About the authors
| First name, Middle name, Last name, Scientific degree, Scientific rank, Current position. Full and brief name of the organization, The organization address. | Rashid A. Mangushev, Doctor of Technical Sciences, Corresponding Member of the Russian Academy of Architecture and Construction Sciences, Professor, St. Petersburg State University of Architecture and Civil Engineering, St. Petersburg; Chief Scientific Officer, Research Institute of Building Physics of the Russian Academy of Architecture and Construction Sciences, Moscow, Russian Federation Email: This e-mail address is being protected from spambots. You need JavaScript enabled to view it , ORCID: 0000-0003-1077-0562 Daria A. Paskacheva, postgraduate student, St. Petersburg State University of Architecture and Civil Engineering, St. Petersburg; engineer, Scientific Research Institute of Building Physics of the Russian Academy of Architecture and Construction Sciences, Moscow, Russian Federation Email: This e-mail address is being protected from spambots. You need JavaScript enabled to view it , ORCID: 0000-0001-6235-8604 |
| Title of the article | Analysis of tests of weak silty clay soils under simple shear conditions |
| Abstract. | Problem statement. The primary challenge in the mathematical description of silty–clay soil behavior lies in the multifactorial nature of the processes occurring during soil deformation under complex loading conditions. Weak soils of Saint Petersburg are characterized by a few pronounced unfavorable properties for construction purposes, including high deformability, low strength, creep, and others, which complicates engineering site investigations, the development of mathematical models for weak soils, and geotechnical analysis in general. Undrained simple shear conditions allow for the most accurate representation of clay soil behavior during excavation works and embankment construction. The aim of this study is to identify fundamental regularities in the behavior of weak silty–clay soils under loading in simple shear conditions. The objectives of the research include conducting tests on weak silty–clay soils with intact structure and on soil pastes, followed by interpretation of laboratory test results to describe soil behavior. Results. The paper presents the results of laboratory tests on weak silty–clay soils with intact structure and soil pastes using a simple shear apparatus. The comparison of drained and undrained tests demonstrates significantly lower shear strength values under undrained conditions compared to drained tests. Analysis of effective stress paths reveals the influence of dilatancy and contraction processes on soil behavior during shearing. Intact soil specimens show more complex effective stress paths, with an initial decrease in effective stresses – like those observed in soil paste tests – followed by an increase in effective stresses after reaching approximately 5% shear strain. The obtained strength parameters of the soil paste, and intact soil are compared: the specimens show identical values of the effective internal friction angle and different values of cohesion. Conclusions. The results make it possible to identify the principal processes governing the deformation of weak clay soils under simple shear conditions, specifically the influence of dilatancy and contraction on effective stress paths. The presented laboratory data can be used for the development of mathematical models of weak clay soils |
| Keywords. | soft silty clay soil, mathematical model of soil, simple shear plant, dilatancy, contraction, shear loading, soil paste, overconsolidation |
| For citations: | Mangushev R.A., Paskacheva D.A. Analysis of tests of weak silty clay soils under simple shear conditions // News of KSUAE, 2025, № 4 (74), p. 8-18, DOI: 10.48612/NewsKSUAE/74.1, EDN: AHRJGY |
