Abstract
The present study investigates changes occurring in the material composition and properties of the South Yakutian carbonate soils during cryogenesis. The nature of the transformations of certain limestone varieties composing the surfaces of rock massifs was determined using scanning electron microscopy, 3D X-ray tomography, as well as lithological–mineralogical and optical–petrographic studies, over a 10-year period. The areas in carbonate rock massifs with increased clay content, pyritisation, dolomitisation, and baritisation, as well as zones of calcite and dolomite junction, were found to be least resistant to the effects of processes associated with water phase transitions, i.e., freezing and thawing. The mineral proportion of limestone on the surface of soil massifs chemically processed over a 10-year period reached 5–7% of the volume of the weathered rocks. In the process of transformation, not only the composition of the rocks changed, but also the nature of the structural bonds that significantly influence their mechanical strength properties. The number of cracks for weathered soil samples increased by 9–16%; their opening increased by 13–18%. For rocks initially having uniaxial compression strength in the range of 33–46 MPa, this strength was reduced by 19–27%. Laboratory experiments on 1000-fold cyclic freezing and thawing of carbonate rock samples (which corresponds to an 8–10-year period of weathering on the surface of a mountain outcrop under the natural conditions of South Yakutia) demonstrate the similarity of these changes with those observed in samples taken from the sides of open pits 10 years ago. In general, soils are influenced by a wide range of environmental factors under natural conditions. The significant influence of alternating temperatures on the changes in the composition and structure of limestones in South Yakutia is characterised in detail.
Highlights
The present study investigates changes occurring in the material composition and properties of the South Yakutian carbonate soils during cryogenesis
The main regularities of such changes have been established for most soil types having rigid structural bonds of crystallisation or cementation type under laboratory conditions
The comparison of investigated varieties of carbonate soils sampled from mine surfaces with “fresh” samples subjected to periodic cyclic freezing and thawing under laboratory conditions demonstrates the similarity of the changes occurring in them
Summary
The present study investigates changes occurring in the material composition and properties of the South Yakutian carbonate soils during cryogenesis. The main regularities of such changes have been established for most soil types having rigid structural bonds of crystallisation or cementation type (such soils defined as rocky according to the classification system adopted in the Russian Federation are characterised by a uniaxial compression strength of at least 5 MPa [8]) under laboratory conditions As a rule, these studies are based on determining the physical and strength characteristics of soil samples after repeated cycles of freezing and thawing [1,9,10,11,12,13,14,15,16,17]. Analytical studies of samples from boreholes identified the development zones of ankeritisation processes, to which the local strengthening of the soil massif turned out to be confined [18,19]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
