Experimental Investigation on the Post-Peak Short-Term and Creep Behavior of Fractured Sandstone

Energies

Weisheng Zhao¹  Yijiang Zong²  Yuhao Jin³  Lijun Han³  Lingdong Meng³ 

[1] Institute of Mining Engineering, Guizhou Institute of Technology, Guiyang 550003, China;School of Transportation Engineering, Jiangsu Vocational Institute of Architectural Technology, Xuzhou 221116, China;State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, China;

关键词: fractured sandstone;    damage;    creep behavior;    long-term strength;    failure modes;   

DOI  :  10.3390/en13030598

来源: DOAJ

【 摘 要 】

Short-term and creep tests of fractured sandstone with different degrees of damage prepared using pre-peak and post-peak unloading tests on intact sandstone were carried out using a servo-controlled rock mechanics system. Based on our experimental results, the influence of confining pressure and damage on short-term mechanical behavior of fractured sandstone with different degrees of damage was first analyzed. The results show that the peak strength, residual strength, elastic modulus, and secant modulus of fractured sandstone increase linearly with increasing confining pressure, but decrease with increasing damage. The short-term failure modes depend on the damage and change from typical shear failure modes to multiple shear failure modes with increasing damage. Then, the influence of the differential stress, confining pressure, and the degree of damage on the creep mechanical behavior of fractured specimens was further investigated. The axial instantaneous strain and creep strain increase linearly with increasing differential stress, and the specimens exhibit significant time-dependent behavior under high stress. The steady creep rate increases with increasing stress, but it decreases with increasing confining pressure and damage. However, the long-term strength and creep failure strength of fractured specimens increase linearly with increasing confining pressure, but they decrease linearly with increasing damage. The creep failure modes of fractured specimens are also the main shear failure modes, which are similar to the short-term failure modes.

【 授权许可】

Unknown