Cyclic liquefaction behavior of weakly cemented and fines-treated sands with gradation effects

The cyclic liquefaction behavior of weakly cemented and fines-treated sands is investigated in this paper. The filling and cementation effects for different base-sand gradations are evaluated by comparing undrained cyclic test results of clean, fines-treated, and gypsum-cemented sands. The tests show significant sensitivity of the undrained cyclic response to gradation parameters. The cyclic behavior of clean and fines-treated sands depends on both the average size and uniformity coefficient of sand particles, while that of cemented sand is more sensitive to the uniformity coefficient. At a given low cement content, uniformly graded sand specimens tend to form ineffective or unstable cementation such that the resulting cyclic behavior would be rather similar to the behavior of sand treated with fines at the same content. In contrast, much stronger cementation can develop within non-uniformly graded sand specimens. Such gradation dependency is examined under different cyclic stress ratios and different conditions of void ratio and relative density. Based on the test results, gradation-dependent relationships between cyclic strength and gradation parameters are proposed to evaluate the cyclic liquefaction resistance of weakly cemented and fines-treated sands.