COMPACTION OF LINEAR ELASTIC-CREEPING INHOMOGENEOUS SOILS

В данной работе рассмотрен процесс уплотнения линейных упругоползучих неоднородных грунтов. Областью изменения независимых переменных является прямоугольник, образованный прямыми х=±ℓ; y=0; y=h. Уплотнение этого прямоугольника безусловно определяется своей сжимаемостью. Сжимаемость основания зависит как от типа грунта, так и от характера нагрузки. При этом деформация сжатия грунтов в основном происходит вследствие сближения твердых частиц между собой и оценивается изменением коэффициента пористости при изменении сжимающих напряжений в скелете грунта. Определение этой зависимости обычно производится лабораторным путем в компрессионных приборах. In this paper, the process of compaction of linear elastic-creeping inhomogeneous soils is considered. The domain of change of independent variables is a rectangle formed by straight lines x = ±l; y = 0; y = h. the Compaction of this rectangle is unconditionally determined by its compressibility. Compressibility of the base depends on both the type of soil and the nature of the load. In this case, the deformation of soil compression mainly occurs due to the convergence of solid particles with each other and is estimated by changing the porosity coefficient when compressive stresses in the soil skeleton change. The determination of this dependence is usually made by laboratory means in compression devices.

THE EFFECT OF TEMPERATURE ON THE ENGINEERING PROPERTIES CONSOLIDATION BEHAVIORS OF SOFT SOIL

Research on soil behavior due to changes in heat temperature in the soil mass is still relatively small. Even though, the phenomenon of increasing temperature in the soil mass is frequently occured. For example, there is an increase in temperature in the ground besides the problem of heat propagation under the road due to land fires, as well as the presence of waste heat from nuclear power plant in the soil medium, the operation of electric cables in the ground which causes heat, and the gas pipelines and oil pipes embedded in the ground, which generates heat around it, as well as thermal energy storage that are embedded in the soil. This research was conducted to get answers to how the behavior of the curve of the clay soft soil consolidation is due to changes in temperature. Mainly to get knowledge about the effect of temperature on changes in the value of mechanical parameters of soil consolidation, such as clay soft soil compression index (Cc), swelling index (Cs), volume change coefficient (mv), coefficient of consolidation (Cv), and hydraulic conductivity (k) of clay soft soil. In conducting the research, the material used was clay soft soil in undisturbed condition originating from a swampland locating in South Kalimantan, Indonesia, while the main tool used was a modified consolidation test device by adding an artificial heating device whose temperature could be adjusted with a temperature control device and temperature sensor. The temperatures applied to the test specimens were 40oC, 60oC 75oC, and 85oC. The results showed that changes in temperature in the soil could affect the compressibility of the soil, where the higher the temperature (heat) of the soil, the greater the soil compressibility. The increase in temperature in the soil causes an increase in the value of soil compressibility parameters such as the soil compression index (Cc), the coefficient of consolidation (Cv), and the swelling index (Cs). The value of compression index (Cc) of clay soft soils has a greater increase than the increase in other compressibility parameters when the temperature of clay soft soil increases (hot). In addition, the presence of high soil temperatures (hot conditions) in the soil can reduce changes in soil volume, where the volume change coefficient (mv) of clay soft soil tends to decrease if the soil temperature increases. Changes in soil temperature also affect soil permeability, where the seepage properties of clay soft soil tend to increase along with an increase in temperature in the soil.

Bearing capacity of piles in a reinforced by pressure cementation soil massif

Studies of the piles bearing capacity after strengthening soil by cement mortar pressure injection were carried out to determine pile foundations bearing capacity increasing patterns in a result of soils cementation. Depending from the volume and cement mortar technological injection parameters, the soil stress state around the pile changes, additional pile-soil compression occurs and the friction along the lateral surface increase, as well as the soil resistance under the pile bottom end. Cementation effect on the pile bearing capacity for different injectors location and the number of piles in the foundation were determined by tests. The research results can be used in the pile foundations reinforcement design in conditions of reconstruction with increasing loads on the foundations.

Tests of Soils on Triaxial Device

The paper briefly describes the methods for testing soils by triaxial compression. Among the many mechanical characteristics of the soil, deformation and strength properties remain as the main and widely used ones, the determination of which is an important experimental task. In recent years, new test schemes, more advanced designs of instruments and equipment for the study of various soils have been proposed. Like any material, the soil has limited strength, and under certain external influences the soil massifs collapse, as a result of which their individual parts get unlimitedly large displacements. Triaxial soil compression is becoming more widespread in the production of engineering and geological studies to justify the construction projects of various engineering structures. Based on the results of this work, recommendations for the practical application of the obtained soil characteristics for the geotechnical geoinformational database of the city of Nur-Sultan are made.