doi:10.16186/j.cnki.1673-9787.2023030010

Received:2023/03/06

Revised:2023/05/06

Published:2024/05/15

Numerical analysis of mechanical behavior of white sandstone with parallel double fissures

WANG Yunfei, DONG He, MA Yongchao, ZHANG Yiwen, YUAN Lele

School of Civil Engineering，Henan Polytechnic University，Jiaozuo 454000，Henan，China

Abstract:   Objectives  In order to explore the influence of parallel double fissures on the mechanical properties， crack propagation， and energy evolution of white sandstone， Methods  the particle flow software PFC2D was used to obtain the mesoscopic mechanical parameters of white sandstone. By changing the two key influencing factors of double fissure inclination and double fissure spacing， multiple uniaxial compression tests were carried out， and the simulation results were analyzed.    Results As the inclination of the fissure increases， so does the peak strength and modulus of elasticity of the rock； With the increase in parallel double fissure spacing， the peak strength and elastic modulus of the rock are greatly reduced at a fissure inclination of 30°. The fissure spacing has no significant effect on the peak strength and elastic modulus of the rock at an inclination of 60°， indicating that the fissure spacing becomes a secondary factor in influencing characteristics； The inclination of the prefabricated fracture has an important impact on the micro-crack development process of the rock， with tensile cracks being predominant in the early stage of crack expansion， and the final destruction form being mostly shear failure. When the inclination angle of the prefabricated fissure is 45°， the crack develops to its most thorough penetration； With the increase in inclination， the strain node where the dissipative energy begins to appear gradually moves backward， and the elastic energy storage limit of the rock is enhanced， with a small rebound in the energy storage limit observed in the range of 0° to 15°.   Conclusions The inclination angle and spacing of parallel double fissures have a crucial impact on the mechanical properties， crack propagation， and energy evolution of white sandstone.    

Key words:parallel double-fissure;discrete elements;acoustic emission;crack propagation;fissure dip angle