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The degree of salinity, the freezing point, and the amount of unfrozen water are key factors in predicting the temperature, humidity, and mechanical behavior of saline permafrost soils used in construction as foundations for buildings. The results of the experimental studies are presented and a method for calculation of the amount of unfrozen water in saline soils is proposed. The calculated and experimental data show good convergence for both sandy and clay soils of different salinity and water content. [ABSTRACT FROM AUTHOR]

Evaluating the liquefaction capacity of saturated loose sandy and clayey soils is an important task to be completed in the course of implementing new construction projects in seismic areas. This article addresses the main characteristics and input parameters of three soil models, including HS small, UBC3D-PLM, and PM4Silt. The behavior of the "soil base–pile foundation–structure" system is examined by using these models to simulate the soil behavior during an earthquake. The results demonstrate the main differences between these models and draw attention to the importance of the choice of a soil model for seismic analysis, particularly when soil liquefaction is considered. [ABSTRACT FROM AUTHOR]

Laboratory experiments on clayey soils under dynamic triaxial compression were conducted to establish a nonlinear relationship between the dynamic modulus of soil deformation and the frequency of impact. The most significant increase in the dynamic modulus of soil deformation is observed under an increase in frequency from 5 to 10 Hz. In comparison with fluvioglacial soils, the dynamic deformation modulus in glacial loams grows slower under an increase in frequency. This confirms the dependence of the obtained relations on the genesis of soils. The research results were used to develop vibration protection systems for high-precision equipment in high-tech industries. [ABSTRACT FROM AUTHOR]

Coir is a promising natural fiber that can be used for soil stabilization through fiber reinforcement. In this paper, weight gain, reduction in water absorption, and single-fiber tensile strength tests are performed to evaluate the application of different natural agents such as neem oil, kerosene, and cashew nutshell liquid (CNSL) in improving the mechanical properties and durability of coir fibers. Tri-axial tests are performed on soil specimens cured for 3, 28, and 180 days to determine the improvement in their shear strength when reinforced with coir fibers treated with different agents. The fiber reinforcement led to an increase in the shear strength of the soil by improving cohesion and friction angle. Among the different agents used, the CNSL is found to be the most effective agent for coir fiber treatment. [ABSTRACT FROM AUTHOR]

Expansive soil, also called swelling soil can cause severe damage to buildings and foundations due to the high swell-shrink behavior corresponding to moisture content changes. Slag, which is defined as the by-product of the iron and steel-making process, has been widely used as a stabilizer agent for developing clay soil mechanical characteristics. This review paper highlighted the findings of previous studies on treating expansive soils utilizing several types of slag. The effect of mixing slag with other additives such as Portland cement and lime on expansive soil swelling properties was reviewed. [ABSTRACT FROM AUTHOR]

The article considers the methods for predicting the technological settlements of buildings in the zone of influence of the construction of deep pit fences in the form of a cut-off wall of the trench type, borehole and bored-secant piles, jacked and vibro-driven sheet piles. The results of studies that allow predicting certain types of technological settlements in various engineering and geological conditions, including soil bases composed of water-saturated weak clay soils and loose sands, are presented. [ABSTRACT FROM AUTHOR]

The article proposes a method for determining the final settlement of combined foundations with injection piles in clay soils. The method takes into account the influence of technological and design factors and the change in the physical and mechanical properties of clay soils in the near-pile space during the construction of such foundations. The method is recommended for the design of free-standing foundations in the conditions of buildings reconstruction and restoration. [ABSTRACT FROM AUTHOR]

The influence of the geneses of disturbed soils on their mechanical characteristics and their changes with moisture content and compaction degree was studied on the basis of tests of technogenic ash and slag mixtures, sandy soils and clays. It was found that in terms of grain composition, strength and deformation characteristics, ash and slag mixtures occupy an intermediate position between sandy and clay soils but demonstrate several specific features, particularly concerning the influence of the water content on the angle of internal friction. [ABSTRACT FROM AUTHOR]

A series of large scale direct shear tests was performed to obtain the shear strength interface parameters for five different geosynthetic reinforcement materials in marginal clayey sandy soil. The performance of geosynthetic layers was evaluated at soil optimum moisture content (OMC) and high moisture content (OMC+6%) conditions. It was observed that the shear strength interface parameters dramatically decreased at 6% wet of optimum in comparison with optimum moisture content. Moreover, a comparison was made between the performance of different geosynthetic layers in a quantitative manner at target moisture content (i.e., OMC+6%). Based on the analysis of large scale direct shear test results, it was concluded that the geosynthetic layer, provided it has high drainage capability, could effectively increase the interface shear strength parameters at OMC+6% condition. [ABSTRACT FROM AUTHOR]

