Abstract: Ground deformations induced by normal fault can cause severe damages to infrastructures and pipe line systems nearby. In this paper, the results of a centrifuge test simulating multiple-step normal faulting in saturated clay are reported. The test focuses on the area and characteristic of distortion zone, fault propagation and location of surface ruptures. Based on the test, it is found that (1) the magnitude of normal fault movement has insignificant effect on the area of the distortion zone at the ground surface; (2) the shape of distortion zone in the clay is triangular and the width of this distortion zone at the ground surface is about the same as the depth of the soil underneath; (3) the main fault rupture propagates upward vertically; and (4) surface ruptures are located at the edge of the distortion zone on the side of the bedrock foot wall. Normal fault displacement required for the development of tension cracks at the ground surface is smaller than that required for fault rupture to outcrop the ground surface.

Key words: geotechnical centrifuge, fault propagation, deformation, saturated clay