Problems of the mechanics of collapsible soils and methods of solving them

Mustafaev, A. A.

doi:10.1007/bf01707264

Cited by 3 publications

(15 citation statements)

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“…One of the most common structurally unstable soils in Uzbekistan is loess soil. Loess soils, when exposed to water, significantly lose their strength characteristics, physical and mechanical properties, and change their original structure [1][2][3][4][5][6][7][8][9]. These changes in soil are referred to as subsidence.…”

Section: Introductionmentioning

confidence: 99%

“…Studies given in [1][2][3][4][5][6][10][11][12][13][14][15][16][17][18] have made a great contribution to the development of construction on loess soils. These studies are mainly experimental and theoretical in nature, revealing the physical essence of the mechanism of the phenomenon of subsidence and its behavior.…”

Section: Introductionmentioning

confidence: 99%

“…Despite a certain success in the field of foundation engineering on these soils, the calculation models of soil settlements have not been developed and the possibility of a reliable description of the stress-strain state of these soils by methods of continuum mechanics has not been stated. The calculation methods currently used in the theory of subsidence, based on the so-called semi-empirical theories, are not universal [3][4]10]. Determinant values for the study of the processes of subsidence are the results of a direct experiment.…”

Section: Introductionmentioning

confidence: 99%

“…According to [4] and from the results obtained in [12][13][14][15][16][17][18], it follows that there is not even a rigorous formulation of this problem, the solution to which is necessary to form a special section in soil mechanics with the involvement of the mathematical apparatus of mechanics of a continuous deformable medium. The existing methods for calculating the stress-strain state of loess soil massif are based on the principle of linear deformability, based on the theory of elasticity and creep [3][4][5][6][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

“…According to the results of experimental studies [3][4], it was revealed that the process of increment of subsidence deformation of loess soils under constant load and with increasing moisture content is similar to the deformation of a continuous medium subjected to temperature effects. With this assumption, a theory of thermal-moisture analogy (moisture elasticity) was developed by Ter-Martirosyan Z.G.…”

Section: Introductionmentioning

confidence: 99%

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Numeric Simulation of Subsidence of Loess Soil under Wetting in a Limited Area

Khusanov Bakhtiyar,

Rikhsieva Barno

2023

ARFMTS

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Loess and loess-like soils, when exposed to water, lose their strength characteristics, and physical and mechanical properties and change their original structure. The stress-strain state is transformed in these soils when wetted. Therefore, the problem of building on loess soils and studying the mechanisms of subsidence of loess soils is relevant. In this article, we consider the problem of determining the subsidence and stress state of the loess soil stratum under its own weight on a limited wetted area. To determine the distribution of water in soil, the method of changing stationary states is used, and to determine the subsidence and stress state, the finite difference method is used. The initial conditions are obtained by solving problems for the natural wetting of the layers of loess soil. The numerical results obtained of the subsidence of the free surface of the layer of loess soil 40 m thick agree well with experimental data on the duration of wetting at a limited size of the source of water. The effect of the duration and moisture content on the process of subsidence and transformation of the stress state are determined. An increase in the size of the water source in soil led to an increase in the high moisture content of the area and an increase in the subsidence of the free surface of loess soil.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numeric Simulation of Subsidence of Loess Soil under Wetting in a Limited Area

Khusanov Bakhtiyar,

Rikhsieva Barno

2023

ARFMTS

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Influence of Pressure and Water Content on Loess Collapsibility of the Xixian New Area in Shaanxi Province, China

Wang¹,

Ma²,

Guo³

et al. 2017

Earth sci. res. j.

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More than 40% area of the Xixian New Area is a loess deposit region, and most of the loess landform is tableland and terrace where the thickness of loess is considerable large. Therefore, loess collapsibility will be the most important geotechnical problem in future foundation investigation and construction. To explore loess collapsibility in the Xixian New Area, we conducted the K0 compression test, based on the collapsibility mechanism, which has different combinations of pressure (0~1.2 MPa) and water content (4%~Sat). Based on the σ-ε curve under different water content, we calculated the generalized collapse settlement and collapsibility coefficient of every water content under every pressure by subtracting the relevant curve from the saturated curve and analyzed the cross action of pressure and water on loess compressibility. The results show that the average collapsibility level of the northern Xixian New Area is self-weight collapsible level II, with a lower limit of 14 m. The compressibility of loess is proportional to pressure and water content. Under low water content, the collapsibility coefficient δs increased while the pressure increased, but under medium and high water content, δs will reach a peak with increasing pressure and after that, δs will decrease until its value is close to constant. When under the same pressure, δs decreases when water content increases. If set the additional strain 1.5% as collapse start criterion, then the first collapse pressure Pi will linear proportional to water content. The initial collapse water content wi will increase sharply when pressure raises under low pressure, but wi will reach a constant value of 26% when pressure is more than 200 kPa. This consequence will be meaningful for future geotechnical investigation and design in the Xixian New Area. Para estimar la colapsabilidad en Xixian se realizó el test de compresión (K 0 ), de acuerdo con el mecanismo de colapsabilidad, con diferentes combinaciones de presión (0~1.2 MPa) y contenido de agua (4%~Sat). Basado en la curva σ-ε con diferentes contenidos de agua se calcularon los coeficientes de asentamiento y colapsabilidad a partir de substracción de la curva en condiciones de saturación y analizando los efectos de presión y contenido de agua. Los resultados muestran que el promedio de colapsabilidad por su propio peso para el área de Xixian es de nivel II, con un límite bajo de hasta 14 m. La compresibilidad de loess es proporcional a la presión y al contenido de agua. Con un bajo contenido de agua, el coeficiente de colapsabilidad (δ s ) se incrementó mientras la presión se aumentó; pero, con contenidos medios y altos de agua, el coeficiente de colapsabilidad alcanzó su pico con el incremento de la presión, y luego bajó para prácticamente estabilizarse. Bajo presión constante, la colapsabilidad descendió al aumentar el contenido de agua. Si se asume como criterio inicial de colapso (Pi) una deformación adicional de 1.5%, Pi es linealmente proporcional al contenido de agua. El contenido de agua inicial de co...

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Comparative research on lower bound depth of collapse loess

Wu¹,

Chu²,

Wang³

2016

Proceedings of the Institution of Civil Engineers - Geotechnica

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The lower bound depth of the self-weight collapse of loess is used to determine the type and grade of a collapsible loess foundation. It is important to select a reasonable foundation treatment depth and to determine negative skin friction neutral points of the pile. This study comprehensively analyses the differences between laboratory and full-scale field testing in determining the lower bound depth of the self-weight collapse of loess. Although this lower bound depth tends to be a unique value, obvious differences were obtained in the test results obtained by the two methods. Generally, the laboratory test results were 1·25–2·90 times greater than those of the field test, mainly owing to differences in saturation, test pressure, the sample stress state and soil non-uniformity. Evaluation of the lower bound depth of the self-weight collapse of loess should therefore be based on field testing and the results from laboratory tests need to be modified. This paper puts forward a new theoretical modification method for this purpose, which could reduce the differences between laboratory and field test results.

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Problems of the mechanics of collapsible soils and methods of solving them

Cited by 3 publications

References 1 publication

Numeric Simulation of Subsidence of Loess Soil under Wetting in a Limited Area

Numeric Simulation of Subsidence of Loess Soil under Wetting in a Limited Area

Influence of Pressure and Water Content on Loess Collapsibility of the Xixian New Area in Shaanxi Province, China

Comparative research on lower bound depth of collapse loess

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