资源开采和地下空间建设逐渐向深部发展，给深部围岩支护体系带来了新的挑战，研发具有高强高韧、超强吸能、可施加高预紧力的围岩支护材料势在必行。基于此，自主研发了一种高强度、高延性，具有微观负泊松比效应的锚杆钢新材料，又称微观NPR（Negative Poisson’s Ratio）材料，这种材料可以被用于加工成锚杆、钢筋、锚索、钢带等多种类型的工程应用材料。本文重点针对微观NPR锚杆钢的锚固剪切力学特性进行实验研究，首先介绍了PR（Poisson’s Ratio）材料、宏观NPR结构和微观NPR材料的基本概念及研发历史；然后开展微观NPR锚杆钢和普通PR锚杆钢的静力拉伸及锚固剪切实验；最后对比分析微观NPR锚杆钢的破坏形态、拉伸力学性能以及锚固抗剪力学特性。实验结果表明，在静力拉伸条件下，相较于普通锚杆钢，微观NPR钢拉伸曲线无屈服平台，具有恒阻大变形的准理想弹塑性特征，大大提高了锚杆材料的强度和变形性能，且其拉伸过程中均匀变形，破断后基本无颈缩；在锚固剪切实验条件下，加锚节理岩体在剪切荷载作用下具有显著的延性破坏特征，有效改善了无锚固节理岩体脆性破坏现象，微观NPR锚杆钢所能提供的抗剪强度远高于普通锚杆钢，并且其承受横向剪切变形能力是普通锚杆钢的2.5倍以上。实验证明微观NPR锚杆钢能够很好的平衡金属材料高强度和高延性的矛盾，极大提升了锚杆钢抗拉、抗剪能力，从材料本质上实现了锚杆的大变形超强吸能特性，在深部地下空间大变形控制等方面具有良好的应用前景。

Resource mining and underground space construction are gradually moving deeper，which results in some new challenges to the deep surrounding rock support system. It is imperative to develop some surrounding rock support materials with high strength，high toughness，super energy absorption，and high preload. Based on this，a new material of anchor steel with high strength，high ductility，and microscopic negative Poisson’s ratio effect has been independently developed，which is also known as the micro NPR material. This material can be processed into bolts，steel bars，anchor cables，steel belts and other types of engineering application materials. This paper focuses on the experimental research on the shear mechanical properties of micro NPR bolt. Firstly，the basic concepts and research history of PR material，macro NPR structure and micro NPR material are introduced. Then，the static tension and bolting shear tests of micro NPR bolt steel and ordinary PR bolt steel are carried out. Finally，the failure modes，tensile mechanical properties and shear resistance properties of micro NPR steel are compared and analyzed. The experimental results show that under static tensile condition，compared with ordinary bolt steel，the tensile curve of micro NPR steel has no yield platform，and has the quasi ideal elastic plastic characteristics of constant resistance and large deformation. It greatly improves the strength and deformation properties of bolt material. During tensile process，it is uniformly deformed and its fracture neck shrinkage is significantly lower than that of ordinary steel. The bolting shear experiment shows that the bolted jointed rock mass has significant ductile failure characteristics under shear load，which effectively improves the brittle failure phenomenon of the unbolted jointed rock mass. The shear strength of micro NPR bolt steel is much higher than that of ordinary bolt steel，and its lateral shear deformation ability is more than 2.5 times that of ordinary bolt steel. Experimental results show that the micro NPR anchor steel balances the contradiction between high strength and high ductility of metal materials，greatly improves the tensile and shear capacity of anchor steel，and essentially realizes the characteristics of large deformation and super energy absorption of steel.

1 PR材料、宏观NPR结构复合材料和微观NPR材料的特点

   1.1 PR材料

   1.2 宏观NPR结构复合材料

   1.3 微观NPR材料

2 微观NPR锚杆钢静力拉伸性能实验研究

   2.1 静力拉伸实验设计

   2.2 拉伸实验结果分析

3 微观NPR锚杆钢锚固剪切力学性能

   3.1 抗剪实验设计

   3.2 实验加载路径设计

   3.3 实验结果分析

4 结论