深埋式大直径钢圆筒结构与土的共同作用

土压力是钢圆筒结构的主要外荷载之一,是分析钢圆筒与土共同作用机理的最重要一环。结合港珠澳大桥岛隧工程西人工岛项目实例,以有限元软件PLAXIS 3D作为分析平台,建立深埋式大直径钢圆筒岛壁结构整体空间弹塑性有限元模型。分析钢圆筒结构的筒前被动土压力分布曲线与筒底竖向土压力分布曲线,并与同工况下二维平面等效理论计算方法得到的土压力曲线以及经典朗肯、库仑土压力进行对比。结果表明,三维数值模拟钢圆筒结构筒前被动土压力最小,随深度增长的趋势与经典土压力相吻合;三维数值模拟筒底竖向土压力与二维平面等效计算结果在分布趋势和数值方面都基本吻合。

Interaction between deep-buried large-diameter steel cylinder structure and soil

The soil pressure is the main load imposing on the steel cylindrical structure,and it is very important for analyzing the interaction mechanism between cylindrical structure and soil.Based on the west artificial island of the island and tunnel project of Hong Kong-Zhuhai-Macao Bridge,we apply the finite element software PLAXIS 3D to establish the whole spatial elastoplastic finite element model of the deep-buried large-diameter steel cylindrical island wall structure,analyze passive soil pressure distribution curve in front of the steel cylinder and the vertical soil pressure distribution curve at the bottom of the steel cylinder,and compare the soil pressure curves with the 2D equivalent calculation method and the classical Rankine and Coulomb soil pressure theories under the same conditions.The results show that the passive soil pressure value in front of the steel cylinder structure using 3D numerical simulation method is the lowest,and the tendency of increasing with depth is consistent with the classical theories.The vertical soil pressure at the bottom of the cylinder using 3D numerical simulation method is basically consistent with the trend and value of the 2D equivalent calculation results.