非饱和土的承载结构与岩土广义结构性

鉴于非饱和土的复杂性，经典的3相模型过于简单，不利于分析相间相互作用及正确定义土中应力。将非饱和土视为一种特殊结构，并细分为6相，定义了其承载结构--广义土结构，进而分析了饱和土与非饱和土的主要差异：承载结构和孔隙流体均不同。基于承载结构的共性，提出了一套定性描述土体结构特点的指标--广义结构性，其普遍适用于描述不同土的承载结构特点。结合实际现象，分析了各指标的合理性，指出湿陷的本质是广义土结构的弱化。此后，分析了两种代表性相间相互作用，揭示了中性应力的物理意义，并合理定义了吸应力，最终明确了土骨架总应力就是“有效应力”。

Bearing structure of unsaturated soil and generalized structural properties

Because of the complexity of unsaturated soil, traditional three-phase model for unsaturated soil is oversimplified, which is unfit for interphase analysis and determination of stresses in soil. Considering a special structure in unsaturated soil , in this work, soil water system is divided into six phases and its bearing structure, named generalized soil structure, is defined. Then the differences between saturated and unsaturated soils are concluded: the bearing structures and pore liquids are different. Based on the similarity of bearing structures, a set of variables to depict the structural properties of soils is defined as generalized structural properties to describe the properties of the bearing structures of different soils. The rationality of some variables is analyzed by explaining some practical phenomena, e.g. the essence of collapse phenomenon is the weakening of the bearing structure of soil. Two representative interphase interactions are discussed and the physical significance of neutral stress is revealed, and the suction stress is redefined. Finally, it proves that the total skeleton stress in the grain is the “effective stress” for unsaturated soil.