A method for determining the coefficient of viscosity based on the field tests of frozen clay soils by static penetration test in quasi-static or relaxation-creeping (with probe stabilization) modes is proposed. The method is developed on the basis of a comparative analysis of the dependence of the soil resistivity under the probe cone on the probing speed and laboratory test data for uniaxial compression. The verification of the method showed its applicability for preliminary evaluation of the coefficient of viscosity for plastic frozen clay soils. [ABSTRACT FROM AUTHOR]

The article presents the main provisions of an elastic-plastic model of undercompacted clays for predicting the behavior of soils in Central Kazakhstan. It also includes the results of experimental studies and calculations of foundation settlements. As a typical example, the results of long-term geodetic observations of deformations of the bases of blast furnaces at the Karaganda Metallurgical Plant are also analyzed. [ABSTRACT FROM AUTHOR]

In this paper, open top steel oil storage tanks resting on stiff clay soil are studied using both API650-2014 procedures and numerical FEM simulation using ADINA-2017 software. Aboveground unanchored tanks with different aspect ratios are numerically studied and analyzed, and the results are compared with API-650 procedures. The main result of this research is that the soil under the tank has an enormous effect on the behavior of the tanks in both static and dynamic stages especially on hydrostatic pressure of fluid and hoop stresses. It is also indicated that API-650 has some shortcomings especially in representing the soil under the tanks and in estimating sloshing height magnitude. For these reasons, code guidelines need more investigations in some specific cases. [ABSTRACT FROM AUTHOR]

This research presents the experimental data on physical modeling of cryogenic heaving of saline soils under laboratory conditions in the external mass transfer and isothermal temperature mode. This paper also reports the regularities of frost heaving of sandy and clayey soils salinized with sodium chloride and sodium sulfate. The mechanism of the development of cryogenic heaving of saline soils is presented. [ABSTRACT FROM AUTHOR]

The article presents a new method for determining the bearing capacity of augercast tapered piles in clayey soils by considering the various factors such as the level of external load, the sequence of operations in the installation of piles, and variations in the physical and mechanical characteristics of soils in the pile space that are responsible for effective performance of piles. This method is also recommended for designing free-standing pile and girder foundations. [ABSTRACT FROM AUTHOR]

This paper explored the impacts of montmorillonite and kaolinite (M-K) ratio as well as consolidation time on small-strain shear modulus and damping ratio of clay soils. A resonant column device was applied to the free vibration column tests. At small shear strain of 0.001%, the shear modulus and damping ratio increased by 57% and 105% respectively when the M-K ratio rose from 0.25 to 4. At higher M-K ratio, the maximum shear modulus grew at a larger rate with consolidation time and then became stable. In contrast, the damping ratio increased more slowly with shear strain at higher M-K ratio. Under a shear strain larger than 0.01%, a negative correlation of the damping ratio with the M-K ratio was found. [ABSTRACT FROM AUTHOR]

We present the results of full-scale and numerical investigations of piles driven and impressed in clay soils. We propose a procedure of application of the data of sounding to the correction of the parameters (specific adhesion and the angle of internal friction) in determining the shear strength of soil along the lateral surface of piles in the numerical investigations. [ABSTRACT FROM AUTHOR]

The paper provides the results of natural studies of consolidation of weak water-saturated clay soils of large thickness performed at the experimental sites located within the Imereti lowland (Olympic objects, Media center, city of Sochi) and a stadium in the city of Kaliningrad (Oktyabrskii island). A development of deformations, stress conditions and variation of pore pressure within the bulk of the weak water-saturated soils were studies, and the calculation results were compared to the actual deformation data. [ABSTRACT FROM AUTHOR]

