Investigation on load-carrying capacity of geogrid-encased deep cement mixing piles

This article discusses the feasibility of a geogrid-encased deep cement mixing (EDCM)
pile for enhancing the load-carrying capacity (Qult) of a conventional deep cement mixing (DCM) pile,
based on the results of experimental and numerical investigations. Firstly, physical model tests were
conducted to observe the load–settlement response and load-transfer mechanism. Subsequently, a series
of three-dimensional (3D) finite-element analyses was performed to investigate the effect of the stiffness
and length of the geogrid encasement. The results indicated that the geogrid encasement effectively
improves the Qult of the DCM piles by a factor of two.With the additional confinement provided by the
geogrid encasement, the geogrid can also provide a greater contribution to the loading transfer. The
increase in Qult became more significant with a lower strength of the DCM. For a particular amount of
geogrid, the EDCM pile with a thicker geogrid provided a higher Qult than that with a longer geogrid.
The optimum length of the geogrid-EDCM pile was found to be approximately twice that of the pile
diameter. Finally, a chart for estimating the efficient effect of geogrid encasements on the Qult of EDCM
piles was proposed.