为了揭示在冲击载荷下锚杆支护材料动态力学特性及应变率效应，为不同震级冲击地压巷道支护设计提供参考与借鉴，最终达到冲击地压巷道分级防控的目的。采用实验室试验对不同冲击韧性锚杆的静态和动态力学特性进行了测试，从微-细观角度分析了不同韧性锚杆的抗冲击性能，分析了应变率大小对锚杆动态力学响应的影响规律。实验结果表明:CRM700锚杆的冲击吸收功分别是HRB500和CRM600的1.30倍和1.14倍，峰值载荷分别是两种锚杆的1.18倍和1.07倍，瞬时变形量分别是两种锚杆的1.33倍和0.91倍;CRM700锚杆和HRB500锚杆断口形态和金相组织显著不同，HRB500锚杆断口源区为韧窝形态，中部扩展区为准解理+少量韧窝，终断区为韧窝形态，金相组织为铁素体+珠光体;而CRM700锚杆断口附近全部为韧窝形态，金相组织为回火索氏体+贝氏体+铁素体。同时，应变率对HRB500锚杆的屈服强度、抗拉强度和应变影响显著，而对CRM600锚杆的影响较小，对CRM700锚杆的影响最小。对比3种锚杆的动态力学特性，CRM700锚杆的载荷曲线和冲击功曲线比较平滑，材料受到冲击载荷后呈现出缓慢断裂的特性，对冲击载荷具有良好的适应性。并且CRM700锚杆强度对应变率敏感性差，应变随应变率的提高显著增大，很好的适应了高应变率下的冲击载荷，在高应变率冲击载荷作用下，能通过增加瞬时变形提高吸能能力。两者晶粒度级别不同，HRB500锚杆的晶粒度为6级，而CRM700锚杆的晶粒度为10级，晶粒度越高，晶粒越小，强化效果越好;同时晶粒减小后晶体界面增多，有效阻碍了裂纹的扩展，晶界面面积相应也增大，晶界上的夹杂物浓度降低，从而避免了沿晶断裂，大大提高了锚杆的抗冲击性能。晶粒尺寸越小，位错在第2相周围积聚的梯度越低，其锚杆力学特性应变率敏感性越弱。总之，无论从冲击载荷曲线和冲击功曲线特征，还是在应变率的敏感性方面，CRM700锚杆均表现出对冲击载荷具有良好的适应性，其在高应变率冲击载荷作用下能通过增加瞬时变形提高吸能能力。

In order to reveal the dynamic mechanical characteristics and strain rate effect of bolt support materials under impact load,so as to provide reference for the support design of different magnitude rock burst,and finally achieve the purpose of classified prevention and control of rock burst.The static and dynamic mechanical properties of different impact toughness bolts are tested in laboratory,the impact resistance of different toughness bolts is analyzed through meso,microscale,and the effect of strain rate on the dynamic mechanical response of bolts is also analyzed.The results show that the impact absorbing energy of CRM700 bolt is 1.30 times and 1.14 times of HRB500 bolt and CRM600 bolt respectively,the peak load is 1.18 times and 1.07 times of the two bolts,and the instantaneous deformation is 1.33 times and 0.91 times of the two bolts.The fracture morphology and metallographic structure of CRM700 bolt and HRB500 bolt are significantly different.The fracture source area of HRB500 bolt is dimple shape,the middle expansion area is quasi cleavage+a small amount of dimple,the final fracture area is dimple shape,and the metallographic structure is ferrite+pearlite,while the fracture area of CRM700 bolt is dimple shape,and the metallographic structure is tempered sorbite+bainite+ferrite.At the same time,the strain rate has a significant effect on the yield strength,tensile strength and strain of HRB500 bolt,but has little effect on CRM600 bolt,and has the least effect on CRM700 bolt.Compared with the dynamic mechanical properties of the three kinds of bolts,the load curve and impact energy curve of CRM700 bolt are relatively smooth,and the material shows the characteristics of slow fracture after impact load,which has a good adaptability to impact load.The CRM700 bolt strength has a poor sensitivity to strain rate,while its strain increases significantly with the increase of strain rate,which is well adapted to the impact load at a high strain rate.Under the impact load at a high strain rate,the energy absorption capacity can be improved by increasing the instantaneous deformation.The grain size of HRB500 bolt is grade 6,while that of CRM700 bolt is grade 10.The higher the grain grade,the smaller the grain size and the better the strengthening effect.At the same time,the decrease of grain size results in the increase of crystal interface,which effectively hinders the crack growth,increases the crystal interface area and decreases the inclusion concentration on the grain boundary.Thus it avoids the intergranular fracture and greatly improves the impact resistance of bolt.The smaller the grain size is,the lower the gradient of dislocation accumulation around the second phase,and the weaker the sensitivity of strain rate to the mechanical properties of the bolt.In a word,no matter from the characteristics of impact load curve and impact energy curve,or in the sensitivity of strain rate,CRM700 anchor rod shows a good adaptability to impact load,which can improve energy absorption force by increasing instantaneous deformation under high strain rate impact load.

1 锚杆静态和动态力学特性

　　1.1 静载荷作用下锚杆杆体力学性能

　　1.2 冲击载荷作用下锚杆杆体力学性能分析

　　1.3 锚杆断口形态和金相组织分析

2 应变率对锚杆力学性能的影响

　　2.1 实验装置

　　2.2 试样制作及试验方案

　　2.3 不同应变率下锚杆力学性能分析

　　2.4 应变率对锚杆延伸率和断口收缩率的影响

　　2.5 应变率对锚杆动态力学性能影响的微观作用机制

3 结 论