土建专业外文翻译7.docx
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土建专业外文翻译7
外文翻译
Problems
1Fromthedatagiveninfigure4.18,calculatethetangentmodulusandPoisson’sratiofortheinitialelasticbehavioroflimestonewithσ3=2.0MPa.
2Aporoussandstonehasauniaxialcompressivestrengthofσc=75MPa.theresultsofaseriesoftriaxialcompressiontestsplottedonshearstress-normalstressaxesgivealinearCoulombpeakstrengthenvelopehavingaslopeof45o
Determinetheaxialstressatpeakstrengthofajacketedspecimensubjectedtoaconfiningpressureofσ3=10MPa.Ifthejackethadbeenpuncturedduringthetestandtheporepressurehadbuiltuptoaequaltotheconfiningpressure,whatwouldthepeakaxialstresshavebeen?
3（a）EstablishanapproximatepeakstrengthenvelopeforthemarbleforwhichthedateshowninFigure4.19wereobtained.
3（b）Inwhatwaysmighttheobservedstress-strainbehaviorofthespecimenshavedifferedhadthetestsbeencarriedoutinaconventionaltestingmachinehavingalongitudinalstiffnessof2.0GNm-1?
Assumethatallspecimenswere50mmindiameter100mmlong.
ROCKSTRENGTHANDDEFORMABILITY
4Aseriesoflaboratorytestsonintactspecimensofquartzitegavethefollowingmeanpeakstrengths.TheunitsofstressareMPa,andcompressionistakenaspositive.
triaxial
compression
σ2=σ3
100
100
135
130
160
150
200
180
298
248
435
335
biaxial
tension/
compression
σ1
σ2
σ3
0
0
0
-13
-13.5
218
50
-13
225
100
0
228
150
0
210
210
0
Developapeakstrengthcriterionforthequartziteforuseinundergroundexcavationdesign.Experiencehasshownthatinsituuniaxialcompressivestrengthofthequartziteisone-halfthelaboratoryvalue.
5Aseriesoftriaxialcompressiontestsonspecimensofaslategavethefollowingresults:
Confiningpressure
σ3（MPa）
Peakaxialstress
σ1（MPa）
Anglebetweencleavageandσ1αo
2.0
5.0
10.0
15.0
20.0
62.0
62.5
80.0
95.0
104.0
40
32
37
39
27
Ineachtest,failureoccurredbyshearalongthecleavage.Determinetheshearstrengthcriterionforcleavageplans.
6InafurtherseriesoftestsontheslateforwhichthedataofProblem5wereobtained,itwasfoundthat,whenfailureoccurredindirectionsotherthanalongthecleavage,thepeakstrengthofrockmaterialwasgivenby
σ1=150+2.8σ3
whereσ1andσ3areinMPa.
Constructagraphshowingtheexpectedvariationofpeakaxialstressataconfiningpressureof10MPa,astheanglebetweenthecleavageandthespecimenaxisvariesfrom0oto90o.
7Thefollowingresultswereobtainedinaseriesofdirectsheartestscarriedouton100mmsquarespecimensofgranitecontainingclean,rough,dryjoints.
Normalstress
Peakshearstrength
Residualshearstrength
Displacementatpeakshearstrength
Normal
Shear
σn（MPa）
τp（MPa）
τr（MPa）
υ（mm）
μ（mm）
0.25
0.25
0.15
0.54
2.00
0.50
0.50
0.30
0.67
2.50
1.00
1.00
0.60
0.65
3.20
2.00
1.55
1.15
0.45
3.60
3.00
2.15
1.70
0.30
4.00
4.00
2.60
0.15
4.20
（a）Determinethebasicfrictionangleandtheinitialroughnessangleforthejointsurfaces.
（b）Establishapeakshearstrengthcriterionforthejoints,suitableforuseintherangeofnormalstresses,0-4MPa.
（c）Assuminglinearshearstress-sheardisplacementrelationstopeakshearstrength，investigatetheinfluenceofnormalstressontheshearstiffnessofthejoints.
