CN100543406C - Geogrid displacement meter - Google Patents
Geogrid displacement meter Download PDFInfo
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- CN100543406C CN100543406C CNB2007100251620A CN200710025162A CN100543406C CN 100543406 C CN100543406 C CN 100543406C CN B2007100251620 A CNB2007100251620 A CN B2007100251620A CN 200710025162 A CN200710025162 A CN 200710025162A CN 100543406 C CN100543406 C CN 100543406C
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Abstract
Geogrid displacement meter is a kind of displacement transducer, be applicable to that the geogrid deformation performance must test, this displacement meter comprises, coil (2), iron core (3), bolt (7), brave type card (8), outer tube (9), interior pipe (10), wherein, interior pipe (10) is positioned on the brave type card (8), is provided with coil (2) on the inwall of interior pipe (10); Outer tube (9) is positioned on another brave type card (8), and iron core (3) is located at the central authorities and the coaxial cable of outer tube (9); In an end of pipe (10) stretch in the outer tube (9), be positioned on same the axis, the other end of iron core (3) stretches in the center pit of coil (2) of interior pipe (10).Characteristics are: change traditional grid strain the transient test of displacement into by the long-term follow-on test of resistance strain gage, not only improved precision but also reduced the complexity of Installation And Test.Adopt brave type to fasten grid dative displacement transducer, it is consistent to make grid displacement and sensor record displacement.
Description
Technical field
The present invention is a kind of displacement transducer, is applicable to the GSZ test, belongs to the technical field of geotechnological sensor test device fabrication.
Background technology
GSZ in China's highway, municipal works and hydraulic engineering as a kind of indispensable building materials and widespread use.But very undistinct to GSZ actual effect in engineering at present, its main cause is that the strain of on-the-spot GSZ can't accurately be tested and obtains.Because geogrid strain obtains just can analyzing the actual capability development of grid.
The main foil gauge that adopts of traditional geogrid strain test is tested.Its specific practice then adopts the distortion of static resistance strain-gauge test load action Under The Grille for pasting foil gauge earlier on the GSZ of laying.Available research achievements shows that the mode that adopts foil gauge tests the distortion of GSZ and exist following problem to cause measuring accuracy not meet the demands:
(1) domestic foil gauge testing range generally is no more than 0.5%, and is when strain surpasses 0.5%, not linear between measured resistance and the strain.For GSZ, the failure strain of grid generally surpasses 10%, adopts the power value of 2% strain correspondence during design.
Program complexity when (2) pasting foil gauge at first adopts ethanol or acetone to clean grid, then adopts 502 glue or epoxy bond.Then adopt materials such as epoxy resin to protect.Foil gauge taping process complexity.
(3) grid strain by using static resistance strainmeter is tested.The major defect of this test is static measurement, and measure needs long-term continuous coverage for this reason.In the engineering site test,, can not long-time continuous observe owing to reasons such as power supplies.And then rewiring is wanted in observation at every turn, and the reading of locating of each wiring static resistance strainmeter is all changing, thereby makes observation data inaccurate.
Above-mentioned reason causes the inaccurate of GSZ test, thereby the on-the-spot performance of GSZ effect is not had a deep understanding.
Summary of the invention
Technical matters: the purpose of this invention is to provide a kind of geogrid displacement meter, i.e. the on-the-spot test sensor of strain or distortion, this sensor is installed simple, and is easy to operate.After grid is installed, adopt the inductance measurement instrument to test this sensor displacement.When sensor is installed, can at first measure the sensor initial length, then measure the distortion after the grid tension, and then can calculate the strain of grid.
Technical scheme: geogrid displacement meter can design according to electromagnetic principle, and this displacement meter comprises magnetic sleeve, coil, and iron core, bolt, brave type card, outer tube, wherein, magnetic sleeve is positioned on the brave type card, is provided with coil on the inwall of magnetic sleeve; Outer tube is positioned on another brave type card, and iron core is located at the central authorities and the coaxial cable of outer tube; One end of magnetic sleeve stretches in the outer tube, is positioned on same the axis, and the other end of iron core stretches in the center pit of coil of magnetic sleeve.Tiger type card comprises brave type card upper lip, and brave type card lower lip is formed by connecting by bolt.Outer tube, magnetic sleeve are the flexible PVC pipe.
This displacement meter mainly is made up of magnetic plug and iron core, and iron core inserts in the coil and can move around.When iron core is subjected to displacement, will cause the variation of coil inductance.Following relation is arranged between the length l of the inductance value of coil and iron core insertion coil:
In the formula: the magnetic permeability (H/m) of μ-magnetic conductor (coil);
L-iron core inserts the length (m) in the coil;
The number of turn of N-coil (m);
Cross-sectional area (the m of A-coil
2).
