ASSESSMENT OF DENSE AND LOOSE STONE COLUMNSAGAINST LIQUEFACTION-INDUCED LATERAL SPREADINGEFFECTS ON PILE GROUPS

A series of shake table experiments were conducted to investigate the efficacy of dense and loosestone column technique as a mitigation method against liquefaction-induced lateral spreading. Twoseparate ۲×۲ pile groups (with and without superstructure weight) were installed in the models. Theprofile of the soil layers consisted of a mildly sloped thick liquefiable layer between two nonliquefiablelayers. The experiments were performed employing Sharif University of Technology ShakeTable and Laminar Shear Box. The models were shaken with a sinusoidal base acceleration with afrequency of ۳ Hz and amplitude of ۰.۳ g. The results including pore water pressure at free field andnear the piles, and displacement and bending moment of the piles are briefly presented and discussedin this paper. The results illustrate considerable advantages of loose stone columns over dense ones formitigation of liquefaction and lateral spreading effects on ۲×۲ pile groups. The results illustrateconsiderable advantages of loose stone columns over dense ones for mitigation of liquefaction andlateral spreading effects on ۲×۲ pile groups. Maximum displacement of the pile caps without and withthe lumped mass in the model with dense stone columns were ۹% and ۲۴% greater than that in themodel with loose tone columns, respectively.

Keywords:

Shake Table Test , Liquefaction , Lateral Spreading , Pile Group , Stone Column