CN108982265B - Experimental device for pile soil shearing action is observed and is measured based on PIV technique - Google Patents
Experimental device for pile soil shearing action is observed and is measured based on PIV technique Download PDFInfo
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- CN108982265B CN108982265B CN201810779841.5A CN201810779841A CN108982265B CN 108982265 B CN108982265 B CN 108982265B CN 201810779841 A CN201810779841 A CN 201810779841A CN 108982265 B CN108982265 B CN 108982265B
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Abstract
The invention discloses an experimental device for observing and measuring pile soil shearing action based on PIV technology, which comprises a frame, a hydraulic loading system, an experimental box, a PIV system, a pile body vertical positioning system and a pile body sensing system, wherein the frame is provided with a hydraulic loading system; the experimental box is used for containing soil samples; the hydraulic loading system is used for applying stress to the soil body and controlling the pile body to be driven into the soil sample; the pile body vertical positioning system is used for vertically positioning the pile body; the PIV system is used for observing the displacement field change of soil particles around the pile and the formation of a shear band of a pile-soil interface in the driving process of the pile body, and the pile body sensing system comprises various sensors arranged on the pile and is used for measuring various parameters. The device can realize the measurement of the lateral resistance and the pile end resistance of the pile in the driving process or the circular vertical load, can observe the deformation of the soil body measured by the pile and the formation of a shear band in real time through the PIV technology, can provide design parameters for engineering, and can also be used for researching the mechanism of the pile soil shearing action by combining visual soil body displacement.
Description
Technical Field
The invention relates to an experimental device for observing and measuring pile soil shearing action based on a PIV (particle image velocimetry) technology, which can observe the pile driving process and the development process of soil deformation and shear band formation when a pile body is subjected to circulating vertical load.
Background
Pile-soil interaction is the determination of the installation and service performance of the pile foundation. Currently, driven piles are widely applied to industrial and civil building foundations, pile-supported roadbeds, port engineering and ocean engineering, and the penetration resistance of the piles when driven into different soil bodies and different soil body depths influences the requirements on driving equipment, so that the measurement of the penetration resistance of the piles in the soil bodies is particularly important for the construction of the driven piles. On the other hand, after the pile is installed, the long-term bearing performance of the pile foundation is determined by the response of the pile-soil interface when the pile is subjected to the action of vertical cyclic load, for example, the problem of pavement settlement of a high-speed roadbed under cyclic vehicle load, the problem of cyclic weakening of the vertical bearing capacity of the offshore wind turbine jacket foundation and the like.
At present, a great deal of research is carried out on the shearing action of a pile-soil interface during the driving process and the cyclic loading of the pile, and the research considers that the key point of disclosing the pile-soil interaction lies in obtaining the displacement field of the soil around the pile and the formation and development of a shear band; there are also some shearing devices based on pile-soil units that are capable of measuring the resistance of the pile interface when vertically loaded. However, these devices cannot intuitively display the soil body displacement and the formation and development of the interface shear band during pile-soil interaction, which are the key factors affecting the pile-soil interface, so in order to reveal the nature of the pile-soil interface shear characteristic, it is necessary to simultaneously obtain the mechanical parameters of the pile during driving and vertical loading and the corresponding soil body displacement and the formation and development of the shear band at this time, and combine the two, so as to reveal the nature of the pile-soil interface shear through the experimental device.
Disclosure of Invention
The invention aims to provide an experimental device for observing and measuring the pile soil shearing action based on the PIV technology, aiming at the defects of the prior art, the device can observe and record the deformation of the pile soil around a driven pile under the conditions of soil penetration and cyclic load and the related mechanical parameters of a pile body in real time, and can research the development rule of a shear zone and the change of a soil particle displacement field. The device is characterized in that: on one hand, various mechanical parameters such as pile tip resistance, pile side resistance, pore water pressure and the like in the driving pile soil-entering process can be measured in real time by arranging various sensors, and on the other hand, soil deformation and shear band formation development process and pile soil particle displacement field in the whole process can be observed in the pile driving process and when the pile body is subjected to circulating vertical load.
