Changes in the thermophysical and mechanical properties of blocked soils during compaction and the promotion

Introduction. It is known that flooded, blocked soils prevail in the North of Russia and in the territory of its Arctic zone. Such soils have a low bearing capacity, which reduces the possibility of their use in the construction of winter roads. Compaction (crimping) of blocked soils changes their thermophysical and physico-mechanical properties by changing the modes of freezing and thawing of weak bases, as well as the bearing capacity of overland winter trucks in wetlands. The article reflects the results of experimental studies of changes in the thermophysical and physico-mechanical parameters of the blocked soil at different degrees of its compaction.

Methods and materials. Low-moisture soil with a high content of organic matter (peat) of more than 50% was used for research. It was compacted with loads, the magnitude of which is typical for sealing (crimping) operations of weak blocked bases on autosomes (0.01, 0.03 and 0.06 MPa), and frozen in a chamber to a temperature of -15 °C. Temperature control was carried out at different depths at predetermined intervals. To do this, we put together a device, the main elements of which are DS18B20 brand thermal sensors and an Arduino Nano microcontroller. The thermal conductivity of thawed and frozen soil was determined using the MIT-1 probe device. A dynamic density meter D-51 was used to determine the strength (hardness) of the samplesand the universal penetrometer PUS-3M.

Results. The properties of the studied organic soil have been clarified. The heat capacity of this soil is determined depending on its humidity, temperature and density. The influence of the degree of soil compaction on the kinetics of its freezing is estimated. The results of the study of the dependence of the conditional strength (hardness) of the soil at different temperatures and densities, as well as the results of the interpretation of the results of dynamic zonation and the modulus of elasticity for the studied blocked soil are presented.

Conclusion. Compaction (crimping) of the blocked soil increases its thermal conductivity and the rate of freezing of the upper layer of the swamp, which helps to accelerate the commissioning of the winter truck. Compaction (crimping) of the blocked soil significantly increases its strength during freezing, which determines an increase in the bearing capacity of autozymers in swamps. The most promising use for operational control of the density and strength of a frozen peat slab on autozymers is dynamic sensing methods with penetrometers of various designs. The results of determining the conditional strength index (hardness) of peat soil using probing with a dynamic density meter and a universal penetrometer are obtained.

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