海域软土地基塑排板堆载预压处理效果研究

Effect of Plastic Drain with Pre-loading Treatment on Soft Soil Foundation in Sea Area

随着我国东南沿海地区的大规模开发,在沿海软土地区修建高速公路势在必行,但由于其自身天然含水率大、压缩性高、抗剪强度较弱等特点无法直接作为高速公路地基,且海域地区往往直接受到潮汐影响,气候环境复杂,施工条件恶劣,因此,选择合理的地基处理方式十分重要.塑排板堆载预压处理方法作为一种成本低、损耗小、施工便捷的地基处理方式被广泛地运用到各类软基工程中.本文以77省道延伸线龙湾至洞头疏港公路工程为依托工程,从沉降、水平位移、孔压三个方面讨论海域软土地区塑排板堆载预压的加固效果,建立路基三维数值分析Flac 3D模型,分析塑排板埋设与未埋设两种工况下路基沉降、孔压、水平位移的变化规律.结果表明:1塑排板堆载预压加固地基效果显著,有效地提高了路基沉降速率,缩短了工期,大大减小了路基工后沉降;2塑排板堆载预压法在一定程度上限制了路基水平位移的发展,使得路基稳定性得到了提高;3塑排板堆载预压法在初期可以有效地加速路基内部孔压消散,提高土体固结速率,但后期效果一般,两种工况差别不大.研究成果可为类似工程提供参考.

With the rapid development of southwest coast in China, the highway built on the soft foundation is increasing. While the soft foundation cannot be used as the foundation of highway for its high soil water content, high compressibility and low shear strength. The complicated climate environment is also a tough problem for the building of highway. A proper group treatment method is very important. In this paper, based on the project of provincial high way, a further study of the reinforcement effect of plastic drain with pre-loading treatment of soft soil foundation is made, the effect factors are analyzed. Meanwhile, the Flac 3D model of the filing of roadbed in two conditions are established to study the variation of vertical and horizontal displacement of roadbed. The results show as follows. 1 ）The effect of pre-loading treatment of soft soil foundation is significant. 2）Plastic drain with pre-loading treatment has restraint on the development of horizontal displacement which also improves the stability of roadbed. 3）Plastic drain with pre-loading treatment can accelerate the dissipate of pore pressure in the early stage, while making little effect in late stage. There is little differences in two conditions. The result will provide the references for similar projects.