Open AccessSTRUCTURAL CHANGES OF HYDROTHERMAL CLAY SOLIS DURING COMPRESSION TESTS
Author(s) -
Ruslan A. Kuznetsov,
M. S. Chernov,
V. N. Sokolov,
O. V. Razgulina,
D. I. Urkovets
Publication year - 2018
Publication title -
inženernaâ geologiâ
Language(s) - English
Resource type - Journals
eISSN - 2587-8247
pISSN - 1993-5056
DOI - 10.25296/1993-5056-2018-13-4-5-12-19
Subject(s) - macropore , hydrothermal circulation , porosity , mineralogy , microstructure , materials science , soil water , compression (physics) , scanning electron microscope , anisotropy , composite material , geology , chemistry , soil science , optics , mesoporous material , biochemistry , physics , seismology , catalysis
To describe the change in the structure of hydrothermal clay soils during the compression tests, a quantitative assessment of the pore space characteristics was carried out. A technique combining the data of scanning electron microscopy (SEM) and computer X-ray microtomography was used for the studies. The joint use of the results of image analysis obtained with the help of SEM and tomography makes it possible to quantify the distribution parameters of structural elements in the size range from fractions of a micron to several millimeters. As an object of research, hydrothermal clays were taken from the pit that was passed within the Vostochno-Pauzhetskoye geothermal field (south of Kamchatka Peninsula). All studied samples are characterized by high values of porosity and humidity. As a result of a quantitative analyses of microstructure it is revealed that in the investigated soils predominate small intermicroaggregate, intergranular, inter-microaggregate-granular micropores with equivalent diameter from 1 to 10 mkm. In this case, the presence of macropores with an equivalent diameter of more than 100 μm is of great importance, since the deformation of the sample occurs primarily due to macropores and small intermicroaggregate micropores. Analysis of the integral parameters of the microstructure (dispersion and anisotropy) were calculated from electron microscopic images obtained by a thousandfold magnification for specimens of the natural state and for specimens after compression tests. Patterns in the change of these parameters as a result of compression tests were not revealed. This fact is explained by the peculiarities of the formation conditions of the investigated soils — the inherited heterogeneities due to the pseudomorphic replacement of the structural elements of the initial volcanogenic rocks by clay minerals. The size, shape and orientation in the space of aggregates of clay particles are determined by the structure of the initial rock and directly by hydrothermal transformations.