蒙脱石的脱水作用对断层摩擦本构行为的影响

EFFECT OF DEHYDRATION OF MONTMORILLONITE ON CONSTITUTIVE BEHAVIOR OF FRICTION

利用高温双轴摩擦装置，研究了含蒙脱石的断层带在不同温度下摩擦滑动的速度依赖性，以期了解脱水作用对摩擦行为的影响。结果表明，断层带摩擦强度随温度而升高，而速度依赖性较为复杂，以１．４ｕ／ｓ为界，室温和１００℃时，低滑动速率下表现为微弱的速度弱化，高滑动速率下则表现为速度强化；２００℃时均为速度强化；３００℃时高滑动速率下仍为速度强化，但低滑动速率下转变为速度弱化；４００℃以上，均为明显的速度弱化。摩擦行为的变化与脱水过程及相应的断层物质变形方式的变化密切相关。

The velocity dependence of friction along fault zone with montmorillonite gouge at different temperatures has been studied on a biaxial friction rig at high temperature.The results show that the frictional strength of fault zone increases with increasing temperature，while the velecity dependence is rather complex. At room temperature and 100℃，the friction shows weak velocity weakening at slip rate below 1．4um／s，but velocity strengthening above 1．4 um／s.At 200℃，velocity strengthening is observed at all slip rates．At 300℃，the friction still shows velocity strengthening at slip rate above 1．4um／s，but changes into velocity weakening at slip rate below 1．4um／s. When temperatures are above 400℃，great velocity weakening is observed at all slip rates. The analysis indicates that the changes in frictional behav-ior are closely related with the dehydration and relevant change in deformation mode of fault gouge.