Can record the displacement variable Δ l of the generation of grid under load action by the helix tube type sensor, the relation by strain and displacement can calculate being deformed into that grid produces:
ε＝Δl/l
0
L in the formula
0Length when initially installing for sensor.
Can further design the grid displacement meter and calculate the strain of grid according to helix tube type inductive displacement transducer test philosophy.GSZ is laid when using as a kind of plastics flexible material at roadbed filling or retaining structure, is compaction by rolling clay, sand or gravelly soil in the upper and lower surface of grid.Make grid and subgrade soil acting in conjunction at the load action Under The Grille by the rubbing action of muscle pedosphere face.The modulus that must consider sensor in grid displacement sensing design and the basically identical of filling material modulus are consistent with displacement and the actual value of guaranteeing to record grid.
1) changes traditional grid strain the transient test of displacement into by the long-term follow-on test of resistance strain gage, not only improved precision but also reduced the complexity of Installation And Test.
2) this instrument is incorporated into inductance principle testing principle in the grid displacement measurement.
3) adopt brave type to fasten grid dative displacement transducer, it is consistent to make grid displacement and sensor record displacement.
Beneficial effect: the inductance type force-displacement meter has when measurement geotechnique distortion to be installed simply, the advantage of measuring accuracy height and instantaneous measurement, thereby in engineering practice, have bigger using value.Major advantage is as follows:
(1) measure geogrid strain with the traditional resistor foil gauge and compare, on-the-spot easy for installation, simple to operate, sensor protection is also easy than resistance strain gage sensor.
(2) measuring geogrid strain with the traditional resistor foil gauge compares, but the big resistance strain gage testing tool of geogrid displacement meter measuring deformation range is the static resistance strainmeter, and the geogrid displacement meter testing tool is the inductance measuring instrument, existing data shows that employing static resistance strainmeter measures strain data stability inadequately, and inductance value measures the good stability of instrument metric data.So the grid displacement meter measures the precision height of strain.
Need uninterruptedly to measure continuously for a long time, and guarantee the long-time continuous measurement because power supply and testing tool itself are very difficult in the on-the-spot test, thereby cause to rebulid when measuring initial reading at every turn, and then cause the metric data precision not high
(3) resistance strain gage needs long-term uninterrupted continuously the measurement, and in the on-the-spot test because power supply and testing tool itself are difficult to guarantee the long-time continuous measurement, and the examination of GSZ inductance displacement instrumentation is a kind of instantaneous measurement, but each all independent quantities are measured wire spacing in the displacement meter two brave type cards, and then draw geotechnique's distortion and displacement.
Description of drawings
Fig. 1 measures principle schematic for inductance.
Fig. 2 is that grid and periphery material concern synoptic diagram.
Fig. 3 is the geogrid displacement meter structural representation.
Have among the above figure: magnetic sleeve 1, coil 2, iron core 3, clay, sand or gravelly soil 4, GSZ 5, grid displacement meter 6, bolt 7, brave type card 8, outer tube 9, viscose glue 10, interior pipe 11, brave type card upper lip 12, brave type card lower lip 13.
Fig. 4 is the upward view of Fig. 3.
Specific embodiment
This displacement meter comprises coil 2, iron core 3, bolt 7, brave type card 8, outer tube 9, interior pipe 11; Wherein, interior pipe 11 is positioned on the brave type card 8, is provided with coil 2 on the inwall of interior pipe 11; Iron core 3, outer tube 9 are positioned on another brave type card 8, and iron core 3 is located at the central authorities and the coaxial cable of outer tube 9; In a pipe end of 11 stretch in the outer tube 9, be positioned on same the axis, in the other end of iron core 3 stretches in the center pit of the coil 2 of pipe 11.
Tiger type card 8 comprises brave type card upper lip 12, and brave type card lower lip 13 is formed by connecting by bolt 7.Outer tube 9, interior pipe 11 are the flexible PVC pipe.
The sensor specific implementation process is as follows:
(1) adopts the moulding of soft viscose glue parcel on the fine copper wire circle group;
(2) coil inside and outside in the parcel moulding puts soft pvc pipe material respectively;
(3) make the U jacket tube of being with iron wire, its middle sleeve adopts soft pvc pipe material;
(4) at pvc pipe material one end and U jacket tube one end of coil brave flute profile anchor clamps are installed, so that fixing GSZ.
The grid displacement transducer through calibration, just can use after making and finishing at the scene.When installing at the scene, at first lay GSZ, then lay one deck layer of sand, and then the grid displacement meter is installed at displacement sensing gauge position.Behind grid displacement meter installation in position, adopt the electric inductance measuring-testing instrument tolerance to survey initial inductance with definite displacement meter two brave type card spacings, and as initial length.