The invention adopts the following technical scheme:
an experimental device for observing and measuring the shearing action of pile soil based on PIV technology comprises a frame, a hydraulic loading system, an experimental box, a PIV system, a pile body vertical positioning system and a pile body sensing system;
the experimental box comprises an organic glass box for containing the soil sample, and one side wall surface of the organic glass box is transparent; the hydraulic loading system is arranged above the experiment box, is used for applying initial soil pressure to simulate the stress state of a soil body and is used for controlling the pile body to be driven into a soil sample; the pile body vertical positioning system is used for keeping the pile body in a vertical state; the pile body is tightly attached to the transparent wall surface of the organic glass box when a soil sample is driven into the pile body, the displacement field change of soil particles and the formation and development conditions of a shear band in the pile driving process of the soil body are observed through the PIV system, and the pile body sensing system is used for measuring information such as pile end resistance, pile side resistance, pore water pressure and the like in the pile driving process.
In the technical scheme, the pile body vertical positioning system comprises three sets of positioning units, wherein one set of positioning unit is arranged at the rear side of the pile body, the other two sets of positioning units are respectively arranged at the left side and the right side of the pile body, each set of positioning unit comprises a positioning plate and a horizontal threaded rod, one end of the threaded rod is fixed with the positioning plate, and the other end of the threaded rod penetrates through the rack and is screwed up at the two sides of the rack through nuts; the three positioning plates surround a hole for the pile body to penetrate through, and each positioning plate is embedded with a ball. The pile body can be vertically driven in the driving process by clamping the pile body through the positioning plates in the three directions, and the resistance brought to the driving of the pile by the positioning plates can be reduced through the balls embedded in the positioning plates. Through the effective length of adjusting three threaded rods, the size of the hole surrounded by three positioning plates can be adjusted to meet the test of pile bodies with different diameters.
Furthermore, an upper plate is covered on the soil sample in the organic glass box, and through holes are formed in the edge of the upper plate for inserting the pile bodies; the hydraulic loading system comprises a main oil cylinder and a secondary oil cylinder which are both arranged on the frame and driven by a servo motor, the lower part of the main oil cylinder is connected with the pile head loading end of the pile body, and the lower end of the secondary oil cylinder is connected with the upper plate. And scale marks can be arranged on the positioning block or on the periphery of the through hole of the upper plate so as to conveniently adjust the size of the hole surrounded by the three positioning plates.
Furthermore, the PIV system comprises a computer, a laser emitter, a synchronizer and a CCD camera, wherein the computer controls the synchronizer to adjust a light source of the laser emitter, and the CCD camera shoots changes of soil particles around the pile in the whole pile driving process and feeds shooting information back to the computer.
Further, the pile body for conventional pile body vertically cut open along the axis, the section pastes tight organic glass case when the pile body is squeezed into soil sample.
The device can observe the deformation process of the soil body, the formation development process of the shear band and the change of the soil particle displacement field around the pile in the pile driving process and the pile body under the cyclic vertical load, and can simultaneously obtain a series of mechanical parameters such as pile side resistance, pile end resistance, pore water pressure and the like in the pile driving process and under the cyclic load action of the pile body.
