The NPR bolt exhibits excellent engineering properties, such as high tensile strength (950 MPa) and significant elongation (30 %). It can efficiently apply high prestress and endure substantial deformations in the surrounding rock. The anchor system of an NPR bolt consists of a mechanical-type anchorage and resin, both crucial for applying prestress and ensuring effective anchorage. This study delves into the action mechanism of the mechanical-type anchorage through mechanical analysis and the finite element method. Results indicate a linear increase in radial stress on the surface between the bolt and the wedge of the NPR bolt in the mechanical-type anchorage section, reaching approximately 13 MPa/mm. The interfacial shear stress on the surface of the NPR bolt increased in a vibrating-chord manner. It was zero at the initial point and peaked at the end of the bolt, which was approximately 110 MPa when the NPR bolt entered the plastic state. The maximum axial force of the bolt, corresponding to tensile load, occurs at the loading end, while the minimum, reaching zero, is at the tail. The decay rate of the axial force is positively correlated with the shear stress on the bolt's surface. The peak Mises stress appeared near the loading end and then gradually decayed, which is about 30 MPa larger than the tensile load strength. For the application of a 100 kN prestress to the NPR bolt, a pretension experiment was conducted, revealing that a pretension value of 140 kN ensures the desired prestress. The limit plate distance was 6 mm, and the wedge exposure was 2 mm after prestressed locking. To assess the resin anchorage performance of NPR bolts with spiral grooves and ribs, a resin anchorage experiment was conducted using C25 perforated concrete and CK2850 resin. Results indicate that use of two CK2850 resins ensured the anchorage stability, with the anchoring performance of NPR bolts with spiral ribs surpassing that of bolts with spiral grooves. Finally, the technique was applied to a shallow-buried tunnel with a long span. Monitoring the axial force of the NPR bolt and the surrounding rock response for approximately 140 days revealed the technology's effectiveness in applying prestress, maintaining the bolt's axial force stability above 100 kN. Arch settlement was controlled at approximately −4.46 mm, the horizontal convergence at about −3.56 mm, and ground surface settlement at about −8.41 mm.

NPR 螺栓具有优异的工程性能，例如高抗拉强度(950 MPa) 和显着的伸长率 (30%)。它可以有效地施加高预应力并承受围岩的大幅变形。NPR 锚杆的锚固系统由机械型锚固和树脂组成，两者对于施加预应力和确保有效锚固都至关重要。本研究通过力学分析和有限元方法深入研究了机械式锚具的作用机理。结果表明，机械式锚固段中NPR锚杆的锚杆与楔块之间表面的径向应力呈线性增加，达到约13 MPa/mm。NPR螺栓表面的界面剪应力以弦振动方式增加。在初始点为零，在螺栓末端达到峰值，当 NPR 螺栓进入塑性状态时，该压力约为 110 MPa。螺栓的最大轴向力（对应于拉伸载荷）出现在加载端，而最小轴向力出现在尾部，达到零。轴向力的衰减率与螺栓表面的剪应力正相关。米塞斯应力峰值出现在加载端附近，然后逐渐衰减，比拉伸载荷强度大约30 MPa。为了对 NPR 螺栓施加 100 kN 的预应力，进行了预拉力实验，结果表明 140 kN 的预拉力值可确保达到所需的预应力。限位板距为6mm，预应力锁紧后楔块暴露量为2mm。为了评估带螺旋槽和肋的NPR螺栓的树脂锚固性能，采用C25穿孔混凝土和CK2850树脂进行了树脂锚固实验。结果表明，使用两种CK2850树脂保证了锚固稳定性，螺旋肋NPR螺栓的锚固性能优于螺旋槽螺栓。最后将该技术应用于大跨度浅埋隧道对 NPR 锚杆的轴向力和围岩响应进行约 140 天的监测，揭示了该技术在施加预应力方面的有效性，将锚杆的轴向力稳定性保持在 100 kN 以上。拱形沉降控制在-4.46毫米左右，水平收敛控制在-3.56毫米左右，地表沉降控制在-8.41毫米左右。