Shear Band Between Steel and Carbonate Sand Under Monotonic and Cyclic Loading

Abstract

Compared to other silica sands, carbonate sands show special engineering properties, i.e., irregular particle shape and high crushability. For pile, anchor or caisson foundations, it is important to precisely assess the interface friction between the structure and the carbonate sand for the design of foundation capacity. Thus, a series of monotonic and cyclic interface shear experiments between steel and carbonate sand have been carried out based on a large ring shear apparatus. In the experiments, the effects of normal stress level, particle size, monotonic and cyclic loadings on shear band thickness were studied. As comparisons, similar monotonic interface shear tests for the standard quartz sand were performed as well. The result shows that the carbonate sand forms thicker shear band than quartz sand because its lower hardness. The shear zone gradually develops with the increase of shear displacement, and the thickness of shear zone develops faster in the initial 2 m shear displacement. The larger the median particle size is, the larger the thickness of the shear band is, but the t/d50 (the ratio of shear band thickness to median size) is gradually reduced. Monotonic or cyclic shear also has certain effect on the thickness of shear zone.