doi:10.16186/j.cnki.1673-9787.2019100085

Received:2019/10/25

Revised:2020/02/29

Published:2021/01/15

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

WANG Xiaolei, ZHAN Sibo, YAN Shunxi, JIANG Pengcheng, ZHOU Ning

College of Mining Engineering， North China U niversity of Science and Technology， Tangshan 063200 ， Hebei， China

Abstract: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 with in 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.

Key words:uniaxial compression;gneiss;bedding direction;acoustic emission characteristic;fracture evolution

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_王晓雷.pdf