A study on Mechanical Seepage Characteristics of Coal‐Rock Mass Under the Combined Action of Multiple Factors

ABSTRACT In deep coal mining, the influence of temperature–pressure coupling on the mechanical properties of coal is a crucial factor inducing dynamic disasters. To reveal the mechanical properties and fracture damage laws of coal under the combined action of temperature, freeze–thaw, saturated freeze–thaw, and pressure, wave velocity, strength, macro–micro failure characteristics, and seepage properties of raw coal samples, freeze–thawed coal samples, and saturated freeze–thawed coal samples were studied using equipment such as a nonmetallic ultrasonic detector, a 4K scientific research camera, and a triaxial fluid–solid coupling device. The experimental results show that the mechanical properties of coal‐rock undergo significant attenuation after drying, freeze–thaw, and saturated freeze–thaw treatments; stress concentration occurs in saturated freeze–thawed coal samples under the temperature–pressure coupling effect; and the permeability of coal‐rock is significantly increased under the combined action of multiple factors.