CPT-Based Evaluation of Liquefaction and Lateral Spreading in Centrifuge

Two series of centrifuge model tests were conducted using Nevada sand. Four saturated models placed in a mildly inclined laminar box and simulating a 6-m-thick deposit were shaken inducing liquefaction effects and lateral spreading. The sand was deposited at a relative density, D-r=45 or 75%; two of the 45% models were subjected to overconsolidation or preshaking. The second series involved in-flight measurements of static cone tip penetration resistance, q(c), simulating the standard cone penetration test (CPT) 36-mm cone. Values of q(c) increased with D-r, overconsolidation, and preshaking. A normalized resistance, q(c1N), was assigned to each of the four liquefaction/lateral spreading models. Increases in D-r, overconsolidation, and preshaking decreased liquefaction and ground deformation, but relative density alone captured these effects rather poorly. Conversely, q(c1N) predicted extremely well the liquefaction and lateral spreading response of the four models, confirming Seed's hypothesis to explain the success of penetration-based seismic liquefaction charts. The depth to liquefaction measured in the four centrifuge models is consistent with the field CPT liquefaction chart.