CN215406216U

CN215406216U - Test bed for simulating earthquake impact on pile foundation

Info

Publication number: CN215406216U
Application number: CN202121814981.5U
Authority: CN
Inventors: 金丹丹; 赵俣
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2021-08-04
Filing date: 2021-08-04
Publication date: 2022-01-04
Anticipated expiration: 2031-08-04

Abstract

The utility model provides a test bed for simulating earthquake impact on a pile foundation, which comprises a box rail system and an impact system, wherein the box rail system comprises a rail and a box body arranged on the rail; the impact system comprises a slide way and an impact ball, the outlet end of the slide way is in butt joint with the end part of the rail, and the impact ball can fall down along the slide way to impact the box body. The test bed can be applied to simulation test and research of the stress characteristic of the pile foundation under the earthquake action, and provides convenience for scientific research personnel to search the interaction condition between the pile and the soil layer. The earthquake impact is simulated by the impact action converted by the impact ball falling along the slideway, the operation is simple and convenient, and the impact loads with different strengths can be realized by adjusting the release height of the impact ball; and both sides set up the blotter around the cushion cap, not only can play the effect of protection architecture safety on the one hand, on the other hand more can play the effect of adjusting different impact load frequencies.

Description

Test bed for simulating earthquake impact on pile foundation

Technical Field

The utility model belongs to the technical field of pile foundation vibration test beds, and particularly relates to a test bed for simulating a pile foundation to be impacted by an earthquake.

Background

The foundation refers to the load-bearing structure below the ground of a building, and the pile foundation is one of the most widely used foundation forms. The pile foundation is a deep foundation, the tops of a plurality of piles are connected into a whole through bearing platforms, the pile foundation has the advantages of high bearing capacity and small settlement, and particularly, compared with a pile-free foundation form, the pile foundation has higher seismic performance.

Although the pile foundation has higher seismic performance, the pile foundation is used as a building structure with the largest earthquake damage shadow, and the stress characteristics of the pile foundation under the action of an earthquake still need to be deeply researched and analyzed, particularly the interaction condition between the pile and the soil layer is searched, but the existing general vibration test bed is difficult to meet the related test research requirements.

SUMMERY OF THE UTILITY MODEL

Aiming at the defects in the prior art, the utility model provides a test bed for simulating pile foundation earthquake impact.

The present invention achieves the above technical objects by the following technical means.

A test bed for simulating earthquake impact on a pile foundation comprises a box rail system and an impact system, wherein the box rail system comprises a rail and a box body arranged on the rail; the impact system comprises a slide way and an impact ball, the outlet end of the slide way is in butt joint with the end part of the rail, and the impact ball can fall down along the slide way to impact the box body.

Furthermore, a bearing platform is fixed at the bottom of the box body and is movably connected with the track.

Further, the bottom of the bearing platform is connected with the track through a flange sliding block.

Furthermore, a baffle is arranged at one end, away from the slide way, of the track, cushion pads are respectively arranged on the front side and the rear side of the bearing platform, the cushion pad on one side is opposite to the baffle, and the cushion pad on the other side is opposite to the slide way outlet.

Further, the impact load frequency is adjusted by replacing the buffer cushions with different hardness.

Further, the box is the ya keli material, and the top is opened, and inboard bottom is equipped with the fixed plate, and the fixed plate surface is equipped with a plurality of ann jacks.

Further, the slide is fillet row structure, including horizontal segment, circular arc section and vertical section.

Furthermore, a height adjusting mechanism for adjusting the release height of the impact ball is arranged in the slide way.

Further, the impact ball is an iron ball.

Further, height adjustment mechanism includes electromagnetism magnetic ring and draws the dish, wherein the electromagnetism magnetic ring sets up in the vertical section of slide to be connected with the cable that draws the dish, draw the dish setting at vertical section top.

The utility model has the beneficial effects that:

(1) the utility model provides a test bed which is used for simulating the impact influence of an earthquake on a pile foundation, so that the test bed is applied to simulation test and research of the stress characteristic of the pile foundation under the earthquake action, and convenience is provided for scientific research personnel to search the interaction condition between a pile and a soil layer.

(2) The test bed has simple and reliable integral structure and moderate size, wherein the earthquake impact is simulated by the impact effect converted by the impact ball falling along the slideway, the operation is simple and convenient, and the impact loads with different strengths can be realized by adjusting the release height of the impact ball.

(3) The test bed is provided with the cushion pads on the front side and the rear side of the bearing platform, so that the safety of the structure can be protected, and different impact load frequencies can be adjusted.

Drawings

FIG. 1 is a block diagram of a test stand according to the present invention;

FIG. 2 is a top view of the test stand of the present invention.

