Further development on MSE wall behavior under seismic loading

A relatively simple rigid plastic multiblock computational model has been developed to predict the permanent seismic displacement of mechanically stabilized earth (MSE) walls. Altogether six reinforced earth walls of height 7.3 m (24 ft) with uniform and non-uniform reinforcement lengths were tested on the National Geotechnical Centrifuge at the University of California, Davis. The walls were subjected to as many as 17 base motions ranging from cosine waves to realistic earthquake-like excitations which were scaled from motions recorded at Kobe (1995) and Santa Cruz (Loma Prieta, 1989). In the initial tests the maximum base acceleration was small, but subsequently increased as the test progressed; the largest event had excitation strength of as much as 0.9g. The analytical model captures many aspects of the characteristic deformation behavior of MSE walls observed in the centrifuge tests. A relatively simple rigid plastic model for predicting the permanent seismic displacement of reinforced earth walls founded in dry cohesionless soils has also been presented. The reinforced earth wall performance is evaluated in terms of translations (Blocks I, II and III) and rotations (Block III). The approach also accounted for the variation in acceleration within the backfill. Using the developed analytical model typical field MSE walls with uneven reinforcement were analyzed. A simple readily usable design procedure to estimate permanent seismic wall displacement has been suggested. The suggested design procedure is applicable to bar mat and strip ribbed reinforced walls with height, H, varying between 4.9 and 9.8 m and with a uniform and non-uniform reinforcement length.