Drawings
FIG. 1 is a schematic view (front view) of the overall structure of the device of the present invention;
FIG. 2 is a schematic view of the overall structure of the apparatus of the present invention (left side view);
FIG. 3 is a schematic view (top view) of the overall structure of the apparatus of the present invention;
FIG. 4 is a partial schematic view of the apparatus of the present invention;
FIG. 5 is an enlarged view of a portion of the apparatus of the present invention;
FIG. 6 is a partial schematic view of the apparatus of the present invention;
FIG. 7 is a schematic diagram of one configuration of a PIV system;
the device comprises a pile head loading end 1, a pile head 2, a bending upright post 3, a positioning plate 4, a secondary reaction beam 5, a threaded rod 6, a secondary reaction column 7, an upper plate 8, an organic glass box 9, a soil sample 10, a base 11, a servo motor 12, a pile body 13, various sensors 14, balls 15, an axial force sensor 16, an auxiliary oil cylinder 17, a primary reaction column 18, an axial force sensor 19, a main oil cylinder 20, a main reaction beam 21, a laser emitter 22, an optical arm 23, a sheet light source emitter 24, an optical arm support 25, a CCD camera 26, a CCD camera 27, a base 28, a synchronizer 29 and a control cabinet.
Detailed Description
The experimental device for observing and measuring the pile-soil shearing action based on the PIV technology comprises a frame, an experimental box, a pile body vertical positioning system, a hydraulic loading system, a pile body sensing system and a PIV system;
referring to fig. 1 and 4, the frame includes a secondary reaction beam 5, a secondary reaction column 7, a curved upright column 3, a base 11, a primary reaction beam 21, and a primary reaction column 18; the primary reaction column 18, the secondary reaction column 7, and the bent column 3 are welded to the base 11, and the primary reaction beam 21 and the secondary reaction beam 5 are connected to the primary reaction column 18 and the secondary reaction column 7 by screws, respectively.
The experimental box comprises an upper plate 8 and a large organic glass box 9, wherein the organic glass box 9 is at least provided with a transparent side wall, so that the PIV system can conveniently monitor the displacement change of soil particles in the pile driving process and the cyclic load.
As shown in fig. 3-4, the pile body vertical positioning system comprises three sets of positioning units, each set comprises a horizontal threaded rod 6 and a positioning plate 4, one set is arranged at the rear side of the pile body, the other two sets are arranged at the left side and the right side of the pile body, the threaded rod 6 penetrates through a bent upright post 3, nuts are arranged at the two sides of the bent upright post and used for screwing to fix the position of the threaded rod 6, the other end of the threaded rod 6 is screwed on the positioning plate 4, balls 15 are embedded on the end surface of the positioning plate 4, positioning plates used for positioning are arranged in 3 directions on the horizontal plane, the central lines of a pile tip and a pile body are aligned to the central lines carved on a glass box in advance, then the position of the pile body is fixed by hands, all the nuts are loosened, the positioning plate 4 is moved to enable a bearing 15 to be tangent with the pile.
The hydraulic loading system is arranged above the shearing system and used for applying consolidation stress to the soil body to simulate different soil body stress states and driving the pile body into the soil body; the servo motor 12 is mainly used for controlling a secondary oil cylinder 17 arranged below a secondary reaction beam 5, the secondary oil cylinder 17 is used for applying pressure, the secondary reaction beam 5 and a secondary reaction column 7 provide reaction force, load is applied to an upper plate, a main oil cylinder 20 arranged below a main reaction beam 21 is controlled by the servo motor 12, the main reaction beam 21 and a main reaction column 18 provide reaction force through the main oil cylinder 20 for applying pressure, and load is applied to a pile.
The pile body sensing system can comprise an axial force sensor 16 arranged right below the oil cylinder and various sensors 14 (corresponding sensors are selected according to parameters required by experiments) arranged on the pile body, the pile body can be composed of a pile head loading end 1, a pile head 2 and a pile body 13, the pile head loading end is connected with a pressurizing device, the pressurizing device is used for driving the pile into the soil or applying a cyclic load to the pile, and the pile body 13 enters a soil sample 10 under the driving pressure to simulate the actual processes of driving the pile into the soil and applying the cyclic load to the pile after the pile is driven into the soil. .
