Mechanical Properties and Acoustic Emission Characteristics of Soft-Hard Interbedded Rocks Under Different Loading Rates

Based on the measured data of sandstone mudstone interbedded rock mass in the Three Gorges Reservoir area, the soft-hard interbedded rock samples were made. Under uniaxial compression, the effects of different static loading rates on the mechanical and acoustic emission characteristics of rock samples with different thickness ratios and different rock formation combinations were explored. The results show that the loading rate and the volume ratio of hard and soft rock are the main factors affecting the peak strength, while the loading rate and the thickness ratio of hard and soft rock are the main factors affecting the final failure characteristics. On the one hand, with the increase of loading rate, the peak strength of the soft-hard interbedded rocks decreases first and then increases; The proportion of hard rock is positively correlated with the compressive strength of rock samples. On the other hand, the ultimate failure mode of rock samples at low loading rate is complete failure of materials, and at high loading rate, 1 ~ 2 main fracture surfaces penetrating soft and hard rock layers are finally formed. The less the volume proportion of soft rock, the more severe the damage to soft rock. In addition, the sudden increase of AF value and the sudden decrease of b value can be taken as early warning signals of large-scale damage of the soft-hard interbedded rock mass. © 2023 Northeastern University. All rights reserved.