Hyperbolic spiral model for predicting reverse fault ruptures in sand based on centrifuge tests
Chaofan Yao, Jiro Takemura, Wenqi Guo, Qixiang Yan
Abstract
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.