Load Transfer Anisotropy at Snakeskin-Inspired Clay-Structure Interfaces
Lin Huang, Alejandro Martínez
Abstract
The scales on the underbelly skin of snakes can generate greater friction coefficients when they move forward than when they move backward. This property is referred to as frictional directionality and could be implemented to increase the efficiency of geotechnical applications such as deep foundations and soil reinforcement elements. To better understand the mechanism of frictional directionality, surfaces were idealized and manufactured based on 3D scans of snakeskin specimens. Previous studies with sandy soil have shown that snakeskin-inspired surfaces mobilized greater peak and residual friction and dilation angles during cranial shearing (i.e., soil moving against the scales) than during caudal shearing (i.e., soil moving along the scales). This paper presents the results of a study on the interface shear behavior of snakeskin-inspired surfaces with kaolin clay. The results of interface shear box tests indicate that shearing in the cranial direction mobilized greater interface strength than shearing in the caudal direction for tests performed at varying shearing rates, overburden stresses, and overconsolidation ratios (OCR). The results are compared with those from tests with a reference rough surface to highlight the differences in behavior resulting from the bio-inspired surface texture. A discussion is also included regarding the frictional anisotropy observed in both clayey and sandy soils.