水-力作用下黏土孔隙结构演化规律研究进展

Research Progress on Evolution Law of Clay Pore Structure under Hydro-mechanical Effect

黏土的微结构直接决定宏观水-力学特性,然而现阶段绝大多数模型都是基于宏观参数所建立,由于缺乏微观机制的支撑,己经难以满足科研和工程需求。因此开展孔隙结构演化研究可以加深对非饱和土复杂水-力学特性的认识。在详细阐述黏土的孔径分布特征及双孔模型的基础上,全面回顾和总结了近年来水-力作用下黏土孔隙结构演化规律的研究成果与最新进展,并进行了相关讨论。结果表明:考虑颗粒集聚体的双孔模型(集聚体间孔隙与集聚体内孔隙)可以更好地解释黏土复杂的水-力学特性。水-力作用对黏土孔隙结构的影响机制不同,根据文献试验数据和理论分析初步总结出水-力作用下土孔隙结构的演化规律。外力荷载只显著影响集聚体间孔隙,对集聚体内孔隙基本不影响;含水率变化会改变土颗粒相对位置,继而影响这两类孔隙结构,但是土水相互作用复杂,导致含水率变化对土孔隙结构影响机制仍不清晰,并且没有统一认识。鉴于此,在研究土水相互作用对微观孔隙影响时应充分考虑物理-化学作用,并构建微观孔隙结构演化与宏观变形的定量关系,这也是今后需要深入研究的方向。

Macroscopic hydro-mechanical properties of clay are directly determined by the microstruc-ture.However,at present,most of the models are established based on macro-parameters,which are difficult to meet the needs of scientific research and engineering due to the lack of micro-mechanisms support.The study of pore structure evolution can deepen the understanding of the complex hydro-me-chanical properties of unsaturated soil.Based on the detailed description of pore size distribution char-acteristics and the dual pore model of clay,the research results and latest progress of pore structure evolution law of clay under hydro-mechanical action in recent years are comprehensively reviewed and summarized,and relevant discussions are carried out.The results show that the dual pore model(in-ter-aggregate pores and intra-aggregate pores)considering particle aggregates can better explain the complex hydro-mechanical properties of clay.Under the hydro-mechanical action,the evolution laws of the pore structure are different.Based on test data and theoretical analysis in literature,the evolu-tion laws of pore structure under hydro-mechanical effect are preliminarily summarized.External load-ing only significantly affects inter-aggregate pore space,and basically has no effect on intra-aggregate pore space.Changes in water content will alter the relative position of soil particles,which then affects the two types of pore structure,but the complexity of soil-water interactions leads to unclear mecha-nisms and a lack of unified understanding of the impact of moisture content changes on soil pore struc-tures.In view of the above,the physical-chemical interaction should be fully considered when studying the effect of soil-water interaction on micro-pores,and the quantitative relationship between the evolu-tion of micro-pore structure and macro-deformation should be established,which is also the direction for further research in the future.