Shear Resistance of Gravel Materials for Structural Layers of Road Clothes

Abstract

Statement of the problem. The normative method for calculating the pavement of a road with low traffic intensity is based on two strength criteria which include checking the thickness of the pavement according to the general modulus of deformation and accumulated residual deformation of the surface of the coa-ting. Both calculation criteria assume the use of linear dependencies linking the precipitation with the pressure. It is known that the linear dependence of the precipitation on the pressure is possible only when the load does not exceed the first critical load of N. M. Gersevanov, at which a limiting state occurs at the most dangerous point of the soil mass according to the Mohr-Coulomb criterion. Thus, the necessity of calculating the pavement by shear resistance has been established. This implies the relevance of the work aimed at determining the adhesion and the angle of internal friction for materials and industrial waste that are not controlled by the regulatory documents of the Russian Federation. Results. The parameters of the limiting Coulomb straight line (coupling and angle of internal friction) of the gravel mix compacted to the requirements for the structural layers of road paving were determined. In solving this problem, the justification for the application of triaxial tests according to the consolidated untrained (CN) test scheme was carried out. The method of ramming a cylindrical sample in a small device of standard sealing equipped with two extension nozzles has been developed. The statistical processing of the test results was carried out and the calculated values of the adhesion and the angle of internal friction of the gravel mixture were established at a humidity of 0.72 of the moisture content of the loamy soil binding crushed stone at the yield boundary. Conclusions. The results make it possible to more reasonably calculate the thickness of the structural layer of a dirt-gravel mix of lower-type road clothes for roads with a low traffic intensity. The results of the work were implemented by designing lower-type road clothes for pilot construction in the conditions of the II, III and IV road-climatic zones of the Omsk region.