1G NPR锚索加锚砂岩单轴力学特性试验研究  

Experimental study on uniaxial mechanical properties of 1G NPR anchor sandstone

作　　者：王炯 姜健[1,2] 王思语 刘鹏 冯增超 漆容之[1,2] WANG Jiong;JIANG Jian;WANG Siyu;LIU Peng;FENG Zengchao;QI Rongzhi(State Key Laboratory for Tunnel Engineering,Beijing 100083,China;School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China)

机构地区：[1]隧道工程灾变防控与智能建养全国重点实验室,北京100083 [2]中国矿业大学(北京)力学与土木工程学院,北京100083

出　　处：《煤炭科学技术》2024年第11期285-295,共11页Coal Science and Technology

基　　金：国家自然科学基金资助项目(52074300);贵州省科技厅科技计划资助项目(黔科合重大专项字[2020]3007,[2020]3008)。

摘　　要：为进一步研究1 G NPR锚索加锚岩体的稳定性,以砂岩为研究对象,设计制作了试验1 G NPR锚索,分别对有侧限、无侧限约束条件下的无锚、普通锚索加锚、1 G NPR锚索加锚的岩石试件进行单轴试验及声发射试验研究。结果表明:在有侧限、无侧限2种约束条件下,1 G NPR锚索加锚岩体单轴抗压强度相较于无锚提高至少20%、相较于普通锚索加锚提高9%以上;破坏特征方面,无锚试件是以张拉破坏为主的拉剪破坏且破坏后的碎散程度高。1 G NPR锚索加锚岩体主要以剪切破坏为主,1 G NPR锚索支护范围内的岩石形态较为完整,整体的碎散程度较低;从声发射角度来看,1 G NPR锚索的累积振铃计数仅为无锚的1/3。相较于无锚岩石试件的前期平缓增加,而在破坏瞬间产生大量的声发射振铃计数,1 G NPR锚索加锚岩石试件的前期呈现阶段增加趋势,在破坏瞬间声发射振铃计数并不会发生爆发式的突增现象。1 G NPR锚索提高了砂岩试件的峰值强度,同时,在峰后阶段,1 GNPR锚索通过多次结构滑移,释放了锚固岩体积累的能量,延缓了裂缝的开展与贯通,破坏后的试件碎散程度更低。The experiment investigates the stability of rock masses anchored with 1G NPR(Negative Poisson’s Ratio)anchor cables.Sandstone was selected as the test material,and 1G NPR anchor cables were designed and applied.Rock specimens were subjected to uni-axial compression and acoustic emission(AE)analysis under both lateral confined and unconfined conditions.The study compares three anchoring methods:unanchored,conventional cable-anchored,and 1G NPR cable-anchored.Experimental results show that the uniaxial compressive strength of rock specimens with 1G NPR anchor cables is at least 20%and 9%higher compared to unanchored and conven-tional cable-anchored specimens,respectively.Failure characteristic analysis reveals that unanchored specimens experience tensile failure,leading to a mixed mode of tension-shear failure,with a high degree of fragmentation after failure.In contrast,the 1G NPR cable-anchored specimens exhibit shear-dominated failure,with the rock mass in the anchoring zone remaining relatively intact,and a lower degree of fragmentation overall.AE analysis further demonstrates that the cumulative ring down count for the 1G NPR cable-anchored specimens is only one-third of that for the unanchored specimens.The cumulative ring down count curve for unanchored specimens shows a gradual in-crease in the early stages,followed by a sharp spike at failure.In comparison,the 1G NPR cable-anchored specimens exhibit a stepwise in-crease in AE activity during the early stages,without a sudden burst of activity at failure.The 1G NPR anchor cables significantly enhance the peak strength of the sandstone specimens.In the post-peak phase,the 1G NPR anchor cables release the accumulated energy of the anchored rock mass through multiple internal structural changes and delay the propagation and penetration of cracks,resulting in the min-imized degree of fragmentation after failure.

关 键 词：1 G NPR锚索 加锚砂岩 抗压强度 声发射 单轴实验 

分 类 号：TU45[建筑科学—岩土工程]