CN108072330A - Deformation of pile foundation distributed test system and test method under dynamic loading - Google Patents
Deformation of pile foundation distributed test system and test method under dynamic loading Download PDFInfo
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- CN108072330A CN108072330A CN201810035102.5A CN201810035102A CN108072330A CN 108072330 A CN108072330 A CN 108072330A CN 201810035102 A CN201810035102 A CN 201810035102A CN 108072330 A CN108072330 A CN 108072330A
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- Prior art keywords
- fiber
- pile foundation
- deformation
- optical fiber
- dynamic loading
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
Abstract
The invention discloses deformation of pile foundation distributed test system and test method under a kind of dynamic loading, system includes strain sensing optical fiber, temperature-compensated fiber, fiber data acquisition and Transmission system, fiber data processing and analysis system and monitoring result display system.By laying distributed sensing fiber in the pile foundation under highway or railroad embankment, and the real-time acquisition and transmission of fiber data are carried out with Transmission system using the fiber data acquisition based on OFDR fiber data acquisition techniques, the information such as dynamic strain response, axle power and the side friction changing rule of pile body are obtained by fiber data processing system again, are shown in the form of chart etc. in monitoring result display system.Compared with prior art, the present invention have many advantages, such as measuring point survival rate is high, gathered data comprehensively, can monitor in real time, human error it is small, realize deformation of pile foundation under dynamic loading monitor in real time and long term monitoring.
Description
Technical field
The present invention relates to deformation of pile foundation distributed test systems under geotechnical engineering monitoring system more particularly to dynamic loading
And test method.
Background technology
In recent years, the construction of highway and railway, which steps, steps on a new stage, security to highway and railway,
Continuously operation property etc. proposes new requirement for comfort and high intensity, while has also been proposed new choose to the construction of foundation engineering
War.In terms of detection of pile foundation in engineering, dynamic strain, axle power and the side friction of pile body are three important sides of detection of pile foundation
Face, at present mainly using the conventional test methodologies such as Reinforcement Stress-count, inclinometer and resistance strain plate, these methods exist with
Lower shortcoming：(1) sensing element is not suitable with and works in harsh environments in the point sensor used；(2) can only adopt
Collect limited data, easy missing inspection, inefficiency can not reflect the deformation characteristics of monitoring object comprehensively；(3) professional technician
Measurement cost is high, and human error is big；(4) information feedback hysteresis, causes to generate error on the time, and the data processing in later stage is not intelligent
Change；(5) measurement accuracy of instrument is low, it is difficult to obtain the subtle variation of monitoring object.Therefore, how pile foundation is easily and effectively monitored
The hot spot and difficult point that are deformed into engineering circles research under dynamic loading.
The content of the invention
Goal of the invention：The object of the present invention is to provide deformation of pile foundation distributed test system and surveys under a kind of dynamic loading
Method for testing, with the dynamic strain of real-time, long-term accurate measurements pile body.
Technical solution：Deformation of pile foundation distributed test system under dynamic loading, including being symmetrically arranged at two in stake
Strain sensing optical fiber and temperature-compensated fiber, fiber data acquisition in root main reinforcement are with Transmission system, fiber data processing with dividing
Analysis system and monitoring result display system；It gathers with fiber data after the optical fiber series connection of adjacent studs and is connected with Transmission system；Optical fiber
Data process＆analysis system input is gathered with fiber data and is connected with Transmission system, output terminal and monitoring result display system
Connection.
The measurement length range for testing system monitoring pile foundation dynamic strain is 0~100m.
Test system is used for bored concrete pile, prefabricated pile and steel-pipe pile.
The test method of deformation of pile foundation distributed test system, comprises the following steps under dynamic loading：
(1) two main reinforcement sides being laid in strain sensing optical fiber and temperature-compensated fiber respectively in stake；
(2) optical fiber is covered into entire steel reinforcement cage；
(3) placing concrete into stake；
(4) by after the optical fiber difference welding between adjacent studs, gather with fiber data and be connected with Transmission system, carry out data
Acquisition；
(5) fiber data processing and analysis system are imported data to, strain data is shown by monitoring result display system.
