The role of abrasion in cyclically sheared soil–structure interfaces

Abstract

A limiting factor in the drive to deliver performance-based design is the lack of knowledge regarding the constitutive behaviour of soil–structure interfaces, particularly in the case of cyclic loading. A series of experiments was undertaken using both a traditional interface shear apparatus (shearing a large body of soil grains over a structural interface) and a novel single-particle interface shear apparatus (involving shearing a single grain over a structural interface). In both cases the soil was sheared across the interface in a cyclical manner (more than 1500 cycles per test). For the traditional apparatus, a clear change in soil particle size distribution and abrasive wear of the structural interface occurs after many cycles. This change results in a significant increase of the interface friction ratio, which is the main parameter used in traditional design – increasing from approximately 0·2 (11°) to 0·7 (35°). The single-particle apparatus validated the results – where a significant increase in the friction ratio after many cycles was also observed. The novel interface behaviour presented in this paper may lead to improved interface constitutive models and consequently more economic and safer geotechnical designs.