3000字英语文章.docx

3000字英语文章.docx

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3000字英语文章

3000字英语文章

篇一：

3000字英文翻译

BoltSupportingofLarge-SpanSoftRockwayin

ShaquColliery

AbstractTheinstabilityoftrapezoidalI-steelsupportisanalysedforthecompoundroofofmaincoalseaminShaquColliery,andthemechanismofboltsupportingisstudied.Aschemeofboltsupportinghasbeengivenandputintopractice,remarkabletechnicalandeicbenefitshavebeengot.

Keywords:

large-span,compoundroof,boltsupporting,mechanism

1.Introduction

InshaqucollieryalargecoalmineminingrarecokingcoalinChina,mostroadwaysarelaidoutinmaincoalseam

roofofcoalseam.Thesoftcompound,whichiscomposedofmudstoneandcoalseam

containsaboundantbeddingsandjoints.Thestrengthoftheroofissolowthatitsuniaxial-saturatedcompressivestrengthisonly10.7Mpa.RQDvalueofcoalseamandiszero,andthatofmudstoneislowerthan10%.Thereisclaymineralsinmudstone,maincompositionsareinterbeddedstrataofilliteandmontmorillonitewhichwillswellwhensoakedbywater,Thespanofpreperationroadwaysandgatewaysiswiderthan4m,andthatofsomemainroadwaysisover5m.Inshaqucolliery,preperationroadwaysandgatewaysweresupportedbytrapezoidalI-steelsupport,thebeamsofwhichwerebentanddamaged,andtheroadwaysweredestroyedseriouslywithinashortperiodjustafterexcavated.Roof

controllingofLarge-SpanSoftRockwaysinthecoalseambecamethekeytotheproductionandconstructionofshaqucolliery.

2.supportingstatusandinstabilityanalysisoftrapezoidalI-steelsupports

trapezoidalI-steelsupportswereusedindrawingroadways,whichroofspanis4.0m,floorspanis4.9m,andhight2.95mandspacing0.5m.Initialresistanceofthesupportswasalmostzerobecauseitwasdifficulttothesupportbeamscontacttheroof,evenifwithhighqualityofinstallation.ThetrapezoidalI-steelsupportswouldnotcarryloaduntilthedisplacementofsurroundingrockexcceded80-100mmbecausethesupportsincreasedveryslowly.Therefore,rightafterexcavation,theroofwouldbendandsubsideseverly.Eighthoursafterexcavation,theroofstratawouldbreakcompletely,andthenformrockcavity.Theweightofcavingrockwouldactonthebeamsofsupports,whichformslooserockpressure.

Bycalculating,theultimateload-bearingcapacityissmallerthanroofpressurewhetheritisuniformalorconcentrated,Basedonthein-situobservation,inflectionvalueofmostroofreached200-300mm.Whenpairedsupportswereused,pairedbeamswerestillbentanddamaged;thenmidpropswereadded,theywerealsodestroyed.Manyroofbeamswerestabilizedonlyif2-3propshadbeenadded.Thesupportsweredamagedcompletely,andmostofthemcouldnotbereused.Thepart

sectionofroadwayshadbecomeinvertedtrapezoid,andtheavailablesectionwasfarsmallerthanthedesignedsection.Partofroadwayswasoutofusebecauseitwasinthedangerofseriouscaving.

3.Mechanismofboltsupporting

Itsmechanismistomakefulluseoftheself-load-bearingcapacityofsurroundingrockbybolting,andthenmakethesurroundingrockstabilizebyitself.Thestabilityofsurroundingrockdependsontheequilibriumstatusofgroundpressure,self-load-bearingcapacityofsurroundingrockandanchoringforceofbolts.Groundpressureistomakesurroundingrockdeformandbreak;self-load-bearingcapacityisthemainfactortostablizesurroundingrock.Anchoringforceofboltscannotchangetheequilibriumstatusofthethreebecauseitisverysmall,comparedwithgroundpressureandself-load-bearingcapacity.Anditsfunctionistochangethedecreasingregularityofself-load-bearingcapacityversusthedeformationofsurroundingrock,andbalanceself-load-bearingcapacityagainstgroundpressureearly.

RoofpressureisthepressureactingontheroofbeamswhenI-steelsupportsareusedtocontroltheroof.Whenroofissupportedbybolts,theroofpressurechangetobethepressureactingontherockwithintheboltingrangebecausethispartofrockischangeintoself-bearingbody.Accordingtothecharacteristicsoftheroofofcoalseams

canbedividedintosixsubstrata.,boltsstrata

Whenthevalueofroofsubsidenceiszero,roofpressureisin-situstress;thenroofpressuredecreaseswiththeincreaseofroofsubsidence.ThevariationofroofpressureisanalyzedbyFLAC,Theresultsareshownascurve1inFig.1.Wheoofsubsidencereaches19mm,thefirstroofsubstratumbeginstobearingtensilestress,thenlostsself-load-bearingcapacity,androofpressuredecreasesto0.67Mpa.Whenroofsubsidencereaches40mm,thesecondsubstratumlosesself-load-bearingcapacity,androofpressuredecreasesto0.16Mpa.Whenroofsubsidencereaches100mm,thefourthsubstratumlosesself-load-bearingcapacity,androofpressuredecreasesto0.08Mpa.Intheinitialstageofroofsubsidence,roofpressuredecreasesrapidly,andinthelaterstageofroofsubsidence,roofpressuredecreasesslowlyandthenhasanincreasingtrend.

