基于三维微观结构的黄土湿陷性成因及潜蚀黄土场地湿陷机理研究

The collapsibility of loess formation mechanism is the basic premise to solve a series of geological disasters related to collapsible loess. This project aims at the causes of loess collapsibility and the mechanism of loess field collapsing under the condition of underground erosion. Firstly, in order to reveal the space that is necessary for the loess contraction during the collapsing process, the comparative study on various micro pores of loess before and after collapsing will be carried out through series of modern microscopic observation methods, tests, and experiments. Secondly, taking the cement between skeleton particles of the micro pores that possibly makes significant contribution to the collapsibility of loess as the key research object, in-depth studies for the composition of cement, the three dimensional space cementation form as well as the cementing strength will be carried out in order to reveal the key physical chemical and mechanical processes causing collapsibility. Thirdly, taking the loess samples with different moisture content as the research object, the various forces between loess particles and their contribution to the structural connection force of loess will be studied in order to reveal the microscopic triggering mechanism of the collapsibility of loess. Finally, taking the mechanism of collapsibility action in the process of underground erosional features formation as the breakthrough, the relationship between water seepage process and collapsing characteristics of loess field during the underground erosion process will be studied by field investigation and exploration. Through this project research, it’s quite possible to reveal the causes and mechanism of loess collapsibility and to provide sound theoretical foundation for preventing and avoiding harms to constructions caused by collapse in a maximum way.

黄土湿陷性成因机理是解决一系列与黄土湿陷性相关地质灾害的基本前提。项目围绕黄土湿陷性成因及潜蚀条件下湿陷性黄土场地宏观湿陷机理开展研究。借助多种现代微观观察手段、测试及试验，开展黄土湿陷前后微观孔隙对比研究，揭示黄土湿陷体缩赖以的空间基础；以对黄土湿陷量有显著贡献的微观孔隙骨架颗粒间的胶结物为重点研究对象，针对胶结物的组成、三维空间胶结形式、胶结强度开展深入研究，揭示导致黄土湿陷的关键物理化学及力学过程；以不同含水率湿陷性黄土试样为研究对象，研究黄土颗粒与水作用时各种作用力大小及其对黄土颗粒结构连接力的贡献，揭示黄土湿陷这一过程的微观触发机理。以黄土潜蚀地貌形成过程中湿陷作用机理研究为突破口，通过野外调查勘探对黄土潜蚀地貌形成过程中地层渗水过程与黄土场地湿陷特征及其二者之间关系进行研究。通过项目研究，从根本上揭示黄土湿陷的成因机理，为最大限度防治和避免湿陷造成的工程危害提供坚实的理论基础。

项目围绕黄土湿陷性成因及潜蚀条件下湿陷性黄土场地宏观湿陷机理开展了深入研究。本项目在现有研究成果积累的基础上，借助多种现代微观观察手段、测试及试验研究，开展了黄土湿陷前后微观孔隙大小、孔隙形状、颗粒排列特征对比研究，揭示了黄土湿陷体积收缩发生的空间基础；对黄土湿陷量有显著贡献的大孔隙的骨架颗粒间的胶结物为重点研究对象，针对胶结物的物质组成、胶结存在形式、胶结物的作用、胶结强度开展了深入研究，解释了导致黄土湿陷的关键物理化学及力学过程；以不同含水率湿陷性黄土试样为研究对象，讨论了黄土颗粒与水作用时黄土颗粒结构及连接对湿陷性的影响，揭示了黄土湿陷这一过程的微观触发机理。通过野外调查勘探及现场试验对黄土潜蚀地貌形成过程中地层渗水过程与黄土场地湿陷特征及其二者之间关系进行了研究。通过项目研究，从根本上揭示了黄土湿陷性的成因及潜蚀环境下湿陷性黄土场地宏观湿陷的湿陷特征及其湿陷机制，项目成果为最大限度防治和避免湿陷造成的工程危害提供了重要的理论基础。