考虑涂抹效应的以面和以线代板修正真空预压简化三维有限元模型

为了解决传统真空预压三维模型建立划分单元困难、计算量巨大、排水板宽高比过大从而影响计算精度的问题,基于排水子结构思想,提出简化排水板的以面代板和以线代板单井三维模型,并验证其正确性.将简化排水板单井模型扩展为群井三维模型,结合工程实例进行数值模拟,与实测数据、二维砂墙等效法和传统三维模型进行比较.结果表明:与传统真空预压三维有限元模型的圆形孔压传递形式不同,以面代板和以线代板模型将孔压传递形式简化成矩形.简化排水板三维模型比二维砂墙等效法更接近于实测数据,与传统三维模型计算精度相近,可以满足工程要求.简化排水板三维模型应用排水子结构可以有效降低模型建立和划分难度.将排水板简化成排水面和排水线,能有效解决因排水板尺寸过小而产生单元长宽比过大的问题,且能有效减少模型的单元数量,提高计算效率.

Modified 3D finite element model of simplified PVDs as surface or line under vacuum preloading considering smearing effect

In order to solve the problems that the traditional vacuum preloading three-dimensional(3D)finite element model(FEM)is difficult to establish and divide the elements, the calculation amount is huge, and the large ratio of width to height of the prefabricated vertical drains(PVDs)affects the calculation accuracy, based on the idea of drainage substructure, two modified 3D FEMs of simplified PVDs as surface or line were proposed and verified. The simplified PVDs single-drain 3D FEMs were extended to multi-drain 3D FEMs, and numerical simulation were carried out in combination with an engineering example, which were compared with the measured data, the two-dimensional(2D)sand wall equivalent method and the traditional 3D FEM. The results show that the modified 3D FEMs of simplified PVDs as surface or line simplify the pore pressure transfer form into a rectangle, which are different from the circular pore pressure transfer form of the traditional vacuum preloading 3D FEM. The simplified PVDs 3D FEMs are closer to the measured data than the 2D sand wall equivalent method, and the calculation accuracy is close to the traditional 3D FEM, which can meet the enginee-ring requirements. The simplified PVDs 3D FEMs with drainage substructure can effectively reduce the difficulty of 3D FEM establishment and division. Simplifying PVDs into drainage surface or drainage line can effectively solve the problem that the unit width to height ratio is too large due to the small size of PVD, and can effectively reduce the number of elements in 3D FEM and improve the calculation efficiency. 〓