珠江三角洲入海口软土次固结系数特性研究

为了查明珠江三角洲入海口软土次固结系数变化特征，为港珠澳大桥岛隧工程提供精细化的沉降设计指标提供基础，通过采取I级不扰动软土样，进行室内分类试验和单向固结试验，获取相应的物理、变形指标，分析次固结系数随荷载变化特征，研究次固结系数与前期固结压力、压缩指数、含水量和塑性指数的相关性。结果显示，次固结系数随着含水量的增加、塑性指数的增大呈线性增长；次固结系数与压缩指数的比值在正常固结下并非是一个常数；次固结系数在前期固结压力前，值小，随着加荷递增，固结系数也增加；前期固结压力之后，主要随着加荷递增，次固结系数呈由大变小的趋势。经过研究，掌握了珠江三角洲入海口正常固结软土的次固结系数变化规律，建立了次固结系数与相关物理力学指标相关关系，为珠三角洲软土变形计算提供了地区性的指导作用。

On coefficient of secondary consolidation of soft clay at estuary of the Pearl river delta

In order to indentify the variation characteristics of the coefficient of secondary consolidation of soft clay at the estuary of the Pearl river delta, and provide a basis on the precise parameters of the settlement design for ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? the tunnel project of? Hong Kong-Zhuhai-Macao Bridge island? , we carry out a classification test and consolidation test on the undisturbed samples of grade I, so as to obtain the relative physical and settlement parameters, analyze the characteristics of the coefficient of secondary consolidation with load changes, and study the correlation between the coefficient of secondary consolidation, preconsolidation pressure, compression index , water content and plasticity index. The results show that the coefficient of secondary consolidation increases linearly with the increase of water content, plasticity index; the ratio of the coefficient of secondary consolidation and compression index is not a constant in the normal consolidation; the coefficient of secondary consolidation is small and increases with the load growth before loading is less than the preconsolidation pressure, it is from large to small with the load growth after loading is more than the preconsolidation pressure. This research ascertains the variation characteristics of the coefficient of secondary consolidation, founds the correlation of coefficient of secondary consolidation and related physical and mechanical indexes, and forms a regional guidance for the deformation calculation of soft clay at Pearl River Delta.