微观负泊松比锚杆静力学特性及其工程应用研究

相比于传统的小变形锚杆支护材料，负泊松比锚杆/索材料具有大伸长量、高强高韧、高恒阻力、吸能等优异力学特性。在宏观负泊松比（NPR）锚杆/索研究和应用基础上，何满潮研发了新一代微观NPR钢材料和微观NPR锚杆。目前微观NPR钢材料的静力学特性研究较少，微观NPR锚杆在城市地下隧道工程的适用性有待于现场应用验证。通过室内静力拉伸试验对微观NPR钢的力学特性进行了研究，结果表明本批次微观NPR钢平均伸长率为34.68%；恒阻力值范围为203.9～ 240.7 kN；拉伸全过程表现为均匀拉伸变形；无屈服平台，破断时无明显颈缩现象。通过理论推导，建立了微观NPR锚杆在微静力拉伸条件下的弹塑性增量本构模型。以某路地铁站风道段为工程背景，介绍了微观NPR锚杆施工工艺，现场测试了极限拉拔力、伸长率及锚杆轴力等方面，结果表明，微观NPR锚杆具有高恒阻力及大伸长量等优势。在围岩大变形隧道开展了支护应用试验，验证了其具有良好的围岩大变形控制效果。

Static characteristics and engineering applications of micro negative Poisson’s ratio bolt

Compared with traditional small deformation bolt materials, the negative Poisson's ratio (NPR) bolt/cable material has excellent mechanical properties such as large elongation, high strength, high toughness, high constant resistance, and energy absorption. Based on the research and application of macro-NPR bolts/cables, He Manchao developed a new type of micro-NPR steel material and a new type of micro-NPR bolt. At present, there are few studies on the static characteristics of the micro-NPR steel, and the applicability of the micro-NPR anchor in urban underground tunnel engineering needs to be verified by field tests. The mechanical properties of the micro-NPR steel were studied by the static tensile test in laboratory. The results show that the average elongation ratio of this batch of micro-NPR steel is 34.68%, and the constant resistance range is 203.9～240.7 kN. The tensile deformation is uniform in the whole process, and there is no yielding platform and no obvious necking when breaking. Through theoretical derivation, the elastoplastic incremental constitutive model of the micro-NPR bolt under micro-static tensile condition was established. Taking the air duct section of a subway station as the engineering background, this paper introduced the construction technology of the micro-NPR bolt, and tested the ultimate pull-out force, elongation ratio, and axial force on site. The results show that the micro-NPR bolt has the advantages of high constant resistance and large elongation. The application test of the bolt supporting was carried out in the tunnel with the large-deformation surrounding rock, and the large deformation control effects of the surrounding rock were verified.