加锚岩体冲击动力特征试验研究

Experimental study on impact dynamic characteristics of bolted rock specimens

  • 摘要: 为研究加锚岩体的冲击动力特征,利用分离式霍普金森压杆(SHPB)试验系统对加锚试件和无锚试件进行不同冲击气压的动力试验,对比分析试件的应力波传播特征、应力应变关系、能量演化以及破坏形态,验证锚杆对动载作用岩体的加固效果,揭示锚杆加固机制。结果表明:①相同冲击气压条件下,加锚试件的透射波幅值与透射能均大于无锚试件,耗散能始终低于无锚试件;随着冲击气压的增大,2类试件的耗散能逐渐增大,但耗散能差异逐渐减小。②加锚试件和无锚试件动态峰值应力与峰值应变均随冲击气压的增大而增大,表现出明显的应变率效应。③锚杆预紧在试件内部产生压应力场,形成环绕锚杆的锥形加固核, 导致在相同冲击气压条件下加锚试件的破碎程度显著小于无锚试件。

     

    Abstract: In order to study the impact dynamic characteristics of bolted rock mass under dynamic loads, dynamic tests with different impact pressures were carried out on bolted and unbolted specimens using the SHPB test system. The stress wave propagation characteristics, stress-strain relationship, energy evolution and failure modes of the specimens were compared and analyzed. The reinforcement effect of rockbolts on rock mass under dynamic loads was verified and the reinforcement mechanism of rockbolts was obtained. The results show that: (1) Under the same impact pressure, the transmission-wave amplitude and transmission energy of bolted specimens are greater than those of unbolted specimens. The dissipated energy of bolted specimens is always lower than that of unbolted specimens. As the impact pressure increases, the dissipated energy of the two types of specimens gradually increases, but the difference in dissipated energy gradually decreases. (2) The dynamic peak stress and peak strain of both bolted and unbolted specimens increase with the impact pressure, showing a significant strain rate effect. (3) The rockbolt pretension generates a compressive stress field inside the specimen, forming a conical reinforcement core surrounding the rockbolt. Under the same impact pressure, the fragmentation degree of bolted specimens is significantly lower than that of unbolted specimens.

     

/

返回文章
返回