Effects of deformation rate and hydrated condition on the mechanical property of sandstone

Accordingtoasetofuniaxialcompressionexperimentsofsandstone,effectsofdeformation rateandhydratedconditiononthecompressivestrength,elasticmodulus,post-peakstrainandacoustic emission(AE)characteristicswereexplored.Aone-dimensionalconstitutivemodelbyconsideringthe effectsofdeformationrateandhydratedconditionforsandstoneisestablishedandverifiedbydefinings seriesofstrengtheningandweakeningfactors.Theresultsshowthat:①Stress-straincurveofdryrock includeselasticstage,weakplasticstageandbrokenstagewhilethecompactionstage,shorterelastic stageandlongerplasticstageappearforwater-saturatedsandstone.②Deformationrateenlargesthe compressivestrengthofsandstone.Thedeformation-ratefactorofstrengthincreaseswiththeincreasing deformation rate.Water has weakening effect on the compressive strength of sandstone,and the differenceofcompressivestrengthbetweenthedryandsaturatedsandstonedecreasesgraduallywiththe increasingdeformationrate.③Theelasticmodulusofdryandsaturatedsandstoneincreaseslinearly withthedeformationrate.Waterhasweakeningeffectontheelasticmodulus.Theelasticmodulusof saturatedsandstoneislowerthanthatofdrysandstone,andtheweakeningfactorundergoeslittlechange atdifferentdeformationrates.④Deformationratehaslittleeffectonthepost-peakstrainofsandstone, thepost-peakstrainofsaturatedsandstoneismuchhigherthanthatofdrysandstone,andthehydraulic strengtheningfactorofpost-peakstrainisnotsensitivetothedeformationrate.⑤CumulatedAEenergy increaseswithdeformationrate,cumulatedAEenergyadvancesfordryspecimenandpostponesforwater-saturatedstone.Accumulationofenergyforwater-saturatedspecimenis3-5timesthatofdryspecimens.