It is in step (1), strain sensing optical fiber is exceptionally straight.
In step (4), protected at adjacent fused fiber splice using thermal expansion pipe.
Operation principle：The present invention is by OFDR (Optical Frequency Domain Reflectometer) fiber data
Acquisition technique is applied under dynamic loading in deformation of pile foundation monitoring, and devises corresponding data handling system, can be accurate
Ground monitors the dynamic strain of pile body, so as to draw the changing rule of pile shaft force, side friction etc..Wherein OFDR Fibre Optical Sensors skill
Art is one kind of Distributed Optical Fiber Sensing Techniques, and with high sensitivity, spatial resolution is high, measurement accuracy is big, anti-electromagnetism is done
Disturb and radiate, over long distances, it is distributed and the advantages that easily coordinate with measured object, can be worked normally under extremely harsh environment.
Its measurement range is the μ ε of -30000 μ ε~30000 and -270 DEG C~900 DEG C, and measurement accuracy is up to 1.0 μ ε and 0.12 DEG C, along entire
The spatial resolution of optical fiber is 10mm, can monitor strain, temperature, amount of deflection and 3D shapes simultaneously, and Rayleigh is based on compared to OTDR
The Brillouin light Time Domain Reflectometry of optical time domain reflection technology, FBG Fiber Bragg Grating FBGs and BOTDR based on Brillouin scattering of scattering
Technology, OFDR fiber datas acquisition technique have broader practice prospect in civil engineering monitoring field.
Advantageous effect：Compared with prior art, the present invention has measuring point survival rate height, gathered data is comprehensive, can supervise in real time
It surveys, the advantages that human error is small, realizes the real-time monitoring of deformation of pile foundation and long term monitoring under dynamic loading.
Description of the drawings
Fig. 1 is schematic structural view of the invention；
Fig. 2 is bored concrete pile vertical section fiber deployment schematic diagram；
Fig. 3 is bored concrete pile cross-section optical fiber layout diagram.
Specific embodiment
As shown in Figure 1, test system includes strain sensing optical fiber 1a, temperature-compensated fiber 1b, fiber data acquisition and passes
Defeated system 5, fiber data processing and analysis system 6 and monitoring result display system 7；As shown in Figure 2 and Figure 3, strain sensing optical fiber
1a and temperature-compensated fiber 1b is symmetrically laid in two 9 sides of main reinforcement of bored concrete pile 2, and the optical fiber series connection of adjacent bored concrete pile 2 is followed by
Enter fiber data acquisition and Transmission system 5；Fiber data processing is gathered with 6 input terminal of analysis system with fiber data is with transmitting
5 connection of system, output terminal are connected with monitoring result display system 7.
Wherein strain sensing optical fiber 1a and temperature-compensated fiber 1b is PE optical fiber, and 1c is the exposed optical fiber outside stake, is needed
In addition protective case 10 is protected；Bored concrete pile 2 is arranged in the soil body 8 of 3 lower section of embankment, and embankment 3 bears road vehicles dynamic load 4
Active force；Fiber data gathers and Transmission system 5, using a stylobate in the fiber data Acquisition Instrument of OFDR technologies, with calculating
Machine is connected the timely transmission for realizing data；Fiber data processing is with analysis system 6, the automatic decision according to the characteristics of fiber data
The position of monitoring object simultaneously extracts the processing such as the smooth, denoising of related data progress；Monitoring result display system 7 will be located
Fiber data after reason by chart etc. intuitively in the form of show.