The PIV system comprises a synchronizer 28, a laser 22, a sheet light source emitting device 24, a light arm 23, a CCD camera 26, a control cabinet 29 and the like, wherein the synchronizer 28 is controlled by a computer to adjust the laser 22, the sheet light source emitting device 24 is used for enabling laser to be shot on the soil body part around the pile, enabling soil particles to reflect light rays with enough intensity, the CCD camera 26 is used for receiving the light rays reflected by the soil particles, monitoring the change of the displacement field of the soil particles in real time, and feeding back the obtained image result to the computer.
In addition, the observation device can also comprise software and a data acquisition system, such as a computer, a data acquisition instrument and the like, wherein the data acquisition instrument is connected with each sensor for data acquisition, and the computer analyzes and processes the data and issues an instruction according to user setting.
The test process using the device of the invention is briefly described below by taking a sand sample as an example:
when the device works, the pile body vertical positioning system and the servo loading system are disassembled, the upper plate is opened, a sand sample is filled in the glass box, the upper plate is covered, the vertical positioning system and the servo loading system are installed, the hydraulic loading system is controlled to apply preload to the upper plate, the soil body is deformed until the soil body is gradually stabilized, and the soil body consolidation state is simulated;
firstly, aligning the pile tip and the central line on the pile to the central line on the glass box, then fixing the position of the pile body by hands, loosening all the nuts, moving the positioning plate to enable the ball to be tangent to the pile body, screwing all the nuts, fixing the position of the positioning plate, and realizing the vertical positioning of the pile body.
And secondly, starting the PIV system to realize real-time monitoring of soil particle displacement in the pile driving process.
And thirdly, controlling the main oil cylinder to apply driving force or cyclic load to the pile through the servo motor, acquiring parameters of each sensor when the pile is driven and bears the cyclic load after being driven in the driving process, and monitoring the change of a real-time soil particle displacement field obtained by the PIV system.
After the test, the shear box was carefully cleaned and prepared for the next set of tests.
Claims (4)
1. An experimental device for observing and measuring the shearing action of pile soil based on PIV technology is characterized by comprising a frame, a hydraulic loading system, an experimental box, a PIV system, a pile body vertical positioning system and a pile body sensing system; the experimental box comprises an organic glass box for containing the soil sample; the hydraulic loading system is arranged above the experiment box, is used for applying initial soil pressure to simulate the stress state of a soil body and is used for controlling the pile body to be driven into a soil sample; the pile body vertical positioning system is used for positioning the pile body so as to keep the pile body in a vertical state; the pile body is tightly attached to one side wall surface of the organic glass box when a pile body is driven into a soil sample, the wall surface is transparent, the displacement field change of soil particles and the formation and development conditions of a shear band in the driving process of the pile are observed through a PIV system, and the pile body sensing system is used for measuring pile end resistance, pile side resistance and pore water pressure information in the driving process of the pile;
the pile body vertical positioning system comprises three sets of positioning units, one set of positioning units is arranged at the rear side of the pile body, the other two sets of positioning units are respectively arranged at the left side and the right side of the pile body, each set of positioning unit comprises a positioning plate and a horizontal threaded rod, one end of the threaded rod is fixed with the positioning plate, and the other end of the threaded rod penetrates through the rack and is screwed up at the two sides of the rack through nuts; the three positioning plates surround a hole for the pile body to penetrate through, and each positioning plate is embedded with a ball.
2. The experimental device for observing and measuring pile soil shearing action based on the PIV technology is characterized in that an upper plate covers a soil sample in the organic glass box, and through holes are formed in the edge of the upper plate for inserting pile bodies; the hydraulic loading system comprises a main oil cylinder and a secondary oil cylinder which are both arranged on the frame and driven by a servo motor, the lower part of the main oil cylinder is connected with the pile head loading end of the pile body, and the lower end of the secondary oil cylinder is connected with the upper plate.
