Experimental study on the shear mechanical properties of the cemented soil-concrete interface

The cemented soil-pipe pile is an expanded pile that is composed of a high-strength, precast, prestressed pipe pile core and an expanded zone of cemented soil. To investigate the shear behaviours of the cemented soil-pipe pile interface, a series of large-scale direct shear tests on the cemented soil-concrete interface under various cemented soil strengths and different normal stresses were conducted in this research. The results revealed that the shear stress increased approximately linearly with the increase of shear displacement. When the bond limit was reached, the interface slid and the shear stress decreased sharply to the residual stress, after which it remained almost constant. The shear stress increased with the increase of the cemented soil strength and normal stress, while the peak stress was found to be relatively less affected by normal stress. The residual stress was found to be less affected by the cemented soil strength, while it increased dramatically with the increase of normal stress. Based on the test results, the shear process of the cemented soil-concrete interface can be summarised as the bond failure stage and the friction slip stage.