XU R C, YAN Z, ZHOU W P, et al．Experimental study on the influence of saturation effect on the tensile strength and acoustic emission characteristics of white sandstone [J].Journal of Henan Polytechnic University( Natural Science) ，doi:10.16186/j.cnki.1673-9787.2023120016.

doi:10.16186/j.cnki.1673-9787. 2023120016

Received：2023-12-07

Revised：2024-04-30

Online：2024-11-19

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

XU Rongchao¹, YAN Zhen ¹, ZHOU Wenpeng ², HU Yubo ¹, WANG Yibo ¹, GAO Liang ¹

1. College of Geosciences and Engineering, North China University of Water Resources and Electric Power, Zhengzhou, Henan 450046, China; 2. Sinohydro Bureau 11 Co., Ltd, Zhengzhou, Henan 450001, China

Abstract: Objectives To investigate the mechanical damage of sandstone under saturation, Methods this study conducted real-time monitoring tests using Brazilian splitting and acoustic emission techniques. The research analyzed the influence mechanism of saturation on the tensile strength, acoustic emission characteristics, and the morphology of split surfaces of sandstone from a macroscopic perspective. Results The research results indicate that: (1) Saturation leads to the dissolution of mineral particles within the white sandstone, reducing the cohesion between particles, resulting in mechanical damage to the sandstone and a decrease in tensile strength by 11.3%; (2) The deformation of white sandstone and the decrease in tensile strength due to saturation result in a significant decrease in the unit area of splitting energy during the loading process; (3) After saturation, the acoustic emission count and cumulative energy of the sandstone weaken during the initial activity, and the peak values of acoustic emission count and cumulative energy occur later than the peak load; (4) Based on the analysis of fracture types using acoustic emission RA-AF, the proportion of tensile fractures in white sandstone decreases after saturation, while the proportion of shear fractures increases. In both states of white sandstone samples, shear fractures show a significant increase in quantity near the peak load; (5) After saturation, the b value of acoustic emission decreases, the proportion of small-scale fractures during the splitting process of white sandstone decreases, and the proportion of large-scale fractures increases. Meanwhile, the sharp decrease in real-time b values during rock splitting loading can serve as a precursor feature of sample failure; (6) Under the influence of saturation, roughness indicators of splitting joint surfaces of white sandstone, including root mean square slope, roughness profile index, actual area of splitting joint surface, and roughness coefficient, all decrease. Conclusions After saturation, the tensile strength of white sandstone decreases significantly, the proportion of large-scale fractures increases, and the roughness of the splitting joint surface decreases.

Key words: water saturation; sandstone; tensile strength; acoustic emission; morphology of joint surface