CN1120162A - Measuring system for indoor dynamic and static triaxial for shearing wave velocity - Google Patents
Measuring system for indoor dynamic and static triaxial for shearing wave velocity Download PDFInfo
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- CN1120162A CN1120162A CN95107918A CN95107918A CN1120162A CN 1120162 A CN1120162 A CN 1120162A CN 95107918 A CN95107918 A CN 95107918A CN 95107918 A CN95107918 A CN 95107918A CN 1120162 A CN1120162 A CN 1120162A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
The system for measuring maximum dynamic shearing modulus of coarse-grain soil at a certain stress under small strain condition (10 to the power 06) is composed of test device and data acqusition and processing device. Said test device consists of base, vibration source, top and bottom sensors and sample container including cylindrical emulsoid membrane and top and bottom covers. The sensors are respectively arranged in upper and lower positions of said sample container. The data from sensors is transmitted to data acquisition and processing device that controls vibration source.
Description
The present invention relates to test the apparatus and method of coarse-grained soil shear wave velocity, belong to the technical field of G01N 3/00 class with the strength characteristics of mechanical stress test solid material.
In the design of earthquake resistant engineerings such as dam, need to determine the kinematic behavior of coarse-grained soil.When the anti-seismic problem of research earth structure and ground, often relate to the dynamic stress strain stress relation, particularly its shearing rigidity or modulus of shearing of soil.And square being directly proportional of modulus of shearing and shear wave velocity, so shear wave velocity is an important physical amount of the geotechnological anti-seismic problem of research.
The device that is used to test shear wave velocity at present mainly contains following defective:
1. Ri Ben resonance column device can only be used for Φ 50) (100 or the small specimen of Φ 70 * 100, can only on the particulate earth material, test, and measuring accuracy only is 10
-4～5 * 10
-6
2. the small strain instrument of Tokyo University can only be used for the following test specimen of Φ 200 diameters, other same resonance column device;
3. the ultrasonoscope of institute of Chinese water section, emissive power is little, probe is little, only is applicable to fine grained soil, because it produces wave of compression and shearing wave simultaneously, old friend worker differentiates difficulty.
In these external these proving installations, because the restriction of oscillograph recording instrument markers precision and the defective of artificial treatment signalling technique can be brought very important error to analysis result.
In the general indoor common employing relative method of vibration experiment the survey sensor in the proving installation is calibrated, that is: compared by sensor and the standard transducer that is calibrated, thereby reach the purpose of calibration.Standard transducer is then in the absolute calibration of national metrological service.And absolute calibration needs standard vibration amount of sensor input.Standard vibration generally will be produced by high precision standard vibration machine (electromagnetic type, fluid pressure type or mechanical type).The modernism of high precision amplitude measurement is to use laser interferance method.The high precision vibration frequency is by the approved qualified frequency meter calibration of national metrological service.As seen this method need be used high-precision sensor, makes the cost of system strengthen.
The objective of the invention is to set up the system of a test coarse-grained soil shear wave velocity; it can obtain the shear wave velocity value under the stress states at different levels in indoor coarse grain or particulate earth material test specimen; and can improve the measuring accuracy of shear wave velocity, thereby determine the maximum shear modulus of this material under stress states at different levels exactly.
Another object of the present invention is to propose a kind of not only soon but also reliable survey sensor scaling method, and it can reduce the requirement to the survey sensor precision, thereby reduces the cost of test coarse-grained soil shear wave velocity system.
