Liquefaction and post-liquefaction behaviors of sands affected by immersion-induced degradation of crushed mudstone

Abstract

A series of undrained triaxial tests was conducted to investigate the effect of crushed mudstone with the immersion-induced degradation on the liquefaction and post-liquefaction properties, and the undrained shearing behavior without precedent cyclic-loading histories of sands containing crushed mudstone. The tested materials with a main particle diameter of 2–0.85 mm were prepared by mixing sands and crushed mudstone to reach the prescribed mudstone content defined by dry mass ranging from 0% to 50%. The mixtures were subjected to immersion under a certain stress level and were subsequently tested. In addition, one-dimensional compression tests were also supplementally performed to visually observe the immersion-induced degradation of crushed mudstone. The test results mainly showed that: (1) the liquefaction resistance, the post-liquefaction undrained strength, and the undrained strength without a precedent cyclic-loading history decreased significantly with increasing mudstone content, Mc, up to 20%; (2) even a small amount of crushed mudstone affected these strengths; (3) the above-mentioned large reductions in the strengths were attributed to the immersion-induced degradation of crushed mudstone; (4) at Mc > 20%, the liquefaction resistance increased while the significant increase in the undrained static strengths with and without precedent cyclic-loading histories was not observed; and (5) the increase in the liquefaction resistance at Mc > 20% may have been attributed to both the gradual increase in the plasticity and the formation of the soil aggregates among deteriorated crushed mudstone, while the increase in the specimen density did not play an important role in such behavior.

Keywords

• Liquefaction
• Post-liquefaction behavior
• Triaxial test
• Sands containing crushed mudstone