恒阻吸能锚杆力学特性与工程应用
Mechanical properties and engineering application of constant resistance energy absorbing bolt
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摘要: 地下工程面临大量高应力、极软岩等复杂条件,导致围岩应力集中、能量积聚,易发生围岩大变形。高强度、高预紧力、高延伸率以及高吸能特性的锚杆支护是大变形围岩的有效支护方式。传统锚杆支护存在强度低、延伸率不足等问题,支护体系易发生破断。基于此,自主研发了具有高强、高延伸率特性、可施加高预紧力的恒阻吸能锚杆,开展了新型锚杆、普通锚杆与恒阻大变形锚杆的静力拉伸与动力冲击对比试验。结果表明,在静力学性能方面,新型锚杆的屈服强度和破断强度分别为普通锚杆的2.06和1.62倍以上,具有高强、恒阻的力学特性。新型锚杆的最大力延伸率和断后延伸率分别是普通锚杆的1.52和1.26倍以上,单位长度吸收的能量是普通锚杆的3.05倍,具有高延伸率、高吸能特性。在动力学性能方面,新型锚杆的单次冲击平均位移量相比普通锚杆降低了47.0%,延伸率是普通锚杆的1.53倍,单位长度吸收的能量是普通锚杆的2.77倍,表明新型恒阻吸能锚杆具有良好的抗冲击能力和整体变形能力。恒阻吸能锚杆具有高强、高延伸率、高吸能特性,提出了恒阻吸能锚杆支护思路,并将新型锚杆在大断面隧道和深部高应力矿井现场进行了应用,现场监测结果表明,采用恒阻吸能锚杆的支护方式能够有效控制围岩变形。Abstract: Underground engineering is faced with a large number of complex conditions such as high stress and extremely soft rock.which lead to stress concentration and energy accumulation of surrounding rock. Large deformation of surrounding rock is easy to occur. The bolt support with high strength.high prestress.high elongation and high energy absorption characteristics is an effective support method for large deformation surrounding rock. The ordinary bolt support has the problems of low strength and insufficient elongation.and the support system is easy to be broken. Based on this.the new constant resistance energy absorption bolt with high strength.high elongation and high prestress is independently developed. The static tension and dynamic impact tests of the new bolt.ordinary bolt and macro constant resistance large deformation bolt are carried out. The results show that the yield strength and breaking strength of the new bolt are 2.06 times and 1.62 times higher than those of ordinary bolt respectively.and the new bolt has the mechanical properties of high strength and constant resistance. The maximum force elongation and elongation after fracture of the new bolt are 1.52 times and 1.26 times higher than those of ordinary bolt respectively.and the energy absorbed per unit length is 3.05 times than that of the latter. The new bolt has the characteristics of high elongation and high energy absorption. In terms of dynamic performance.the average displacement of single impact of the new bolt is 47.0% lower than that of the ordinary bolt.the elongation is 1.53 times higher than that of the latter.and the energy absorbed per unit length is 2.77 times higher than that of the ordinary bolt. They indicate that the new constant resistance energy absorbing bolt has good impact resistance and overall deformation ability. The new constant resistance energy absorption bolt has the characteristics of high strength.high elongation and high energy absorption. The idea of constant resistance energy absorption bolt support is put forward. The new bolt is applied in large section roadway and deep high stress coal mine. The field monitoring results show that the support method of constant resistance energy absorption bolt can effectively control the deformation of surrounding rock.