Abstract: This paper presents a case history of the mitigation of no return slurry incident in the three-axis soil mixing for a deep excavation support project in Suzhou. Throughout the exploratory soil borings and laboratory testing, it is suggested that the groundwater conditions changed during the dewatering and piling operations in the silty and sandy soils. The disturbed silty and sand soils are the main cause that resulting the no slurry returning. Adding the bentonite into the soil strata would significantly improve the returning of the slurry in the soil mixing.

Key words: ThreeAxis Soil Mixing, No Slurry Return, Bentonite Additives, Groundwater Conditions