Analysis of Laboratory Test Results of Elastic Properties of Soil Cement

Abstract

Purpose. The authors set the goal of determining the principles of the concept of reverse conversion to substantiate the use of underground metro structures as shelters for critical infrastructure facilities. Methodology. The laboratory test program consisted of obtaining the characteristics of soil cement and analyzing the results obtained in the case of use as a railway track base. During construction work, soil cement samples were taken. After selection, the samples were cut with special equipment, and the cut points were ground to ensure full contact with the press plates. After the soil cement samples were placed in the compaction device under a load of 0.03 MPa and left under this load for 72 hours. The loading of the samples was carried out in stages with a holding time of at least 5 minutes until stabilization. The tests were processed, analyzed and considered within the framework of the analysis of elastic properties. Findings. When the pressure reached 1.12 MPa, the sample was kept for 30 minutes, the settlement was 0.093 mm. After that, unloading was carried out in stages to a pressure of 0.03 MPa with stabilization of each stage. Analysis of the constructed graph shows that the residual deformation is 0.03 mm, and the total at a pressure of 1.12 MPa is 0.093 mm. Analysis of the graph shows the creation of a hysteresis loop, which characterizes the operation of soil cement in the elastic mode. At the same time, the deformation modulus E at different loading stages is in the range of 560…750 MPa. Soil cement demonstrates stable elastic properties, which makes it an effective material for use in civil, industrial and railway construction. Originality. The article, based on the results of laboratory tests of soil cement, finally proves its high elastic properties under the action of cyclic loads, which simulate the action of the rail-sleeper grid on the ballast and the railway subgrade. Practical value lies in obtaining the values ​​of the modulus of elasticity of soil cement, which can be further used for practical calculations of predicting the settlements of soil bases.