8AtriaxialcompressiontestistobecarriedoutonaspecimenofgranitereferredtoinProblem7withthejointplaneinclinedat35otothespecimenaxis.Aconfiningpressureofσ3=1.5MPaandanaxialstressofσ1=3.3MPaaretobeapplied.Thenajointwaterpressurewillbeintroducedandgraduallyincreasedwithσ1andσ3heldconstant.Atwhatjointwaterpressureissliponthejointexpectedtooccur?
Repeatthecalculationforasimilartestinwhichσ1=4.7MPaandσ3=1.5MPa.
9Intheplaneofcrosssectionofanexcavation,arockmasscontainsfoursetsofdiscontinuitiesmutuallyinclinedat45o.TheshearstrengthsofalldiscontinuitiesaregivenbyalinearCoulombcriterionwithc’=100kPaandφ’=30o.
DevelopanisotropicstrengthcriterionfortherockmassthatapproximatethestrengthobtainedbyapplyingJaeger’ssingleplaneofweaknesstheoryinseveralparts.
10Acertainslatecanbetreatedasatransverselyisotropicelasticmaterial.Blocksamplesoftheslateareavailablefromwhichcoresmaybepreparedwiththecleavageatchosenanglestothespecimenaxes.
Nominateasetofteststhatcouldbeusedtodeterminethefiveindependentelasticconstantsinequation2.42requiredtocharacterizethestress-strainbehavioroftheslateinuniaxialcompression.Whatmeasurementsshouldbetakenineachofthesetests?
5Pre-miningstateofstress
5.1Specificationofthepre-miningstateofstress
Thedesignofanundergroundstructureinrockdiffersfromothertypesofstructuraldesigninthenatureoftheloadsoperatinginthesystem.Inconventionalsurfacestructures,thegeometryofthestructureanditsoperatingdutydefinetheloadsimposedonthesystem.Foranundergroundrockstructure,therockmediumissubjecttoinitialstresspriortoexcavation.Thefinal,post-excavationstateofstressinthestructureistheresultantoftheinitialstateofstressandstressesinducedbyexcavation.Sinceinducedstressesaredirectlyrelatedtotheinitialstresses,itisclearthatspecificationanddeterminationofthepre-miningstateofstressisanecessaryprecursortoanydesignanalysis.
Themethodofspecifyingtheinsitustateofstressatapointinarockmass,relativetoasetofreferenceaxes,isdemonstratedinFigure5.1.AconvenientsetofCartesianglobalreferenceaxesisestablishedbyorientingthexaxistowardsminenorth,ytowardsmineeast,andzverticallydownwards.Theambientstresscomponentsexpressedrelativetotheseaxesaredenotedpxx,pyy,pzz,pxy,pyz,pzx.UsingthemethodsestablishedinChapter2,itispossibletodetermine,fromthesecomponents,themagnitudesofthefieldprincipalstresspi（i=1,2,3）,andtherespectivevectorsofdirectioncosines（λxi,λyi,λzi）forthethreeprincipalaxes.Thecorrespondingdirectionanglesyieldadipangle,αi,andabearing,ordipazimuth,βi,foreachprincipalaxis.Thespecificationofthepre-miningstateofstressiscompletedbydefiningtheratiooftheprincipalstressesintheformp1:
p2:
p3=1.0:
q:
rwherebothqandrarelessthanunity.
Theassumptionmadeinthisdiscussionisthatitispossibletodeterminetheinsitustateofstressinawaywhichyieldsrepresentativemagnitudesofthecomponentsofthefieldstresstensorthroughoutaproblemdomain.Thestateofstressintherockmassisinferredtobespatiallyquitevariable,duetothepresenceofstructuralfeaturessuchasfaultsorlocalvariationinrockmaterialproperties.Spatialvariationinthefieldstresstensormaybesometimesobservedasanapparentviolationoftheequationofequilibriumfortheglobalz（vertical）direction.Sincethegroundsurfaceisalwaystraction-free,simplestaticsrequiresthattheverticalnormalstresscomponentatasub-surfacepointbegivenby
Pzz=γz（5.1）
Whereγistherockunitweight,andzisthedepthbelowgroundsurface.