The object of the present invention is achieved like this:
Indoor dynamic and static triaxial apparatus shear wave velocity measurement system is made up of proving installation, data acquisition and processing (DAP) device.The data acquisition and processing (DAP) device is made up of prime amplifier, wave memorizer, control interface board, isolation controller and computing machine.Wherein:
Proving installation comprises pedestal, test specimen container, vibration source, goes up lower sensor, position about last lower sensor is placed in the test specimen container, and vibration source places on the upper sensor.The test specimen container is by the cover plate up and down of cylindrical latex film, circular band permeable hole, the vibration isolation plate constitutes up and down.Lower cover and pedestal connect, and the bottom of latex film is enclosed within on the lower cover, and following vibration isolation plate places on the lower cover, and lower sensor places down on the vibration isolation plate, and the top of latex film is enclosed within on the upper cover plate, and last vibration isolation plate places under the upper cover plate; The end face of upper cover plate connects the piston of a band cap, opens fairlead on the piston cap; Test specimen container outside is with a steel cage that connects with pedestal, and the top of steel cage has the center pit that holds piston, and the side has fairlead, is filled with liquid in the cavity between steel cage and the test specimen container.
The output of last lower sensor is the input of welding wave storer after prime amplifier amplifies, and computing machine is sent in the output of wave memorizer, the computer control isolation controller, and the output of isolation controller connects the vibration source in the proving installation.
During test, computing machine sends a pulse to isolation controller, the latter just gives the vibration source output in the proving installation ac supply signal, the horizontal exciting force that vibration source produces is by sensor senses up and down and send into the data acquisition and processing (DAP) device, read, analyze, handle by computing machine at last, finish and gather and treatment process.
The method of calibration measurements sensor is:
1. a pair of survey sensor that will select for use is placed on the same position place, to they excitings;
2. to doing Spectrum Analysis,, then continue step 3 if both Hz-KHz and energy distribution are quite approaching by the data of these two sensor acquisition, otherwise the alternative sensor, and change step 1;
3. both waveforms are done time-domain analysis,, then adopt this a pair of sensor, otherwise the alternative sensor changes step 1 if the ski-jump of both received signals is synchronous.
Describe the present invention below in conjunction with drawings and Examples.
Fig. 1 is the block diagram of system of the present invention;
Fig. 2 is the block diagram of system of second kind of scheme of the present invention;
Fig. 3 is a proving installation organigram of the present invention.
Referring to Fig. 1, the present invention is made up of proving installation A, data acquisition and processing (DAP) device.The data acquisition and processing (DAP) device is made up of prime amplifier B, wave memorizer C, isolation controller D and computing machine E.Two survey sensors and a vibration source are arranged among the proving installation A, and prime amplifier B is a four-way, and wave memorizer C selects the BS4791 type for use, and isolation controller D is a controlled electronic switch.
The output of two survey sensors connects the input of prime amplifier B among the proving installation A, the input of the output welding wave storer C of prime amplifier B, wave memorizer C and isolation controller D all are inserted in the bus slot of computing machine E, the control signal of computing machine E connects the control end of isolation controller D, the input termination AC power of isolation controller, the output of isolation controller connects the vibration source among the proving installation A.Isolation controller has two effects: prevent that high pressure from entering computing machine 1.; 2. available computers is controlled the exciting number of times of vibration source.
Referring to Fig. 2, second scheme of the present invention is by being made up of proving installation A, prime amplifier B, hyperchannel extension box G, signal generator H, isolation controller D and computing machine E.China's A/D8010 type far away digital-to-analog conversion plate is housed in the bus slot of computing machine E, and the result of this digital-to-analog conversion plate conversion is read, analyzes, is handled by computing machine E, finishes and gathers and treatment process.Prime amplifier B selects SYS-I type four road prime amplifiers for use, and signal generator H is used for a given standard signal, and whether reliable with the calibration image data, whether detection system is working properly.A DS6521 type memory for digits oscillograph also can be placed in this unit, be used for to the shear wave velocity of test specimen directly gather, demonstration, waveform judge.
The output of two survey sensors connects the input of prime amplifier B among the proving installation A, the output of prime amplifier B connects digital-to-analog conversion plate among the computing machine E through hyperchannel extension box G, the output of signal generator H also connects this digital-to-analog conversion plate, the output of isolation controller D connects the vibration source among the proving installation A, the power supply termination AC power of isolation controller D, the control signal of computing machine E connects the control end of isolation controller D.
