions: horizontal, vertical, and clockwise at 45 degrees. It can achieve horizontal vibration, vertical vibration, and simultaneous horizontal and vertical vibration. It can provide more test plans and study the liquefaction characteristics of sand more comprehensively.

[0025] (2) Vibration can be generated and directly transmitted to the model box through the joint action of components such as the motor, eccentric wheel, automatic cycle timing controller and frequency converter, and the vibration frequency can be changed to control the duration of vibration.

[0026] (3) The model box is made of highly transparent polyvinyl chloride (PVC) plastic board, and the deformation, displacement and other parameters of the sand inside the model box can be recorded and observed by high-speed cameras and other equipment. The entire vibration table is movable, easy to assemble, highly reliable and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The overall schematic diagram of the shaking table for sand liquefaction test.

[0028] Figure 2 This is a schematic diagram of the table top, limit block, positioning steel plate and structure of the utility model.

[0029] Figure 3 The utility model is a schematic diagram of the structure of the motor, eccentric wheel, frequency converter, automatic cycle timing controller and protective cover.

[0030] Figure 4The utility model is a schematic diagram of the electric motor transmission shaft and the eccentric wheel and the structure.

[0031] Figure 5 It is a plan view of the connection between the model box and the tabletop, and the horizontal, vertical and 45-degree clockwise fixed connection between the motor and the positioning steel plate of the utility model (without the protective cover installed).

[0032] Figure 6 It is a schematic diagram of the limit block, mechanical spring and structure plane of the utility model.

[0033] Figure 7 It is a schematic diagram of the side-sway jack, universal pulley and structure plane of the utility model.

[0034] Figure numerals: 1. base; 2. side rocking jack; 3. universal pulley; 4. limit block; 5. mechanical spring; 6. table; 7. positioning steel plate; 8. model box; 9. motor; 10. eccentric wheel; 11. protective cover; 12. frequency converter; 13. automatic cycle timing controller. DETAILED DESCRIPTION

[0035] The following is a detailed description of the present invention in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0036] Example 1

[0037] This embodiment provides a sand liquefaction test vibration table, such as Figure 1 As shown, it includes: a base 1, a side rocking jack 2, a mechanical spring 5, a table 6, a positioning steel plate 7, a model box 8, a motor 9, an eccentric wheel 10, a frequency converter 12, and an automatic cycle timing controller 13;

[0038] A limited block 4 is welded on the top of the base 1, and a side-roll jack 2 is fixedly installed on the four legs of the base 1, and a universal pulley 3 is fixedly installed on the output end of the side-roll jack 2;

[0039] like Figure 2 , Figure 5 , Figure 6 As shown, the upper side of the table 6 is connected to the model box 8, and a positioning steel plate 7 is vertically welded on the lower side of the table 6. The positioning steel plate 7 is used to fix the motor 9. There are two positioning steel plates 7, and the two positioning steel plates 7 are parallel; the bottom surface of the table 6 and the corresponding positions of the base 1 are welded with a limiting block 4, and the table 6 and the corresponding limiting blocks 4 of the base 1 are connected through a mechanical spring 5;

[0040] like Figure 3 , Figure 4As shown, the transmission shaft of the motor 9 is fixedly connected to the eccentric wheel 10; the eccentric wheel 10 rotates under the drive shaft of the motor 9 to generate an exciting force, thereby causing the table 6 to vibrate; the frequency converter 12 is wired to the motor 9, and the automatic cycle timing controller 13 is wired to the frequency converter 12.

[0041] The positioning steel plate 7 is preset with bolt holes in the horizontal direction, vertical direction and 45 degrees clockwise direction. The motor 9 and the positioning steel plate 7 can be fixedly connected in three directions, namely, horizontal direction, vertical direction and 45 degrees clockwise direction, by bolts. Three vibration modes, namely, vertical vibration, horizontal vibration and simultaneous horizontal and vertical vibration, can be realized respectively to simulate different earthquake conditions.

[0042] The automatic cycle timing controller 13 controls the power-on time of the entire circuit, thereby controlling the vibration time of the motor 9 and protecting the circuit; the frequency converter 12 can adjust the speed of the motor 9 before or during operation, thereby controlling the vibration frequency and protecting the motor from overcurrent, overload, short circuit and overheating.

[0043] like Figure 7 As shown, in a specific embodiment, the telescopic rod of the side-shaking jack 2 is engraved with a scale, and the telescopic length can be read. The entire vibration table can be moved after the four universal pulleys 3 are evenly stressed in a horizontal plane through the side-shaking jack 2.

[0044] In a specific embodiment, the length, width and height of the inner net dimensions of the model box 8 are 80 cm, 40 cm and 50 cm respectively, and the bottom plate and the table top 6 of the model box 8 have the same length and width, both of which are 100 cm×100 cm.

[0045] In a specific embodiment, the model box 8 is made of a 2 cm thick polyvinyl chloride plastic plate. The model box 8 has high strength and high transparency. When conducting a sand liquefaction test, the deformation, displacement and other parameters of the sand inside the model box 8 can be recorded and observed by a high-speed camera or other equipment. The bottom plate of the model box 8 is cantilevered, and a high-speed camera or other equipment can be installed on the bottom plate.

[0046] In a specific embodiment, the power of the motor 9 is 3HP2.238kW, the transmission shaft of the motor 9 is stepped, the transmission shaft of the motor 9 is connected to the eccentric wheel 10 by a flat key, a transmission shaft radial bolt and a transmission shaft axial bolt, and a high-strength gasket with a diameter larger than the transmission shaft is installed between the axial bolt and the eccentric wheel 10. This connection method can prevent the eccentric wheel 10 from loosening radially and axially, and ensure that the power of the motor 9 is smoothly transmitted to the eccentric wheel 10. A protective cover 11 is installed on the outside of the eccentric wheel 10 to further ensure safety.

