Centrifugal modeling of drains for slope stabilization

Horizontal drains are commonly used to stabilize slopes or embankments in which ground-water seepage is the main cause of instability. When using horizontal drains to remedy an unstable slope, the length, spacing, and position of the drains must be chosen. These drain-placement parameters are usually chosen on the basis of engineering judgment; sometimes they are obtained from published design charts. This paper presents a methodology that can be used to develop or experimentally verify such charts. Model slopes are tested in a geotechnical centrifuge to evaluate the influence of horizontal drains on the distribution of piezometric levels within slopes. The observed results, from those experiments in which drains were installed in the model slopes, were compared to reference conditions obtained from experiments without drains. The limited capacity of the centrifuge used in this research precludes a complete verification of the published design charts, but the results demonstrate the usefulness of the centrifugal modeling technique in studying the process of slope stabilization.