Q值實驗室測量的超聲波方法.pdf

1、中國科學(xué)技術(shù)大學(xué)碩士學(xué)位論文Q值實驗室測量的超聲波方法姓名：李偉東申請學(xué)位級別：碩士專業(yè)：固體地球物理指導(dǎo)教師：施行覺2000.5.1AbstractThemethodsformeasuringQvaluesbyultrasonicinlaboratoryTheQvaluerepresentsthedissipationofmechanicalenergyinmaterialThemechanismofattenuationinclud

2、esinnerfriction，scattering，theflowofporefluidsandsoonTheevalueofrockisaffectedbypressure，temperature，thepropertyandsaturationofporefluid，etcByusingechotechnique，theattenuationcanbecalculatedfrONtheechoesthatpropagateddif

3、ferentdistance，thentheQvaluecanbecalculatedinsuccessionTheintroductionofbufferrodanddiffractioncorrectionimprovedtheechotechniqueThatmakesthetechniquewidelyusedSpectraratiotechniqueistheclassicalmethodforcalculatingevalu

4、esinlaboratoryGroundingonthecemodel，theevaluecanbecalculatedfromthespectraratioofthewavesthatrespectivelypropagatedthesampleandreferenceRcfractioncoefficientanddiffractionmustbeconsideredtominishtheerrorWithultrasonicofl

5、owfrequency，theQvalueofextentionalwavecanbecalculatedbywaveinversiontechniqueInordertoenhancetheprecision，velocitiesshouldbeinvertedfromthephasesfirstlyTheequivalentacousticimpedancetechniquethathastheadvantageofspectrar

6、atiotechniqueandechotechniquewasproposedTransducersandcouplantwereequatedtoananelasticmaterial，andtheequivalentmaterialwasassumedtobeperfectlybondedwiththesampleandreferenceWithdiffractioncorrection，fromsecondwave，the0)a

7、luevaryingwithfrequencythencanbeestimatedbyspectraanalysisBasingonthedefinitionofQvalue，theenergytechniquewasproposedbyProfShiFromtheenergydifferencebetweenthewavesthatpropagatedthesamplesofdifferentlength，theQvaluebetwe

8、enQDandQ。CanbecalculatedTheQvaluesofaluminiumandgraniteweremeasuredbywaveinversiontechniqueAndtheresultwerediscussedAlthoughtheresultoflaboratorycannotbedirectlyappliedtoseismicsurveys，itseemsthattherelationshipsobserved