Experimental study on the effect of water saturation on the tensile strength and acoustic emission characteristics of white sandstone

Xu Rongchao; Yan Zhen; Zhou Wenpeng; Hu Yubo; Wang Yibo; Gao Liang

doi:10.16186/j.cnki.1673-9787.2023120016

Abstract：Objectives To investigate the mechanical degradation of white sandstone under water saturation by analyzing the macroscopic effect of saturation on tensile strength,acoustic emission(AE)characteris-tics,and fracture surface morphology.Methods Brazilian splitting tests and real-time AE monitoring were conducted on white sandstone specimens in both water-saturated and natural(dry)states to assess the ef-fect of water saturation.Results The experimental results indicate that:(1)Saturation leads to the dissolu-tion of mineral particles within the white sandstone,reducing the cohesion between particles,causing me-chanical damage and an 11.3%decrease in tensile strength;(2)The deformation and strength reduction caused by saturation result in a significant decrease in the unit area splitting energy during loading;(3)Af-ter saturation,the acoustic emission count and cumulative energy weaken during early activity,with their peak values occurring later than the peak load;(4)Acoustic emission RA-AF analysis shows that the pro-portion of tensile fractures decreases after saturation,while shear fractures increase.In both saturated and natural states,shear fractures increase sharply near peak load;(5)The acoustic emission b-value de-creases after saturation,indicating a reduction in small-scale fractures and an increase in large-scale frac-tures during splitting.A sharp drop in real-time b-value during loading can serve as a precursor to speci-men failure;(6)Saturation causes a decrease in roughness indicators of the splitting joint surface,includ-ing root mean square slope,roughness profile index,actual joint surface area,and roughness coefficient.Conclusions Water saturation significantly reduces the tensile strength of white sandstone,increases the proportion of large-scale fractures,and results in a smoother fracture surface.