中文摘要：

研究土体结构强度对了解土体开裂破坏过程和预防相关工程地质问题有重要意义.以南京地区下蜀土为对象,采用超微型贯入试验方法,分析了试样在干燥过程中的结构强度演化特征.结果表明所采用的超微型贯入试验方法为定量研究土体在干燥过程中结构强度的演化规律提供了可行的途径,该方法具有操作简单、精度高和含水率适应范围大等优点;在干燥过程中,当试样处于高含水率阶段时（w≥24.27%）,剖面上的结构强度基本保持一致,空间差异性较小;在低含水率阶段（w〈24.27%）,试样结构强度空间差异性显著增强,随深度的增加,结构强度呈递减趋势并逐渐趋于稳定;总体上,土体的结构强度在干燥过程中随平均含水率的减小呈指数递增趋势,这主要是由于土体水分蒸发导致吸力增加,土颗粒之间的作用力增强.此外,由于土体发生收缩变形,土体孔隙比减小,土颗粒间联接点增加,也会对结构强度产生贡献.

英文摘要：

Study on the structural strength of soil is significant to the understanding of the soil cracking process and preventing related engineering geological problems.This paper takes the Xiashu soil in Nanjing as the object and uses the Super-Mini-Penetration (SMP )test.It analyzes the evolution characteristics of the structural strength of specimens during the drying process.The results show that the SMP test method is a better way for the quantitative study of structural strength of soil during the drying process.This method has the advantages of simple operation, high precision and a wide range of moisture content.During the drying process,the structural strength of specimen section remains stable and its spatial difference is very small in the high moisture content range(w≥24.27%).In the relative low water content range (w<24.27%),the spatial difference of soil structural strength become more evident.As the penetration depth increase,the structural strength decreases and gradually become stable.The soil penetration stress increases exponentially as the average moisture content decreases,which is mainly due to the increase of soil suction caused by the soil water evaporation and the enhancement of interaction force among soil particles.In addition,the decrease of pore ratio and the increase of the soil particle joint point due to the shrinkage deformation of soil will also contribute to enhance the structural strength of clayey soil.