简介：Thispaperreportsstick–slipbehaviorsofIndiangabbroasstudiedusinganewlarge-scalebiaxialfrictionapparatus,builtintheNationalResearchInstituteforEarthScienceandDisasterPrevention(NIED),Tsukuba,Japan.Theapparatusconsistsoftheexistingshakingtableastheshear-loadingdeviceupto3,600kN,themainframeforholdingtwolargerectangularprismaticspecimenswithaslidingareaof0.75m2andforapplyingnormalstressesrnupto1.33MPa,andareactionforceunitholdingthestationaryspecimentotheground.Theshakingtablecanproduceloadingratesvupto1.0m/s,accelerationsupto9.4m/s2,anddisplacementsdupto0.44m,usingfourservocontrolledactuators.Wereportresultsfromeightpreliminaryexperimentsconductedwithroomhumidityonthesamegabbrospecimensatv=0.1–100mm/sandrn=0.66–1.33MPa,andwithdofabout0.39m.Thepeakandsteady-statefrictioncoefficientswereabout0.8and0.6,respectively,consistentwiththeByerleefriction.Theaxialforcedroporshearstressdropduringanabruptslipislinearlyproportionaltotheamountofdisplacement,andtheslopeofthisrelationshipdeterminesthestiffnessoftheapparatusas1.159108N/mor153MPa/mforthespecimensweused.Thislowstiffnessmakesfaultmotionveryunstableandtheovershootingofshearstresstoanegativevaluewasrecognizedinsomeviolentstick–slipevents.Anabruptslipoccurredinaconstantrisetimeof16–18msdespitewidevariationofthestressdrop,andanaveragevelocityduringanabruptslipislinearlyproportionaltothestressdrop.Theuseofalarge-scaleshakingtablehasagreatpotentialinincreasingthesliprateandtotaldisplacementinbiaxialfrictionexperimentswithlargespecimens.