EFFECT OF FINES CONTENT ON LIQUEFACTION RESISTANCE DURING STEADY-STATE CONDITIONS

Liquefaction takes place in a large strain with constant stress and at a constant volume, known as steady-state conditions. Liquefaction also occurs in sandy soils with fine grain content, which affects the relative density and uniformity coefficient. Palu City is an area severely affected by the liquefaction phenomenon after the 2018 Central Sulawesi earthquake. Thus, a series of studies are needed to determine liquefaction susceptibility at steady-state conditions with the influence of variations of fine-grained content. This research was conducted by analyzing the grain size distribution and the influence of fine grain content that affected the relative density and uniformity coefficient at steady-state conditions to obtain the value of cyclic liquefaction resistance. The tests were carried out in a laboratory in the form of grain size distribution analysis, proctor standard, and triaxial consolidated undrained using sand with a fines content of 2%, 5%, 9%, 13%, and 17%. The study revealed that the sand of Palu City, based on grain gradation,, is in the most liquefiable soil range. Moreover, with the addition of the fines content, the higher the Cu value, the larger the range and the more diverse the grains. These results strengthen the undrained strength of the sand under axial load at steady-state conditions. In conclusion, the gradation will affect the void ratio and the critical-state line.