Method for Estimating Tensile Stresses and Elastic Modulus of Frozen Soil with Evolving Crack

Abstract

Strength characteristics and Young’s modulus of frozen soil are necessary for the analysis of many engineering problems. However, a number of issues in this area remain relevant. The purpose of this work: the development of a technique for indirect determination of tensile stresses and modulus of elasticity of frozen soil using three-point bending tests with evolving crack. Object of study: beams with a rectangular cross-section width of 55 mm, height 39 mm and a length of 320 mm made of artificially frozen sandy loam. The subject of research is the regularities of behavior under load of the beam with an evolving crack, and the corresponding tensile stress at the three-point bending. Methods: in this study, the methods of mathematical processing of the results of the testing, received at the SHIMADZU AGS-X test machine at three-point bending of a beam with evolving crack. The moisture content in the material for each sample was measured using SHIMADZU MOS-120H moisture analyzer. Results: it is found that the load extremum does not correspond to the extremum of the tensile stress in the cross section of the beam with crack. The tensile stress extremum is offset and corresponds to the downward branch of the curve “load – deflection”. This means that the destruction of the material under the action of tensile stresses occurs not at maximum load but at the maximum value of tensile stresses at the downward branch of the curve “load – deflection”. The practical significance of this result lies in the possibility of its use both in the design of new structures and in the inspection of structures in disrepair.