Karim Sultanovich Sultanov

• PhD; DSc; Prof.
• Professor (Full) at Uzbekistan Academy of Sciences

The interaction between a semi-infinite underground pipeline and the surrounding soil during longitudinal seismic wave propagation is examined in the article. The wave travels through the soil with its front perpendicular to the pipeline's axis, and the nonlinear laws of interaction (friction) on the surface of their contact, including the Amonton-...

At present, worldwide, underground pipelines are strategic objects of life support for the population and industry (gas and oil pipelines, water lines, etc.). Therefore, ensuring their strength and stability, guaranteeing their uninterrupted operation is an urgent problem of our time. To solve this problem, first, it is necessary to have a reliable...

The study is devoted to the dynamic problems of the deformed state of earth dams under seismic influences. A method for solving wave problems was developed to determine the stress-strain state of earth structures, in particular, earth dams. Using the method of finite differences, an algorithm for solving problems and calculation formulas was develo...

The strength of textile yarns is of paramount importance to obtain high-quality materials and products. The yarn breakage in the technological processes of textile production significantly affects the quality of the products. In modern technological processes, the yarn velocity is increasing and its breakage is growing. To prevent or reduce breakag...

Nonlinear laws of interaction of underground pipelines with soil are considered, based on linear-elastic, visco-elastic laws of shear strain in soils, and Coulomb’s law. Mathematical expressions are derived that relate the parameters of interaction to the strength characteristics of soil under shear, which allows them to be used in calculations for...

Wave propagation in an elastic cylindrical body interacting with an external moving absolutely non-deformable medium (a cage) under a shock load on the front end is considered. The friction force arising on the contact surface directly depends on the parameters of the propagating waves and, due to the external medium motion, - it is active. The sta...

Featured Application Main gas and oil pipelines are critical elements of the world’s infrastructure. The integrity of pipelines during earthquakes is a subject of intensive research. At present, underground pipelines’ strength to the effect of seismic loads (seismic resistance) is calculated incorrectly. The existing methods do not consider seismic...

Рассматривается распространение волн в упругом цилиндрическом теле, взаимодействующем с внешней движущейся абсолютно недеформируемой средой (обоймой) при ударной нагрузке на передний торец. Сила трения, возникающая на контактной поверхности, прямо зависит от параметров распространяющихся волн и в силу движения внешней среды - она является активной....

One of the main reasons for the nonlinearity of the tension diagrams of cotton yarns is the variability of their moduli of elasticity and plasticity under strain. The changes in strain moduli obtained from the tensile diagrams confirm this. The strain curve has ten parameters, the values of which depend on the method of yarn manufacture and the str...

Our results on the strength parameters of cotton yarns manufactured by carded and combed systems by ring and rotor spinning (CD-carded ring-spun, OE-carded rotor-spun, CM-combed ring-spun) are presented. Experiments to test yarns for strength were conducted on a “Statimat C” tensile installation at speeds of the lower end of the yarn from 100 mm/mi...

The unsteady-state axisymmetric problem of longitudinal interaction of a cylindrical body with external elastic medium is considered in the paper. The condition of Coulomb friction is accepted at the contact boundary. The solution is implemented by the finite difference method. The results are shown in graphs and analyzed. The changes in stress, ve...

Based on existing data of experimental studies of underground structure-soil interaction, a condition for boundary interaction between the underground pipeline and soil was developed. The proposed condition (a model) of interaction at the contact boundary takes into account the structural destruction of the contact soil layer and the cyclical natur...

The results of numerical solutions of an axisymmetric two-dimensional problem of a rigid underground pipeline interaction with elastic-viscous-plastic soil are presented. The pipe-soil interaction begins when the underground pipeline moves in an axial (longitudinal) direction. The changes in velocity, displacement, shear stress, shear strains in th...

This paper is devoted to the development of a method for determining longitudinal stresses in underground pipelines under periodic dynamic load, taking into account the complex process of pipe-soil interaction. The method is based on the solution of a two-dimensional axisymmetric unsteady wave problem for the “underground pipeline-soil” system. In...

The paper presents the results of numerical solution obtained by the modified finite difference method according to the Wilkins scheme, to a two-dimensional unsteady-state problem of the plane shock wave propagation in an underground elastic pipeline, interacting with surrounding soil. Soil is considered to be an undeformable body moving relative t...

A two-dimensional axisymmetric problem of shear wave propagation around an underground pipeline under longitudinal motion of the pipeline is solved numerically. Due to the significant difference in pipeline and soil rigidity, the underground pipeline is considered to be a rigid undeformable body and the soil medium around the pipeline is modeled by...

The problem of longitudinal wave propagation in a cylindrical body in the presence of an incompressible external medium in a length limited area is solved in the paper in a one-dimensional statement. Along with the non-uniformity of motion, the friction force arising on the contact surface directly depends on the parameters of propagating waves. Nu...

The monograph is devoted to experimental and theoretical study of rigid body interaction with soil. Based on experimental results the local laws of interaction of long underground pipelines and fragments of external surface of large-scale underground structures with soil of disturbed and undisturbed structure are built. Numeric solutions of the pro...

Te monograph is devoted to the construction of the laws of strain in textile yarns (coton yarns) under tension, taking into account their nonlinear strain and structural changes. Te monograph gives a parametric analysis of the constructed law of nonlinear strain of coton yarn; the main parameters of the law and their changes are determined dependin...

The results of laboratory experiments on the dynamic compression of loess soil samples at a falling weight deflectometer (FWD) are presented. From the results of the experiments, preliminary values of the mechanical characteristics of soils are determined. A numerical solution of the wave problem, the statement of which is identical to the experime...

