非饱和土微观结构与粒间吸力的研究进展

吸力是非饱和土研究的重点也是其难点。重点在于自然界中诸多物理现象可以用吸力去解释,难点在于非饱和土吸力的量化测试技术现在还不成熟。非饱和土作为地球表层广泛存在的三相组合材料,其力学性质远远比饱和土复杂,归根结底在于土中水气界面形成的弯液面收缩膜,导致了土体孔隙产生吸力。非饱和土体的强度变形特征就是其内部吸力不断变化的宏观表现形式,其宏观物理力学性质与吸力之间存在一个桥梁——微观结构。对非饱和土微观结构和吸力理论、试验研究的整体把握是完善土力学的一个重要方法。开展对非饱和土液桥动态结构演化及吸力力链分布特性的研究,是全面了解非饱和土力学性能的重要基础之一,也是深入把握和量化非饱和土吸力的重要手段。

Advances in research on microstructure and intergranular suction of unsaturated soils

Suction is a focus of unsaturated soil research and investigation on suction is challenging. Many physical phenomena in nature can be explained by suction, and the research challenge is that the quantitative measurement technology of unsaturated soil suction is immature. Unsaturated soil, as a three-phase composite material widely exists on the earth surface, has far more complicated mechanical properties than saturated soil. The main reason is that a curved liquid surface contraction film is formed at the water-air interface in the unsaturated soil, which causes the soil pores to produce suction. The strength and deformation characteristics of unsaturated soil are the macroscopic manifestations of its internal suction, and the microstructure serves as a bridge to connect macroscopic physical and mechanical properties with suction. It is an important way to improve soil mechanics to grasp the microstructure of unsaturated soil as well as the theory and experiment of suction. It is pointed out that the research on the dynamic structure evolution of unsaturated soil-liquid bridge and the distribution characteristics of suction force chain is an important basis to fully understand the mechanical properties of unsaturated soil, and it is also an important means to grasp and quantify the suction of unsaturated soil.