During deep coal mining, interlayer rock strata subjected to high static stress and low-frequency dynamic load are prone to fracture and instability, often leading to dynamic disasters. To investigate the dynamic response of rock fracture, deformation, and mechanical behavior under low-frequency disturbances, uniaxial compression tests were conducted on perforated sandstone specimens at different loading rates. This study explores the crack evolution, fracture ejection patterns, and dynamic strain behavior of sandstone under disturbance. The results reveal the following key findings: (1) The mechanical properties of sandstone are significantly influenced by the loading rate, with peak strength increasing nonlinearly as the loading rate rises. When the loading rate increases fivefold, the average peak strengths of the single-hole, double-hole, and triple-hole specimens increase by 9.67%, 14.64%, and 9.44%, respectively. However, as the number of perforations increases, the overall load-bearing capacity of sandstone decreases, and the average peak strengths are reduced by 12.58%, 12.15%, and 13.23%, respectively. (2) The acoustic emission (AE) characteristics and stress-time evolution curves of sandstone exhibit distinct inflection points. AE activity is relatively weak during the crack initiation stage, but AE events increase sharply before failure, accompanied by an exponential rise in AE energy. This phenomenon can serve as an early warning indicator of dynamic failure in high-stress sandstone under low-frequency disturbances. (3) Based on the failure modes and the extent of surface spalling and block ejection, sandstone failure can be classified into three types. The mean σ_c/σ_z values for type Ⅰ, Ⅱ, and Ⅲ specimens are 0.959, 0.765, and 0.687, respectively, indicating significant differences in mechanical properties among different failure modes. (4) The strain distribution in the rock specimens is closely related to the number of perforations. As the number of perforations increases, pronounced stress shielding zones and horizontal tensile strain zones develop between the holes during loading, providing the main pathways for crack propagation.

This study improves the roller friction experiment platform for monitoring the temperature of flame-retardant conveyor belt in order to realize the early warning of belt conveyor fire. Mass spectrometry is used to analyze the patterns of temperature rise and smoke composition of steel cord flame-retardant conveyor belt in the early stage of friction accident. Results show that as friction progresses, the flame-retardant conveyor belt exhibits symmetrical distribution of surface temperature, where the highest temperature gradually approaches to the center of the conveyor belt and the composition of smoke changes with temperature. The steel cord flame retardant conveyor belt warming process could be divided into three stages according to their warming rate and smoke composition output: stage of oxidation reaction (ambient temperature to 100 ℃), stage of substitution reaction (100~160.2 ℃), and pyrolysis reaction (after 160.2 ℃). The initial stage features low heat capacity of the conveyor belt with quickly-rising temperature, where the products are mostly alkyl and ester compounds. The second stage exhibits gradual increase of heat capacity, slowly-rising temperature, where the products are mostly nitro, ether, and carboxylic acid compounds. The last stage features stable heat capacity of the conveyor belt, the lowest heating rate, where the chlorine-containing compound is detected for the first time in the smoke composition.