Static and dynamic performance of rebar bolts and its adaptability under impact loading

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 load-ing,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 im-pact. Whereas,when the impact energy is higher than 9 kJ,the energy dissipation capability of the bolt decreases sig-nificantly. 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.