饱和细粒土固结过程中矿物组分与有机质的三维表征  

THREE-DIMENSIONAL CHARACTERIZATION OF MINERAL AND ORGANIC COMPOSITIONS IN PROCESS OF CONSOLIDATION OF SATURATED FINE-GRAINED SOIL

作　　者：刘治清 宋晶 李学[1] 杨玉双 任玉琦 

机构地区：[1]中山大学地球科学与工程学院,广州510275 [2]广东省地质过程与矿产资源探查重点实验室,广州510275 [3]澳大利亚联邦科学与工业研究组织 [4]中国科学院上海应用物理研究所,上海201204

出　　处：《工程地质学报》2017年第5期1299-1306,共8页Journal of Engineering Geology

基　　金：国家自然科学基金(41402239;41572277;61505266);广东省自然科学基金(S201204000733)资助

摘　　要：饱和细粒土颗粒细小,比表面积大,易与土体中的孔隙水、有机质相互结合形成团聚体,这种结合形式对土体的物理力学性质有着重要影响。本文从三维微观结构角度探讨饱和细粒土的多物质结构特征对其固结演化性质的作用。土样分成4种组分:孔隙,有机质,多矿物组分和伊利石为主的矿物组分。通过同步辐射显微CT技术联合数据约束模型,获取多物质三维结构表征。伊利石为主的矿物组分,与孔隙呈共存结构,即使在1600kPa高压作用下仍不易排出孔隙水。有机质与伊利石为主的矿物组分易结合形成有机黏土颗粒,有机质不仅吸附在组分表面,而且嵌入组分结构内部;在土体固结过程中,有机质存在富集特征,40~400μm直径的有机质总体积逐渐增大,削弱土颗粒间的连结强度。本研究采用定性与定量分析相结合,获取了固结过程中矿物组分与有机质的结构表征,为特殊土体的微宏观性质分析提供一种可行性研究方法。The particles in the saturated fine-grained soils are small. Their specific surface areas are large. The pore water and organics in the soil tends to form aggregates. This combination has important influence on the physical and mechanical properties of the soil. In this paper,the effect of multi-material structure of saturated finegrained soil on its consolidation and evolutionary properties is discussed from the perspective of three-dimensional microstructure. The components in the soil samples are classified into four groups： pores,organics,multi-mineralsand illite-dominated minerals. The structures were analyzed by synchrotron radiation μCT combined with the data constrained modelling in the consolidation process. The results show that illite-dominated minerals are hydrophilic and displaya coexistence of multiple phases in a voxel with pore,so that the water is difficult to be discharged under high pressure（ 1600 kPa）. Organics combined with illite minerals form organoclay agglomerated particles. It is not only adsorbed on the illite-dominated mineral surface,but also embedded in the mineral structure. The organics migrated in consolidation progress,which is illustrated by gradually increased volume of organics（ in 40 ~ 400μm diameter）. The strength of the soil between the soil particles weakened. This research utilizes qualitative and quantitative analysis to obtain evolutionary characteristics of minerals and organics. The approach presented would be applicable in studying the relationship between microstructure and macro-properties for special engineering soils.

关 键 词：矿物组分 有机质 同步辐射 μCT 数据约束模型 

分 类 号：P642.11[天文地球—工程地质学]