爆炸挤淤置换法筑堤沉降的有限元分析

Finite Element Analysis on the Settlement of Levee Improved by the Blasting Replacement

利用室内试验获得的模型参数结合有限元计算,对深厚淤泥质软基处理建成后的海堤短期和长期沉降问题开展了计算分析。对抛石填料和地基土分别采用莫尔-库伦模型和修正剑桥模型,在地应力平衡的基础上,实施抛石堆载,堆载完成后,开展了工后10年的沉降分析。分析表明,抛石体堆载后,地基土地应力急剧增加,海堤两侧土体向上隆起,下部土体沉降;海堤建成后的621.2天累计沉降达1.2m,孔隙水压仍未消散;建成10年后,海堤累计沉降达1.55m;表明海堤建成后的短期和长期沉降均较大,对重大海堤工程,工后的沉降研究与控制显得必要。

A sea levee over the thick mucky soft cohesive soils was improved by the blasting replacement method and both the short term and the long term settlement of the levee were analyzed using finite element method with laboratory test determined parameters.In the analysis,the riprap was modeled as the Mohr-Coulomb model and the soft soil was presented by modified Cam-Clay model.The riprap surcharge was placed on the improved soils and the settlement monitoring was performed in a 10 years after the completion of the levee.The monitoring and analysis results indicate that,after the riprap surcharge,the incremental stress in the soil increased significantly and the soft soil heaving were observed at both sides of the levee and the settlement was observed at the levee.The accumulative settlement after 621.2days of the levee completion was 1.2meters and the excessive pore water pressure was not dissipated completely.At time of 10 after the levee completion,the accumulative settlement was 1.55 meters.It is suggested that both the short term and long term settlements after the construction of the sea levee are significant,therefore,for the important sea levees,the control of the post construction settlement is very important.