Reserch on the prediction of settlement of a large-scale reclaimed island

在大型填海造岛工程中，下伏结构性更新世粘土屈服后压缩量的预测十分重要。本研究的目的是建立一种预测更新世粘土屈服后特性的方法，在本研究的第一部分中，提出了更新世粘土屈服后压缩模型，考虑了塑性屈服引起的粘土结构劣化的影响。采用弹粘塑性有限元方法，将压缩模型引入到数值计算中。采用弹粘塑性有限元分析方法，采用屈服后压缩模型，对海上机场建设引起的填海粘土地基应力和变形进行了分析。根据计算结果，发现在更新世粘土沉积中，即使在更新世粘土之间的透水砂层中，沉降也在增加，而没有显著的超孔隙水压力消散。本文通过大量的Fallcone试验、十字板剪切试验和固结试验的结果表明，粘土的力学性质是由一个特定的液限和孔隙比来表征的。利用这些特定的液限和孔隙比，提出了广义的e-logp方程，称之为标准化压缩曲线的再造海洋粘土。

In the construction of a large-scale reclaimed island, it is very important to predict the post yield compression of underlying structural Pleistocene clay. The aim of this reserch is to establish a method of predicting the post yield behavior of Pleistocene clay.In the first part of this research, post yield compression modelling for Pleistocene clay is proposed, considering the effect of deterioration of clay structure due to plastic yielding. The compression model is incorporated into the numerical procedure in terms of elasto-viscoplastic finite element method. Stress and deformation of the reclaimed marine clay foundation due to offshore airport construction is assessed by the elasto-viscoplastic finite element analysis with post yield compression model. Based on the calculated performance, it is found that settlement advaces without a significant dissipation of excess pore water pressure in the Pleistocene clay deposits, even in the permeable sand layrs among Pleistocene clays.In the second part of this reserch, the compression characteristics of reconstituted marine clays are examind as a flame work for the assessment of compression characteristics of Pleistocene clay. Based on the results of a number of Fallcone tests, Vane shear tests and consolidation tests, it is shown that the mechanical properties of clays are characterized by a specific values of the liquid limit and void ratio. Using these specific values of liquid limit and void ratio, the generalized e-logp equation termed normalized compression curve of reconstituted marine clays is proposed.