加载速率对锚杆及其锚固效应影响的实验研究

研究加载速率对锚杆及其锚固效应意义重大.对金属锚杆杆体进行了不同加载速率的室内拉伸实验,并用PFC2D颗粒流软件模拟加载速率对锚固效应的影响.结果表明：锚杆杆体强度随加载速率的增加而增大,有效检测锚杆杆体强度的加载速率应在0.5 mm/s左右;拉拔荷载随加载速率的增加而增大,且锚固体的破坏拉拔荷载与加载速率为线性关系,有效测试拉拔力的加载速率为10 mm/s;随着加载速率的增加,破坏形态最终会向锚杆拔出及产生大范围破碎区转变;根据加载速率对锚固强度的影响,可将其分为弱影响范围（v＜ 10 mm/s）、中等影响范围（10 ＜v＜ 100 mm/s）和强影响范围（v＞100 mm/s）,强影响范围内加载速率对轴应力及剪应力大小有着明显影响,易造成锚固段上部应力严重集中.

Experimental study on impact of loading rate on bolt and anchoring effect

This paper follows from the belief that the research on the effect of loading rate on bolt and anchoring is of greater importance.The research involves subjecting metal bolts to indoor tensile tests with different loading rates and simulating the impact of loading rate on anchoring effect using PFC2D.The results show：a bolt rod body has an increasing strength due to an increased loading rate and is required to have the loading rate of less than 0.5 mm/s for an effective strength test ; a bolt rod body has a drawing load increasing along with an increase in loading rate,and shows a liner relationship between the failure drawing load of anchorage body and loading rates,and is defined to have the test rates of less than 10 mm/s necessary for an effective test of drawing loads ; an increase in loading rates points to the tendency of failure modes to turn to bolt drawing and wide scope of broken zone;the impact of loading rate on anchoring strength justifies the division of the scope into soft one （v ＜ 10 mm/s）,moderate one （10 ＜ v ＜ 100 mm/s）,and strong one （v ＞ 100 mm/s） which has loading rates with an obvious influence on the magnitude of axial stress and shear stress,more likely contributing to a serious stress concentration on the upper part of anchoring section.