The test method of system is as follows：
(1) by strain sensing optical fiber 1a and temperature-compensated fiber 1b, U-shaped adjacent symmetric is laid in bored concrete pile 2 respectively
Two 9 sides of main reinforcement of steel reinforcement cage, to reduce destruction of the grouting to sensor fibre；It is bound at reinforcing cage stirrup with band,
It is during binding that strain sensing optical fiber 1a is suitably exceptionally straight, active force is not applied to temperature-compensated fiber 1b；In addition, by temperature before laying
Degree compensated optical fiber 1b puts on the hollow circular-tube with rigidity, is not stressed with the optical fiber ensured in pipe, and in optical fiber bottom AB
Gluing knot hollow circular-tube and optical fiber, prevent hollow circular-tube from being slided along optical fiber.
(2) fold remaining optical fiber in reinforcement cage hoisting, decentralization to be fixed on steel reinforcement cage, after steel reinforcement cage is welded again
Continue to arrange, until fiber lengths cover entire steel reinforcement cage；Two kinds of optical fiber reserve setting length respectively at pile crown, in order to
Later stage is connected with the optical fiber on adjacent bored concrete pile.
(3) before in placing concrete, the optical fiber for stretching out pile body with protective case is protected, is prevented in filling process
Optical fiber is damaged；
(4) after the fiber deployment on all bored concrete piles is good, to the strain sensing optical fiber 1a and temperature stretched out on adjacent pile crown
Degree compensated optical fiber 1b carries out welding respectively, thermal expansion pipe need to be added at fused fiber splice to increase rigidity and durability, selection is in
Strain sensing optical fiber 1a and temperature-compensated fiber 1b on the bored concrete pile at most edge carry out welding with wire jumper respectively, are accessed after welding
In two passages of data collecting instrument, the connectedness of measurement circuit sets relevant parameter, the test acquisition of data is carried out, with true
The validity of fixed number evidence.
(5) fiber data processing and analysis system 6 are imported data to, system carries out fiber data automatic business processing, and
It is shown in monitoring result display system 7, after obtaining pile strain data, can side friction and axis be changed into according to formula
The relevant informations such as power, to analyze pile body deformation feature.
(6) monitored wire jumper and stretched out the optical fiber of pile body and fold and be put into the can with notch and protect, and aside
Stick warning mark.
The measurement length range of the test system monitoring pile foundation dynamic strain response is 0~100m, is carrying out the number in later stage
During according to acquisition and monitoring in real time, can extended fiber length, fibre-optic terminus is arranged in work station or office, it is outer to prevent
The adverse circumstances on boundary are inconvenient caused by data collection task.
Claims (6)
1. a kind of deformation of pile foundation distributed test system under dynamic loading, it is characterised in that：Including being symmetrically arranged at stake
Strain sensing optical fiber (1a) and temperature-compensated fiber (1b), fiber data acquisition and Transmission system on interior two main reinforcements (9)
(5), fiber data processing and analysis system (6) and monitoring result display system (7)；The adjacent studs optical fiber series connection after with light
Fine data acquisition is connected with Transmission system (5)；The fiber data processing is gathered with analysis system (6) input terminal and fiber data
It is connected with Transmission system (5), output terminal is connected with monitoring result display system (7).
2. deformation of pile foundation distributed test system under dynamic loading according to claim 1, it is characterised in that：The survey
The measurement length range of test system monitoring pile foundation dynamic strain is 0~100m.
3. deformation of pile foundation distributed test system under dynamic loading according to claim 1, it is characterised in that：The survey
Test system is used for bored concrete pile, prefabricated pile and steel-pipe pile.
4. a kind of test method using deformation of pile foundation distributed test system under dynamic loading as described in claim 1,
It is characterized in that：Comprise the following steps：
(41) strain sensing optical fiber (1a) and temperature-compensated fiber (1b) are laid in the side of two main reinforcements (9) in stake respectively
Face；
(42) optical fiber is covered into entire steel reinforcement cage；
(43) placing concrete into stake；
(44) by after the optical fiber difference welding between adjacent studs, gather with fiber data and be connected with Transmission system (5), carry out data
Acquisition；
(45) fiber data processing and analysis system (6) are imported data to, dependent variable is shown by monitoring result display system (7)
According to.
