单轴压缩下不同层理方向对片麻岩声发射特征影响的试验研究  

Experimental research of the effect of different bedding direction on acoustic emission characteristics of gneiss under uniaxial compression

作　　者：王晓雷 詹思博 闫顺玺 蒋鹏程 周宁 WANG Xiaolei;ZHAN Sibo;YAN Shunxi;JIANG Pengcheng;ZHOU Ning(College of Mining Engineering,North China University of Science and Technology,Tangshan 063200,Hebei,China)

机构地区：[1]华北理工大学矿业工程学院,河北唐山063200

出　　处：《河南理工大学学报（自然科学版）》2021年第1期138-145,共8页Journal of Henan Polytechnic University（Natural Science）

基　　金：国家自然科学基金资助项目(51134005)。

摘　　要：为探究不同层理方向岩体的损伤演化规律和变形破坏中的声发射特征,选用具有明显层理构造的片麻岩试样开展单轴压缩条件下的声发射试验,分析轴向平行和垂直层理片麻岩试样失稳破裂、声发射时序参数和声发射空间定位演化特征。结果表明:不同层理方向对岩石破裂影响显著,轴向平行层理片麻岩试样峰值载荷稍高于轴向垂直层理的,裂纹起裂应力水平较高,声发射定位点由加载初期离散无序分布转为向沿层理聚集,破裂时主裂隙沿层理面贯通上下端或沿层理扩展形成垮落区,最终表现为典型的张拉破坏,岩石达到峰值载荷后瞬间失稳,呈突发式破坏特征;轴向垂直层理试样起裂应力水平较低,进入声发射剧烈期参数波动更为显著,事件点在试样中部聚集产生倾斜带状剪切裂纹密集区,破裂时出现多种破裂模式,主要以剪切滑移破坏为主。岩石达到峰值载荷后应力发生多次跌落,呈渐进式破坏特征。In order to explore the damage and AE characteristics of gneiss with different directions of bedding plane during the deformation and failure,the gneiss samples were prepared in two types,i.e.,the axis of the samples parallel to and perpendicular to the direction of bedding plane.The uniaxial compression AE experiment was carried out to analyze the macro fracture,AE time series parameters,and the AE spatial evolution characteristics of axial parallel bedding and axial vertical bedding gneiss samples.The results showed that different bedding directions had significant influence on rock fracture.The peak load and crack initiation level of axially parallel bedded gneiss were higher than that of axially vertical bedded gneiss.Acoustic emission spatial location points shifted from discrete and disordered distribution in the initial loading phase to distribution within stratification.In the process of fracture,the main fissure penetrated along the bedding upwards and downwards,or expanded to form a collapse zone,which eventually manifested as a typical tensile failure.After reaching the peak load,the rock suddenly became unstable and showed the characteristics of burst failure.Compared with the parallel samples,the crack initiation stress level of the vertical samples was lower,and the fluctuation of AE parameters was more intense in the severe period.The acoustic emission location points gathered along the bedding in the middle of the specimen,which resulted in obvious shear crack zone.During rupture,multiple fracture modes occurred at the same time,mainly by shear slip failure.After the rock reache the peak load,the stress dropped many times,showing progressive failure characteristics.

关 键 词：单轴压缩 片麻岩 层理方向 声发射特征 破裂演化 

分 类 号：O319.56[理学—一般力学与力学基础]