To study the dynamic characteristics of carbon-fiber-reinforced soil, carbon fiber was uniformly dispersed into clay soil. A series of resonant column tests was carried out at constant soil dry density. Samples prepared with fiber contents of 0%, 0.05%, 0.10% and 0.15% and water contents of 12%, 16% and 20% were studied. Scanning electron microscopy was used to examine the carbon-fiber-reinforced clay soil at the microscopic level. The results show that the maximum dynamic shear modulus increases and the damping ratio decreases with decreasing soil water content. With increasing fiber content, the maximum dynamic shear modulus increases at first and then decreases; the optimal carbon fiber content was 0.10%. The damping ratio increases with increasing soil fiber content. Scanning electron microscopy analysis indicated two reinforcement mechanisms: friction effect and limiting lateral deformation. Results of this study indicate that carbon fiber is conducive to the dissipation of vibration energy. [ABSTRACT FROM AUTHOR]

This study investigates the influence of soil composition on soil strength by performing direct shear test on various samples, including artificial soil with different components, artificial mixed soil with different amounts, natural soil with different moisture contents, and sandy soil with different sizes. The test results show that soil strength is determined by the joint effect of inter-particle friction and cohesion. Mineral composition and water content are the main factors affecting clay strength. Changes in the mineral composition and water content of clay alter the contact state and connection of its particles, thereby significantly affecting the macroscopic properties of the soil. Different grain compositions modified the shear deformation characteristics by altering the arrangement and intergranular engagement of the particles, consequently affecting the strength. The results of this study provide further insight into the micro and fine mechanism of the soil shear strength characteristics of different components. This study also offers guiding significance in engineering practice. [ABSTRACT FROM AUTHOR]

A method is developed for calculating the settlement of single double-bladed metallic screw piles in clayey soils for the foundations of temporary buildings. The method is based on the use of a patented design of a screw double-bladed pile and takes account of the nonlinear load dependence of its settlement. It is established that for clayey soils with semi-solid consistency the discrepancy obtained between the experimental final settlements of double-bladed screw piles and the computational data obtained by the proposed method does not exceed 20-30%. [ABSTRACT FROM AUTHOR]

The rapid treatment of soft soil foundation is one of the main ways to solve problems associated with road construction. This study was conducted to determine the most effective stabilizer to increase the strength of wet and soft clay soils within 72 hours for rapid road construction. Extra admixtures are added to accelerate the reactions of cement and improve the stabilization effect. Using the unconfined compressive strength test (UCS), the effectiveness of admixtures was compared with that of a common cement-based binder. The results show that the addition of extra admixtures could rapidly improve the early strength of cement stabilized soils. [ABSTRACT FROM AUTHOR]

The thermally stimulated acoustic emission of samples of sandy-clay soils under a mechanical load was studied experimentally. The characteristics of the acoustic emission upon freezing and thawing of soils as a function of their content of clay and sandy particles as well as the magnitude of the load were determined. It was shown that different stages of the stress-strain state of soils can be identified according to the thermally stimulated acoustic emission parameters. A numerical thermo-acousto-emission criterion for evaluating the rupture rate of structural bonds in frozen soils upon their warming and the change of the stress state was developed. [ABSTRACT FROM AUTHOR]

The result of experimental studies of the operation of CFA piles in weak clay soils arranged for the foundations of renovated buildings are presented. A method using data on the auger impressing force and the physical-mechanical characteristics of the soils around the shaft of the CFA pile is proposed for calculating the carrying capacity of the soils. [ABSTRACT FROM AUTHOR]

In this paper, using the resonant column test, electron microscope observation, and microscopic structure analysis, the relationship between the maximum dynamic shear modulus and the microscopic particles arrangement of remolded clay soil was examined. Focusing on the soil microstructure, this study found that, as the effective consolidation stress increases, the soil particles are rearranged in an orientation parallel to the direction of maximum principal stress and maximum shear stress. The probabilistic entropy of the soil particle arrangement decreases, the mechanical wave velocity in the continuous medium of the soil particles increases, and the maximum dynamic shear modulus increases. [ABSTRACT FROM AUTHOR]

A process aspect of installing bored situ-cast piles-the cleaning of widened borehole sections and its impact on the pile bearing capacity in slightly moist clay soil-is examined. Results are presented of field static tests on bored situ-cast piles fabricated using both the manufacturing process and installed in boreholes after they have been completely cleaned of drilling waste. A significant divergence is established between design and experimental values of soil resistance R under the pile, which suggests a need to update SP 24.1330.2011. [ABSTRACT FROM AUTHOR]

