Сomparative analysis of methods for calculating stamp modules of soil deformation

Abstract

Introduction. The purpose of the article is a comparative analysis of methods for calculating stamp modules of soil deformation regulated by various standards of the Russian Federation.Materials and methods. The experimental determination of the deformation modules for the soil of the roadbed was performed using stamp tests. The tests were carried out in a soil tray by loading and unloading a soil base compacted to the required compaction coefficient of 0.98. The load was applied by steps, and the stamp draft was measured after completion of deformation stabilization from each step. The criterion for stabilizing the deformation was a decrease in the speed to 0.02 mm / min and the time of application of the load, which should be at least 120 s. After measuring the elasto-plastic draft of the soil, the model was unloaded. Unloading is also carried out by steps. As a result, the dependences of the elasto-plastic and elastic draft of the soil model of the roadbed from the pressure in the form of hysteresis loops are constructed.Results. The calculations of the soil deformation modulus were performed according to the various methods regulated by the standards of the Russian Federation. The calculation results are grouped into data samples that are processed by mathematical statistics methods. When processing data, each sample is checked for the presence of gross errors. The data samples are checked for belonging to one general population. To check whether three samples belong to one general population, the Kruskal W. H. and Wallis W. A. criterion was applied. Based on this comparison, we made judgments about the significance of differences in the samples.Discussion and conclusions. To determine the deformation modulus of soil and road pavements made of granular materials, a method for calculating the modulus of deformation using a method that assumes a nonlinear dependence of deformations on pressures, described by a second-degree polynomial is recommended.