Simplified Estimation of Earthquake-Induced Settlements in Saturated Sand Deposits

ABSTRACT

This study presents a simplified method for estimating earthquake-induced settlements of saturated sand deposits based on previously available studies and undrained cyclic loading tests followed by drained reconsolidation under non-zero or zero lateral strains for various sands. It has been shown that: (1) the volume change of different sands over a wide density range can be uniquely related to “relative compression” as defined by ∆ e/(e_i – e_min); (2) the total volumetric strain of saturated sand is not obviously influenced by a swelling history following undrained cyclic loading; and (3) the volumetric strain after undrained cyclic loading is not significantly affected by the boundary constraint of non-zero or zero lateral strains. It has been found that the relationship between the logarithm of the relative compression after complete or incomplete liquefaction and the logarithm of the maximum shear strain induced during preceding undrained cyclic loading is approximately linear over a range of maximum shear strain from 0.01% to 10% and of relative densities from 20% to 90% for five sands under non-zero or zero lateral strain conditions. The results predicted by the proposed method compare favorably with experimental observations of shaking table tests on saturated sand in a laminar container. The proposed method may therefore be used as a first approximation for estimating earthquake-induced settlements of saturated sand deposits.