Results are presented for field studies of the operation of metal screw piles in clay soil that is intended for the erection of foundations of rapidly erected temporary buildings. Experiments show that two-blade piles exhibit high effectiveness in plastic clay soil, as compared to piles with one blade. It was determined experimentally that introducing a second blade on the pile shaft increases its bearing capacity in plastic clay soil by up to 30% as compared to a one-blade screw pile. [ABSTRACT FROM AUTHOR]

A comparison is made of estimated settling values for a single pile, obtained using numerical (using the PLAXIS 2D software package) and analytical methods per SP 24.13330.2011, as well as with the results of field experiments. [ABSTRACT FROM AUTHOR]

The standard penetration test (SPT) and Menard's pressuremeter test (PMT) are among the available in-situ techniques. This research has been carried out with the aim to develop correlations among the in-situ parameters obtained by both methods. [ABSTRACT FROM AUTHOR]

The influence of subjectivity in determining plasticity parameters for overconsolidated clay soil on the settlement of structure beds is estimated. An elastic-plastic model of soil with isotropic hardening (PLAXIS Hardening Soil) was used to calculate settlement. It was shown that subjectivity in determining the plasticity may result in a bed settlement value that is different by 10.5%-22.0% [ABSTRACT FROM AUTHOR]

A spatial model of dilatating soil under triaxial load conditions with different regimes are described on the basis of a hypothesis that the Coulomb dry friction force acts in the plane of tangential particle shear. Spatial soil deformation over time is described in accordance with the theory of inherited creep in the form of the sum of deformations due to changes in volume and shape, with due regard for their interrelation. [ABSTRACT FROM AUTHOR]

The effectiveness of methods is considered for the compaction of weak water-saturated clay soil in building beds under complex geological engineering conditions in the vicinity of Sochi. Results are presented of experiments to compact weak clay soil using geosynthetic drains, sand mats, and sand points. It is shown that soil consolidation and compaction processes occur most effectively using vertical geosynthetic drains. [ABSTRACT FROM AUTHOR]

Results are presented for investigation of the physico-mechanical properties of clayey soils stabilized by injection of a cement-sand grout. Complex monitoring is proposed for processes involving stability of clayey bed soils over time with use of statistical, seismic, electrical, georadiolocation penetration, etc. Relationships between the change in strength and deformations characteristics of the clayey soils and the volume of grout injected are derived. Laws governing variation in geophysical parameters are established for the bed soil being stabilized over time. Recommendations are proposed for selection of stabilization parameters for clayey bed soils. [ABSTRACT FROM AUTHOR]

Positions taken in Building Code 25.13330.2011 and GOST R 25100-2011 are examined as applies to analyses of fissured clayey soils. The need for considerably more precisely defined regulatory procedures, for example, for evaluation of the block disintegration of soils to ensure correct convergence between calculations and results of field tests, is noted. [ABSTRACT FROM AUTHOR]

The theory of correlation-regression analysis is used for statistical processing of archival survey data, and correlation relationships between the compression modulus based on data derived from plate tests and the specific resistance of the soil beneath of cone of the probe during static penetration are investigated for Quaternary clayey soils of various origin. Results of the study can be used to validate tables in Appendix "H" of Building Code 47.13330.2012. [ABSTRACT FROM AUTHOR]

Results are presented for experimental and numerical investigations of vertically loaded cast-in-place piles on the basis of which a working diagram is constructed and a method proposed for analysis of these piles based on static-penetration data. [ABSTRACT FROM AUTHOR]

Generalization of the problem concerning the bearing capacity of a bed composed of slowly consolidating saturated clayey soils is examined with consideration of preliminary compaction and the coefficient of instantaneous pore pressure. Diagrams and tables are presented for the coefficients of terminal bearing capacity of the bed for a broad range of initial data. [ABSTRACT FROM AUTHOR]

Results are cited for investigation of the deformation properties of deep-seated deposits in the area of Saint Petersburg. A procedure is proposed for processing results of static-penetration tests with consideration of the coefficient of anisotropy. A relationship between variation in the compression modulus and depth of soils in the undisturbed stratum of Vend deposits is derived. [ABSTRACT FROM AUTHOR]

Procedures are presented for determination of rheological properties based on the principle of stress relaxation in triaxial compression. An empirical relationship, which permits a reduction in the time required to conduct the experiments, is derived. Determinations of the ultimate long-term strength are presented. [ABSTRACT FROM AUTHOR]

