Dilatancy Of Wheat In Triaxial Tests

Grain is as an important biological agriculture as agriculture and producers in China. Grain storage and processing impairment and other problems in the process is a long-standing problem. For the study of the physical and mechanical properties of domestic and foreign food are many, but the analysis of the basic physical properties of wheat and related factors measuring method is not perfect, in addition to the use of triaxial tests on mechanical parameters such as friction angle of wheat, cohesion, dilatancy discrete element simulation analysis and other aspects not widespread.Based on the mechanical properties of triaxial tests on wheat, dilatancy related factors were analyzed, and by PFC discrete element simulation showing stress- strain relationship and microscopic parameters and the results obtained from the analysis of triaxial tests carried out comparative law the main tasks are as follows:(1)Specification according to relevant national grain parameter determination on the basic physical properties of selected wheat were investigated, to get the etermination results of initial water content, configuration, water content of wheat under the corresponding density, bulk density, grain, porosity, etc. analysis the influence rule of moisture content on density, bulk density, porosity, etc.(2)Using soil triaxial test apparatus and triaxial test was carried out on the configuration a certain moisture content of wheat, the change of wheat pore ratio, shear rate and confining pressure parallel comparison test, under the condition of the right to obtain corresponding the stress-strain relationship of wheat, and Mohr coulomb theory are used to get the molar circle, obtained by the strength of the Moore circle envelope analysis to get the strength coefficient of wheat(internal friction Angle φ and cohesion of c).(3)For the void ratio, shear rate and confining pressure under the condition of the internal friction Angle of wheat φ and cohesion of parameter c were analyzed, To make c、φ values by the moisture content and void ratio, shear rate, the influence of confining pressure curve, And analysis may lead to the change rule of macroscopic and microscopic factors.(4) Using discrete element software PFC3 D triaxial test of wheat, to simulate the process of shear on wheat triaxial test of concrete mesoscopic parameters related to calibration. Through the simulation analysis of stress-strain relationship of wheat, volume change rule, to simulate the dilatancy characteristics of triaxial test are analyzed. Through the analysis of mechanical parameters of the mesoscopic particles(such as stiffness, friction coefficient, etc.) and macroscopic mechanical parameters(e.g., internal friction Angle, cohesive force, elastic modulus, poisson’s ratio and dilatancy Angle, etc.), the influence of the changing rule and mesoscopic parameters which are obtained by simulation, and the corresponding macroscopic parameters, further validation and improvement of triaxial test results.