Dynamic Centrifuge Tests on Soft Clay Reinforced by Soil-Cement Grids

This paper describes the centrifuge model construction procedure for a soft clay profile reinforced by soil-cement grids and presents the results and observations of seismic site response during a preliminary dynamic centrifuge test. These tests are the first in a series of centrifuge tests investigating the stiffening effect of soil-cement grid reinforcement on the seismic response of soft clay sites. The results showed that for high intensity base motions, soil nonlinearity reduced the soil peak horizontal acceleration (PHA) in an unreinforced soil profile, while in a reinforced profile, the surface PGA was greater than the base peak acceleration. The soil-cement grid with Ar=30% and improvement depth/grid spacing = 0.7 did not help reduce the induced excess pore water pressure and settlement in the surrounding soil. However, the settlement of the soil-cement grid was significantly smaller than the surrounding soil settlement.