| Abstract: | The use of stone columns on settlement and liquefaction susceptible soils. The new Paradisus Coco Beach Resort in Rio Grande (Puerto Rico) is located on an old swamp area which has been filled with relatively clean to silty sands. The swampy deposits consist of organic silts, peat and loose fine to medium sand and silty sand. The project required the placement of 1.0 to 1.5 meters of additional fill together with the construction of light structures. The need for the fill triggers the development of settlements in the underlaying weak and compressible stratum. Furthermore, the susceptibility of the loose sand to liquefaction during an earthquake was considered. This paper describes the soil improvement by means of vibro‐replacement, the purpose of which was threefold: reduction in total and differential settlement, acceleration of settlements during the surcharge period and densification of the loose sand to reduce its liquefaction potential. The predesign is presented together with relevant construction details of the preliminary trial areas from which the final column diameter and grid spacing were derived. Instrumentation together with settlement observations during the surcharge period are presented as well and compared with the initial predictions. Finally an analysis of the results was done with the program DC‐Vibro (DC‐Software GmbH) for the verification of the results following the approach of Priebe. |
