Theoretical Analysis of Joint Friction

关节摩擦力的理论分析

• 批准号: 0609533
• 负责人: Joseph Walsh
• 金额: $ 8.15万
• 依托单位: Walsh Joseph B
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0609533&HistoricalAwards=false
• 关键词: Theoretical; Analysis; Joint; Friction

Earthquakes cannot be predicted because we haven't been able to answer the question, Why should a fault, which has been inactive, start sliding unstably? The study of friction, which goes back to the times of da Vinci and probably before, established that the force required to slide an object is proportional to its weight. More recently, sensitive studies of rock friction in the laboratory have shown that the force also depends on time and on sliding velocity. Although time and velocity do not have a large effect on friction force, nevertheless the effect is important because it has allowed theoreticians to begin to study topics like stability, the triggering of sliding, etc. not only of earthquakes but also rock faces in mining and excavation settings.One difficulty that arises in the interpretation of experimental results is the problem of scale. The size of samples is measured in centimeters, whereas natural faults are many kilometers in length and depth; and the disparity in the scales of time that are characteristic of natural and laboratory processes is as great. The analysis that is being carried out is designed to bridge the gap caused by the disparity in time and length scales. The approach is to develop a theoretical model that simulates the behavior observed experimentally. The non-dimensional parameters that characterize the process are identified using linear viscoelastic theory. These parameters are then applied to natural faulting situations.

地震无法预测，因为我们无法回答这个问题，为什么一个不活跃的断层会开始不稳定地滑动？对摩擦的研究可以追溯到达·芬奇时代，甚至更早。研究表明，物体滑动所需的力与其重量成正比。最近，在实验室里对岩石摩擦的敏感研究表明，力也取决于时间和滑动速度。虽然时间和速度对摩擦力的影响不大，但这种影响是重要的，因为它使理论家们开始研究诸如稳定性、滑动触发等问题，不仅是地震，而且是采矿和开挖环境中的岩面。在解释实验结果时出现的一个困难是尺度问题。样品的大小以厘米为单位测量，而自然断层的长度和深度可达数公里；自然过程和实验室过程在时间尺度上的差异也同样巨大。目前正在进行的分析是为了弥补由于时间和长度的不同而造成的差距。方法是建立一个理论模型来模拟实验观察到的行为。表征过程的无量纲参数是用线性粘弹性理论确定的。然后将这些参数应用于自然断层情况。