CN1458522A - New technological method-1 for detecting shear wave speed in geotechnical static and dynamic triaxial instrument - Google Patents
New technological method-1 for detecting shear wave speed in geotechnical static and dynamic triaxial instrument Download PDFInfo
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- CN1458522A CN1458522A CN 03129927 CN03129927A CN1458522A CN 1458522 A CN1458522 A CN 1458522A CN 03129927 CN03129927 CN 03129927 CN 03129927 A CN03129927 A CN 03129927A CN 1458522 A CN1458522 A CN 1458522A
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Abstract
Upper and lower casings, radiator, vibrator, electric cable and other parts constitute one new kind of sensor. The radiation body is light hard metal cylinder in the height 2 cm over greater than a traditional sensor, and is used as both shearing wave radiator and the device for applying force, fixing soil sample and draining water. The vibrator is a ring made of composite PZT piezoelectrical ceramic and epoxy resin material and has upper and lower surfaces with sliver plated, upper and lower electrodes connected to cable and leading out wire junction to fix the cable to the casing. Alternately changed or pulsed voltage is applied to the vibrator to produce torsion vibration, which radiates outwards in wave form via the radiator. The present invention has the advantages of the sensor of composite piezoelectrical material and in shape suitable for measuring soil sample shearing wave speed, low vibration frequency, small volume, great radiation energy, pure shearing waveform, etc.
Description
Technical field
The present invention relates to a kind of Geotechnical Engineering measuring technology.
Background technology
In Geotechnical Engineering, the shear wave velocity of soil layer is an important soil nature parameter, has obtained the attention of height and application widely.Bending unit method commonly used is carried out the test of shear wave velocity at present quiet the geotechnique, the dynamic triaxial apparatus.There is following shortcoming in this method: 1. bending unit need insert the certain degree of depth of test specimen (being generally 3mm), thereby cause disturbance certain in the insertion depth scope, also cause simultaneously the uncertainty of shearing wave spread length, the error that only this item causes can reach 16%; 2. the interference of near-field effect and stray wave makes the initial time of shearing wave have bigger subjectivity, and the measuring error of bringing thus can reach 30%; What 3. bending unit produced is a kind of polarized wave, and the sensitive direction that must will transmit and receive the unit during test is arranged unanimity, could effectively receive test signal; 4. because flexure element needs often to insert in the soil, and insulation and waterproof problem are more difficult, this has also limited the serviceable life of this device.In addition, the plain edition shearing wave sensor that adopts in ultrasonic engineering generally is to utilize single-sheet thickness shear type PZT wafer to make.There is following problem indoor in such sensor when carrying out the measurement of soil sample shear wave velocity: 1. thickness shear is a kind of dither pattern (being used to make the wafer vibration frequency of sensor thickness shear-vibration pattern usually greater than 400kHz), electromechanical coupling factor is lower, the sensor emittance is little, and the shearing wave propagation distance is very short; 2. the characteristic impedance of PZT wafer is much larger than the characteristic impedance of soil sample, and this makes and be difficult to coupling between the two, thereby has further reduced to enter the shearing wave energy of the soil body; 3. can't suppress compressional wave disturbs, especially for medium as clay, the high loss of this class of saturated loosening sand, compressional wave disturbs very serious, and this makes this method only be fit to the shear wave velocity of test dry sand, and needs to cooperate filtering technique to discern skill mutually with certain shaking.Therefore, almost can't in dynamic and static triaxial test, utilize this class sensor.
Summary of the invention
The purpose of this invention is to provide a kind of simple in structure, frequency of operation is low (5kHz-30kHz), the scissoring vibration emittance is big and can match with various quiet, moving triaxial shear equipments and test the new technology of shear wave velocity, thereby overcome bending unit method and the existing shortcoming of plain edition shear wave velocity sensor.
Technical method of the present invention is shown in accompanying drawing 1～accompanying drawing 3.The new technology-1 of, dynamic triaxial apparatus build-in test shear wave velocity quiet the geotechnique by on lower casing (1), radiator (2) and oscillator (3) form new sensor (the following sensor that is called for short), radiator (2) is the hard metal cylinder of lightweight, its center is provided with discharge pipe line (6), there is a semi-circular recesses outer, end of radiator (2), is tightly connected by the O type circle (7) in the groove between radiator (2) and the upper and lower shell (1).The height of radiator (2) is greater than more than the traditional sensors 2cm.Upper case (1) is hollow flange-like, and lower case (1) is provided with cable fairlead (9), and a base fixed orifice (8) is arranged at the bottom, so that fix with the bolt (5) and the base of triaxial apparatus.Radiator (2) is both as the radiator of shearing wave, simultaneously also as afterburning, soil sample is fixed and the device of draining.It is circular that oscillator (3) adopts PZT piezoelectric ceramics and epoxy resin composite material to make, and adopt along the mode of annulus shear-polarization and polarize, and silver-plated as electrode at the upper and lower surface of annulus, under the effect of alternating electric field, annulus will produce twisting vibration.Upper and lower two electrodes of oscillator are connected with cable (4), and cable is by cable fairlead (9) and pass the pinout connector of being made up of inner sleeve (12) outer tube (11) and O-ring seal (13) (10) and be fixed in lower casing (1).Outer tube (11) is fixing with upper and lower shell (1), and extruding inner sleeve (12) makes O-ring seal (13) distortion and cable (4) is sealed.Last lower casing adopts stainless steel or other metals to make.When applying the voltage of alternation for oscillator (3) by cable (4), oscillator produces twisting vibration, this vibration with the form of ripple by radiator to external radiation.On the contrary, when radiator receives torsion vibration signal, just drive oscillator and produce twisting vibration, so, the electric charge of alternation produced at the upper and lower surface of oscillator.
