Stabilization of Deep Open Excavations in Soft Soil by Jet Grouting

Jet grouting was adopted to stabilize excavation for the construction of an underground irrigation tank and amphitheater in soft clay. Triple fluid jet grouting was used to form jet grout columns of 1.7m diameter in the soft clay. Precutting with water jetting was necessary to ensure that the design column diameter was achieved in the upper filled ground consisting of very stiff well-compacted sandy clay. Seven trial columns were executed to determine the jetting parameters. Monitoring of lateral ground displacements indicated that the jet grout stabilization scheme was successfully implemented and that lateral displacement to excavation depth ratios can be maintained within 0.24%.