岩土损伤理论基本问题研究

Study on the Basic Problem of Damage Theory of Geomaterial

岩土损伤理论远未成熟,根源在于其基本问题没有得到解决。根据岩土的基本力学特性,给出了岩土耗散势存在的充要条件,证明了岩土耗散势不存在且不可解耦。同时,给出了岩土流动势存在的充要条件,证明了岩土流动势不存在且不可解耦。通过结构性土体损伤过程的能量耗散分析,获得了与经典损伤力学定义一致的损伤变量。基于能量耗散原理,获得了合理的损伤演化方程,建立了结构性土体损伤本构模型。通过与修正剑桥模型、三轴试验结果对比,表明本模型能够较好地模拟土体的力学特性。

The damage theory of geomaterial is far from mature, since there are still unsolved basic problems. According tothe basic mechanical characteristics of geomaterial, the sufficient and necessary condition is put forward for the existence of dissipa?tion potential of geomaterial, and it is testified that the dissipation potential doesn’t exist for geomaterial and can’t be decoupleel. Itis proved that the flow potential function can not be decoupled into two functions of plasticity and damage. At the same time, andcannot lie decoupled the sufficient and necessary condition is provided for the existence of flow potential of geomaterial also, and itis certified that the flow potential of geomaterial didn’t exist and can not be decoupled. Through the analysis of the energy dissipa?tion of the damage process for structural soil, the damage variable is obtained, which is consistent with the definition of classicaldamage mechanics. Based on the principle of energy dissipation, a reasonable damage evolution equation is obtained. The constitu?tive model of geomaterial is established for structural damage. By contrast with the modified Cam?clay model and the triaxial test re?sults, it is shown that the model can well simulate the mechanical properties of soil.