饱和砂土吸力基础沉贯过程中渗流场分布

Seepage field distribution of saturated sandy soil during suction caisson sinking

针对不同长径比的传统吸力基础及裙式吸力基础,采用有限元数值模拟的方法,研究其在饱和砂土内吸力沉贯过程中的土体渗流场分布规律。研究结果表明:传统吸力基础在沉贯过程中,土中渗流场均呈现层状分布,水头等值线密集分布于主桶内部土体,相对比较平缓;而主桶外部水头等值线变化较小且分布比较稀疏。裙式吸力基础渗流场主要存在于主桶内部和裙结构内部,并向外扩散至部分土体。吸力沉贯过程中土体的水头损失主要集中在主桶内部和裙结构内部,土体中的孔压分布和传统吸力基础规律一致,即成层状分布并未出现泡状的孔压分布形式。研究成果对揭示吸力基础沉贯机理有理论指导意义。

Considering traditional suction caisson and the skirted suction caisson with different length-diameter ratios,numerical simulation was carried out to study the distribution of the seepage field during the caisson suction sinking in saturated sandy soil. The results show that for the traditional suction caisson,the seepage field distributes in a layered form during suction installation,and the water head contour lines inside the main bucket distribute densely,with relatively smooth gradient. Water head contour lines outside the main bucket vary little and distribute sparsely,with steep gradient. For the skirted suction caisson,the seepage fields lie mainly inside the main bucket and the skirted structure,and further extend to outside soil. During the suction-penetration construction,the head loss mainly concentrates inside the bucket and the skirted structure,and the distribution of pore water pressure for the skirted suction caisson is similar to that of the traditional suction caisson,which exhibits a layered form instead of a bulb-shape form. The results can help understand the installation mechanism of the suction caisson in sandy soil.