一维动静组合加载下石灰岩力学特性试验研究

Experimental Study on Mechanical Properties of Limestone under Combined One-dimensional Static and Dynamic Loading

为研究岩石承受高地应力和动力扰动作用下破坏问题,利用改进的SHPB试验装置,开展一维动静组合加载下石灰岩试件动态力学试验研究。选取有无轴压两种情况对试件进行不同应变率的冲击压缩试验。结果表明:石灰岩试件动态应力—应变曲线受轴压影响较大,轴压不同时曲线形态有所不同,轴压相同时曲线形态基本相似。试件动态强度增长因子与应变率之间呈现较好的线性关系,随应变率增加而增大。试件单位体积吸收能随入射能增加而增大;入射能相同,有轴压时试件单位体积吸收能比无轴压时小;随入射能增大,透射能相对趋于稳定,此时试件单位体积吸收能迅速增加。试件破坏形态与轴压密切相关,无轴压时为劈裂破坏,有轴压时为压剪破坏。

In order to study the failure of rock subjected to high geostress and dynamic disturbance, dynamic mechanical tests of limestone specimens under one-dimensional dynamic and static combined loading were carried out by using an improved SHPB test device. The impact compression tests of specimens with different strain rates were carried out in two cases with or without axial compression. The results show that the dynamic stress-strain curves of limestone specimens are greatly influenced by axial compression;the curves are different under different axial compression, and the curves are basically similar under the same axial compression;there is a good linear relationship between the dynamic strength growth factor and strain rate, which increases with the increase of strain rate;the absorption energy per unit volume of specimen increases with the increase of incident energy;the absorption energy per unit volume of specimen under axial compression is smaller than that without axial compression when the incident energy is the same;the transmission energy tends to be relatively stable with the increase of incident energy, and the absorption energy per unit volume of specimen increases rapidly;the failure modes of specimens are closely related to axial compression, splitting failure occurs when there is no axial compression, and compression-shear failure occurs when there is axial compression.