Influences of the Normal Loading Condition and Surface Texture on Interface Shear Behavior between Sand and Suction Caisson Wall

Abstract The mechanical behavior of the interface between soil and the suction caisson wall determines the installation behavior and bearing capacity. A series of interfacial shear tests are conducted to study the effects of the normal loading condition and the interface texture on the sand-suction caisson interface shear characteristics. The movement and crushing behavior of sand particles in the shear zone are analyzed. It is found that with the increase of shear displacement, the shear stress-displacement curve under a constant normal load condition (CNL) has an obvious strain-softening trend. On the contrary, the shear stress increases linearly with increasing the shear displacement under a variable normal load condition (VNL). The frictional coefficient, the broken zone thickness, and the shear deformation band thickness for a convex suction caisson wall-sand interface are significantly larger than those of the grooved interface. It is also found that the presence of the water film reduces the friction between sand particles and suction caisson wall. Under large displacement shearing, the degree of sand particle breakage becomes significantly higher than that under small displacement shearing. These results help understand the shear characteristics of the sand-suction caisson wall and invent the new type of the suction caisson.