Influence of the effect of crumpling of clay soils in compression tests on the determination of the subsidence of the base

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Oleksandr Piatkov
Veronika Zhuk
Olha Poliukhovych

Abstract

The effect of "compression error" - the effect of crumpling samples of dusty clay soils in compression tests - has been investigated experimentally.


For this purpose, compression tests of sands and loams were carried out on a special compression device with a ring area A = 360 cm2 and a height hk = 7 cm.


The second difference of this device is the presence in the upper stamp of holes with a diameter of up to 5 mm for the installation of screw marks, which were placed in clay soil samples at a distance of up to 5 mm from the contact surface between the stamp and the soil.


The modulus of deformation is the main deformation mechanical characteristic of the soil. It is known from practice that more reliable values of this characteristic can be obtained by testing soil bases with stamps in the field. However, when designing the foundations of shallow foundation, as a rule, apply odometric tests of soils in the laboratory on standard compression devices with a ring area of 60 cm2 and a height of hk = 25 mm by the method of 2 curves [6]. To obtain the calculated values, the compression modules are corrected using transient coefficients [7, 4].


And most importantly, when determining the values of odometric laboratory modules, using standard compression devices, the result is affected by the "compression error". That is, the initial data for the calculated modules of deformation of the engineering-geological elements of the base can be significantly underestimated, which has been confirmed many times by complex pair (stamp-odometer) studies of soils under compression.


Studies of soil compression in compression conditions, conducted in the laboratory of foundations and foundations of KNUBA [2] prove the possibility of improving the results of odometric tests of soils for compression, bringing them closer to the strain.


 

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Author Biographies

Oleksandr Piatkov, Kyiv National University of Construction and Architecture

Associate Professor of the Department of Geotechnics, Ph.D., Associate Professor

 

Veronika Zhuk, Kyiv National University of Construction and Architecture

Associate Professor of the Department of Geotechnics, Ph.D., Associate Professor

 

Olha Poliukhovych, Kyiv National University of Construction and Architecture

Master of the Department of Geotechnics

 

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