The problem of the bearing capacity of a bed comprised of slowly consolidating saturated clayey soils is examined. The solution is reduced to standard form. Tables of coefficients of bearing capacity are given for a broad range of angles of internal friction and coefficients of pore-water pressure. [ABSTRACT FROM AUTHOR]

Interaction between a large-scale model of a combined pile-shell foundation with a clayey soil bed is examined under field conditions. The influence exerted on the change in the stress-strain state of the soil bed by prestressing of the soil after pressing of the under-shell space and an increase in external load is described [ABSTRACT FROM AUTHOR]

Results are presented for experimental investigations of the performance of vertically loaded soil-cement piles installed by jet-grouting procedure in clayey soils. The rational range of application of these piles and suggestions for their design are discussed. [ABSTRACT FROM AUTHOR]

Methods of improving the properties of clayey soils with modern stabilizers are presented for their use as bases and a construction material in transportation construction. The properties and parameters of clayey soils treated with a stabilizer are examined. [ABSTRACT FROM AUTHOR]

A method for the installation and the range of application of limestone drains, their design characteristics and special engineering features, and equipment for their fabrication are presented. Test requirements are outlined for determination of computed characteristics of soft saturated clayey soils. A procedure is presented for analysis of total-settlement characteristics and prediction of secondary settlement during preconstruction consolidation under load and deep stabilization by reinforcing limestone drains. [ABSTRACT FROM AUTHOR]

A solution is presented for calculation of the total settlement of a strip foundation with allowance for additional stresses, which develop in the region under consideration due to displacement of the loaded section of the boundary, and can be determined by solving the second basic boundary problem of the plane theory of elasticity for a half plane. Expressions for the strain components of the second basic boundary problem are presented in closed form, and formulas are derived for calculation of settlement due to a uniformly distributed load. Settlements of the bed, which is composed of sandy and clayey soils, are calculated. [ABSTRACT FROM AUTHOR]

A viscoelastoplastic hardening model, developed by the author, which dwells upon the notion concerning the work of weak clayey soils, is presented. Use of the model makes it possible to examine the problem of the interaction of buildings on different types of foundations, and also the effect of deep pits on the surrounding development. [ABSTRACT FROM AUTHOR]

The subjectiveness of technicians who determine the plastic limit of clayey soils of different grain-size distribution is evaluated. It is demonstrated that subjective determination of characteristics may lead to erroneous classification of soils with respect to type and consistency. [ABSTRACT FROM AUTHOR]

The one-dimensional problem of evaluating the stress-strain state of a freezing layer of clayey soil by analytical methods is stated and solved with consideration of its linear deformability and creep. Problems of interaction between a cylinder formed from a freezing clayey soil of unit thickness and a rigid constraining element (ring) and a cylindrical body of finite stiffness (pile) are examined in the elastic statement. [ABSTRACT FROM AUTHOR]

In Dzagov's study under discussion [], he views one of the causes of noncorrespondence between computed and actual slump-type settlements to be overestimation of the limiting value adopted in standards for the relative slump-type settlement ε = 0.01, which when equaled or exceeded, the soils are referred to as prone to slump-type settlement. In our opinion, the basic cause lies in the overly simplified model constructed for slump-type settlement, which has been adopted in regulatory documents. The problem of the proneness to slump-type settlement and slump-type settlements should be resolved in a threedimensional statement as a consequence of failures due to loss of soil strength. Mr. Dzagov's suggestion to exclude the initial slump-settlement pressure psl as conditional and of no physical significance is put forth for support. The need to account for the effect of a temperature increase of the water wetting the soil, which contributes to an increase in slump-type settlement, is also correctly stated in []. In our view, the remaining suggestions are debatable. [ABSTRACT FROM AUTHOR]

Laboratory-derived dependencies of the change in grain-size distribution, water properties, density, and equivalent cohesion of frozen morainic clayey loam on the number of freeze-thaw cycles are presented. [ABSTRACT FROM AUTHOR]

The upper-Jurassic soils of Moscow, which are frequently the bed and medium on which underground structures and deep pits are installed, are examined. Archival materials derived from surveys are statistically processed using the theory of correlation-regression analysis, and correlation relations between the compression modulus based on plate-test data and the physical parameters and specific resistance of the soil under the tip of the probe are investigated during static probing. Factors for conversion from the compression modulus of the soils examined to the compression modulus as determined by a plate are obtained. [ABSTRACT FROM AUTHOR]