Work

Study on mechanical properties and damage characteristics of prefabricated crack specimens under water–lithology interaction

Year: 2025

Type: article

Abstract: To investigate the influence of moisture content and lithology on the pre-splitting and pressure-relief effectiveness of the thick overlying roof above coal seams, laboratory uniaxial compression, Brazilian splitting, and shear tests were conducted under three lithological types and four moisture content conditions, utilizing acoustic emission (AE) monitoring, scanning electron microscopy (SEM), computed tomography (CT) scanning, and X-ray diffraction (XRD) techniques. The experimental results indicate that: (1) The increase in moisture content enhances the plasticity of the rock mass while reducing its brittleness and post-failure fracture toughness. The saturated sandy mudstone exhibits the greatest reduction in uniaxial compressive strength and shear strength, by 46.85 % and 67.6 %, respectively, whereas the saturated siltstone shows the largest decrease in tensile strength, by 36.6 %. (2) With increasing moisture content, all lithological specimens exhibited a higher proportion of shear failure and a lower proportion of tensile failure. The proportion of shear cracks in saturated siltstone and saturated sandy mudstone increased by 8.4 % and 6.2 %, respectively, while in saturated coarse sandstone, the proportions of shear cracks and total pore volume increased by 13.3 % and 78.82 %, respectively. (3) The strength degradation mechanism of the prefabricated crack models during water immersion was jointly governed by electrostatic attraction, hydration repulsion, friction, and external load. The interaction and competition among these four factors resulted in the observed strength degradation characteristics of the prefabricated crack models. These findings provide a theoretical reference for evaluating overburden stability in engineering under water–rock interaction.

Source: Results in Engineering

DOI: 10.1016/j.rineng.2025.108425

Authors: Desong Zang, Ruxiang Qin, Xiaolou Chi, Qiang Fu

Institution: Anhui University of Science and Technology

Language: English

Topic: Rock Mechanics and Modeling

Subfield: Mechanics of Materials

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,940

Funders: Anhui University of Science and Technology, National Key Research and Development Program of China