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针对冲击危险巷道锚杆支护结构破坏特征及冲击载荷对锚杆–围岩支护系统的特殊要求,设计研发了新型防冲吸能锚杆(索)。基于塑性弯曲理论分析了吸能锚杆(索)的吸能原理,利用自主设计的静–动加载试验系统,进行吸能锚杆(索)的静力拉伸试验与冲击拉伸试验。结果表明:吸能锚杆(索)在拉伸过程中六角管衬里被挤压变形,同时给摩擦圆柱提供滑移阻力,六角管的管壁厚度、套筒内径及摩擦圆柱直径三者的装配参数对吸能阻力具有重要影响;无论是静力拉伸还是冲击拉伸,吸能锚杆(索)的轴力–位移曲线均存在轴力初始增长、轴力平稳和轴力突增—平稳3个阶段;在轴力平稳阶段内锚杆杆体基本处于弹性状态,摩擦滑移结束后,锚杆杆体开始受力屈服;吸能结构在吸收能量的同时很好的延迟或减缓了锚杆杆体受力屈服。与普通锚杆相比,吸能锚杆(索)具有良好的“自保护性”与“冲击适应性”。现场试验表明,吸能锚杆(索)能够有效削弱冲击能对巷道围岩的作用。
Aiming at the damage characteristics of bolt supporting structure of roadway with impact danger and the special requirements of impact load on the supporting system of bolt and surrounding rock, a new type of anti-erosion energy absorbing anchor rod (cable) was designed and developed. Based on the plastic bending theory, the energy absorption principle of energy absorption anchor rod (cable) was analyzed. Static tensile test and impact tensile test of energy absorption anchor rod were carried out by the self-designed static-dynamic loading test system. The results show that the hexagonal pipe lining is squeezed and deformed during the drawing process, and the friction cylinder is provided with the sliding resistance, the pipe wall thickness of the hexagonal pipe, the inner diameter of the sleeve and the diameter of the friction cylinder The parameter has an important influence on the resistance of the energy absorption. The initial axial force, the steady axial force and the sudden increase of the axial force exist both in the axial force-displacement curve of the energy-absorbing anchor rod (cable) 3 stages. When the axial force is stable, the anchor rod body is basically in the elastic state. After the frictional sliding, the anchor rod body begins to yield force. The energy absorption structure can delay or slow down the anchor rod body while absorbing energy Force submission. Compared with ordinary anchor, energy-absorbing anchor rod (cable) has a good “self-protection” and “impact adaptability.” Field tests show that the energy absorption anchor rod (cable) can effectively weaken the impact of impact energy on the surrounding rock.