岩石强度时效性演化模型

在一定的外界荷载作用下，岩石材料的强度会随时间不断降低，在工程上常表现为由于强度的弱化而导致岩体的突发性破坏行为以及岩体的长期强度等不同现象和问题。因此，岩石强度的时间效应研究对岩体工程施工安全和工程长期稳定性都具有重要的指导意义。在对大量试验结果分析的基础上，总结了岩石强度演化规律与内在机制，发现岩石强度的损失与岩石本身的固有强度、所受应力状态（屈服接近度）以及应力作用的持续时间有关，在此基础上，提出了以岩石凝聚力和内摩擦角随上述因素变化为核心的岩石强度时效性演化模型。通过对多组试验数据的模拟分析表明，提出的岩石强度时效性演化模型能很好地描述岩石强度的演化规律，可以较好地定量反映不同应力水平下岩石强度弱化过程，且物理意义明确，为岩石强度的时间效应研究开拓了一个新的思路和方法。

Time-dependent theoretical model of rock strength evolution

The rock strength will decrease under a certain stress, which can lead to different performances in engineering such as the abrupt destroying by strength weakening, long-term strength and so on. So the research on time dependence of rock strength is very important to construction safety and long-term stability of rockmass engineering. Based on the analysis of a large number of test results, evolution characteristics of rock strength and their mechanisms are summarized, and it is can be found that strength weakening of rock is related to the inherent strength of rock, the stress state (yield approach index) and the performing duration of stress. Therefore, time-dependent theoretical model of rock strength is proposed by properly theoretically characterizing the evolutions of cohesion and frictional angle of rock. Simulations to some sets of test data show that the proposed model can perfectly and quantitatively describe the evolution of weakening process of rock strength; moreover, the model is of clear physical concept. The effort of this paper gives a new method to study the time-dependence of rock strength.