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№6/2015

 

Magazine «Engineering Geology» , 6/2015

 

HISTORY, THEORY AND METHODOLOGY

Trofimov V.T., Krasilova N.S.

Development of views on significance of permafrost factors for formation of engineering-geological conditions and on application of permafrost study achievements for regional engineering-geological investigations of the permafrost zone ...6

The article deals with the development stages of views on the role and goals of studying the permafrost environment as one of the factors of engineering-geological conditions. The classical permafrost study concepts on permafrost soils and their massives, the regularities of their distribution used in regional engineering geology, the position of permafrost grounds in the general engineering-geological classification of rocks are characterized. The features of hydrogeological conditions in the permafrost zone, the spatial regularities and dynamics of development of permafrost processes in this zone, their role in complication of engineeringgeological conditions are described. The ways and detail level of reflection of permafrost condition indicators on general, smallscale and medium-scale engineering-geological maps are shown.

Key words: permafrost conditions; permafrost grounds; underground ices; ice content of rocks; average annual temperature of permafrost grounds; zonality; permafrost processes; solifluction; thermokarst; kurums; cryopegs; engineering-geological maps, permafrost maps.

HYDROGEOLOGY

Lekhov M.V., Pozdniakov S.P.

Determining the permeability of bed sediments of a water body using falling head testing in а piezometer ...22

The authors recommend to determine the permeability of bottom sediments of a water body using data of falling head tests in a piezometer. The calculation is carried out according to the observation data of the water level in the piezometer during the recovery period after a slug test. The article substantiates two semianalytical graph-analytic calculation methods based on the assumption of quasi-stationary flow near the piezometer bottom. The vertical anisotropy of permeability is considered. Validity of the semianalytical methods is confirmed by a numerical experiment in the 1WELL program of simulation of axisymmetric flow in cylindrical coordinates. Specific features of mathematical modeling of a plane source (the piezometer hole bottom) near the border (under the bottom of a water body) is described.

Key words: permeability; anisotropy; piezometer; piezometer bottom; slug test; water basin; bottom sediments; soils; axisymmetric seepage; calculation methods; numerical model; spherical flow; 1WELL program.

SOIL’S STUDIES

Frolova Ju.V., Gvozdeva I.P., Chernov M.S., Kuznetsov N.P.

Engineering-geological aspects of hydrothermal alterations of tuffaceous rocks in the Geysers Valley (Kamchatka Peninsula) ...30

Hydrothermal alterations of tuffaceous rocks in the Geysers Valley (Kamchatka Peninsula) are considered in the paper. Two facies of hydrothermal-metasomatic rocks such as argillizated rocks and low-temperature propylites are distinguished. The time history of physical-mechanical properties of rocks at hydrothermal alterations is analyzed.Dependences of their strength and deformation properties on the content of secondary minerals such as zeolites, clay minerals, quartz are obtained.

Key words: Geysers Valley; tuffs; physical-mechanical properties; hydrothermal alterations; secondary minerals; smectites; landslide.

SOIL MECHANICS

Ter-Martirosian A.Z., Ter-Martirosian Z.G., Trinh Tuan Viet

Interaction of a long pile of finite rigidity with enlarged base and the surrounding soil ...44

The article presents formulating and solving tasks on interaction of a long pile of finite rigidity with enlarged base and the surrounding soil having nonlinear and rheological properties. The authors show that the depth distribution of longitudinal stresses in the pile shaft and tangential stresses at its contact with the soil is not linear, and this nonlinearity essentially depends on the nonlinear properties of the soil, the lengthdiameter ratio of the pile and its stiffness. The solutions obtained in the closed form allow to determine the settlement of the pile at its foot and head levels as well as the stresses at its foot level. The authors also consider tasks on interaction of a long compressible pile and the surrounding soil within the contact weakened layer. For this purpose a coefficient of rigidity of the contact layer and a coefficient for taking into account the soil viscosity of this layer are introduced.

Key words: long pile with enlarged base; interaction with the surrounding soil; rigidity (stiffness); viscosity; nonlinearity; stresses; settlement; coefficient of rigidity of the contact layer; coefficient for taking into account the contact layer viscosity.

Seredin V.V., Khrulev A.S.

Distribution of stress in the areas of fracture cracks of gypsum based on thermal radiation data ...52

Any material including rocks contains defects. When a body is loaded, stress concentration occurs around a defect. It causes growth and propagation of cracks. This process leads to formation of the main fracture (destruction) crack. From the physical point of view, loads (external stresses) on rock should realize themselves in the rock in the form of acoustic emission and heat. It was experimentally established that the temperature of material in the area of the main fracture crack is controlled by a special stressed state type (compression/tension). The minimal temperature values are observed in the conditions of uniaxial tension, and the temperature regularly increases in the conditions of uniaxial compression. A method of determination of the stressed state of gypsum was developed on the basis  of the revealed regularities.

Key words: main fracture crack; stressed state of material; temperature; rocks.

Budanova T.E., Ozmidov O.R.

Application of second-order curves for calculation of indicators of soil deformation properties according to the data of compression tests by the stress relaxation method ...56

The authors of the article propose to carry out approximation of compression test data obtained by the stress relaxation method using a polynomial function of the «vertical pressure — deformation» dependence. It permits to automatize numerical processing of the test results, compare data of compression tests carried out by various methods and obtain «secant» deformation moduli in any range of vertical pressures.

Key words: oedometer deformation modulus; stress relaxation method; compression curve approximation.

ENGINEERING GEODYNAMICS

Slyshkina E.S., Baranov A.A., Bershov A.V.

Stability calculation of the northern slope of the Aibga ridge near the Esto-Sadok village (Sochi, the Krasnodar Territory) ...62

The article deals with landslide processes on the northern slope of the Aibga ridge in the valley of the Mzymta river (North Caucasus). Two-dimensional (in the PLAXIS 2D AE software package) and three-dimensional (in the MIDAS GTS NX software package) calculations of the landslide slope stability in the static conditions and under seismic load are described. Analysis of the obtained results is presented.

Key words: Aibga ridge; Mzymta river valley; Esto-Sadok village; Sochi; landslide slope; slope stability calculation; two-dimensional slope stability assessment; three-dimensional slope stability assessment; two-dimensional modeling; three-dimensional modeling; seismic impact.

English abstracts ...72

 

 

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