Effect of micropiles on liquefaction of cohesionless soil using shake table tests

Abstract

Micro piles are used effectively in many applications of ground improvement to increase the bearing capacity and decrease the liquefaction potential, particularly in strengthening the existing foundations. The present study aims at carrying out an experimental study in which micro piles of various diameters are placed at different spacing and their corresponding effects on liquefaction of loose saturated cohesionless soil are studied. The effect of micro pile injection on liquefaction remediation is studied using shake table tests on a scaled down model and the number of cycles required for liquefaction are observed. The results show that, by using micro piles, the response of loose cohesionless soils under seismic loading can be significantly improved and the liquefaction potential of the loose saturated soil decreases considerably. It is observed that spacing to diameter ratio of 6- to 7 is very effective in controlling liquefaction for a peak ground acceleration of 0.4 g. As the value of peak ground acceleration reduces, the optimum spacing to diameter ratio of micropiles increases. Therefore, the liquefaction resistances of sandy saturated soil can be improved if spacing and diameter of micropiles are properly chosen.