Enhancement Of The Behavior Of Laterally Loaded Model Scale Piles Embedded In Calcareous Sand By Soil Improvement

This study aimed to explore the behavior of laterally loaded pile embedded in calcareous sand.Calcareous sand from Nan-sha Island were used for the experiment.A model scale piles were tested to investigate the effect of pile head fixation on the behavior of the pile against lateral loading,additionally to explore the potential pile behavior enhancement corresponding to soil improvement application.The Investigations concerned about the evaluation of maximum resistance of the virgin soil condition compared to the resistance increase due to grout injection,the soil deformation with respect to correspondence pile maximum applied load and the efficiency of injection process determining the grout bulb coverage depth and thickness.A new pumping system had been developed to facilitate the injection operation and pressure control procedure,an instrumented pile with two injection pipes connected to a pair of diametrically opposed holes at the upper one third of the pile.Several iterations had been conducted exploring the injection procedure applicability in a similar grain size distribution sand to evaluate the injection procedure and the appropriate pump pressure to be used during the real experiment,ultra-fine cement with mean particle size of 5 micron used for grout mixing as it was discovered to overcome pipe clogging problems encountered.Four experiments were conducted in order to examine the pile behavior under different condition.An instrumented pile was tested by gradually applying horizontal loading at the pile head following ASTM D3966 loading protocol.Virgin soil and grouted soil were tested with both free head and fixed head pile.Experimental results are discussed and interpreted which indicated a significant enhancement of the pile behavior due to post grouting process,higher ultimate soil resistance with lower pile deformation due were observed for post grouted pile compared to virgin soil condition.Experimental work results were used to validate a finite element model which can be used to examine the feasibility of applying soil improvement by gout injection on a prototype scale pile behavior.