Anisotropic permeability evolution of high void ratio soil under static compression (a case study on clayey loess soil)

Iranian Journal of Earth Sciences

مقالات آماده انتشار، پذیرفته شده، انتشار آنلاین از تاریخ 29 فروردین 1401

نوع مقاله: Original Research Paper

شناسه دیجیتال (DOI): 10.57647/j.ijes.2024.1602.09

نویسندگان

Gholamreza Shoaei^* ؛ Masoud Enayat؛ Mohammad Reza Nikudel

Department of Engineering Geology, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, Iran.

چکیده

Decreasing the void ratio of soil due to static compression causes soil structure changes and developing anisotropic structure. This phenomenon as a common result causes the development of anisotropic permeability ratio (kh/kv or rk). When the soil shows a high void ratio, it generally contains macropores that have the most effect on the permeability, soil structure changes, and rk evolution during compression. Thus, in this research, two high void ratio samples of clayey loess soil with a granular structure (containing macropores) were prepared to investigate the rk evolutions during one-dimensionally static compression. So, horizontal and vertical permeability of samples were measured at each new void ratio, from high to low values. The tests implemented by a 3D permeameter apparatus that was designed for this research. This apparatus was equipped with a camera to study the soil macrostructure changes during tests. The results show that rk have different trends during compression, so, three stages of permeability anisotropy variations recognized as A, B and C. At high void ratios (stage A), the connected macropores produce high pseudo anisotropic permeability that rapidly decreased during compression. At low void ratios, rk increased due to particle orientation. The Stage B that has minimal values of rk with low variations is the transition stage from A to C stage.

کلیدواژه‌ها

Vertical and horizontal permeability؛ soil structure؛ void ratio؛ macropore؛ particle orientation