摘要:
岩体中层理对切缝药包爆生裂纹的扩展有重要影响。 本文采用焦散线方法研究垂直层 理介质在切缝药包单孔/双孔爆破下爆生裂纹的扩展规律。 结果表明:与无层理介质相比,在垂 直层理介质中,切缝药包单孔爆破下爆生裂纹的扩展速度下降,炮孔一侧裂纹扩展的最终长度降 低约15.5% ;爆炸应力波在层理处产生的反射波使相向扩展爆生裂纹尖端的应力强度因子KdⅡ增 大、Kd Ⅰ降低,抑制了爆生裂纹的扩展,且炮孔距离层理越近,层理对该侧炮孔处裂纹的阻碍效应 越强;切缝药包双孔同时起爆时,相邻炮孔产生的爆炸应力波对相向扩展的爆生裂纹有促进作 用,使裂纹尖端的应力强度因子和裂纹扩展速度均显著提高,裂纹直接穿过垂直层理继续扩展, 提高了层理岩体中爆生裂纹定向扩展的能力,裂纹扩展的最终长度较单孔爆破时增大50% 以 上。 研究结果为层理岩体中开展切缝药包定向断裂爆破提供参考。
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.
点击查看大图
下载: