Preparation method of hollow cylindrical sample of inclined sedimentary sand

Limited by the functions of existing geotechnical test instruments，the stress path can only be controlled to rotate around a single stress axis at present. The research on the rotation of stress around two or three stress axes is still a blank in soil mechanics. In this paper，the experimental research methods of stress directional dependence are systematically combed from two aspects：controlling the rotation of sample deposition surface and controlling the principal stress direction. The sample preparation device of hollow cylindrical sample of inclined sedimentary sand was designed and developed. Based on the technology of sand rain method，the whole mould rotates at a constant speed by the motor of the sample preparation device. So that sand particles are inclined deposited along the radial direction under the action of gravity and centrifugal force. Then，the inclined sedimentary sand hollow cylindrical samples with a fixed angle between the deposition surface and the horizontal plane can be prepared. The directional rotation of the sample deposition surface around σ 3 is realized. Then，with the help of hollow cylinder apparatus to control the stress rotating angle around σ 2 ，controlling of the three magnitudes and two directions of the three principal stresses can be achieved. Eighteen samples with inclined sedimentary surface were produced with the mixture of quicklime and colored sand. Image analysis and statistics analysis on the inclination of sedimentary surface show that inclined angles of deposited surfaces are close to the theoretical value，and the distribution of inclined angle deviation conforms to the normal distribution. It proves that the sample preparation device of hollow cylindrical sample of inclined sedimentary sand is reliable. It lays the foundation for further revealing the special mechanical properties of geotechnical materials and enriching and perfecting the theory of soil mechanics. © 2022 Academia Sinica. All rights reserved.