Analytical approach for estimating ground deformation profile induced by normal faulting in undrained clay

Abstract

Although theoretical models have been developed to predict the location of the failure surface in soil induced by bedrock faulting, no analytical tool is available to estimate subsurface ground deformation. In this paper, a newly developed semi-empirical approach is introduced and developed for calculating surface and subsurface deformations induced by normal faulting in undrained clay. Based on observations from centrifuge model tests, the ground deformation mechanisms are identified by three regions; namely, a stationary zone, a shearing zone, and a rigid body zone. By using an error function to represent vertical displacement continuously, the ground deformation profile can be described quantitatively. It is revealed that the ground deformation profile depends on vertical displacement of the bedrock hanging wall, soil thickness, dip angle of the bedrock fault plane, and a shape parameter that is a function of the undrained shear modulus normalized by the undrained shear strength. Validation and consistent agreement are obtained between calculated ground deformation profiles and other independent centrifuge test results and reported numerical data.