预裂炮孔近区煤体爆破损伤特性研究

Study on Blasting Damage Characteristics of Coal Body near Pre-splitting Blasthole

为探究工作面预裂炮孔近区煤体动力损伤及应力传递过程,选用HJC、RHT损伤模型,对单孔装药及双孔爆破工况开展爆破模拟。研究结果表明:单孔爆破下RHT模型的损伤随时间呈近似线性增长,HJC模型的爆破损伤随时间呈二次函数增长;单孔爆破中峰值压力与爆心距呈二次函数;双孔爆破下HJC、RHT模型的爆炸近区压力峰值相差2.27%,但远区峰值压力差值≥8.0 MPa;双孔爆破下RHT模型应力波传播:两孔贯穿-后向外扩展;HJC模型应力波传播:由爆破孔向四周扩展,后作用孔间区域;单孔/双孔爆破中HJC模型能量吸收时间分别为RHT模型的6~10倍,RHT模型可表征煤岩爆破演化。研究成果可为工作面安全高效施工提供参考。

In order to examine the dynamic damage and stress transfer process of the coal body near pre-existing cracks in the working face,utilized the HJC and RHT damage models to conduct blasting simulations for single-hole charging and double-hole blasting scenarios.The results indicate that damage growth under the RHT model for single-hole blasting is approximately linear with time,while the HJC model predicts a quadratic function of damage growth with time.The peak pressure and distance to the bursting center for single-hole blasting form a quadratic function.For two-hole blasting,the HJC and RHT models show a 2.27%difference in peak pressure in the near area,while the difference in peak pressure in the far area is≥8.0 MPa.Under the RHT model for two-hole blasting,the stress wave propagates as the two holes penetrate and expand outward.In contrast,the HJC model predicts stress wave propagation from the blasting holes to the surrounding area,followed by the inter-hole region.The energy absorption time of the HJC model in single-hole/double-hole blasting is 6-10 times longer than that of the RHT model.Moreover,the RHT model effectively captures the evolution of coal-rock blasting.These research findings can offer valuable insights for the safe and efficient construction of working faces.