土体耗散势的不存在与不可解耦

Inexistence and un-decoupling of dissipation potential for geo-materials

从热力学出发,发现了基于不可逆热力学土体损伤理论所存在的两大基本问题:①岩土材料是否存在耗散势函数;②耗散势函数可否分解为塑性势函数和损伤势函数,即塑性、损伤两种耗散机制可否解耦。分别给出了全量型和增量型两种耗散势函数存在的充分必要条件并加以严格证明,结合土体的基本变形性质,证明了土体不存在耗散势函数。进一步考察耗散势函数的解耦性,给出了全量型和增量型这两种耗散势函数塑性耗散与损伤耗散可解耦的充分必要条件并进行了严格论证,结合土体的基本变形性质,证明了土体塑性耗散和损伤耗散机制不可解耦。从而证明了塑性耗散势与损伤耗散势都是不存在的。

Based on the concept of thermodynamics,two fundamental constitutive issues in the thermodynamics theory of damage-elasto-plasticity are proposed：first,existence or inexistence of the dissipative potential;second,the dissipation potential can or cannot be decomposed into a damage potential and a plasticity potential,namely,whether or not the two mechanisms can be decoupling.Within this framework,sufficient and necessary conditions for the existence and the coupling of a dissipation potential are given under total and increment forms,and it proves the sufficient and necessary conditions strictly in theory.According to the mechanical properties of the geo-materials,the inexistence and the un-decoupling of the dissipation potential are also proved.