大圆筒人工岛围堰结构稳定性和筒底地基应力的有限元分析

Stability of Large Cylindrical Cofferdam for Man-made Island and Finite Element Analysis of Foundation Stress at the Bottom of Large Cylinder

通过三维弹塑性有限元分析结果得出考虑地基强度弱化效应时,沉入式大圆筒结构稳定性安全系数有所降低,但降低程度小于地基强度的弱化程度;施工期大圆筒围堰结构的变位模式主要为绕筒底附近某点发生转动变位,岛内侧的大圆筒底部地基应力大于岛外侧;正常使用期,结构的变位模式则主要为平动变位,岛内侧大圆筒底部地基应力也大于岛外侧,但地基应力分布相对比较均匀。

By using 3D elastic-plastic finite element model,it shows that the stability safety factor of large cylindrical structure decreases when strength weakening effect of soft base is taken into consideration,but the decreasing degree is less than the weakening extent. The displacement mode of large cylindrical cofferdam in construction period is mainly the rotating displacement around one point close to the bottom of large cylinder. And the foundation stress at the bottom of larger cylinder inside the man-made island is larger than that outside. Besides, it is also obtained that the displacement mode of the above structure is translational displacement in normal term of service. And the foundation stress at the bottom of larger cylinder inside the man-made island is also larger than that outside,but the foundation stress distribution is comparatively uniform.