This study presents some consolidated undrained triaxial compression (CU) tests of sand-low plastic silt (ML) mixtures, with ML contents of 0 %, 10 %, 20 %, 30 %, 40 %, and 50 %. The tests were performed on each mixture at three effective consolidation stresses (ECSs) of 50, 100, and 150 kPa. Triaxial testing equipment equipped with submersible local linear variable differential transformers (LVDTs) was employed to obtain accurate non-linear stiffness responses of the tested specimens over the course of the test. The testing results showed that the minimum and maximum void ratios (e min and e max ) of the specimens decreased until 20 % ML additions and then increased. Increasing the ECS of the test increased the deviatoric stress, contractive volumetric response and secant modulus (Eu) of all mixtures. Increasing the ML content at a given ECS decreased the deviatoric stress of the mixtures. The ML additions increased the excess pore water pressure (PWP) of the mixtures. The sand with low ML contents (0, 10, and 20 %) exhibited an initial contractive behaviour, followed by a dilative response. However, sand mixed with 30, 40, and 50 % ML were dominated by contractive response. The Euvalues of sand decreased with the ML additions. Consequently, these suggest that sand grains can retain their dilative nature and stability when the ML contents are low (i.e., sand-dominated soil matrix). However, when ML dominates the soil matrix, the mixtures exhibited a dominant contractive response with decreasing mean effective stress in their stress paths.

Using an energy-based approach and a wide range of marine silt content (SC), along with simulating different field conditions, a systematic experimental study was conducted through a series of strain-controlled cyclic triaxial tests on the undrained cyclic response of saturated Konarak carbonate sand-silt mixtures that originated from the northern coasts of the Oman Sea. The results revealed that the trend of variation in capacity energy (cumulative dissipated energy required to initiate liquefaction, Wliq) of sand-silt mixtures versus variation in SC was highly dependent on the relative density (Dr). Using the concepts of equivalent intergranular void ratio (e*) and equivalent interfine void ratio (ef*), a new relationship was proposed to estimate the Wliq of the Konarak sand-silt mixtures under different field conditions. To take into account the effects of SC, the energy-based pore water pressure model model proposed by Jafarian et al. (2012) was revised with modified calibration parameters. Similarly, as there exists a distinct relationship between energy dissipation and the excess pore water pressure generation during cyclic loading, a significant correlation is also observed between energy dissipation and stiffness degradation for carbonate soil.