【摘要】 本文从物体流变失稳的概念出发，对岩石试件的弱化失稳．流变先稳的过程及二者之间的关系进行了初步分析．认为岩石试件的流变失稳是在外力作用下．随着时间的推移而失去原有的平衡状态，此时试件内变形和应变加速度趋于无穷。提出了试件流变失稳的理论判据。文中最后从微分方程解的稳定性概念出发，对简单的流变模型建立的微分方程进行了稳定性分析．指出工程中常见的影响失稳的主要因素是应力峰值的转移与岩性的变化。并认为无论何种因素导致的围岩应力处于全程应力曲线的峰值强度后．对平衡系统的稳定性都是不利的。更多还原

【Abstract】 This paper, based on the concept of material instability, analyses the procedure of soft,creep instability for rock sample and the relations between them,proposes that the rheological instability of the rock sample is due to the loss of its original equilibrium with time under the external force, and then the rock sample deformation or strain acceleration tend to be infinite. The article gives the rock sample rheological instability criteria in theory. In the end, this paper,based on the concept of solution stability for the differential equaition, analyses the stability for the simple rheological model, points out that the main reasons causing the instability are stress peak shiff or rock behaviour change. The paper puts forward that no matter what causes the stress of the surrounding rock to be after the peak value in the whole stress strain curve, it is unfavourable for the equilibrium.更多还原