Damage and hardening evolution characteristics of sandstone under multilevel creep–fatigue loading

• DOI: 10.1007/s40948-024-00751-3
• Publication Date: 2024-02-08T10:02:42Z
• Authors: Zhang Bichuan; Liang Yunpei; Zou Quanle; Ning Yanhao; Kong Fanjie
• Keywords: Hardening (computing); Fatigue limit

Abstract During the operation of artificial underground structures, surrounding rock experiences fatigue and creep damage caused by several types disturbances under long-term constant loading. To quantify mechanical response sandstone creep–fatigue loading, a damage–hardening evolution model based on linear superposition concept is proposed. In model, coupling applied to represent synergistic effect fatigue. Creep–fatigue tests specimens are conducted multilevel The hardening effects loading complex. Hardening dominant low loads, high loads. strength undergoes increasing decreasing trends this path, Mohr–Coulomb envelope discussed. proposed can be used describe test data process. With number, acoustic emission amplitude, energy, cumulative counts increase. However, amplitude more sensitive than indicating that it suitable for describing Furthermore, peak frequencies AE signals mostly distributed in 0–15 kHz, 15–30 30–45 45–55 kHz regions. signal proportion zone decreases with number. other frequency zones increase This phenomenon illustrates crack scale increases