Influence of the crushed stone content on the deformation modulus of the soil-crushed stone layer

Abstract

Introduction. The purpose of the article is to study the dependence of the deformation modulus of the soil-crushed stone layer of the road surface from the content of crushed stone in the soil-crushed stone mixture and the soil moisture in it. The goal was achieved by performing stamp tests of the models of a road clothing and a roadbed.Materials and methods. The research was carried out by performing stamp tests of models of the roadbed and single-layer road clothes with a soil-crushed stone surface. Before the stamp tests, laboratory work were carried out to determine the parameters subject to input control for crushed stone and soil. Models of road clothes are built from crushed stone materials and soil in the tray. Tests of the roadbed and road clothes are carried out using a rigid round stamp included in the standard kit.Results. The modules of deformation of the soil of the roadbed and road surfaces with a soil-crushed stone layer are calculated from the polynomial dependence of settlement on pressure, regulated by ПНСТ 311-2018. According to the test results, the modulus of deformation of the soil of the roadbed, and the general modulus of deformation on the surface of the soil-crushed stone layer, with different content of crushed stone by the volume of the mixture, were determined. The lowest value of the deformation modulus corresponds to the minimum content of crushed stone in the mixture, which is 40 % by volume of the mixture. The highest value of the deformation modulus was obtained at the maximum content of crushed stone in the mixture, which is 60 % by volume of the mixture. Using the general modules of deformation of different road surfaces and the modules of deformation of the soil of the roadbed, the calculation of the deformation modulus of the soil-crushed stone layer with different content of crushed stone in it is performed. To take into account the influence of moisture of the cohesive soil used in the mixture, correction coefficients are given, the values of which are established by laboratory tests. These coefficients allow us to calculate the modulus of deformation of the soil-crushed stone layer depending on the content of crushed stone and the moisture of the soil used in it.Discussion and conclusions. As a result of experimental work, the modules of deformation of soil-crushed stone of different compositions were determined, with the help of which the design of road surfaces was carried out with the subsequent construction of experimental sites in each of the three road building climatic zones of the Omsk region.