Soil-solid interface shear strength review and its possibility on interlayer slope stability analysis

A landslide has been one of the many problems in geotechnical engineering, whereas, from one of the cases, a failure happened at the interface layer between the overburden and its underlying soil. As interface shear strength has become one of the growing topics in research, this paper summarizes and discusses the research development of interface shear strength and its possibility to explain the interface shear behavior at a slope. The discussion was limited to cohesive soils and experiment-based behavior of the interface shear. Some research has been selected in order to understand the development of interface shear strength through time and two examples of slope interlayer shear behavior were selected. It was known that there are three common tests of interface shear behavior used: simple shear, direct shear, and ring shear test. The development of interface shear strength started at 1960s between soil and construction materials where the four major components were defined. As the research grows, many other types of soils, interfaces, and the effect of the tests became the topic of the research. In the end, the examples given from modeling the interface shear behavior from a slope gives a new perspective of cases for interface shear strength in slope analysis.