为提升中空注浆锚杆锚固承载性能,克服因地下水浮力而导致地基基础变形难题,研发了一种装配式密布孔带分叉的多用途中空注浆锚杆。利用正交试验法设计了锚杆拉拔试验方案,并借助数值计算方法,研究了不同设计参数(周向注浆孔数量、轴向注浆孔距离、注浆孔孔径及相邻注浆孔之间的偏角,简称孔数、孔距、孔径及孔偏角)与锚杆的抗拉强度之间响应规律,得出最佳因素水平组合,并对最佳因素水平组合锚杆进行真实应力-位移分析。结果表明:各影响因素对锚杆杆体抗拉强度的主次顺序为孔距>孔数>孔偏角>孔径,其中孔距因素贡献率最大为69.65%,孔距因素对于杆体抗拉强度影响呈现正比关系;锚杆拉拔锚固变形经历了弹性黏合、塑性变形、塑性失效、滑移脱黏四个阶段的发展,最后结果表明锚杆与混凝土之间黏结失效是锚固性能下降的主要原因。
In order to improve the anchorage bearing capacity of hollow grouting anchor rods and effectively overcome the issue of foundation deformation caused by groundwater buoyancy, a novel multi-purpose prefabricated hollow grouting anchor rod with dense holes and branching grouting was developed. An orthogonal experimental method was used to design the anchor rod pull-out test scheme. Using numerical calculation methods, the response relationship between different design parameters (i.e., circumferential grouting hole number, axial grouting hole distance, hole diameter, and the offset angle between adjacent grouting holes, abbreviated as hole number, hole distance, hole diameter, and hole offset angle) and the anchor rod's tensile strength was studied. The optimal factor-level combination was obtained, and the real stress-displacement analysis was conducted on the anchor rod with the optimal factor-level combination. The results show that: The influence factors on the tensile strength of the anchor rod body follow the order: hole distance > hole number > hole offset angle > hole diameter, with the hole distance factor contributing the most (69.65%). The effect of the hole distance factor on the tensile strength of the rod is proportional. The anchor rod's pull-out anchorage deformation undergoes four stages: elastic bonding, plastic deformation, plastic failure, and slippage debonding. These results indicate that the bonding failure between the anchor rod and the concrete is the primary cause of the reduction in anchorage performance.
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