Grain grading method and system for simulating soil modeling based on DEM (Digital Elevation Model)

The invention provides a grain grading method and system for simulating soil modeling based on a DEM (Digital Elevation Model), which comprises the following steps of: describing elasticity and damping among grains by adopting a mechanical model, substituting a description result into a grading proportion, adjusting the volume of the grains after being stacked, and calculating a weight coefficient of interaction force among the grains through a kernel function, performing DEM simulated soil layer automatic enumeration and combination, and calculating the number of particles of each layer by combining a particle dynamic model; obtaining a particle model accumulation angle experiment result according to the number of the particles of each layer, performing angle verification on the result and an actual soil sample accumulation angle experiment, and if verification is passed, inputting the number of the particles of each layer into a particle generation part of a value DEM by combining the adjusted volume to obt