深厚软土地基上插入式钢圆筒的结构稳定性

Stability of inserted steel cylinder structure on deep soft foundation

结合港珠澳大桥岛隧工程东人工岛工程实例,基于PLAXIS 3D有限元软件计算平台,利用可同时考虑剪切硬化和压缩硬化的土体弹塑性本构模型Hardening-soil model,对深插式大直径钢圆筒岛壁结构三维数值计算展开研究,分析施工全过程中各控制工况下钢圆筒的变位情况,并与二维理论计算和现场实测位移相验证,探讨深厚软黏土地基上大圆筒结构的变形与稳定特性。结果表明,三维数值模拟钢圆筒位移和实测位移相近,两者均大于二维平面等效计算位移值;当钢圆筒有足够的直径和埋深时,即使其插入深厚软黏土地基,水平和竖向变位均较大,但是其结构稳定性也较好。分析成果对类似工程以及大直径钢圆筒结构在软土地基上的推广应用具有一定的参考意义。

Combined with the example of the East Artificial Island of the Hong Kong-Zhuhai-Macao Bridge Island Tunnel Project,based on the PLAXIS 3D finite element software calculation platform and the Hardening-soil model,which can consider both shear hardening and compression hardening,the 3D numerical calculation of the deep-inserted large diameter steel cylinder island wall structure is studied,and the displacement of the steel cylinder under various control conditions in the whole construction process is analyzed.The deformation and stability characteristics of large cylinder structure on deep soft clay foundation are discussed,which are verified by 2D theoretical calculation and field displacement measurements.The results show that the displacement of the steel cylinder in 3D numerical simulation is similar to the measured displacement,both of which are larger than the equivalent displacement in 2D plane.When the steel cylinder has enough diameter and buried depth,even if it is inserted into deep soft clay foundation,the horizontal and vertical displacement are larger,but its structural stability is also better.The analysis results have certain reference significance for similar projects and the popularization and application of large diameter steel cylinder structure in soft soil foundation.