主体地下结构与支护结构相结合的复杂深基坑分析

结合一具体工程对主体地下结构与支护结构相结合的复杂深基坑进行了分析。基于土体硬化模型的平面有限元方法对基坑的施工过程进行了模拟,结果表明:该方法能较好地模拟围护结构的变形和墙后的地表沉降;同时主体地下结构的巨大支撑刚度有效地控制了基坑的位移,因而基坑开挖对地铁没有产生不利的影响。采用考虑梁板共同作用的三维有限元方法分析了变标高的首层水平支撑体系的受力和变形,基于切向弹簧边界分析了地下一层水平支撑体系的受力和变形,分析结果成功地指导了基坑的设计。

Analysis of a complicated deep excavations supported by substructures

The analysis of a complicated deep excavation supported by substructures was presented.The plane strain FEM was adopted to model the excavation procedure by using an advanced soil model(hardening soil model).The results show that this method gives good prediction of both the deformation of the soil retaining structures and the settlement of the soils behind the wall.Effect on the adjacent metro caused by the excavation was also analyzed.It shows that the adjacent metro structures are under good protection due to the huge stiffness of the substructures used as struts during the excavation.3D FEM considering the interaction between beams and slabs was adopted to calculate the deformation and internal forces in the first level strut system whose components were located at different elevations.Deformation and internal forces of the second level strut system were analyzed by applying a tangent spring boundary to the model.The calculated results were used as guidance to the design of the supporting system.