POSSIBILITY OF APPLICATION OF О. SHASHENKO’S CRITERION TO THE FORECAST OF STRENGTH OF SANDY LOAM SOILS

Abstract

Purpose. Experimental dependences "destructive tangential stress – vertical load" has the form of a curvilinear line, which is sometimes called the Coulomb – Mohr envelope. In this case, the Coulomb – Mohr strength criterion gives a value of the destructive tangential stress other than zero, which, in turn, leads to an overestimation of the holding forces when calculating the stability and strength of soil foundations and structures. The analysis showed that the problem of considering physical nonlinearity of the strength properties of clay soils is relevant, and one of the ways to solve it is to use the well-known in the mechanics of soil strength O. Shashenko’s criterion. The purpose of the scientific article is the following – according to the known experimental results of consolidated – drained tests of sandy loam soil in the device of single-plane shear, it is necessary: to perform approximation of experimental data using linear dependence (Coulomb – Mohr strength criterion) and nonlinear dependence (O. Shashenko’s strength criterion); to estimate the accuracy of the approximation using the relative standard error and to extrapolate the approximation results to the region of low pressures. Methodology. According to the relevant recommendations, the properties of soils and their classification were determined. Also, according to the recommendations, the strength of the soil at its natural moisture and when water-saturated were determined. The obtained results are presented in tabular form. Material constants that are included in the Coulomb – Mohr and O. Shashenko’s criteria were determined. The conformity of the strength criteria to the experimental data was evaluated, and extrapolation of these criteria in the field of low pressures was performed. Results. In the field of change of experimental data, the dependence "destructive load – vertical pressure on the soil", established within O. Shashenko’s criterion of strength, has a better fit of the experiment than a similar dependence on the criterion of Coulomb – Mohr. The criterion of soil strength proposed by O. Shashenko can be used to predict the strength of sandy soils. Scientific novelty. Approximation of experimental results of consolidated-drained tests of sandy soil in the device of single-plane shear using the strength criteria of Coulomb – Mohr and O. Shashenko is performed. Practical value. A comparative analysis of the results is carried out and the use of O. Shashenko’s strength criterion for forecasting the strength of sandy soils is substantiated.