自稳定超前斜撑排桩支护数值模拟研究应用

Study and Application of Numerical Simulation of Self-stabilization and Advance Inclined Bracing Pile Support

文章提出一种新型的超前斜撑排桩支护结构形式,适用于深度不大的大面积开挖,在同等条件下,较比于分片开挖或内支撑开挖具有更好的支护效果,是一种快速开挖的支护方法。该新型围护结构采用钻孔灌注桩或型钢水泥土搅拌桩作为挡墙,通过引入独立基础作为超前斜撑体,形成自稳定斜撑体系,实现斜撑支护超前布置,解决传统斜撑支护体系的发展瓶颈。文章结合工程实例,前期通过采用Plaxis 3D对该新型支护方案进行有限元数值模拟,通过工况的模拟,发现该支护体系中排桩受力良好,弯矩分布均匀,能很好地控制基坑的变形,可应用于该工程。从后期施工中监测反馈的数据来看,该新型支护体系方案较比于常规支护方案,在安全、经济、施工进度上效果更显著,可为类似工程基坑支护设计提供参考。

A new type of advanced diagonal bracing row pile support structure is proposed,which is suitable for large area excavation with small depth.Under the same conditions,it has better support effect than piecewise excavation or internal bracing excavation,and is a fast excavation support method.The new enclosure structure uses bored pile or steel cement soil mixing pile as the retaining wall.By introducing an independent foundation as the advanced diagonal brace,a self stable diagonal brace system is formed to achieve the advanced layout of diagonal bracing and solve the development bottleneck of the traditional diagonal bracing system.In combination with the project example,the finite element numerical simulation of the new support scheme was carried out by using plaxis 3D in the early stage.Through the simulation of working conditions,it was found that the row piles in the support system were well stressed,the bending moment was evenly distributed,and the deformation of the foundation pit could be well controlled.From the monitoring feedback data in the later construction,the new support system scheme is more effective in safety,economy and construction progress than the conventional support scheme,which can provide reference for the design of foundation pit support in similar projects.