Earthquake Performance of Large-Scale MSE Retaining Walls

The use of Mechanically Stabilized Earth (MSE) walls in civil engineering construction has become an increasingly popular alternative to conventional gravity and semi-gravity retaining walls over the last several decades. The low cost and ease of construction of MSE walls, combined with their excellent performance record, are well-suited for many applications. Extensive research has been conducted to characterize the behavior of MSE walls under seismic loading; however, these tests have necessarily used reduced-scale models due to the limited weight capacity of small shaking tables and geotechnical centrifuges. To circumvent these shortcomings, the principal investigators are conducting the largest seismic tests ever performed on MSE walls using the UCSD Large High Performance Outdoor Shake Table (LHPOST). These landmark tests will provide a unique data set from which to compare and validate results obtained from similar previous research on reduced-scale wall models, as well as to refine numerical models used to characterize the fundamental dynamic behavior of these retaining wall systems.

In order to accomplish this objective, a Large Soil Confinement Box (LSCB), with maximum inner dimensions of 10.1 m length, 5.8 m width, and 7.6 m height, has been designed to handle the enormous forces that come from testing a large retaining wall and soil backfill at a lateral acceleration of 0.7g. The LSCB is composed of an outer steel frame and inner liner of high strength concrete panels. Designed to be modular with regard to both width and height, it has the ability to accommodate soil structure specimens with widths of 4.6 m and 5.8 m and heights ranging from 3.1 m to 7.6 m. Using the LSCB, seismic shaking tests on 6 m MSE walls are scheduled to begin in January 2013.