Shaft capacity of the pre-bored grouted planted pile in dense sand.

The pre-bored grouted planted pile is a new type of composite pile foundation that consists of a precast concrete pile and the surrounding cemented soil. A series of shear tests were conducted in a specific shear test apparatus to investigate the shaft capacity of the different pile-soil interfaces. The test results show that the frictional capacity of the cemented soil-sand interface is controlled mainly by the sand properties, while the strength of the cemented soil slightly influences the interface properties by affecting the normalized roughness coefficient Rn. The frictional capacity of the concrete-sand interface is similar to the frictional capacity of the cemented soil-sand interface, and the existence of mud cake layer virtually hampers the frictional properties of the interface. The maximum skin friction of the concrete-cemented soil interface increases approximately linearly with the increasing cemented soil strength, and the value of the maximum skin friction is much larger than that of the cemented soil-sand interface of identical cemented soil strength, which demonstrates the integrity of the pre-bored grouted planted pile in the load transfer process. [ABSTRACT FROM AUTHOR]