断层区纳米颗粒的成因机制及其对断层滑动的影响

Formation Mechanisms of Nanoparticles Infault Zone and Their Influence in Fault Slip

摘要: 由于脆性破裂条件下难以产生小于1 μm的颗粒，关于断层区产生的纳米颗粒成因一直存在争议。本文总结了前人关于纳米颗粒成因机制的观点，如热分解作用、冲击加载和亚临界扩展、脆韧性机制、颗粒边界滑移、岩石矿物粉末化作用等。当孤立的球状纳米颗粒出现时，其有助于润滑断层，导致摩擦系数下降，进而促进断层快速滑动。随着断层滑动摩擦产生高温，球状纳米颗粒相互粘结，形成集合体，润滑作用消失，摩擦系数增强，断层滑动趋于缓慢而稳定。关于纳米颗粒的成因和对断层润滑作用，尚存在诸多争议。未来的研究应该集中于不同矿物之间、不同温压条件、不同应变速率之间纳米颗粒形成条件和对断层滑动影响的对比研究，以期获得不同矿物之间纳米颗粒形成的条件和对断层弱化作用的影响。

Abstract: The formation of nanoparticles in fault zoneslip surface has been controversial, because it is difficult to produce particles smaller than 1 μm under the brittle condition. In this paper, the previous views on the formation mechanisms of nanoparticles in fault zone are summarized, such as thermal decomposition, shock loading, subcritical crack growth, brittle-ductile mechanism, grain boundary sliding, rock and mineral powder, etc. When the isolated spherical nanoparticles appear, they contribute to lubricating the slip surface, leading to the decrease of friction coefficient and promoting the fault rapid slip. With the high temperature generated by frictional heating, the isolated spherical nanoparticles adhere to each other, forming agglomerated nanoparticle aggregates. As the lubrication effect disappears and the friction coefficient increases, the slip tends to be slow and stable. There are still many debates about the formation of nanoparticles and their effect on fault lubrication. The future researches should focus on the comparative study of the formation conditions of nanoparticles between different minerals, temperature and pressure conditions, strain rates and their effects on fault slip, so as to obtain the formation conditions of nanoparticles between different minerals and their effects on fault weakening.