In the control system of deep soft rock roadway surrounding rock, preload force plays a crucial role. This paper centers around a new type of constant resistance large deformation anchor cable, also known as NPR (Negative Poisson's Ratio) anchor cable. Based on its static tensile mechanical properties, a comparative experimental study is conducted to investigate the biaxial compressive mechanical properties of NPR anchored rock and PR (Poisson's Ratio) anchored rock with different preload forces. Comprehensive analyses are performed to evaluate the strength characteristics, deformation damage characteristics, and acoustic emission characteristics of both types of anchored rock. The results indicate that as the preload force increases, both types of anchored rock experience an increase in elastic modulus and peak strength. The maximum enhancement of elastic modulus, peak strength, and residual strength of NPR anchored rock relative to unanchored intact specimens is 39.19 %, 11.85 %, and 49.41 %, respectively. At each level of preload force, the NPR anchored rock exhibits higher peak strength and residual strength compared to the PR anchored rock. With the increase of preload force, the damage mode of the anchored rock evolves from mixed tension-shear damage mainly tension damage to mixed tension-shear damage mainly shear damage, the final failure pattern integrity of NPR anchored rock is higher than that of PR anchored rock. Simultaneously, it is found that the increase in preload force significantly reduces the degree of concentration in the acoustic emission counts during the early stages of strain in the anchored rock. Under high preload force conditions, both the cumulative counts and cumulative energy of acoustic emission in the NPR anchored rock are much lower than those in the PR anchored rock. Finally, the discussion proposes the concept of static toughness of anchored rock, aiming to evaluate and compare the comprehensive mechanical properties of anchored rock by considering strength and deformation capacity. Through calculations, the static toughness of NPR anchored rock shows an average increase of approximately 294 % compared to PR anchored rock with different preload forces, and the optimal range for applying preload forces to NPR and PR anchor cables is found to be between 70 % and 90 % and between 30 % and 50 %, respectively. Simultaneously, based on the unified strength theory, a strength criterion of prestressed NPR anchored rock is established. The calculation results provides preliminary validation for the theoretical expression of this strength criterion.

中文翻译：

---

不同预紧力NPR锚固岩双轴压缩力学性能试验研究

在深部软岩巷道围岩控制系统中，预紧力起着至关重要的作用。本文围绕一种新型恒阻大变形锚索，又称NPR（负泊松比）锚索。基于其静态拉伸力学性能，对不同预紧力下NPR锚固岩和PR（泊松比）锚岩的双轴压缩力学性能进行了对比试验研究。对两种锚固岩体的强度特性、变形损伤特性、声发射特性进行综合分析评价。结果表明，随着预紧力的增加，两种类型的锚固岩石的弹性模量和峰值强度都会增加。NPR锚固岩石相对于未锚固完整试件的弹性模量、峰值强度和残余强度的最大提高分别为39.19%、11.85%和49.41%。在每个预紧力水平下，NPR 锚固岩石均比 PR 锚固岩石表现出更高的峰值强度和残余强度。随着预紧力的增大，锚固岩体的破坏模式由拉剪混合破坏为主，演变为拉剪混合破坏为主，剪切破坏为主，NPR锚固岩体最终破坏模式完整性高于PR锚固岩体。岩石。同时发现，预紧力的增加显着降低了锚固岩石应变早期声发射计数的集中程度。在高预紧力条件下，NPR锚岩的声发射累积计数和累积能量均远低于PR锚岩。最后讨论提出了锚固岩静韧性的概念，旨在综合考虑强度和变形能力来评价和比较锚固岩的综合力学性能。通过计算，不同预紧力下NPR锚岩的静韧性比PR锚岩平均提高了约294%，并且发现NPR和PR锚索施加预紧力的最佳范围在70%到70%之间。分别为 90% 以及 30% 和 50% 之间。同时，基于统一强度理论，建立了预应力NPR锚岩的强度准则。计算结果对该强度准则的理论表达式进行了初步验证。