5. the test method according to claim 4 using deformation of pile foundation distributed test system under dynamic loading,
It is characterized in that：It is in step (41), the strain sensing optical fiber (1a) is exceptionally straight.
6. the test method according to claim 4 using deformation of pile foundation distributed test system under dynamic loading,
It is characterized in that：In step (44), protected at the adjacent fused fiber splice using thermal expansion pipe.
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| CN201810035102.5A CN108072330A (en) | 2018-01-15 | 2018-01-15 | Deformation of pile foundation distributed test system and test method under dynamic loading |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108917635A (en) * | 2018-07-24 | 2018-11-30 | 河海大学 | Pipe deforming monitoring system and application method based on OFDR technology |
| CN109187194A (en) * | 2018-10-26 | 2019-01-11 | 南京大学 | A kind of soil body tensioning mechanical characteristic fiber-optic monitoring based on OFDR and test method and device |
| CN111549832A (en) * | 2020-05-08 | 2020-08-18 | 河海大学 | Energy pile test system and method based on high-precision distributed optical fiber monitoring |
| CN114184272A (en) * | 2021-12-10 | 2022-03-15 | 唐山市智明电子科技有限公司 | Intelligent railway sleeper |
| CN114411833A (en) * | 2022-03-10 | 2022-04-29 | 河海大学 | High-speed railway bridge pile foundation long-term dynamic response monitoring system and monitoring method |
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| CN1888330A (en) * | 2006-07-25 | 2007-01-03 | 南京大学 | Bored concrete pile foundation distributing optical fiber sensing detecting method and system |
| CN101713691A (en) * | 2009-12-22 | 2010-05-26 | 浙江大学 | Health-monitoring system of distributed sensing fiber tunnel |
| CN101915552A (en) * | 2010-07-23 | 2010-12-15 | 水利部交通运输部国家能源局南京水利科学研究院 | Method for measuring geogrid deformation and stress by utilizing fiber bragg grating |
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2018
- 2018-01-15 CN CN201810035102.5A patent/CN108072330A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1888330A (en) * | 2006-07-25 | 2007-01-03 | 南京大学 | Bored concrete pile foundation distributing optical fiber sensing detecting method and system |
| CN101713691A (en) * | 2009-12-22 | 2010-05-26 | 浙江大学 | Health-monitoring system of distributed sensing fiber tunnel |
| CN101915552A (en) * | 2010-07-23 | 2010-12-15 | 水利部交通运输部国家能源局南京水利科学研究院 | Method for measuring geogrid deformation and stress by utilizing fiber bragg grating |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108917635A (en) * | 2018-07-24 | 2018-11-30 | 河海大学 | Pipe deforming monitoring system and application method based on OFDR technology |
| CN109187194A (en) * | 2018-10-26 | 2019-01-11 | 南京大学 | A kind of soil body tensioning mechanical characteristic fiber-optic monitoring based on OFDR and test method and device |
| CN109187194B (en) * | 2018-10-26 | 2023-10-13 | 南京大学 | OFDR-based soil body tension mechanical property optical fiber monitoring and testing method and device |
| CN111549832A (en) * | 2020-05-08 | 2020-08-18 | 河海大学 | Energy pile test system and method based on high-precision distributed optical fiber monitoring |
| CN114184272A (en) * | 2021-12-10 | 2022-03-15 | 唐山市智明电子科技有限公司 | Intelligent railway sleeper |
| CN114411833A (en) * | 2022-03-10 | 2022-04-29 | 河海大学 | High-speed railway bridge pile foundation long-term dynamic response monitoring system and monitoring method |
| CN114411833B (en) * | 2022-03-10 | 2023-03-10 | 河海大学 | High-speed railway bridge pile foundation long-term dynamic response monitoring system and monitoring method |
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Application publication date: 20180525 |