Analysis of variables affecting the change in the coefficient of clay soils’ moisture conductivity

Abstract

The paper analyzes studies to determine the coefficient of soil moisture conductivity, conducted by various authors, while it is established that the humidity and density of clay soil have a significant impact on its value. Methods for determining soil moisture conductivity are considered. The study’s purpose is stated, which consists in establishing the influence of variables on the change in the coefficient of clay soil moisture conductivity used for the construction of the earth roadbed in Western Siberia. The article considers the key issues of preparing and conducting the experimental part of the study. To set up the experiment, a full factorial experiment model of second-order rotatable planning was chosen. For the experiment, the soil was selected, the selection of which was made from the working layer of the Tobolsk — Tara — Tomsk highway earth roadbed at the Tara — Sedelnikovo section in the Omsk region. The authors conducted obtained research results processing by mathematical statistics methods. It has been established that the moisture conductivity values and the moisture flow intensity are slightly affected by the variable «initial humidity», the variables «mass of water, soil density, water level, total moisture capacity, moistening time» have the greatest influence. The factor analysis of the obtained results showed that the test procedure for determining the coefficient of moisture conductivity according to Sectoral Highway Regulations 218.046-01 in the PKFG-F device evaluates the moisture transfer in the soil of capillary moisture with the effect of water column pressure. The studies carried out in the work indicate a noticeable influence of the variable «mass of water» and a slight influence of the variable «initial moisture», which may indicate that the film mechanism of moisture migration is not taken into account when testing the soil under study in the PKVG-Futurum device. The article was written based on the author’s dissertation research on the topic “Justification of the regional calculated values of the clay soils characteristics for the pavement design in Western Siberia” (Siberian Transport University, Novosibirsk, 2017) in terms of using the experiment results to determine the moisture conductivity coefficient.