爆炸荷载作用下岩石动态裂纹扩展的数值模拟

Numerical simulation of dynamic cracks propagation of rock under blasting loading

运用岩石破裂过程分析软件RFPA-dynamic,就爆炸荷载的加载速率、炮孔到自由边界的距离以及两炮孔中间空孔的大小对动态裂纹扩展方式的影响进行了研究。结果表明:随着加载速率的减小,炮孔周围的破碎区逐渐减少;裂纹开始萌生的位置逐渐由破碎区外边缘向炮孔孔壁转移;萌生的分支小裂纹逐渐减少,主裂纹扩展长度逐渐增大。由于自由边界的影响,炮孔向下扩展的裂纹逐渐弯向水平方向,且炮孔到自由边界的距离越小,这种趋势越明显。由于空孔的导向作用,使靠近空孔的裂纹逐渐弯曲向空孔处扩展,同时在空孔孔壁两端产生一条向炮孔扩展的裂纹;空孔半径大小对裂纹的导向作用,并无明显的影响;材料的非均匀性,对裂纹的扩展方式有显著的影响。

The influences of the blast loading rate,the distance from the guide hole to the free boundary and the radius of the guide hole between the two charge holes,on the dynamic propagation of cracks in rock were studied using realistic failure process analysis（RFPA-dynamic）.The results show that,as the loading rate decreases,the crushed zone around the charge hole is gradually reduced;the position of the crack initiation moves gradually from the crushed zone to the charge hole;and the number of small branch cracks gradually decreases while the length of the main crack increases.Due to the influence of the free boundary,the cracks that were previously downward now gradually bend in the horizontal direction,and this tendency becomes more observable as the distance from the charge hole to the free boundary gets shorter.As a result of the guidance of the guide hole,the cracks close to the guide hole gradually curve to the guide hole and,at the same time,a crack is formed at both ends of the guide hole wall that propagates to the charge hole.The radius of the guide hole has no obvious effect on the guiding role,but the nonuniformity of the material does have a significant effect on the way the cracks propagate.