Reference numerals:

11-a track; 12-a baffle plate; 21-a cushion cap; 22-a slide block;

23-a cushion pad; 24-a box body; 25-fixing the plate; 31-a slide;

32-iron balls; 33-an electromagnet ring; 34-pulling the disc; and 4, testing the pile.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the utility model and are not to be construed as limiting the utility model.

One, structure setting

The test bed for simulating the pile foundation to be impacted by the earthquake comprises a box rail system and an impact system, wherein the box rail system comprises a box body 24 and a track 11, the box body 24 is of an open-top structure and is used for placing the pile foundation to be tested, and the box body 24 can freely translate along the track 11; the impact system comprises a slide way 31 and an impact ball, wherein the impact ball falls down along the slide way 31 from a high position during testing, so that the box body 24 is impacted by utilizing the kinetic energy converted from the gravitational potential energy of the impact ball, the box body 24 is enabled to translate along the track 11 after being impacted, and the impact effect of an earthquake on a pile foundation is simulated.

As shown in fig. 1 and fig. 2, a section of track 11 is arranged on a horizontal base, one end of the track 11 is provided with a baffle 12, and the other end is butted with an outlet of a slide way 31. The whole slideway 31 is of a round angle structure and consists of a horizontal section, a circular section and a vertical section; the impact ball matched with the slide way 31 is an iron ball 32, an electromagnet ring 33 is arranged in the vertical section of the slide way 31, and the electromagnet ring 33 is used for adsorbing and fixing the iron ball 32 by the electromagnetic force of the electromagnet ring 33; when the electromagnetic ball valve works, the electromagnet ring 33 is connected with an external power supply, and the switch controls the electrification and the outage of the electromagnet ring 33, so that the electromagnet ring 33 can adsorb or release the iron ball 32; a pull disc 34 is arranged at the top of the vertical section of the slide way 31, and a pull rope of the pull disc 34 is connected with the electromagnet ring 33 and used for adjusting the height of the electromagnet ring 33 in the slide way 31; the pull disc 34 and the electromagnet ring 33 are combined to form a height adjusting mechanism for adjusting the release height of the iron ball 32, when in use, the electromagnet ring 33 firstly absorbs the iron ball 32, then the pull disc 34 adjusts the height of the electromagnet ring 33 and the iron ball 32 absorbed thereon, when in the selected height position, the electromagnetic force of the electromagnet ring 33 is cut off to release the iron ball 32, and the iron ball 32 falls along the slide way 31 and rolls out from the horizontal section thereof to output horizontal impact outwards.

Of course, the impact ball may be made of other materials with suitable quality besides the iron ball 32, and correspondingly, the height adjusting mechanism for adjusting the release height of the impact ball may also be made of other existing structures with the same effect, for example, a plurality of slots and baffles may be arranged in the vertical section of the slideway 31 along the height direction, or the pull disc 34 may be arranged and the electromagnetic ring 33 may be replaced by a clamping device.

In this embodiment, the box body 24 is made of acrylic material, which is relatively light and high in hardness, and is not easily damaged by sand in the box and external impact load; a fixing plate 25 is arranged at the bottom of the inner side of the box body 24, the fixing plate 25 is connected with the box body 24 through bolts, and a plurality of inserting holes are formed in the upper surface of the fixing plate 25 and used for inserting the test piles 4; during actual test, one or more test piles 4 are inserted into the fixing plate 25 according to the pile foundation structure to be tested, and sand is filled into the box body 24 to form the pile foundation to be tested. The box body 24 is fixed on the bearing platform 21, the bearing platform 21 is of a steel structure, the bottom of the bearing platform 21 is provided with a sliding block 22, the sliding block 22 is preferably a flange sliding block, and the flange sliding block has the advantages of high strength, small friction coefficient and the like; the sliding block 22 is matched with the track 11, so that the bearing platform 21 is arranged on the track 11 through the sliding block 22, and of course, the bearing platform 21 can also be arranged on the track 11 through other existing structures such as a roller, a ball and the like; for protection, two cushions 23 are respectively arranged at the front and the rear sides of the bearing platform 21, wherein the cushion 23 at one side is opposite to the baffle 12, and the cushion 23 at the other side is opposite to the outlet of the slideway 31.

In the utility model, the size of the track 11 is not too short, and because the pile is impacted by earthquake and is a slow vibration attenuation process, the track 11 needs to be provided with a certain length to ensure that the box body 24 does not move to the head early to collide, thereby causing the external interference of the test result.

