爆炸荷载下岩体破裂影响因素研究

A Study of Influence Factors of Rock Mass under Blasting Load

为研究岩体在爆炸荷载作用下裂纹扩展的影响因素,采用ANSYS/LS-DYNA动力有限元软件对砂岩爆破裂纹扩展机理进行数值模拟,并考察地应力、自由面和节理等因素对爆破裂纹扩展的影响。结果表明:爆生气体与应力波联合作用下的裂隙区半径是应力波单独作用下裂隙区半径的1.85倍,爆生气体的存在使破岩过程更为有效;当侧压系数不变时,随着初始应力的增加,裂隙区扩展半径减小;自由面产生的反射拉伸应力波导致平行于自由面的裂纹产生;自由面与节理平行或垂直对爆破裂纹的分布有很大影响。研究成果可为中硬岩的爆破开挖工程提供参考。

In order to study the fracture factors in the rock mass under the blasting load, the dynamic finite element software ANSYS/LS-DYNA was employed to study the fracture mechanism of the rock under blasting load,and the influence of initial stress,free boundary and joint on rock dynamic fracture was discussed. The results indicate that the radius of the crack zone under the combined action of the explosion gas and the stress wave is 1.85 times as the stress wave alone, and the existence of the explosive gas makes the rock breaking process more effective; when the lateral pressure coefficient maintains constant, the increase in the initial stress causes the decrease in the crack radius; The reflected tensile stress wave from free surface leads to crack initiation parallel to the free surface; The free surfaces parallel or perpendicular to the joint has great influence on the distribution of blasting crack. The research results can provide reference for blasting excavation engineering medium hard rock.