锚杆静-动力学特性及其冲击适用性

利用自主研制的静-动加载试验系统开展了等强与非等强螺纹钢锚杆的静力拉伸实验及有无预应力加载的动力冲击实验。结果表明:在静荷载作用下等强与非等强螺纹钢锚杆都经历了“线弹性变形-屈服平台-强化阶段-径缩破坏”的4个阶段;冲击加载时锚杆的屈服阶段可划分为瞬态屈服与稳态屈服，瞬态屈服的峰值载荷明显高于稳态屈服载荷，且相同直径条件下与静力加载相比锚杆屈服伸长量减小;当冲击能量低于9 kJ时，锚杆杆体能承受多次冲击扰动，且冲击后能够保证足够的杆体强度，但当冲击能量高于9 kJ时，锚杆抗冲吸能性能显著下降，低能量冲击时非等强螺纹钢锚杆的抵抗能力明显优于等强螺纹钢锚杆;无论从锚杆的动态轴力-位移曲线还是从锚杆的峰值载荷与伸长量上看，预应力对冲击载荷下锚杆的动力响应特征无明显影响，但进行防冲支护时，有必要提高预应力加载水平。

Staticanddynamicperformanceofrebarboltsanditsadaptabilityunderimpactloading

In order to study the mechanical performance of whorl steel anchor under static and dynamic loads,the self developed static and dynamic loading test system was used to carry out a static tensile experiment and dynamic impact experiment under the prestress loading or non prestress load on the equal strength and non equal strength rebar bolts.The results show that under static loading,equal strength and non equal strength rebar bolts all have experienced four stages:“linear elastic deformation yielding platform strengthening stage radial shrinkage failure”;under impact loading,the yielding stage of anchor bolt can be divided into transient yield and steady yield.The peak load of transient yield is higher than that of steady yield load,and the corresponding yield elongation of bolt decreases;with the increase of bolt diameter,the yield elongation increases under impact condition.Compared with the equal strength anchor bolts,non equal strength bolts have good adaptability under impact loading.When the impact energy is less than 9 kJ,the anchor rod body not only can withstand multiple impact disturbances,but also can ensure enough strength after impact.Whereas,when the impact energy is higher than 9 kJ,the energy dissipation capability of the bolt decreases significantly.No matter from the dynamic axial force displacement curve or the peak load and elongation of the bolt,the prestress has no obvious influence on the dynamic response characteristics of the bolt under the impact load,but it is necessary to improve the loading level of the prestress for anti impact bolt support.