长板-短桩工法处理深厚海相软土效果分析

Effect Analysis of Improved Deep Marine Soft Soil Through Drainage Consolidation and Mixing Pile Method

将长的塑料排水板与短的水泥土搅拌桩联合处理的方法称为长板-短桩工法,为了更好地将该工法应用于海相软土地区,采用岩土三维有限差分软件FLAC3D,建立长板-短桩复合路基数值分析模型,研究了搅拌桩的桩长、桩间距和桩径对路基沉降、搅拌桩轴力的影响.研究结果表明:数值计算得到的结果跟现场沉降观测值比较接近,证明了模型建立和材料参数选取的正确性.路基沉降随桩长和桩径增加而减小,随桩间距增加而增大.搅拌桩桩身上部存在桩侧负摩阻力,桩身轴力随深度增加而先增大后减小.桩间距增大时,桩身轴力略微增大;随桩径增加,不同深度桩身轴力均增大.研究成果可为该工法的推广应用提供工程经验参考.

The method combining long plastic drainage plate with short cement-soil mixing piles is called D-Mmethod. In order to develop the application of D-M method in marine soft soil,FLAC3D and the geotechnical 3-d finite difference software are used to establish a long plate-short pile composite roadbed numerical model to study the influence of pile length and pile spacing on subgrade settlement and axial force of the mixing pile. The resultsshow that the numerical results obtained are similar to settlement observation at the scene,which proves that thecorrectness of modeling and parameters. Subgrade settlement decreases with the increaseing of pile length and thepile diameter but increases with the increasing of pile spacing. The negative skin friction resistances exist in the topof mixing pile,and the axial force of pile shaft increases firstly and then decreases with the increasing of depth.When the pile spacing increases,the axial force of pile shaft increases slightly. With the increasing of the pile diameter,the axial force of the pile shaft at different depths increases. The results of this study can provide reference for engineering application of the method.