LI Y R, WANG Z B, SUN X H, et al.Evolution of acoustic emission and failure precursor characteristics of Malan loess under uniaxial compression[J].Journal of Henan Polytechnic University(Natural Science) ,2025,44(5):171-179.

DOI:10.16186/j.cnki.1673-9787.2024010067

Received: 2024/01/31

Revised: 2024/05/21

Published:2025/07/23

Evolution of acoustic emission and failure precursor characteristics of Malan loess under uniaxial compression

Li Yanrong, Wang Zhibin, Sun Xiaohui, He Shengdi, Zhao Jianbo

College of Mining Engineering， Taiyuan University of Technology， Taiyuan 030024， Shanxi， China

Abstract: Objectives This study aims to identify effective precursor signals during the deformation and failure process of Malan loess under uniaxial compression. Methods Uniaxial compression tests were conducted on Malan loess specimens. Stress-strain data and acoustic emission （AE） signals were collected throughout the deformation and failure process. The evolution of AE characteristics under compressive loading was analyzed. Results Distinct AE signals were observed during the failure process of dry Malan loess， with AE ringing counts corresponding well to different deformation stages. As moisture content increased， the regularity of AE signals gradually weakened. Under dry conditions， AE ringing counts increased sharply near peak strength， with peaks occurring immediately prior to specimen failure. This indicates that AE anomalies precede axial strain and can serve as early warning indicators for loess failure. The distribution of AE RA （rise time/amplitude） and AF （average frequency） values reflected crack propagation modes， with shear failure being the dominant mechanism. Before reaching peak strength， both AE fractal dimension and b-value dropped significantly； high-frequency components disappeared， while low-frequency and high-energy signals increased and shifted markedly toward lower frequency bands. These observations reflect an evolution from small-scale microcracking to large-scale macro-fracture during the compression failure process of Malan loess. Conclusions Key precursor indicators for failure in Malan loess include： a peak in AE ringing counts， a sudden drop in fractal dimension and b-value， and a spectral shift characterized by the disappearance of high-frequency and emergence of low-frequency AE signals. These features can be used for early detection and prediction of failure in loess under compression.

Key words:Malan loess;acoustic emission;ringing count;fractal dimension;spectral characteristics