Fault deformation can cause severe damage to structures located within the fault zones. A logarithmic spiral model was developed by D. A. Cole and P. V. Lade in 1984 to predict the shapes and locations of fault ruptures in sand caused by dip–slip faulting, based on 1g sandbox tests. However, it shows poor predictions for reverse fault ruptures observed in centrifuge tests. In this study, centrifuge modelling of reverse faulting was performed to explore the reasons for the poor predictions by the logarithmic spiral model. These faulting tests were conducted in free-field conditions with different sand densities and soil thicknesses. Based on results of centrifuge tests from both the present study and previous research studies, a hyperbolic spiral model is proposed to predict approximately the shapes and locations of reverse fault ruptures in sand. The results show that the 45° − ϕ_max/2 rather than 45° − ψ_max/2 controls the surface direction angle of the outcropping rupture. Validation of the hyperbolic spiral model shows a promising prediction in centrifuge tests both in the present study and previous research studies.

中文翻译：

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基于离心机试验预测砂岩反向断层破裂的双曲线螺旋模型

断层变形会对位于断层带内的结构造成严重破坏。DA Cole 和 PV Lade 于 1984 年开发了一个对数螺旋模型来预测由倾滑断层引起的砂岩中断层破裂的形状和位置，基于 1 g沙盒测试。然而，它对离心机测试中观察到的反向断层破裂的预测很差。在这项研究中，对逆断层进行离心建模，以探索对数螺旋模型预测不佳的原因。这些断层测试是在具有不同沙子密度和土壤厚度的自由场条件下进行的。基于本研究和以往研究的离心机试验结果，提出了一种双曲线螺旋模型来近似预测砂岩中反向断层破裂的形状和位置。结果表明，45° −  ϕ _max /2 而不是 45° −  ψ _max/2 控制露头破裂的表面方向角。双曲螺旋模型的验证在本研究和以前的研究中都显示了离心机测试中的有希望的预测。