Foundation liquefaction and densification countermeasures for earth embankments

Abstract

In a series of two separate centrifuge model tests, the seismic response of a cohesive earth embankment overlying a layer of loose saturated clean sand is studied, with and without a liquefaction countermeasure. As a countermeasure, the foundation zones under the embankment toes are densified. Currently, such testing results offer a valuable alternative to actual full-scale dynamic response, which is virtually non-existent for retrofitted embankments. In this paper, a thorough literature survey of embankment failures due to foundation liquefaction is presented first, evincing the practical significance of this problem. In addition, in-situ embankment foundation liquefaction countermeasure projects and previous model testing studies are briefly discussed. Thereafter, the conducted experiments are presented, and effectiveness of densification countermeasure is discussed based on the recorded dynamic response. The implemented densification technique is found to reduce embankment vertical deformations by about 50%, and reduce cracking and lateral spreading of the embankment by about 70%.