斜交超浅埋地铁段桩板结构路基的设计与施工研究

在与超浅埋上海地铁#9线斜交的沪杭客运专线某段线路施工中，存在着地铁盾构管片扰动破环与上部开挖引起地铁盾构上浮这两大技术难题，经过设计比选，提出桩板结构路基的结构型式、几何尺寸与计算方案；考虑超浅埋地铁地段施工的高风险性，提出桩板结构路基的关键施工技术，包括:全套管钻孔桩施工技术、结构施工工艺流程等。实践证明，在斜交超浅埋地铁段，采用桩板结构路基在施工与运营期间未出现安全隐患，桩板结构路基有效控制了沉降变形，达到了确保既有地铁安全运营的目的。

Study on Design and Construction of Subgrade in Pile-board Structure for Skewed Over-shallow-embedded Metro Section

In the construction of Shanghai-Hangzhou Passenger Dedicated Line and Shanghai Skewed Over-shallow-embedded Metro Line 9，two world-level technical problems，destruction of shield segment disturbance and upward moving of the shield caused by excavation at the upper portion，arisen.Through comparison of design schemes，subgrade in pile-board structure is proposed with the geometric dimension and calculation procedure thereof.Considering high risk of construction of over-shallow-embedded metro section，the key techniques for such subgrade is put forward，including cased borehole pile construction and structural construction process.The practice has proved that in skewed over-shallow-embedded metro section，subgrade in pile-board structure does not lead to any potential safety hazard in the course of construction and operation.It controls settlement and deformation effectively，ensuring safe operation of the existing metro.