3. The experimental facility for observation and measurement of pile soil shearing action based on PIV technology as claimed in claim 1, wherein the PIV system comprises a computer, a laser emitter, a synchronizer, and a CCD camera, the laser emitter light source is adjusted by the synchronizer controlled by the computer, the CCD camera shoots the change of the soil particles around the pile during the whole pile body driving process, and feeds the shot information back to the computer.
4. The experimental device for observing and measuring pile soil shearing action based on the PIV technology as claimed in claim 1, wherein the pile body is a conventional pile body which is longitudinally split along the axis, and the section of the pile body is tightly attached to the organic glass box when the pile body is driven into a soil sample.
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| CN110057681B (en) * | 2019-04-17 | 2021-06-22 | 辽宁工程技术大学 | Device and method for measuring rock type II fracture energy and observing rock surface velocity field |
| CN110132514B (en) * | 2019-05-10 | 2020-10-20 | 浙江大学 | Transparent shearing model box for vibration table test |
| CN112798418A (en) * | 2021-01-29 | 2021-05-14 | 贵州民族大学 | Experimental device for observe and measure stake soil interact of unsaturated soil |
| CN114215118A (en) * | 2021-11-05 | 2022-03-22 | 山东电力工程咨询院有限公司 | Tubular pile sinking test device |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2535723A1 (en) * | 2010-02-12 | 2012-12-19 | NGK Insulators, Ltd. | Method of fluid observation and fluid for observing flow |
| CN103758159A (en) * | 2014-01-02 | 2014-04-30 | 河南科技大学 | Model pile foundation load simulation experimental device |
| CN105588771A (en) * | 2016-03-16 | 2016-05-18 | 中国电建集团华东勘测设计研究院有限公司 | Variable-frequency vertical cyclic loading device capable of applying complicated loading mode |
| CN105696632A (en) * | 2016-02-01 | 2016-06-22 | 河南理工大学 | Transparent soil model test device for mining area pile foundation bearing force and test method |
| CN108035387A (en) * | 2017-12-28 | 2018-05-15 | 浙江大学 | Controllable confined pressure is used for the experimental provision for simulating closing pile installation process |
| CN207379851U (en) * | 2017-11-11 | 2018-05-18 | 广州环保投资集团有限公司 | Cyclic load load testing machine based on transparent soil model |
| CN108613884A (en) * | 2018-04-11 | 2018-10-02 | 浙江大学 | A kind of ring shear apparatus being contemplated that constant stiffness constant volume Chang Yingli |
-
2018
- 2018-07-16 CN CN201810779841.5A patent/CN108982265B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2535723A1 (en) * | 2010-02-12 | 2012-12-19 | NGK Insulators, Ltd. | Method of fluid observation and fluid for observing flow |
| CN103758159A (en) * | 2014-01-02 | 2014-04-30 | 河南科技大学 | Model pile foundation load simulation experimental device |
| CN105696632A (en) * | 2016-02-01 | 2016-06-22 | 河南理工大学 | Transparent soil model test device for mining area pile foundation bearing force and test method |
| CN105588771A (en) * | 2016-03-16 | 2016-05-18 | 中国电建集团华东勘测设计研究院有限公司 | Variable-frequency vertical cyclic loading device capable of applying complicated loading mode |
| CN207379851U (en) * | 2017-11-11 | 2018-05-18 | 广州环保投资集团有限公司 | Cyclic load load testing machine based on transparent soil model |
| CN108035387A (en) * | 2017-12-28 | 2018-05-15 | 浙江大学 | Controllable confined pressure is used for the experimental provision for simulating closing pile installation process |
| CN108613884A (en) * | 2018-04-11 | 2018-10-02 | 浙江大学 | A kind of ring shear apparatus being contemplated that constant stiffness constant volume Chang Yingli |
Non-Patent Citations (1)
| Title |
|---|
| 竖向荷载作用下挤扩支盘桩桩周土***移场变化规律研究;张敏霞 等;《岩石力学与工程学报》;20170430;第36卷;全文 * |
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