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The study of effects of particle breakage on the mechanical properties of soil composed of porous particles is challenging due to the heterogeneity of the shape and inner void structure of individual particles, even for an identical soil sample, which imparts a compound effect on the mechanical properties. Advancements in three-dimensional (3D) printing technique have enabled the replication of objects with the same shape but different inner structures. This study investigated the feasibility of replicating porous and non-porous particles with the same particle shape characteristics, such as form, waviness, and texture, using 3D printing technique. The particle shape characteristics were evaluated using image analysis. Single particle crushing and triaxial compression tests were conducted to characterize the mechanical properties of the 3D printed and porous volcanic soil particles. It is observed that the mechanical response in the single particle crushing test varies for volcanic soil, which may be attributed to the heterogeneity in the shape and porosity of the particles. However, for each type of 3D printed particle, the response has a high repeatability and varies based on particle porosity. Furthermore, the effects of porosity on the shear response are demonstrated through triaxial tests on 3D printed particles of different porosities. It is noted that although a quantitative comparison is not possible, a qualitative similarity is observed in the response of the 3D printed porous particles with natural porous volcanic soil. Thus, insights into the mechanical response of porous particles can be gained using 3D printed particles. [ABSTRACT FROM AUTHOR]

This study aims to identify the characteristics of a large-scale embankment constructed from volcanic soil in snowy-cold regions during all seasons and to confirm the validity of the prediction method for rainfall-induced failure that has been proposed in previous studies. To realize the aims, a series of laboratory-based model tests will be conducted initially on small-scale embankments constructed with a representative volcanic soil. Thereafter, a large-scale embankment was constructed in Sapporo City, Hokkaido, Japan. The same volcanic soil as that used in the model testing was utilized as the construction material. Taking into consideration the results of the field monitoring, model test, and stability analysis, the aspects of slope failure were clarified. It was shown that the rainfall-induced failure of an embankment could be uniquely evaluated by estimating the changes in water content in zones exposed to freezing and thawing. Finally, a stability monitoring protocol based on infiltration theory is discussed in detail. [ABSTRACT FROM AUTHOR]

Bearing capacity of anisotropic sand beds beneath structures subjected to monotonic and cyclic loadings was experimentally elucidated. Using a model ground of Toyoura sand prepared by the air-pluviation method, a series of loading tests on model structures under several foundation conditions was carried out. Firstly, the effect of fabric anisotropy on bearing capacity and its mobilisation mechanism was revealed, and secondly the applicability of countermeasures constructed by side walls and sheet piles on the bearing capacity was investigated on sand deposits with fabric anisotropy. The test results showed that fabric anisotropy of sand deposits affects the bearing capacity remarkably under monotonic and cyclic loading conditions, and that constructions of side wall and sheet piles are advantageous as countermeasures against ground failures, although their prevention effects on bearing capacity vary with the changes in depositional conditions. [ABSTRACT FROM AUTHOR]