Referring to Fig. 3, proving installation A comprises pedestal 12, test specimen container, vibration source 13, upper sensor 5, lower sensor 7, piston 9, steel cage 6.The test specimen container is by the cover plate up and down 3 and 8 of cylindrical latex film 4, circular band permeable hole, vibration isolation rubber plate 10 and 11 constitutes up and down.
Lower cover 8 connects with pedestal 12, the bottom of latex film 4 is enclosed within on the lower cover 8, following vibration isolation rubber plate 11 places on the lower cover 8, lower sensor 7 places down on the vibration isolation rubber plate 11, the coarse grain earth material test specimen of packing in the latex film 4, test specimen top are put into upper sensor 5, vibration source 13 in regular turn, are gone up vibration isolation rubber plate 10, and the top of latex film 4 is enclosed within on the upper cover plate 3, the end face of upper cover plate 3 is connected with the piston 9 of band cap 1, has fairlead 2 on the piston cap 1.The vibration isolation rubber plate is in order to cut off other path of shearing wave up and down.
Test specimen container outside is with a steel cage 6 that connects with pedestal 12, the top of steel cage 6 has the center pit that holds piston 9, the side has fairlead, and from then on the fairlead 2 of the signal wire of the power lead of vibration source 13, upper sensor 5 and lower sensor 7 on piston cap 1 draw in the hole.Be filled with de aerated water (promptly not having air water) in the cavity between steel cage 6 and the test specimen container.
Vibration source 13 horizontal positioned, it is that the vibration source box constitutes by electromagnet and shell thereof, also available magneto-electric shakes and leads device and by computer or mechanical type pulse control.Sensor is a speed pickup, and also usable acceleration or displacement transducer require it highly sensitive good with one-way.
The input of the output of upper sensor 5 and lower sensor 7 welding wave storer C after prime amplifier B amplifies, the output of wave memorizer C is sent into computing machine F by control interface board D, computing machine F is by control interface board D control isolation controller E, and isolation controller E is output as the alternating current that the vibration source 13 among the proving installation A provides exciting to use.
Sample dimensions is Φ 300 * 750, and the confined pressure σ 3 of test specimen is applied by the de aerated water around the test specimen container by air compressor, and the axle pressure σ 1 of test specimen is then provided by the large-scale electro-hydraulic servo coarse-grained soil of 100T static and dynamic test machine oil potential source.In pressure process, the moisture in the test specimen can be from cover plate up and down and is flowed out the permeable hole of vibration isolation plate up and down.
When test specimen unit weight is higher, damage in pressure process for preventing lower sensor, can overlap a protective cover 14 in the above.
In the test during each exciting, send out a positive pulse for isolation controller D by computing machine E, so isolation controller D gives vibration source 13 inputs an of short duration ac signal, make electromagnetic actuation once, apply a horizontal exciting force promptly for the vibration source box, act on the horizontal exciting force in coarse-grained soil test specimen top by the vibration source box.So just test specimen has been imported a shearing wave of propagating from top to bottom.This exciting force is sent in the data acquisition and processing (DAP) device after by upper and lower sensor senses.Then the software in the computing machine reaches the b place according to the vertical range between the upper and lower sensor and shearing wave by a and takes time, and can try to achieve the velocity of propagation of shearing wave by test specimen:
Wherein: VS is a shear wave velocity, and H is the test specimen original height, and ts is Δ T, and promptly shearing wave reaches the b place by a and takes time.Common available VS=(H-Δ H)/Δ T formula represents that H-Δ H is test specimen true altitude after the stabilization by consolidation under different stress.
When vibration source 13 vertically is placed on the test specimen top with the test specimen coaxial direction, and the sensor receive direction also is the test specimen coaxial direction, and the ripple that records at this moment is wave of compression VP.
The survey sensor that the present invention adopts is demarcated with following method in advance:
1. a pair of survey sensor that will select for use is placed on the same position place, to they excitings;
2. to doing Spectrum Analysis,, then continue step 3 if both Hz-KHz and energy distribution are quite approaching by the data of these two sensor acquisition, otherwise the alternative sensor, and change step 1;
3. both waveforms are done time-domain analysis,, then adopt this a pair of sensor, otherwise the alternative sensor changes step 1 if the ski-jump of both received signals is synchronous.
