Based on the discussion , this paper expatiated the essential principle of the plastic mechanics in rocks include the material yield criterion , loading - unloading criterion , plastic potential theory , hardening rules , and application in geotechnical engineering
2.
After the streamlines and potential lines were plotted , the potential line of the hardening and softening parts were taken as the same ellipse form . in order to establish the softening elasto - plastic model of qi loess , the plastic potential function used is in a ellipse form and the plastic work function was used as its hardening parameter
3.
This paper uses the method of tensor to proof the tenable condition of generalized plastic potential , discuss the mathematical essential of the associated and disassociated flow rule and the relation of the yield surface and plastic potential surface , reason the expression of plastic factor strictly . debate the limitation on drucker ' s postulate . subsequently , this paper gives the mathematical basis of constitutive theory involving the rotation of principal stress axes . so it is proved that the mathematical and mechanical foundation of the generalized plastic mechanic