Theoretical Study on the Stressed State of the Disc-Shaped Cohesive Bulk Material

Abstract: Building processes are associated with impacts on the ground. The ground's ability to resist the load created by structures or to withhold the impact of earth-moving machines is estimated by the plasticity theory methods. The article presents a theoretical analysis of the stressed state of a layer of disc-shaped bulk material. The obtained theoretical models of the minimal, maximal and extreme stressed states of a layer of the material represent all the possible cases of an impact on the ground. The equations of theoretical models cannot produce a concrete analytical solution to all of the material's space which is why a method has been evolved for solving the model equations by means of terminal differences. This is substantiated by an example of calculations made in case when the ground sustains an impact of a jet of fluid used by earth-moving machines and other tools of hydraulic mechanization of construction works. The obtained solution makes it possible to create a slide line field containing cycloidal (slide lines are cycloidal) and transient zones. Under the load exceeding critical, the material moves along the slide lines away from the axis (minimally stressed state) and protrudes from the surface outside the stress zone (maximally stressed state). It is noteworthy that once an extra load is added in the protrusion zone, the ground hardens rather than fails. Thus, the obtained solution also explains the compressing capability of the tamping roller whose theoretical substantiation was previously missing.