Centrifuge modelling of normal fault–foundation interaction

Abstract

Earthquake fault ruptures may emerge at the ground surface causing large differential movements. When fault ruptures emerge at or adjacent to the position of existing foundations, significant damage can be caused. However, the study of recent faulting events revealed that in some circumstances the fault-rupture emergence is deflected by the presence of buildings leaving the buildings intact. A centrifuge modelling study has been conducted to investigate how normal faults interact with strip foundations which run parallel to the strike direction. The study confirms that fault rupture may be deviated by the presence of the foundation so that the foundation is protected from the most serious differential movements. However, whilst the fault propagates to the soil surface the foundation has to withstand initial movements before the final fault rupture emergence mechanism is activated. The centrifuge results suggest that it is the bearing pressure of the foundation which causes the deviation of the fault rather than the kinematic restraint of the foundation. The interaction between the earthquake fault and the shallow foundation depends on the foundation bearing pressure, foundation width, soil depth and position of the fault relative to the foundation and these aspects should be considered in design. Results from the tests are used to validate a series of finite element analyses as reported in an accompanying paper.

Bridge–Pier Caisson foundations subjected to normal and thrust faulting: physical experiments versus numerical analysis

“…The numerical analysis cannot possibly capture such complicated soil response in full detail, but it does predict the final rupture paths fairly accurately. and centrifuge model tests [15,31], but they also compare qualitatively well with field observations [28]. In general, normal faults tend to refract at the soilbedrock interface, becoming steeper.…”

Numerical modeling of the interaction of pressurized large diameter gas buried pipelines with normal fault ruptures

“…By comparing experimental data and numerical predictions, it was possible to point out that the discretization along the horizontal direction plays the most important role; accordingly, a structured mesh of quadrilateral elements featuring node spacing of 0.25 m and 0.50 m in the horizontal and vertical directions, respectively, provided a reasonable trade-off between accuracy and computational efficiency. In Figure 2, displacement and strain fields obtained with such space discretization are compared with the available experimental data for a fault offset of around 1.2 m, see [4]. The corresponding vertical displacement profiles at a depth of z=0.9 m, are compared in Figure 3.…”

“…The corresponding vertical displacement profiles at a depth of z=0.9 m, are compared in Figure 3. In this figure, numerical results are also illustrated at varying amplitudes x of the region across which the fault offset is imposed along the bottom surface of the model, showing a limited dependency of the solution using widths smaller than 1 m. [4]) and numerical vertical displacement profiles at a depth from surface z=-0.9 m. Results obtained using different amplitudes x (=1m, 0.5m, or 0.25m) of the region across which the fault offset is imposed along the bottom surface of the model are compared.…”

Interaction of piled foundation with a rupturing normal fault

“…Particular reference is made to the latter publication in this journal, in which the employed numerical methodology has been extensively and successfully validated through class 'A' predictions of centrifuge model tests performed at the University of Dundee, with an embedded square-in-plan caisson foundation. See also the related experimental work of Bransby et al (2008aBransby et al ( , 2008b and Ahmed & Bransby (2009).…”