Description of drawings
Fig. 1 is each component-assembled figure of the present invention.The upper and lower shell of 1-wherein; The 2-radiator; The 3-oscillator; The 4-cable; The 5-set bolt; The 6-discharge pipe line; 7-O type circle; 8-base fixed orifice; 9-cable fairlead; The 10-pinout connector.
Fig. 2 is oscillator (a 3) structural drawing.
Fig. 3 draws the structural drawing of joint (10) for cable.11-outer tube wherein; The 12-inner sleeve; The 13-O-ring seal.
Fig. 4 carries out the embodiment Experimental equipment of shear wave velocity measurement in quiet, dynamic triaxial apparatus for the present invention.14-triaxial cell wherein; 15-is two shear wave velocity sensors up and down; 16-soil sample test specimen; The 17-latex film; 18-sound wave emissions receiving instrument; The 19-draining valve; 20-triaxial apparatus gusset; 4 outgoing cables.
Specific embodiment
With reference to accompanying drawing 1～4.Upper and lower shell is that stainless steel or other metal are made, and physical dimension is φ 40mm～φ 80mm * 30～80mm (size according to supporting triaxial apparatus is fixed).Radiator is the right cylinder of the hard metal of lightweight, and concrete size matches with shell, and the center is provided with the drainage path of φ 3mm.Oscillator is the annulus (vibration frequency as required is fixed) of φ 10mm～φ 30mm * φ 20mm～φ 75mm * 5mm～30mm.Earlier the upper/lower electrode and the outgoing cable (4) of oscillator connected during assembling, then cable is drawn shell by the cable fairlead, pass cable and draw joint cable is fixed on the shell.In radiator and outer casing end groove, put O type circle.Pressurization is pressed into radiator and the oscillator that bonds together in the shell.
Adopt radiator to be of a size of φ 39.1mm, upper sensor (radiator and oscillator) height 50mm, lower sensor height 70mm adopts oscillator to be of a size of φ 10mm * φ 20mm * 5mm.It is indoor that this sensor (15) is positioned over triaxial pressure, and the device of forming dynamic triaxial apparatus build-in test shear wave velocity as shown in Figure 4.During use, lower sensor is fixed on the base of triaxial cell with set bolt (5), and sensor cable is drawn the pressure chamber.Soil sample test specimen (16) outside with φ 39.1mm * 80mm puts latex film (17) then, and latex film grows part and is enclosed within on the radiator of upper and lower part sensor.Pressurization in the pressure chamber, draining valve (19) about opening on the rows of sensors water lines carries out discharging consolidation, through behind the official hour, with sensor emission one alternate electrical signal of sound wave emissions receiving instrument (18) to top or bottom, make the sensor emission shearing wave, shearing wave is by behind the soil sample test specimen, received and become the electric charge of alternation, this electric signal to amplify through sound wave emissions receiving instrument (18) the shearing wave conversion of signals by the sensor of the other end to receive.Being recorded from being transmitted into the time interval of reception by the sound wave emissions receiving instrument, promptly is the time of shearing wave by soil sample, and the length of test specimen is known, and then the shear wave velocity of soil sample can be determined.
Beneficial effect of the present invention is: first Application is turned round the principle of cutting vibration, piezo-electricity composite material is made be applicable to survey The sensor of examination soil sample shear wave velocity. Sensor has that vibration frequency is low, volume is little, emittance is big, penetration thickness is big The advantage such as pure with the shearing wave waveform, that antijamming capability is strong. Vibration frequency for test diameter 3.91cm sample sensor Rate can be accomplished 10kHz, has greatly improved the measuring distance of shear wave velocity. Simultaneously, adopt piezo-electricity composite material to be easy to transfer The impedance matching of joint oscillator and native test specimen, this has also increased the shearing wave emittance that enters the soil body. Its sealing device can In the water of 1Mpa pressure, work, and seepage does not take place. The present invention easily shears with existing various quiet, moving three axles Instrument matches, and forms shear wave velocity and quiet, moving three axles shearing joint test equipment, thereby forms a kind of novel geotechnique connection Close experimental rig.
