Characteristics of Microseismic Generated During the Failure Process of Various Types of Rocks Under Uniaxial Compressive Condition

Rock lithology has a significant influence on rock failure. Different types of rocks generally exhibit various rock failure manners. Also, the microseismic (MS) generated during the failure process of different types of rocks will present different characteristics. In this paper, uniaxial compressive tests on small‐scale specimens with seven types of rocks, including granite, basalt, red sandstone, gray sandstone, marble, limestone, and mudstone, were conducted. The characteristics of the MS under different rock‐type conditions are systematically investigated and the influence of rock type on the characteristics of the MS is studied. The experimental results indicate that the MS generated during the failure of these rocks with high brittleness, such as granite, basalt, red sandstone, and gray sandstone, occur during the late loading period. For the rocks with low brittleness, such as limestone and mudstone, MS occurs during the middle loading period. The evolutions of the b ‐value of the MS under different rock‐type conditions exhibited different characteristics. For the granite, basalt, red sandstone, and gray sandstone, the b ‐value monotonously decreased to less than 1 before the final overall rock failure; for the limestone and mudstone, the b ‐value first exhibited some fluctuation and then decreased to less than 1. Also, for most rock types, the higher the rock strength, the smaller the minimum and the decreasing rate of b ‐value before the overall rock failure. Also, with the increase of the rock strength, the stress, when the AMAI becomes active, is higher. Otherwise, many low‐frequency and high‐amplitude MS signals occurred before the overall failure of the granite, basalt, gray sandstone, and red sandstone; however, for the limestone, marble, and mudstone, only a few low‐frequency and high‐amplitude MS can be observed. The obtained results mentioned above can provide a better understanding of the failure characteristics of different rock types.