摘要
裂隙岩体锚固力学特性是围岩支护设计的基本依据。针对新型负泊松比锚索(NPR)的支护效能,通过相似物理模型实验,对比研究不同预制裂隙倾角下NPR锚固体与普通(PR)锚固体力学特性差异,分析锚固体强度特性、变形破坏特性和声发射特性。随着裂隙倾角的增大,锚固体应力-应变曲线形态由双峰值逐渐向单峰值演变,锚固体弹性模量先增大后减小,峰值强度不断增大,NPR锚固体弹性模量和强度均明显高于PR锚固体。考虑岩体峰值强度时,NPR锚索最佳支护倾角为60°~90°,而PR锚索仅在支护倾角90°时达到最优支护效果。2类锚固体均呈现拉剪复合破坏特征,但NPR锚索未破断,锚固体完整性好,而PR锚索发生破断,锚固体完整性差。NPR和PR锚固体内部分别在预制裂隙倾角为75°和45°之前产生剪切破坏,超过此角度后则转变为张拉破坏。NPR锚固体自由面变形小且较为均匀,局部位移差较小,而PR锚固体自由面变形较大且不均匀,局部位移差较大。声发射特征显示,由于NPR锚索的持久约束作用,锚固体振铃计数更为均匀,而PR锚固体振铃计数较大值则集中在应变初期锚索破断时刻。
The anchorage mechanical characteristics of fractured rock mass are the fundamental basis for surrounding rock support design.Focusing on a novel anchor cable with a negative Poisson's ratio(NPR)effect,a comparative study was conducted on the mechanical properties of the NPR anchored body and the conventional(Poisson's ratio,PR)anchored body under different prefabricated fracture in-clination angles through similar physical model experiments.The strength characteristics,deformation and failure characteristics,and acoustic emission characteristics of the anchored bodies were analyzed.As the fracture inclination angle grows,the stress-strain curve of the anchored body gradually transitions from double peaks to a single peak.The elastic modulus of the anchored body first increases and then de-creases,while the peak strength continuously rises.The elastic modulus and strength of the NPR an-chored body are much higher than those of the PR anchored body.Considering the peak strength of the rock mass,the optimal support angle for the NPR anchor cable ranges from 60°to 90°,whereas that for the PR anchored body is only 90°.The failure mode of the anchored body is a tensile-shear mixed failure.The NPR anchor cable remains unbroken,maintaining good integrity of the anchored body.In contrast,the PR anchor cable breaks,resulting in poor integrity of the anchored body.Shear failure occurs within the NPR and PR anchored bodies before their prefabricated fracture angles reach 75°and 45°,respectively.Beyond these angles,tensile failure dominates within the anchored bodies.The free surface of the NPR anchored body exhibits slight and uniform deformation with minor local displacement differences,whereas that of the PR anchored body shows severer and more uneven deformation with noticeable local displacement differences.Acoustic emission characteristics reveal that for the NPR anchored body,the ring count is distributed relatively uniformly due to the persistent restraining effect of the NPR anchor cable.However,for the PR anchored body,the higher ring count is primarily concentrated at the moment of cable failure in the initial stage of strain.
作者
缪澄宇
崔力
孙晓明
谭雨泽
李志虎
MIAO Chengyu;CUI Li;SUN Xiaoming;TAN Yuze;LI Zhihu(State Key Laboratory for Tunnel Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China)
出处
《采矿与安全工程学报》
北大核心
2025年第4期779-788,共10页
Journal of Mining & Safety Engineering
基金
国家自然科学基金项目(52174096,52304110)
中国矿业大学(北京)大学生创新训练项目(202306003)。
关键词
NPR锚索
锚固体
相似实验
双轴压缩
力学特性
NPR anchor cable
anchored body
similarity experiment
biaxial compression
mechanical property
