浅谈下穿铁路顶进式框架桥的设计

Design of Jacking Frame Bridge under Railway

由于结构简单,施工方便,框架桥在实际中得到了广泛的应用。为了不中断铁路运营,采用限速行车,直接顶进的桥涵称顶进式框架桥。采用顶进式施工方法是在保证铁路安全运行的前提下,在铁路路基一侧预制钢筋混凝土箱型框架结构,采用高压油泵带动油压千斤顶同时借助于预先修好的后背支撑,将框架结构顶入既有线路路基内,成为顶进式立交桥。顶进式框架桥在设计中应注意顶底板及边墙结构尺寸的布置,合理的孔跨比布置既能保证结构的安全性,又能合理地节约投资,降低造价;工作坑的设计也是顶进式框架桥设计的重要部分,工作坑后背的计算,滑板、锚梁和导向墩的设置对于结构安全有着重要的意义;必须考虑铁路运行中的防护措施设计,以保证铁路在施工过程中的安全。

Frame bridge has been widely used in practice because it’s simple and convenient. The jacking frame bridge is a way of directly jacking into the bridge and culvert by speed limited driving in order not to interrupt the railway operation. The advantage of jacking construction method is that under the premise of ensuring the safe operation of railway, the reinforced concrete box frame prefabricated on one side of the railway subgrade will be driven by high-pressure oil pump, and supported by the back of the pre-built. In the design of jacking frame bridge, attention should be paid to the layout of top and bottom plate structure size. Reasonable hole span ratio layout can ensure the safety of the structure and save investment and reduce the cost;The design of the working pit is also an important part of the design of the jacking frame bridge. The calculation of the back of the working pit and the setting of the sliding plate, anchor beam and guide pier are of great significance to the structural safety;The design of railway protection measures must be considered to ensure the safety of railway in the construction process.