Failuretosatisfythisequilibriumcondition（equation5.1）inanyfielddeterminationofthepre-miningstateofstressmaybeavalidindicationofheterogeneityofthestressfield.Forexample,theverticalnormalstresscomponentmightbeexpectedtobelessthanthevaluecalculatedfromequation5.1,forobservationsmadeintheaxialplaneofananticlinalfold.
Acommonbutunjustifiedassumptionintheestimationoftheinsitustateofstressisaconditionofuniaxialstrain（‘completelateralrestraint’）duringdevelopmentofgravitationalloadingofaformationbysuperincumbentrock.Forelasticrockmassbehavior,horizontalnormalstresscomponentsarethengivenby
（5.2）
WhereνisPoisson’sratiofortherockmass.
Ifitisalsoassumedthattheshearstresscomponentspxy,pyz,pzxarezero,thenormalstressesdefinedbyequations5.1and5.2areprincipalstresses.
Reportsandsummariesoffieldobservations（Hookeretal.,1972;BrownandHoek,1978）indicatethatfordepthsofstressdeterminationsofminingengineeringinterest,equation5.2israrelysatisfied,andtheverticaldirectionisrarelyaprincipalstressdirection.Theseconditionsarisefromthecomplexloadpathandgeologicalhistorytowhichanelementofrockistypicallysubjectedinreachingitscurrentequilibriumstateduringandfollowingorebodyformation.
译文
问题
1在σ3=2.0MPa的条件下，石灰石的初始弹性行为包括计算切线模量和泊松比可由图4.18所给出的数据显示出来。
2多孔砂岩的单轴抗压强度σc=75MPa。
由一系列的三轴压缩试验结果绘制出的剪应力正常应力轴显示的库仑强度峰值线性强度包络图有一个45o的倾斜。
确定套嵌标本遭受的围压σ3=10MPa轴向强度应力峰值。
如果套嵌在试验过程中被刺破，孔隙水压力已建立起一个平衡的围压值，那么轴向应力峰值又会怎样？
3（a）建立一个大理岩近似峰值强度包络图如图4.19所示。
3（b）通过采取何种方式可以观测到试样的应力应变行为由不同的试验进行了常规试验机上得出的线性刚度为2.0GNm-1？
假定所有标本，直径为50mm长100毫米。
岩石强度和应变
4一系列完整的石英岩试样的实验室试验给出了以下平均强度峰值。
应力的单位是兆帕，并且压缩性为刚性。
三轴压缩
σ2=σ3
100
100
135
130
160
150
200
180
298
248
435
335
双轴
拉伸/压缩
σ1
σ2
σ3
0
0
0
-13
-13.5
218
50
-13
225
100
0
228
150
0
210
210
0
制定一个石英岩的峰值强度标准用于地下洞室的开挖设计。
经验表明，石英岩的原位单轴抗压强度值是实验室所测值的一半。
5一系列板岩试样的三轴压缩试验结果如下：
围压
σ3（MPa）
轴向应力峰值
σ1（MPa）
解理和σ1的角度α
（o）
2.0
5.0
10.0
15.0
20.0
62.0
62.5
80.0
95.0
104.0
40
32
37
39
27
在每一个试样中，试样沿着解理面发生剪切破坏。
进而确定解理平面图的抗剪强度标准。
6在问题5所得数据的基础上，对板岩做了一系列进一步的实验，人们发现，当破坏方向不是沿着解理时，岩石材料的峰值强度由公式
σ1=150+2.8σ3计算得到。
其中σ1和σ3的单位为MPa。
构建一个图表显示了轴向应力峰值在围压为10兆帕时的预期变化，因为解理和试样轴向之间的夹角从0o到90o变化。
7以下结果是在一系列100毫米见方的含有新鲜，粗糙，隐形裂隙交织的花岗岩试样上进行直接剪切试验得到的。
正应力
峰值抗剪强度
残余抗剪强度
位移峰值抗剪强度
法向
切向
σn（MPa）
τp（MPa）
τr（MPa）
υ（mm）
μ（mm）
0.
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