Timing signal, exciting is three times continuously, and the waveform of the gained as a result of these three excitings should repeat unanimity.
The foundation of this method is: as long as the basic parameter unanimity of two sensors, then the relative error between them must be very little.Because what the present invention only was concerned about in test is the time intervals of two sensors between take-off behind the exciting constantly, so the absolute error of sensor itself can not considered.
During test, vibration source and upper and lower sensor are not placed on earlier and carry out exciting in the test specimen, and it is done Spectrum Analysis, obtain its excited frequency bandwidth in 0～80HZ.And then vibration source and last lower sensor be placed on carry out exciting in the test specimen, also obtain a spectrogram, its frequency span is about 0～240HZ, again according to time domain figure contrast and frequency-domain analysis, can find really the frequency content (being the fundamental frequency and the resonance frequency of excited frequency, test specimen) that test specimen is worked in 0～200HZ.For the ski-jump of shear wave velocity more easy to identify, utilize the digital filtering function of software again, the interference wave more than the 200HZ is filtered.And ski-jump poor that goes up the lower sensor received signal, being shearing wave reaches the b place Δ T that takes time by a.
The present invention is used to test coarse-grained soil, also can be used for testing fine grained soil.Its proving installation has adopted the cover plate up and down of band permeable hole, thereby both can be used for the unsaturation test specimen, also can be used for saturated test specimen.This device constitutes the test specimen container with latex film, and at test specimen container overcoat steel cage, topping up body in the cavity between steel cage and test specimen container, impose on the confined pressure of sample by this liquid transfer, thereby not only can be used for diameter 300mm and bigger test specimen, also can be used for the less test specimen of diameter, can be used for power triaxial test machine, also can be used on the static(al) triaxial apparatus.
The present invention makes ripple pass time measurement accuracy and brings up to the microsecond level by Millisecond.The Waveform reproduction ability is strong, and time scale is accurate, and excited frequency and response frequency energy ingredient are clear, and processing procedure shortens, and has improved the measuring accuracy of shear wave velocity greatly.It can be 10
-6Measure the maximum dynamic shear modulus under certain stress condition under the small strain condition.
The transducer calibration method that the present invention adopts, not only soon but also reliable, it had reduced the requirement to sensor accuracy, thereby had reduced the cost of system.
The test findings that the sandy gravel test specimen of certain engineering carries out is shown that the present invention has successfully solved the problem of measuring its shear wave velocity more accurately and determine its maximum dynamic shear modulus in indoor coarse-grained soil test specimen with the present invention.
The present invention has following distinguishing feature:
1. low cost is easy to implement;
2. the shearing wave vibration source is pure, and the sensor one-way is good, and waveform ski-jump spacing is clear and legible, and precision is more than 0.02%;
3. the test specimen perturbation is minimum in the exciting process, and the test specimen axial deformation is generally 10-6(amesdial, four in the elastic range Half code table unchanged value during exciting after the test specimen stabilization by consolidation);
4. can under high consolidation stress state, test, simulate the stress condition of on-the-spot test.
