Abstract: Thejointshavesignificanteffectsoncrackpropagationinslitchargeblasting. Inthispaper, thecausticmethodisadoptedtostudythelawofcrackpropagationinverticaljointedmediaunderslit chargeblasting. Theresultsshowthatcomparedwiththeintactmediawithoutjoint,insingleslitcharge blastingthevelocityofinduceddynamiccrackislowerinthemediawithverticaljoint,andthecrack lengthononesideoftheboreholedecreasesbyabout15.5%. Thereflectedwave,generatedbythereflectionofstresswaveattheverticaljoint,increasesthestressintensityfactorKdⅡ,whereasdecreasesthe Kd Ⅰoftheoppositepropagatedcrack,whichleadstosuppressingtheforwardpropagationofdynamic crack. Thecloserthedistancebetweentheholeandthejoint,thestrongerthesuppressingeffectofthe
jointoncrackpropagation. Underdoubleslitchargeblastingwithsimultaneousinitiation,theexplosion stresswave,generatedbytheadjacentborehole,hasapositiveeffectonthecrackpropagationwithoppositedirections,whichmakesboththedynamicstressintensityfactorandcrackvelocityincreasesignificantly,leadsthedynamicpassingthroughtheverticaljointsdirectlywithoutdeflection,improesthe directionalpropagationabilityofdynamiccrackinjointedrock,and the length of crack increasesby morethan50% comparedwiththesingleslitchargeblasting. Theresultsprovideatheoreticalbasisfor carryingoutdirectionalfractureblastingwithslitchargeinjointedrockmass.