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本文通过三峡石英闪长岩为代表的致密岩石和葛洲坝砂岩为代表的疏松岩石,应变速率在10~(-6)～10~(-2)(1/秒)量级范围内测得的σ～ε曲线分析指出,速率效应对岩石力学特性影响随不同岩石而异。文中着重分析了高孔隙率砂岩,在静力试验范围内不同应变速率下试件的应力应变性状;得出了应变速率对破坏应力影响的指数关系式;并进一步指出不同应变速率对裂纹扩展应力影响比对破坏应力影响尤为明显。与此同时,还阐述了影响机制,指出速率效应实质上是粘性效应和断裂效应。对所研究的砂岩,通过松弛特性试验表明,主要表现为断裂效应。
In this paper, loose rock represented by tight rock represented by the Three Gorges quartz diorite and Gezhouba sandstone is used, and the strain rate is measured in the range of 10~(-6)~10~(-2)(1/sec). The ～ε curve analysis indicates that the effect of velocity on rock mechanics varies with different rocks. This paper focuses on the analysis of the stress-strain behavior of specimens with different porosity at different strain rates in high-porosity sandstones. The exponential relationship between the strain rate and the failure stress is obtained. Furthermore, it is pointed out that different strain rates affect the crack propagation stress. The influence of stress ratio is especially obvious on the damage stress. At the same time, it also elaborated on the impact mechanism and pointed out that the velocity effect is essentially a viscous effect and a fracture effect. For the sandstones studied, it was shown by the relaxation characteristics test that the fracture performance was mainly manifested.