Numerical Study of Failure Mechanism and Effectiveness of Control Measure of Soft Rock Roadways Affected by Humidity Diffusion

The failure characteristics of heat-treated sandstone subjected to splitting loading and the pore-crack distribution effects

Mechanical response and failure mechanisms of sandstone under water–rock interaction: a multi-scale study and constitutive modeling

Experimental and Numerical Study of Water Effects on Mechanical and Fracture Behavior of Sandstone: A Case Study

Water significantly modifies rock mechanical performance and fracture characteristics through water content and water distribution. Nevertheless, the evolution laws of rock mechanical properties and underlying fracture mechanisms under variable water conditions remain incompletely clarified. In this study, uniaxial compression tests were carried out on sandstone samples with diverse water immersion durations. Experimental observations reveal that the uniaxial compressive strength (UCS) and elastic modulus of sandstone follow negative exponential attenuation with prolonged immersion time, with maximum reductions of 50.1% and 25.6%, respectively. Under equivalent water contents, samples featuring dry exteriors and wet interiors possess lower strength than those with wet exteriors and dry interiors. A self-developed numerical code incorporating humidity diffusion effects was subsequently adopted to interpret water-controlled sandstone fracture behaviors. Numerical outputs verify that water-induced softening and heterogeneous water distribution exacerbate rock material heterogeneity and internal stress non-uniformity, triggering tensile microcracks along dry–wet interfaces. As the immersion duration rises, the rock failure mode transitions from shear-dominated mixed failure to tension-dominated failure, and finally reverts to shear-dominated mixed failure. Macroscopic rupture is predominantly governed by the gradual coalescence of tension-generated microcracks. This study offers a theoretical foundation to advance the understanding of water-triggered mechanical degradation and fracture mechanisms in sandstone.

Mechanical properties and damage constitutive model of tuff under stress–seepage coupling during low-temperature curing

Given the challenging conditions of high-alpine and high-altitude metal mining, complex factors affecting rock mass quality, and the intricate mechanisms of slope instability, this study focuses on the tuff from the high-alpine and high-altitude region of China. The deformation, strength, and failure characteristics of the tuff specimen were investigated through uniaxial compression tests, stress–seepage coupling triaxial compression tests under low-temperature curing conditions and nuclear magnetic resonance analysis. A damage constitutive model for the tuff specimen considering curing temperature was established. Results show that low temperatures significantly promote the development and interconnection of pores and fissures within the tuff specimen. Low-temperature and stress–seepage coupling increase the number of pores and fissures and drive their growth toward larger sizes. The tuff specimen undergoes compaction, elastic deformation, plastic yielding, and failure under triaxial compression. As temperature decreases, failure transitions from simple shear to combined shear-tensile failure, with extended compaction and shortened plastic yielding phases, leading to enhanced brittleness. A low temperature–load coupling damage variable was introduced based on nuclear magnetic resonance porosity and the Weibull distribution function, effectively modeling the stress–strain relationship and strength characteristics of the tuff specimen under low-temperature and stress–seepage coupling, with a good fit between experimental and theoretical.

Study on the Influence of Structural Plane Dip Angle on Mechanical Properties of Surrounding Rock

Numerical Simulation Study of the Permeability Evolution of Sandstone during the Loading and Failure Process Based on FDEM

Rock failure under hydromechanical coupling is a complex process that has attracted considerable attention in deep underground engineering. In this study, a hydraulic coupling analysis method for rock loading and failure is developed based on the finite–discrete-element method (FDEM) combined with the grain-based model, which integrates the dual-medium seepage–stress coupling theory to simultaneously capture pore and fracture seepage. Numerical simulations of sandstone under varying confining pressures were performed and validated against laboratory experiments, and the effects of confining pressure and weak joint content on the permeability evolution were systematically investigated. The results demonstrate that the permeability evolution during loading is governed by the competitive interplay between matrix seepage and fracture seepage, exhibiting a nonlinear pattern. Higher confining pressures prolong the stage of slow permeability growth, whereas an increase in the weak joint content reduces strength and stiffness, leading to an earlier occurrence of the permeability inflection point and an enhanced dominance of fracture flow in controlling macroscopic permeability. These findings provide new insights into the mechanisms of hydromechanical coupling in fractured porous rocks and offer theoretical support for predicting and controlling hydraulic hazards in deep rock engineering.