Second, application testing

The actual sample is manufactured and tested according to the structure, wherein the total mass of the box body 24 and the lower bearing platform 21 is 41.84kg, the mass of the pile foundation in the box body 24 is 299.25kg, the mass of the iron ball 32 is 11kg, and the release height range of the iron ball 32 in the slide way 31 is 0.05-1 m. During the test, the platform 21 is moved to a side close to the slide rail 31 along the rail 11, the iron ball 32 is attracted to the lower end of the electromagnet ring 33 by magnetic force, the height position of the iron ball 32 is manually adjusted by using the pull disc 34, and then the electromagnetic force of the electromagnet ring 33 is cut off, so that the iron ball 32 falls along the slide rail 31 and impacts the platform 21.

During the test, various sensors can be arranged on the bearing platform 21 and the box body 24 and are used for monitoring the impact condition and the corresponding damage influence on the pile foundation model. Table 1 below shows the measured falling height of the iron ball 32 in relation to the impact load applied to the box 24.

Table 1: falling height and impact load of iron ball

Height/m of iron ball free falling body	Impact load/m.s^-2
		0.05	2.84
0.2	5.68
		0.3	6.96
0.5	8.98
		0.7	10.63
1.0	12.7

According to actual tests, the difference of the hardness of the cushion 23 can also affect the vibration frequency of the box body 24 caused by simulating earthquake impact, the following table 2 shows the corresponding relationship between the measured hardness of the cushion 23 and the vibration main frequency of the box body 24, and as can be seen from the table 2, the cushion 23 with lower hardness can be selected when low-frequency impact load needs to be simulated, and conversely, the cushion 23 with higher hardness can be selected when high-frequency impact load needs to be simulated.

Table 2: hardness of buffer and vibration frequency of box

Shore hardness of buffer pad	Dominant frequency/Hz
		50	90～120
60	100～150
		70	160～190
80	180～210
		90	200～230

The test proves that the test bed for simulating the impact of the pile foundation by the earthquake can better realize earthquake wave simulation, the impact load and the frequency can be freely adjusted, the whole device has simple and reliable structure and moderate size, and can meet the requirement of researching and analyzing the stress characteristic of the pile foundation under the action of the earthquake.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

The present invention is not limited to the above-described embodiments, and any obvious modifications, substitutions or alterations can be made by those skilled in the art without departing from the spirit of the present invention.

Claims

1. The utility model provides a simulation pile foundation receives earthquake test bench for impact which characterized in that: comprises a box rail system and an impact system, wherein the box rail system comprises a track (11) and a box body (24) arranged on the track (11); the impact system comprises a slide way (31) and an impact ball, wherein the outlet end of the slide way (31) is butted with the end part of the track (11), and the impact ball can fall down along the slide way (31) to impact the box body (24).

2. The test bed for simulating earthquake impact on pile foundation of claim 1, wherein: the bottom of the box body (24) is fixedly provided with a bearing platform (21), and the bearing platform (21) is movably connected with the track (11).

3. The test bed for simulating earthquake impact on pile foundation of claim 2, wherein: the bottom of the bearing platform (21) is connected with the track (11) through a flange sliding block.

4. The test bed for simulating earthquake impact on pile foundation of claim 2, wherein: the novel bearing platform is characterized in that a baffle (12) is arranged at one end, away from the slide way (31), of the track (11), cushion pads (23) are respectively arranged on the front side and the rear side of the bearing platform (21), the cushion pad (23) on one side is opposite to the baffle (12), and the cushion pad (23) on the other side is opposite to an outlet of the slide way (31).

5. The test bed for simulating earthquake impact on pile foundation of claim 4, wherein: the impact load frequency is adjusted by replacing the buffer pads (23) with different hardness.

6. The test bed for simulating earthquake impact on pile foundation of claim 1, wherein: the box (24) is the ya keli material, and the top is opened, and inboard bottom is equipped with fixed plate (25), and fixed plate (25) surface is equipped with a plurality of ann jacks.

7. The test bed for simulating earthquake impact on pile foundation of claim 1, wherein: the slideway (31) is of a round corner row structure and comprises a horizontal section, an arc section and a vertical section.

8. The test bed for simulating earthquake impact on pile foundation of claim 7, wherein: a height adjusting mechanism for adjusting the release height of the impact ball is arranged in the slide way (31).

9. The test bed for simulating earthquake impact on pile foundation of claim 8, wherein: the impact ball is an iron ball (32).

10. The test bed for simulating earthquake impact on pile foundation of claim 9, wherein: the height adjusting mechanism comprises an electromagnet ring (33) and a pull disc (34), wherein the electromagnet ring (33) is arranged in the vertical section of the slide way (31) and connected with a pull rope of the pull disc (34), and the pull disc (34) is arranged at the top of the vertical section.