混凝土介质中空气间隔装药的爆破机理

基于LS-DYNA非线性有限元程序,采用JHC混凝土损伤演化模型,研究了不同装药结构及不同 空气比情况下炮孔近区混凝土损伤的破坏机理。3种装药结构计算结果表明:随着空气比的增加,破坏方式 由压剪破坏转变为拉伸破坏,不同的空气比可应用于不同的爆破目的;对于梯段爆破,空气层位于上部的装药 结构爆炸能量利用率最好,当空气比为40%时,炮孔中部混凝土单元破坏方式由压剪转为拉伸破坏,表明存 在一个合理的空气比,可以提高爆炸能量利用率;对于预裂、光面爆破,空气层位于中部的装药结构爆破效果 最优;起爆方式对梯段爆破效果的影响要比预裂和光面爆破效果明显。

Blasting mechanism of air-decked charge in concrete medium

Basedonthenon-linearfinite-elementprocedureofLS-DYNA,theJohnson-Holmquist- Cook(JHC)modelwasadoptedtoinvestigatethedamageevolutionoftheconcreteneartheblasthole inthecasesofdifferentchargingstructuresanddifferentair-deckedratios.Thecalculationresultsfor threechargingstructuresshowthatthereisagradualchangefromcompression-shearfailuretotensile failurewiththeincreaseofair-deckedratioandthatdifferentair-deckedchargingstructurescanbeappliedtodifferentblastingpurposes. Forbenchblasting,thehighestutilizationratioofexplosionenergybelongstothetopair- deckedchargingstructure.Whentheair-deckedratioreaches40%,thefailuremodeoftheconcreteelementchangesfromcompression- shearfailuretotensilefailureinthemiddleoftheblasthole. Itisindicatedthatacertainreasonableair-deckedratioexistsanditcanbeused toimprovetheutilizationratioofblastingenergy.Forpresplittingblastingandsmoothblasting,the bestblastingeffectbelongstothemiddleair-deckedchargingstructure.Detonatingmannerscanaffect benchblastingmorestronglythanpresplittingblastingandsmoothblasting.