In geotechnical engineering, the soil-structure interface is an important aspect to be taken into account in soil-structure interaction because it relates to the stability of supported structure. In particular, the shear behavior of the soil-structure interface plays a key role in the design of civil engineering structures and their analysis over time. The interface is a thin zone of soil in contact with the structure where major stresses and strains develop in. To our knowledge, previous works on the characterization of the mechanical behavior of the soil-structure interface mainly include typical soils (sand or clay) or natural soils, in contact with variable structural materials (concrete, steel, wood). However, natural soils are very complex, partly due to geological heterogeneities, and the mechanical response of typical soils do not always represent accurately intermediate soils between sand and clay. Previous studies on the mechanical behavior of those soils are significantly represented in the literature, especially in experimental research, however it is rather poorly documented on the interface between these soils and structural materials, whereas their response to mechanical loadings is different. The objective of this paper is to characterize the shear behavior of the soil-structure interface for intermediate soils between sand and clay, by experiments at the laboratory scale. Artificial mixtures of silica sand and kaolinite-rich clay are chosen to represent the intermediate soils in this study. For this propose, the research is organized in a main experimental campaign that aims to investigate the effect of the clay fraction, from 0% (sand) to 55% (kaolin clay) on the mechanical behavior of a soil-concrete interface by a direct shear device in the laboratory. The characterization of the shear behavior of the soil-concrete interface at various clay and sand fractions allows to enlighten the role of soil microstructure at the soil-structure interface on the stability of civil engineering structures.

中文翻译：

---

粘土分数对砂土混合物与混凝土界面剪切行为的影响

在岩土工程中，土-结构界面是土-结构相互作用中需要考虑的一个重要方面，因为它关系到支撑结构的稳定性。特别是，土-结构界面的剪切行为在土木工程结构的设计及其随时间的分析中起着关键作用。界面是与结构接触的土壤薄层区域，主要应力和应变在此产生。据我们所知，先前关于土壤-结构界面力学行为表征的工作主要包括典型土壤（沙子或粘土）或天然土壤，与各种结构材料（混凝土、钢材、木材）接触。然而，天然土壤非常复杂，部分原因是地质异质性，典型土壤的力学响应并不总是准确地代表沙子和粘土之间的中间土壤。以前对这些土壤的力学行为的研究在文献中得到了显着体现，特别是在实验研究中，但是对这些土壤和结构材料之间的界面的记录却很少，而它们对机械载荷的响应是不同的。本文的目的是通过实验室规模的实验来表征沙子和粘土之间的中间土的土-结构界面的剪切行为。本研究选择硅砂和富含高岭石粘土的人工混合物来代表中间土壤。对于这一提议，该研究被组织在一个主要的实验活动中，旨在通过直接的方法研究粘土含量（从 0%（沙子）到 55%（高岭土））对土壤-混凝土界面力学行为的影响。实验室中的剪切装置。不同粘土和砂组分下土壤-混凝土界面剪切行为的表征可以揭示土壤-结构界面处土壤微观结构对土木工程结构稳定性的作用。