Analysis of Deep Jet Grouting Field Trial in Clay

This paper describes the investigation and back-analysis of a full scale jet grouting field trial using the triple fluid technique, to study the performance of jet grout column formation in soft marine clays. Cored samples obtained from the grouted soil mass indicated that although jetting in the marine clay was satisfactory, the lower levels encountered stiff desiccated clay, resulting in a smaller column size being formed. The cutting performance was evaluated using an analytical model for jetting with a compressed air shroud. The additional jet penetration distance achievable in using a compressed air shroud was estimated to be approximately 160%. The importance of obtaining accurate soil strength profiles for the soils to be grouted, including stress history, is emphasized.