Ran AN ^1,2 Xinyu Liu ³ Xianwei Zhang ^4* Shilong Gan ⁵

• ¹ University of Bristol, Bristol, United Kingdom
• ² School of Civil Engineering, Hefei University of Technology, Hefei, Anhui Province, China
• ³ Huazhong University of Science and Technology, Wuhan, Hubei Province, China
• ⁴ State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences (CAS), Wuhan, Hubei Province, China
• ⁵ Hefei University of Technology, Hefei, Anhui Province, China

In the expansive realm of Earth Science, soil mechanics serves as a crucial bond among geology, civil 15 engineering, and environmental science. The depth and breadth of its research profoundly impact the safety 16 and sustainability of human living environment and infrastructure construction. In practical engineering 17 applications, a wide variety of special soils are frequently encountered in construction, including residual 18 soil, expansive soil, glacial sediment, diatomaceous earth, coral sand, loess, frozen soil, contaminated soil 19 and so forth. The distinctive chemical, physical, and mechanical properties of these soils present numerous 20 obstacles to the conventional theory of soil mechanics. 21Traditional theory of soil mechanics is primarily based on homogeneous sand or clay, with relatively simple 22 and predictable mechanical properties. However, the mechanical behavior of special soils is complex and 23 variable due to its distinct geological origin and microstructure. In order to achieve a comprehensive 24 understanding of the engineering behavior of special soils and effectively guide engineering practice, it is 25 imperative to conduct a multiscale characterization that encompasses in-situ investigation, laboratory testing, 26 microscopic observation, and cross-scale analysis. Through this process, researchers have the potential to 27 unveil the structural characteristics and mechanical mechanisms of special soils, thereby enabling accurate 28 predictions of their behavior under diverse engineering conditions and environmental circumstances. 29 To advance the development of theory, testing, and simulation of soil mechanics, as well as to Architectural Sciences, conducted biaxial tests on coral sand using a two-dimensional discrete 55 element method to investigate the effects of particle shape and particle crushing on its mechanical 56 behavior. The findings indicated that the impact of particle shape and inherent anisotropy on shear The utilization of modified and enhanced special soils in engineering applications has become 75 increasingly imperative as the need for sustainable and efficient construction continues to escalate. The special soils treated with reinforcement and modification, such as those exhibiting high strength, 77 low permeability, or enhanced environmental performance, have the potential to significantly