Dynamic Response of Vertical Sand Drains in a Zone with Seismic Amplification

Preloading is a usual method used to accelerate the process of consolidation of fine-grained soils and increment its bearing capacity. To improve this technique, vertical sand drains with a given diameter and between one or two permeable strata are placed under an embankment which is intended to increase pore pressure and induce the process of consolidation. Countless research concerning the effectiveness of vertical sand drains has been made, but its capability to hold stable without suffering considerable damage, which may affect its performance, during and after a seismic event is an issue that remains unknown. This paper shows an analysis concerning the dynamic response of vertical sand drains during an earthquake. First, a free field dynamic analysis using data of an earthquakes occurred in Mexico City in a zone composed by highly compressive clays capable of increasing the dynamic response of the soils will be carry out. Then, the change in the response in the surface will be obtained considering the sand drains in the model and considering the sand drains along with the embankment. Also, the performance of the drains (deformations) during the maximum response of the soil will be obtained. The analysis will be performed by means of the Finite Element Method (FEM) using MIDAS GTS NX software, including additionally an extensive explanation about the basis taken into account to create the model (soil static and dynamic properties, boundary conditions, etc.). Finally, conclusions about the results will be made including remarks about the model creation.