[0047] In the specific implementation, four limit blocks 4 are welded on the bottom surface of the table 6 and the corresponding positions of the base 1. The limit blocks 4 have a diameter of 10 cm and a height of 5 cm. The mechanical spring 5 has a height of 15 cm, a wire diameter of 2 cm, and an inner diameter of 10 cm. After the model box is filled with sand samples and the motor is installed, the corresponding limit blocks 4 are not in contact with each other, which can provide vertical support force and restrict horizontal movement.

[0048] In a specific implementation, the base 1 is a base formed by welding square steel.

[0049] In a specific embodiment, the table top 6 is preset with bolt holes, and the table top 6 and the model box 8 are connected through the bolt holes and the bolts arranged in the bolt holes.

[0050] Furthermore, lubricating oil or grease is applied at the connection between the transmission shaft of the motor 9 and the eccentric wheel 10 and at the connection between the limit block 4 and the mechanical spring 5 to reduce friction.

[0051] In specific applications, select the vibration direction and install the motor 9. When the vibration table is moved to the predetermined position, the side rocking jack 2 is shaken and the universal pulley 3 is retracted, and the base 1 is grounded. Power is turned on, and the vibration frequency and vibration duration are set by the frequency converter 12 and the automatic cycle timing controller 13 respectively. Saturated sand samples are prepared by the water falling sand method and other methods, and sensors such as water pressure gauges and soil pressure boxes are buried in the sand samples. After starting, the change law of parameters such as pore water pressure and soil pressure is observed, and the liquefaction characteristics of sand are further analyzed.

[0052] Components not described in detail in this embodiment are all existing components that can be purchased through public channels.

[0053] The above description of the embodiments is to facilitate the understanding and use of the utility model by those skilled in the art. It is obvious that those familiar with the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the utility model is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the utility model without departing from the scope of the utility model should be within the scope of protection of the utility model.

Claims

1. A sand liquefaction test vibration table, characterized in that: include: Base (1), lateral rocking jack (2), mechanical spring (5), table (6), positioning steel plate (7), model box (8), motor (9), eccentric wheel (10), frequency converter (12), automatic cycle timing controller (13); A limiting block (4) is welded on the top of the base (1); the upper side of the table top (6) is connected to the model box (8); a positioning steel plate (7) is vertically welded on the lower side of the table top (6); the positioning steel plate (7) is used to fix and install the motor (9); two positioning steel plates (7) are provided, and the two positioning steel plates (7) are parallel; limiting blocks (4) are welded on the bottom surface of the table top (6) and the corresponding positions of the base (1); the table top (6) and the corresponding limiting blocks (4) of the base (1) are connected via a mechanical spring (5); The transmission shaft of the motor (9) is fixedly connected to the eccentric wheel (10); the eccentric wheel (10) is driven by the transmission shaft of the motor (9) to rotate to generate an exciting force, thereby causing the table (6) to vibrate; the frequency converter (12) is wired to the motor (9), and the automatic cycle timing controller (13) is wired to the frequency converter (12); The positioning steel plate (7) is preset with bolt holes in the horizontal direction, the vertical direction and the clockwise direction of 45 degrees. The motor (9) and the positioning steel plate (7) can realize three fixed connection modes in the horizontal direction, the vertical direction and the clockwise direction of 45 degrees through bolts, and can respectively realize three vibration modes of vertical vibration, horizontal vibration and horizontal and vertical vibration at the same time, so as to simulate different earthquake working conditions.

2. A sand liquefaction test vibration table according to claim 1, characterized in that: The four legs of the base (1) are fixedly mounted with a side-sway jack (2), and the output end of the side-sway jack (2) is fixedly mounted with a universal pulley (3); the telescopic rod of the side-sway jack (2) is engraved with a scale, so that the telescopic length can be read.

3. A sand liquefaction test vibration table according to claim 1, characterized in that: The inner net dimensions of the model box (8) are 80 cm in length, 40 cm in width and 50 cm in height respectively. The bottom plate and the table top (6) of the model box (8) are of the same length and width, both of which are 100 cm×100 cm.

4. A sand liquefaction test vibration table according to claim 1, characterized in that: The material of the model box (8) is a 2 cm thick polyvinyl chloride plastic plate.

5. The sand liquefaction test vibration table according to claim 1, characterized in that: The power of the motor (9) is 3HP. The transmission shaft of the motor (9) is stepped. The transmission shaft of the motor (9) is connected to the eccentric wheel (10) via a flat key, a transmission shaft radial bolt and a transmission shaft axial bolt. A high-strength gasket having a diameter greater than that of the transmission shaft is installed between the axial bolt and the eccentric wheel (10).

6. A sand liquefaction test vibration table according to claim 1, characterized in that: A protective cover (11) is installed on the outer side of the eccentric wheel (10).

7. The sand liquefaction test vibration table according to claim 1, characterized in that: The limit block (4) has a diameter of 10 cm and a height of 5 cm; the mechanical spring (5) has a height of 15 cm, a wire diameter of 2 cm, and an inner diameter of 10 cm.

8. The sand liquefaction test vibration table according to claim 1, characterized in that: The base (1) is a base welded from square steel.

9. The sand liquefaction test vibration table according to claim 1, characterized in that: The table top (6) is preset with bolt holes, and the table top (6) and the model box (8) are connected via the bolt holes and bolts arranged in the bolt holes.

10. The sand liquefaction test vibration table according to claim 1, characterized in that: The connection between the transmission shaft of the motor (9) and the eccentric wheel (10) and the connection between the limit block (4) and the mechanical spring (5) are coated with lubricating oil or lubricating grease to reduce friction.

Images