Strength characteristics of rock anchored by NPR bolt with different preloads Strength characteristics of rock anchored by NPR bolt with different preloads

最小化 最大化

Vol20 No.3: 834-844

【Title】Strength characteristics of rock anchored by NPR bolt with different preloads

【Author】SUN Xiao-ming1,2; CUI Li1,2; ZHANG Yong1,2*; WANG Lei1,2; JIANG Ming1,2

【Addresses】1 State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China; 2 School of Mechanics and Civil Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China

【Corresponding author】ZHANG Yong

【Citation】Sun XM, Cui L, Zhang Y, et al. (2023) Strength characteristics of rock anchored by NPR bolt with different preloads. Journal of Mountain Science 20(3). https://doi.org/10.1007/s11629-022-7798-3

【DOI】https://doi.org/10.1007/s11629-022-7798-3

【Abstract】This study compares the strength characteristics of rocks anchored by NPR bolts and ordinary bolts with varied preloads, based on the mechanical properties of NPR bolts (with a negative Poisson's ratio). The results show that the uniaxial compressive stress-strain curve of ordinary anchored rocks exhibits noticeable abrupt changes. After reaching peak strength, the bolt breaks, whereas the stress-strain curve of NPR-anchored rocks is smoother. The NPR bolt enters the stage of continuous resistance after reaching maximal strength and does not break. As the preload increases, the strength of the anchored rock grows linearly. A calculation equation for the strength of the anchored rock is proposed based on the preload. The theoretical equation fits the test results well, and the fitted parameters show that NPR bolts can better increase the strength of the rock. The concept of dynamic toughness UC of anchored rock is proposed to reflect the comprehensive mechanical properties of anchored rock, including strength and plasticity. As the preload increases, the UC of ordinary anchored rock first decreases and then increases, while the UC of the NPR anchored rock does not change significantly with the preload when the strain is small, and the UC increases with the increase of the preload when the strain is large.

【Keywords】NPR bolt; Anchored rock; Rock bolt; Uniaxial compression; Preload; Strength characteristics