Assessment of lumped particles effect on dynamic behaviour of fine and medium grained sands

One novel aspect addressed here is the effect of the lumped particle on the dynamic behaviour of cohesionless soil. The effects of particle size and fines content on cyclic soil behaviour have been previously studied by mixing fine particles separately with cohesionless soil. The studied cohesionless soil in the quaternary alluvium deposit on Middle Ganga Plain in India contains a significant amount (10%-20%) of soil lumps. Therefore, the present study using strain-controlled cyclic triaxial tests addressed the effect of parameters mentioned above on the liquefaction resistance of sand where the fines were present in a lumped form. A series of undrained cyclic triaxial experiments have been performed on isotropically consolidated samples to quantify the effects of soil lumps present in various types of sand. Experimental results have shown less cyclic resistance for soil samples with lumps compared to clean sands of equivalent grain size. This is believed to be due to lumped particle crushing, and soil particle rearrangement during the sample saturation and loading. This affects dynamic properties such as shear modulus. From the results, it can be concluded that the presence of such soil lumps in cohesionless soil is reducing the initial shear modulus and the soil becomes more susceptible to liquefaction.

Automated summary

This study investigated the effect of lumped particles on the liquefication resistance of sand through strain-controlled cyclic triaxial tests. The results showed that soil samples with lumps had lower cyclic resistance compared to clean sands, likely due to particle crushing and rearrangement. Therefore, the presence of soil lumps in cohesionless soil reduces the initial shear modulus and makes the soil more susceptible to liquefaction.