Claims (2)
1. indoor dynamic and static triaxial apparatus is sheared and is made up of proving installation, data acquisition and processing (DAP) device by fast test macro, described proving installation comprises pedestal, test specimen container, vibration source, goes up lower sensor, the upper and lower sensor position up and down that is placed in the test specimen container, vibration source places on the upper sensor, it is characterized in that:
Described data acquisition and processing (DAP) device is made up of prime amplifier, wave memorizer, isolation controller and computing machine;
Described test specimen container is by the cover plate up and down of cylindrical latex film, circular band permeable hole, the vibration isolation plate constitutes up and down; Described lower cover and described pedestal connect, the bottom of described latex film is enclosed within on the described lower cover, and described vibration isolation plate down places on the described lower cover, and described lower sensor places on the described vibration isolation plate down, the top of described latex film is enclosed within on the described upper cover plate, and the described vibration isolation plate of going up places under the upper cover plate;
The piston of the end face connecting band cap of described upper cover plate is opened fairlead on this piston cap;
Described test specimen container outside is with a steel cage that connects with described pedestal, and the top of this steel cage has the center pit that holds described piston, and the side has fairlead, is filled with liquid in the cavity between this steel cage and the described test specimen container;
Described isolation controller is an electronic switch;
Described output of going up lower sensor connects described wave memorizer input after described prime amplifier amplifies, described computing machine is sent in the output of described wave memorizer, the output signal of described computing machine connects the control end of described isolation controller, and the output of described isolation controller connects the vibration source in the described proving installation.
2. the method for the calibration measurements sensor that adopts in the indoor dynamic and static triaxial apparatus shear wave velocity measurement system is characterized in that:
1. a pair of survey sensor that will select for use is placed on the same position place, to they excitings;
2. to doing Spectrum Analysis,, then continue step 3 if both Hz-KHz and energy distribution are quite approaching by the data of these two sensor acquisition, otherwise the alternative sensor, and change step 1;
3. both waveforms are done time-domain analysis,, then adopt this a pair of sensor, otherwise the alternative sensor changes step 1 if the ski-jump of both received signals is synchronous.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN95107918A CN1049976C (en) | 1995-08-04 | 1995-08-04 | Measuring system for indoor dynamic and static triaxial for shearing wave velocity |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN95107918A CN1049976C (en) | 1995-08-04 | 1995-08-04 | Measuring system for indoor dynamic and static triaxial for shearing wave velocity |
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| Publication Number | Publication Date |
|---|---|
| CN1120162A true CN1120162A (en) | 1996-04-10 |
| CN1049976C CN1049976C (en) | 2000-03-01 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN95107918A Expired - Fee Related CN1049976C (en) | 1995-08-04 | 1995-08-04 | Measuring system for indoor dynamic and static triaxial for shearing wave velocity |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101393091B (en) * | 2008-10-31 | 2011-09-07 | 中国科学院力学研究所 | Calcareous sand cementationsample preparation and inspection method thereof |
| CN103644966A (en) * | 2013-12-29 | 2014-03-19 | 中国科学技术大学 | Periodic signal enhancement detection device and method |
| CN104596852A (en) * | 2014-11-25 | 2015-05-06 | 宁波大学 | Rock-soil body temperature-control dynamic characteristic test system and test method |
| CN109752262A (en) * | 2019-01-18 | 2019-05-14 | 中国水利水电科学研究院 | A method of covering layer soil body dynamic shear modulus parameter is determined based on relative density in situ |
-
1995
- 1995-08-04 CN CN95107918A patent/CN1049976C/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101393091B (en) * | 2008-10-31 | 2011-09-07 | 中国科学院力学研究所 | Calcareous sand cementationsample preparation and inspection method thereof |
| CN103644966A (en) * | 2013-12-29 | 2014-03-19 | 中国科学技术大学 | Periodic signal enhancement detection device and method |
| CN104596852A (en) * | 2014-11-25 | 2015-05-06 | 宁波大学 | Rock-soil body temperature-control dynamic characteristic test system and test method |
| CN104596852B (en) * | 2014-11-25 | 2017-03-01 | 宁波大学 | A kind of Rock And Soil temperature control Dynamic Characteristics Test method |
| CN109752262A (en) * | 2019-01-18 | 2019-05-14 | 中国水利水电科学研究院 | A method of covering layer soil body dynamic shear modulus parameter is determined based on relative density in situ |
| CN109752262B (en) * | 2019-01-18 | 2020-10-27 | 中国水利水电科学研究院 | Method for determining dynamic shear modulus parameter of covering soil mass based on in-situ relative density |
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| Publication number | Publication date |
|---|---|
| CN1049976C (en) | 2000-03-01 |
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