泥质软岩蠕变机制研究

在分析已有岩石蠕变机制研究成果的基础上,以南宁盆地泥岩为研究对象,进行一系列单轴压缩无侧限蠕变试验和有侧限蠕变试验来分析泥岩的蠕变特性,配合扫描电镜,着重分析泥岩蠕变过程中细观和微观结构的变化并提出岩石的蠕变机制,即岩石的蠕变是岩石损伤效应与硬化效应共同作用的结果。通过构建蠕变、损伤及硬化综合曲线说明蠕变3个阶段的形成机制:第一阶段硬化效应强于损伤效应,蠕变规律主要服从于硬化效应的衰减变化规律;第二阶段损伤效应强于硬化效应,蠕变规律主要服从于损伤效应的等速变化规律;第三加速蠕变阶段的硬化效应已不显现,蠕变规律服从损伤效应的加速变化规律。泥质软岩的蠕变机制与金属材料蠕变机制在蠕变参与对象及机制方面不同。

STUDY OF CREEP MECHANISM OF ARGILLACEOUS SOFT ROCKS

Based on the analysis of existing research results of rock creep mechanism，the mudstone in Nanning Basin is taken as the mainly research object；and its creep property is deeply discussed by a series of tests under unconfined uniaxial compression and confined uniaxial compression. Especially，the creep changes of meso- and micro-structure are researched combining with scanning electron microscope(SEM) images of mudstone. It¢s indicated that the creep mechanism of the argillaceous soft rock is the result of the interaction between the damage effect and hardening effect. It is reasonable to explain and illustrate the mechanism of three creep phases by using the comprehensive curves，which include the creep curve，the damage effect curve and the hardening effect curve：at the first stage，hardening effect is much stronger than the damage effect and the creep mainly obeys the decay law of hardening effect at this stage；at the second stage，the damage effect is stronger than the hardening effect，and the creep mainly obeys the constant-rate law of the damage effect at this stage；at the third stage，the hardening effect disappears and the creep obeys the acceleration law of the damage effect. The creep mechanisms of the argillaceous soft rock and the metal materials are different in terms of magnitude of objects and the mechanism.