UCLA

Two large scale 9 m radius centrifuge tests were conducted at the NEES@UCDavis experimental facility to understand the interaction between soft peat and stiffer levee fills, to gain insight into the volume change behavior of organic soils under cyclic loading, and to study deformation potential of saturated sandy levees resting on peat due to liquefaction of the levee fill. This study has potential applicability to the Sacramento-San Joaquin Delta where unengineered levee fills rest atop soft compressible peat soils. This paper focuses on the interaction between a nonliquefiable clay levee resting atop soft peat during application of a sine sweep base excitation. Transfer functions derived from the data were compared with results of 1-D ground response analyses. The 1-D analyses capture reasonably well the first mode response of the levee-foundation system, but do not capture a prominent rocking mode. The rocking mode has not been previously observed experimentally for embankment systems and can impose substantial local demands on the levee fills and foundation peat near the edges of the levee.