深部高地应力下岩石双孔爆破的损伤规律

为了研究岩石在深部高地应力下的爆破损伤演化规律,基于HJC损伤本构建立岩石双孔爆破模型,采用隐-显式序列算法,综合考虑炮孔间的相互作用、埋深以及侧应力系数因素的影响,设置不同工况条件开展数值计算。结果表明:无地应力条件下,在孔距50～130 cm变化的过程中,发现沿炮孔孔心连线方向的损伤半径逐渐增大,垂直孔心线方向损伤半径逐渐减小;有效破碎面积的变化呈现钟形曲线,存在最佳孔间距d=70 cm使孔间损伤裂纹贯通的同时,有效破碎面积达到最大。地应力工况条件下,在侧应力系数λ=1时,有效破碎面积减小,x和y方向损伤半径均减小,损伤裂纹的扩展受到抑制。而在λ≠1时,损伤裂纹更偏向于地应力较大的方向发育,另一方向的损伤扩展受到抑制。深度即地应力的大小对岩体爆破效果并无线性关系,深度越大,对应侧应力系数下地应力对爆破效果的作用越明显。

Damage law of rock double holes blasting under deep high in-situ stress

In order to study the evolution law of blasting damage under deep and high in-situ stress, a rock double holes blasting model based on the HJC damage constitutive structure was established. The implicit-explicit sequence algorithm was adopted, the interaction between the blast holes, the buried depth and the influence of the lateral stress coefficient was considered comprehensively, and the numerical calculation under different working conditions was set up. The results show that under the condition of no ground stress, in the process of hole spacing from 50 cm to 130 cm, the damage radius along the direction of the hole line gradually increases, while the damage radius along the direction of the vertical connection line gradually decreases. The variation of the effective fracture area presented a bell curve, and the optimal hole spacing d=70 cm maximized the effective fracture area when the damage cracks connected between the holes. Under the condition of in-situ stress, when the lateral stress coefficient λ=1, the effective fracture area decreases, the damage radius in x and y directions decreases, and the crack propagation is inhibited. When λ≠1, the damage crack tends to develop in the direction of greater in-situ stress, and the damage propagation in the other direction is inhibited. Depth is also the size of the ground stress on the rock blasting effect and wireless relationship, the greater the depth, the more obvious effect of the ground stress on the blasting effect under the corresponding side stress coefficient.