Side Of The Constrained Particle System Janssen Turned To Research, Than The Problem

Janssen model has being used for the design of silos for a long time. The descendants had disputation about Janssen's two assumptions, and they tried to improve his model.This article gave a brief introduction about the silo effect of the main models,and mainly introduced the Janssen continuum model which had significant association with my experimental work. People need to treat a great many large-scale particle systems in life, so it has great significance to find and build right elastic theory for granular matter.Coulomb standard specified the maximum of the shear stress in granular matter under a given pressure.We got a diagram which can be easily used in analyse if combined the coulomb standard with the Mohr circle.This paper described such Mohr-Coulomb failure diagram, and introduced some exemples where this method was used such as the cracks.It discussed practice value of the Mohr-Coulomb analysis.By up-down perturbing the base of a silo,various bottom pressure can be obtained.The work measured the minimum value of the so obtained pressures, as function of filled grain mass and silo diameter, respectively for two different grain sizes.It is found that the data can be well fitted by the Janssen formula, with a ratio about 1.5-2 between horizontal and vertical stresses, which is much bigger than the ratio 0.4-0.6 estimated with the Jaky formula in the Norm of silo engineering, implying that the stresses for these minimum pressure silos can be close to the Rankine passive state. This supports that silo obeys well the assumptions given by Janssen, in spite that it can be stayed in various states.Measurement and calculation of the Janssen coefficient are important problems that are general concerned about in the field of granular matter. In this paper, nonlinear elasticity theory was used to establish equations. It analyzed the stress distribution in the two-dimensional rectangular sample, and obtained the calculated result of the lateral pressure coefficient.These results confirmed the rationality of the classical elasticity theory that was applied to static granular matter. It could be also used to compare with the experimental results, and it provided an possible explanation about why the steering ratio is much larger than Jaky formula estimates in experimental observations.