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

在大型填海造岛工程建设中，对下伏结构性更新世粘土的屈服后压缩进行预测是非常重要的。本研究的目的是建立一种预测更新世粘土屈服后行为的方法。在本研究的第一部分，考虑了塑性屈服导致粘土结构恶化的影响，提出了更新世粘土的屈服后压缩模型。采用弹粘塑性有限元方法将压缩模型引入到数值过程中。采用弹粘塑性有限元分析方法，采用屈服后压缩模型，对海上机场建设中填海粘土地基的应力和变形进行了分析。根据计算结果发现，在更新世粘土沉积物中，甚至在更新世粘土之间的渗透性砂层中，超静孔压并没有得到显著的消散。在本研究的第二部分，研究了重塑海相粘土的压缩特性，为评价更新世粘土的压缩特性提供参考。根据大量的落锥试验、叶片剪切试验和固结试验的结果表明，粘土的力学性质是由特定的液限和孔隙率来表征的。利用这些液限和空隙比的特定值，提出了重塑海相粘土归一化压缩曲线的广义e-logp方程。

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.