Investigation of the Physical, Chemical and Mechanical Properties of Ariake Clay under the Reclamation Dick and Analysis of the Behavior of the Reclamation Dike by Finite Element Method

根据取芯资料和土工试验结果，对围堤下/围堤周围有明粘土的物理、化学和力学性质进行了研究。主要研究结果如下：（1）围堤下有明粘土层处于正常固结状态，冲积有明粘土层的固结沉降远大于深层。(2)对于原状有明粘土，降落锥贯入深度与十字板抗剪强度之间存在唯一的关系。当<Lf>W_L&gt; 100%时，落锥法和JIS法测得的液限（W_L）基本一致;当W_L&gt; 100%时，两者的差值随W_L的增大而增大。(3)重塑有明粘土的强度增长率和内摩擦角分别比原状粘土大15 ~ 20%和5 ~ 20%。有明粘土的粒度分布对Hvorslev强度参数有影响。有明粘土的不可逆比（Λ）在0.6 ~ 0.8之间，不受粒度分布和塑性指数（I_p）的影响。(4)重塑有明粘土的恒速率固结试验结果与应变速率无关。相反，原状有明粘土的固结屈服应力与应变率有关。此外，采用弹塑性有限元法对现场围堤和离心模型试验基础的性状进行了分析。通过与现场观测结果和离心模型试验结果的比较，表明该分析方法完全适用于软土地基围堤的性状分析。

The physical, chemical and mechanical properties of Ariake clays under/around the reclamation dikes were examined based on core boring data and soil test results. The following main results were obtained : (1) Ariake clay layers under the reclamation dike are normally consolidated and the consolidation settlement of the alluvial Ariake clay layer is considerably larger than that of the deeper layers. (2) There is the unique relation between fall cone penetration depth and vane shear strength for undisturbed Ariake clays. Liquid limit (W_<Lf>) obtained by fall cone method is well coincident with that (W_L) obtained by JIS method in W_L≦100% and the difference between rLf and W_L increases with the increase of W_L in W_L>100%. (3) The rates of strength increase and the internal friction angles of remolded Ariake clays were 15〜20, 5〜20% greater than those of undisturbed ones respectively. The grain size distribution of Ariake clay has an effect on Hvorslev's strength parameters. Irreversibility ratio (Λ) of Ariake clay is in the range of 0.6〜0.8 and is not affected with grain size distribution and plasticity index (I_p). (4) The results of the consolidation test using constant rate of strain loading for remolded Ariake clays are independent on strain rate. To the contrary, the consolidation yield stress of undisturbed Ariake clays is dependent on strain rate.Moreover, the behavior analyses of the reclamation dike in the field and of the footing in the centrifuge model test using the elasto-plastic finite element method were carried out. It was found from the comparisons of the results of these analyses with those of the field observation and with those of the centrifuge model test that this analysis method was sufficiently applicable to the behavior analysis of the reclamation dike on the soft ground.