Certain highway one highway section intends adopting GSZ to carry out the roadbed reinforcement, to reduce the non-uniform settling of ground.But undistinct to grid concrete performance characteristic in engineering, need adopt sensor to measure the effectiveness of the strain of GSZ earlier in testing laboratory with the research grid for this reason.In specific implementation process, adopt resistance strain gage and grid displacement meter to test simultaneously.
Resistance strain gage is pasted before grid is laid, and the grid displacement meter is installed after grid is laid.Banket after above-mentioned two kinds of sensors are installed and finished and carry out compacting, then adopt the non-uniform settling of water bag simulation ground.When uneven settlement of foundation, measure the distortion of grid.Wherein resistance strain gage adopts the static resistance strainmeter to test, and the inductance measuring instrument is adopted in the measurement of grid displacement meter.
Test findings shows in the resistance strain gage measurement process, the amplitude of the fluctuation of microstrain is 100-200 microstrains during same non-uniform settling, and the displacement fluctuation that obtains that the grid displacement meter measures only is 0.01mm (initial distance is 100mm between brave type card), is 10 microstrains for the strain fluctuation.
Also simulated the operating mode of on-the-spot test in addition in the test, i.e. the dismounting of wiring is to the influence of test result.Initial microstrain changes most ofly at 1000 more than the microstrain during dismounting of resistance strain gage, and the grid displacement meter measures and obtains displacement fluctuation and be essentially 0.This result further shows the long-term Continuous Observation of resistance-strain built-in testing needs, otherwise the influence of wiring will bring huge error to test result, and then there is not this phenomenon in the grid displacement meter.
Claims (1)
1. a geogrid displacement meter is characterized in that this displacement meter comprises coil (2), iron core (3), bolt (7), a pair of brave type card (8), outer tube (9), interior pipe (11); Wherein, interior pipe (11) is positioned on the brave type card (8), is provided with coil (2) on the inwall of interior pipe (11); One end of iron core (3), outer tube (9) is positioned on another brave type card (8), iron core (3) be located at outer tube (9) central authorities and with outer tube (9) coaxial cable; One end of interior pipe (11) stretches in the outer tube (9), interior pipe (11) is positioned on same the axis with outer tube (9), the other end of iron core (3) stretches in the center pit of coil (2) of interior pipe (11), tiger type card (8) comprises brave type card upper lip (12), brave type card lower lip (13), be formed by connecting by bolt (7), outer tube (9), interior pipe (10) are the flexible PVC pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2007100251620A CN100543406C (en) | 2007-07-13 | 2007-07-13 | Geogrid displacement meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2007100251620A CN100543406C (en) | 2007-07-13 | 2007-07-13 | Geogrid displacement meter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101109615A CN101109615A (en) | 2008-01-23 |
| CN100543406C true CN100543406C (en) | 2009-09-23 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNB2007100251620A Expired - Fee Related CN100543406C (en) | 2007-07-13 | 2007-07-13 | Geogrid displacement meter |
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Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101793020A (en) * | 2010-03-04 | 2010-08-04 | 中国矿业大学 | Geogrid strain testing device and testing method thereof |
| CN102175127B (en) * | 2011-01-21 | 2013-06-05 | 吉林省交通科学研究所 | Real-time online monitoring method and device of cracking instability of highway subgrade |
| CN102353322B (en) * | 2011-06-07 | 2013-06-12 | 汉通控股集团有限公司 | dynamic safety-monitoring and alarming system and method in building (structure) mechanical-dismantling process |
| CN102735155A (en) * | 2012-06-23 | 2012-10-17 | 合肥高创传感器有限公司 | Special sensor for high-speed rail track monitoring |
| CN105115387B (en) * | 2015-09-28 | 2017-11-03 | 华中科技大学 | Geogrid strain measuring equipment and method for measurement in a kind of model test |
| CN105651185A (en) * | 2016-03-18 | 2016-06-08 | 沈阳建筑大学 | Fiber bragg grating displacement sensor for measuring relative displacement |
| CN108700399B (en) * | 2017-06-30 | 2020-10-02 | 深圳市柔宇科技有限公司 | Distance measuring device, distance measuring method and flexible display device |
| CN109459094B (en) * | 2018-12-29 | 2023-11-21 | 山东大学 | Grating displacement testing system and method based on ten-axis sensor |
| CN112009997B (en) * | 2019-05-30 | 2022-07-05 | 宝山钢铁股份有限公司 | Grid anti-deformation device |
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- 2007-07-13 CN CNB2007100251620A patent/CN100543406C/en not_active Expired - Fee Related
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| CN101109615A (en) | 2008-01-23 |
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