Mechanical characteristics of soils under dynamic and static loads are determined in laboratory conditions on special devices. Dynamic loads in the devices are initiated by an impact on a soil sample. Under the impact the waves are initiated in soil; they significantly affect the stress-strain state of soil samples placed in the device. Depending o...

The experimental diagrams between stress and strain components for soft soils are non-linear. Nonlinear diagrams qualitatively differ for soils of undisturbed and disturbed structures. It is believed that the manifestations of nonlinear properties of soil are associated with micro-destruction of soil structure under compression and, therefore, with...

Topical issues of textile yarn breakage in technological processes are considered in the paper. Based on a comparative analysis of cotton yarns specific breaking load with cotton fibre specific breaking load obtained in experiments, it was concluded that when the yarn breaks, the cotton fibres do not. This conclusion contradicts hypothesis of Aleks...

The idea that mathematical simulation of the process of textile yarn stretching which reveals new features of its destruction in technological processes is substantiated in the paper. Mathematical model should take into account textile yarn motion velocity in technological processes, acting external forces, and the reliable law of yarn strain under...

The method to define strain characteristics of soil under dynamic loading is proposed based on the results of experiments on dynamic compression of soils on the device for dynamic loading in laboratory conditions; the method allows solving wave problems with the statement similar to the statement of experiments. Using the proposed method, the modul...

Based on the physically nonlinear law of deformation under tension, a formula for determining and predicting the strength of cotton yarn is proposed. © 2018 Ivanovo State University of Chemistry and Technology. All rights reserved.

Nonlinear relations based on Winkler-like and Coulomb laws are proposed to describe the process of shear interaction between structures and soil. Their advantages and shortcomings are illustrated, along with the suitability of experimental results.

The existence of a soil contact layer when there is shear interaction between a rigid body and the soil has been demonstrated by an analysis of the numerical solution of a one-dimensional unsteady problem on the interaction of a rigid strip with a non-linearly deformable soil medium. The occurrence of a peak value of the shear stress and subsequent...

On the basis of results of experiments on stretching of a cotton yarn nonlinear dependences of the stretching force on longitudinal deformation of a thread are received. It is assumed that change of mechanical characteristics of a yarn is the reason of manifestation of nonlinear deformation of a cotton yarn at stretching and changes of the module o...

On the basis of results of experiments the nonlinear elastic and visco-plastic model of deformation of cotton yarn at stretching is constructed and adequacy to the received model to skilled data is shown.

We present the results of quasistatic extension tests for a cotton thread until break. The obtained nonlinear dependence of the tensile force on the thread strain in elongation are used to construct the laws of nonlinear deformation of cotton threads treated as composite materials. To determine the parameters of the developed nonlinear deformation...

The results of numerical solution of the nonstationary wave problem of longitudinal wave propagation in the bar-soil system are given. The barmaterial and the soil are assumed to be linearly viscoelastic (standard linear body). A nonlinear interaction condition is satisfied on the bar-soil contact boundary. The laws of propagation of longitudinal w...

There are considered the aspects of stability of Muruntau open pit edges and complex of high-angle conveyor KNK-270 during the interconnection of possible seismic loads and dynamic loads, which appear in the conditions of mining operations in open pit. The basic characteristics of dynamic loads were defined on the basis of obtained records of detec...

Some mechanisms by which longitudinal waves are attenuated in non-linear viscoelastic media, whose equation of state takes into account the presence of structural changes, are demonstrated. It is shown that the degree of attenuation of a longitudinal wave in such media is a linear function of the frequency.

Results are presented for numerical solutions of the nonunidimensional problem of determining the slump-type deformations of a soil mass subject to uniform wetting. An equation that we developed for the state of the soil, which accounts for variation in the stress-strain state as the soil is wetted, is used here. Results of calculations are compare...

A structural material change (failure) in deformation is the considerable factor which should be taken into account in the state equations. Some longitudinal waves damping mechanisms are demonstrated in nonlinear viscoelastic media with the state equation accounting for the presence of structural changes. It is shown that the longitudinal wave damp...

Equations of state of soils prone to slump-type settlement, which take into account the degree of wetting in the initial stage, are developed on the basis of familiar models of the deformation of continua. Moreover, parameters characterizing the strength characteristics (indicators) of the soils are treated as functions dependent on degree of wetti...

Using a model of an elastic and viscoelastic (standard-linear) solid, a non-linear equation of state is constructed to model the volume deformation of soft soils. The moduli of bulk compression are assumed to be non-linear functions of a parameter which characterizes the structural failure of the soil. It is shown that this law describes observed e...

Experimental studies have established that the shear interaction of underground structures with soil is influenced by the physicomechanical properties of the soil, the roughness of the structure-soil contact surface, the contact pressure normal to the surface, and the rate of relative displacement (shear). Thus, the laws governing the interaction o...

Mathematical model for soil-structure interaction is built on the basis of experimental studies of underground structure fragment - soil interaction. The model shows that tangential stress dependence relative displacement on underground structure - soil local surface is function of normal pressure to contact surface, relative displacement, undergro...

Studies of the interaction between seismic blast waves and underground structures are conducted to select boundary conditions on the contact surface between these structures and the soil. In relation to this, a law governing longitudinal interaction between an elongated underground structure and the soil which, among other things, combines conditio...

The stresses and the particle velocities in the soil, the loading at the obstacle, and its displacement were investigated earlier in experimental investigations of the interaction of explosion waves with obstacles [1–4]. Below we present the results of experimental investigation involving simultaneous measurement of stresses and strains of soil dur...