Claims (3)
1. quiet the geotechnique, the novel technical method-1 of dynamic triaxial apparatus build-in test shear wave velocity, on it is characterized in that adopting, lower casing (1), radiator (2) and oscillator (3) etc. are formed new sensor, radiator (2) is the hard metal cylinder of lightweight, the radiator center is provided with discharge pipe line (6), there is a semi-circular recesses outer, end, the height of radiator (2) is greater than more than the traditional sensors 2cm, radiator (2) is with last, be tightly connected by the O type circle (7) in the groove between the lower casing (1), oscillator (3) adopts PZT piezoelectric ceramics and epoxy resin composite material to make circular, employing polarizes along the mode of annulus shear-polarization, upper and lower surface at annulus is silver-plated, the upper/lower electrode of oscillator is connected with cable (4), pinout connector (10) is fixed in lower casing (1) with cable (4), upper case (1) is hollow flange-like, and lower case-1 is provided with cable fairlead (9), and a blind hole is arranged at the bottom.
2. according to the novel technical method-1 of described, the dynamic triaxial apparatus build-in test shear wave velocity quiet of claim 1 the geotechnique, it is characterized in that described pinout connector (10) is made up of inner sleeve (12) outer tube (11) and O-ring seal (13), cable (4) passes internal and external casing (12,11), outer tube (11) is fixing with lower casing (1), and extruding inner sleeve (12) makes O-ring seal (13) distortion that its cable (4) is sealed.
3. according to the novel technical method-1 of claim 1 or 2 described, dynamic triaxial apparatus build-in test shear wave velocities quiet the geotechnique, it is characterized in that described radiator (2) both as the radiator of shearing wave, simultaneously also as afterburning, soil sample is fixed and the device of draining.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03129927 CN1204400C (en) | 2003-05-23 | 2003-05-23 | New technological method-1 for detecting shear wave speed in geotechnical static and dynamic triaxial instrument |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03129927 CN1204400C (en) | 2003-05-23 | 2003-05-23 | New technological method-1 for detecting shear wave speed in geotechnical static and dynamic triaxial instrument |
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| Publication Number | Publication Date |
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| CN1458522A true CN1458522A (en) | 2003-11-26 |
| CN1204400C CN1204400C (en) | 2005-06-01 |
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| CN 03129927 Expired - Fee Related CN1204400C (en) | 2003-05-23 | 2003-05-23 | New technological method-1 for detecting shear wave speed in geotechnical static and dynamic triaxial instrument |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101520340B (en) * | 2009-03-27 | 2010-07-28 | 中国民航大学 | Penetration soil layer original position elastic wave testing device |
| CN105388219A (en) * | 2015-10-26 | 2016-03-09 | 东南大学 | Piezoelectric ring excitation device for testing granular material shear wave velocity and indoor testing device |
| CN107860648A (en) * | 2017-12-21 | 2018-03-30 | 云南农业大学 | Portable triaxial machining wave velocity testing instrument |
| CN109465173A (en) * | 2018-10-23 | 2019-03-15 | 武汉大学 | A kind of rock mass structure shearing wave transducer and preparation method based on piezoelectric ceramic micro-displacement actuator |
| CN109632494A (en) * | 2019-01-28 | 2019-04-16 | 浙江大学 | The consolidation testing device of complex spectrum induced polarization method and flexure element method |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023219648A1 (en) | 2022-05-09 | 2023-11-16 | Lockheed Martin Energy, Llc | Flow battery with a dynamic fluidic network |
-
2003
- 2003-05-23 CN CN 03129927 patent/CN1204400C/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101520340B (en) * | 2009-03-27 | 2010-07-28 | 中国民航大学 | Penetration soil layer original position elastic wave testing device |
| CN105388219A (en) * | 2015-10-26 | 2016-03-09 | 东南大学 | Piezoelectric ring excitation device for testing granular material shear wave velocity and indoor testing device |
| CN107860648A (en) * | 2017-12-21 | 2018-03-30 | 云南农业大学 | Portable triaxial machining wave velocity testing instrument |
| CN107860648B (en) * | 2017-12-21 | 2024-02-09 | 云南农业大学 | Portable triaxial shear wave speed tester |
| CN109465173A (en) * | 2018-10-23 | 2019-03-15 | 武汉大学 | A kind of rock mass structure shearing wave transducer and preparation method based on piezoelectric ceramic micro-displacement actuator |
| CN109465173B (en) * | 2018-10-23 | 2020-04-24 | 武汉大学 | Rock mass structure shear wave transducer based on piezoelectric ceramic micro-displacement actuator and preparation method |
| CN109632494A (en) * | 2019-01-28 | 2019-04-16 | 浙江大学 | The consolidation testing device of complex spectrum induced polarization method and flexure element method |
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| Publication number | Publication date |
|---|---|
| CN1204400C (en) | 2005-06-01 |
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