Theself-load-bearingcapacityoftheroofwithoutboltingiscalculateduponthetheoryoflaminatedbeam,theresultareshownascurve2inFig.1.Whenroofsubsidenceiszero,theself-load-bearingcapacityisatitsutmostvalue0.0625Mpa;whenroofsubsidenceis100mm,roofstratahavebroken,mostofself-load-bearingcapacityhaslost,andtheresidualself-load-bearingcapacityisonly0.0375Mpa.Theself-load-bearingcapacityoftheroofwithboltingiscalculateduponthetheoryofcombinedbeam,theresultareshownascurve3inFig.1.Whenroofsubsidenceiszero,theself-load-bearingcapacityisatitsutmost

value0.4Mpa;whentheroofsubsidencereaches40mmtheself-load-bearingcapacitydecreasesto0.225Mpa,andwhenroofsubsidencereaches100mm,theself-load-bearingcapacitydecreasesto0.1Mpa.

AsshowninFin.1,theself-load-bearingcapacityofroofstratawithoutboltingislowerthanroofpressureduringthewholecourseofroofsubsiding,soroofstratacaveinevitably.Whenbolted,roofstrataischangedfromlaminatedbeamintocombinedbeam,andtheselr-load-bearingcapacityincreasesmarkedly.Whenroofsubsidencereaches44mm,theself-load-bearingcapacityexceedsroofpressure,thenroofstratastabilizedbyitself.

4Anchoringtechnology

Basedontheabovestudyofboltingmechanism,largesettingresistance,highspeedofresistanceandhighfinalresistancearethekeytechnologytothelarge-sponsoftrockroadwaybeforeroofstratadetaching,whichincludes:

（1）toimprovethesettingresistanceincreasingandachievehighspeedofresistanceincreasing,tomaketherealworkingpropertiesofboltscoordinateself-load-bearingpropertiesofroofstrata,whichenablestomakefulluseoftheself-load-bearingcapacityofroofstrata;

（2）toraiseboltingreliability,andsolvethedifficultproblemsthatanchoringforcebetweenboltsandsoftrockissmallandeasytolose.

4.1Blotingscheme

篇二：

关于家庭教育的优势和限制素质教育的常见论点（关于教育学的英语文章（3000字左右）及其翻译）

外

国

家

庭

教

育

的

优

势

和

限

制

ArgumentsabouttheStrengthsandLimitationsofHomeSchooling

MICHAELH.ROMANOWSKI

关于家庭教育的优势和的常见论点

迈克尔·H·罗曼诺夫斯

TodayinAmericanculture,fewpeopleareunfamiliarwith

HomeSchooling.Mosteitherknowsomeonewhohomeschools

theirchildrenorhaveheardofafamilythathasselectedthis

increasinglypopularalternativetopublicandprivateschool

education.Byallats,themovementhasbeengrowingsteadily

overthepastfewyears.TheU.S.DepartmentofEducation

estimatedthatapproximatelyfifteenthousandstudentswerehome

schooledin1984,withthatnumberincreasingtobetweentwo

hundredthousandandthreehundredthousandstudentsin1988.

Currently,itisestimatedthatbetween1.2and1.7millionstudentsin

gradesK-12arehomeschooledintheUnitedStates（Lines1988;

Ray2021）.Thisspectaculargrowthnotonlytestifiestothedemand

byparentsforalternativeandless-institutionalizedoptionsfortheir

children＇education,butalsohasestablishedhomeschoolingasa

significantandlegitimateforceintheAmericaneducational

landscape.

在当代的美国文化中，很少有人不晓得家庭教育的。

而且大多数

人认识一些对孩子进行家庭教育的人，或者听说过某个家庭选择了

这种日益流行的，相对于公立学校和私立学校而言，非传统的教育方

式。

据报道，家庭教育在过去的一年里一直在平稳发展。

美国教育部

估计，在1984年，美国大约有1.5万学生接受家庭教育，然而到了

1988年，这一人数已经增长到了20万到30万之间。

目前据估计，

中均在美国学前教育及学前教育中，约有1200万到1700万的学生接受的是

家庭教育（引自Line和Ray的著作）。

这种引人注目的增长，不仅表

明了家长们对孩子教育工作的多样化和非制度化选择的需求，而且确立了

家庭教育在美国教育领域的重要的、合法的地位。

Oneofthemorefascinatingaspectsofthiseducational

movementsisthattoday＇shomeschoolingfamiliesrepresenta

diversesamplingoftheAmericaneducationalpopulation.Once

reservedprimarilyforfundamentalistChristianswithreligious

motivationsforeducatingtheirchildrenathome,homeschooling

nowembracessuchawiderangeoffamiliesthatishassurfacedasa

mainstreamalternativeformofeducation.Therecentupsurgein

homeschooling＇spopularityhasdrawnpeoplefromallethnic

groupsandsocialclasses,andarapidlyincreasingnumberof

minorityfamilieshomeschooltheirchildren（Knowles1988;

Nazareno2021;Ray2021;Wahisi2021）.Ideologicallyhome

schooledrepresentabroadcross-sectionofAmericansociety;one

canfindfamiliesholdingtoconservativeandliberal,religiousand

secularvalues,beliefs,andpoliticalviewpoints（Mayberry1987;

VanGalen1988）.Homeschooling＇srapidgrowth,coupledwiththe

diversityofitspractitioners,allbutdisheslong-acceptedviewthat

publicschoolsservechildrenfromdiversebackgroundsequallywell.However,aswithallformsofeducation,therearebothprosand

constohomeschooling.Inthisarticle,Iaddressmyfamilieschoose

homeschooling,andIsummarizethemostargumentsput

forthbyadvocatesandcritics