Soil improvement case studies using jet grouts

ABSTRACT Jet grouting technology has been found widespread application in recent years in Turkey. Necessary technology is locally available in most places. Applications can be completed in a relatively less time and the cost is not very high when compared with other alternatives. Besides jet grout columns can also function as load carrying deep foundations. This aspect of the technology has triggered some debates especially over the lateral load carrying capacity of jet grout columns since they are not manufactured with traditional reinforcing steel bars. Reported successful performance of jet grout applications during the 1999 Marmara Earthquake were not enough to avoid suspicions of practicing engineers. Main reason for this is thought to be the insufficient information regarding load transfer mechanism from the superstructure to the column head and response of the columns to kinematical loads. This dissertation has targeted both aspects of seismic lateral loads within the context of a jet grouting application case study in Bostanlı district of the city of Izmir. Simple analytical and numerical methods that are commonly available were used. It was found that capping layer can be quite effective in reducing transferred inertial loads and inertial loads can be much more smaller with the positive contribution of soil-structure interaction effects to column response. Further studies on this subject are considered as feasible. Kinematical effects, on the other hand, were found to be negligible for the studied soil profile and earthquake loading. Calculated bending moments were several magnitudes smaller than those for the reinforced concrete pile and it is thought that flexible soilcrete material is the main cause for this positive behavior.