Theoretical Analysis of Joint Friction

地震是无法预测的，因为我们还不能回答这个问题，为什么一个不活跃的断层会开始不稳定地滑动？对摩擦力的研究可以追溯到达芬奇时代，甚至可能更早，它确定了滑动物体所需的力与其重量成正比。最近，实验室中对岩石摩擦力的敏感研究表明，摩擦力还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，因为它使理论家不仅开始研究稳定性、滑动的触发等问题，而且还开始研究采矿和挖掘环境中的岩面。解释实验结果的一个困难是尺度问题。样本的大小是以厘米为单位测量的，而自然断层的长度和深度都有许多公里；自然过程和实验室过程在时间尺度上的差异也同样巨大。正在进行的分析旨在弥合时间和长度尺度上的差异造成的差距。方法是开发一个理论模型，模拟实验观察到的行为。用线性粘弹性理论确定了表征这一过程的无量纲参数。然后将这些参数应用于自然断层的情况。

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.