顶进框架桥下穿京沪铁路与京沪高速铁路预留立交桥对接的设计探索和实践

Reserved Overpass on Beijing-Shanghai High Speed Railway Connected with the Rigid Frame Bridge Jacked through Existing Beijing-Shanghai Railway: Design and Practice

河北省廊坊市规划龙河园区路下穿京沪高速铁路和既有京沪铁路,该地区地下水位较高,地基土质大多为粉质黏土,渗透系数小,京沪高速铁路已预留了立交桥,为了实现下穿顶进框架桥在既有京沪铁路下与京沪高铁预留立交桥的成功对接,同时将施工对京沪高速铁路的影响减少到最小的目的,通过理论上分析施工降水对京沪高速铁路影响,在设计上采取有效的止水措施,同时将对接处的施工方案进行细化、优化等方法,保证了框架桥的顺利顶进到位,同时也将顶进施工对京沪高速铁路的影响减少在了可控制的范围内。从设计上看,在京沪高速铁路路基外侧设置足够长和深的止水帷幕,工作坑四周设置止水帷幕形成一个封闭的降水区域,在框架桥的顶进过程中及时进行封水等措施,起到了很好的止水效果,保证了施工降水时京沪高速铁路路基附近水位不变化,确保了京沪高速铁路的路基稳定。

Park Road in Langfang city of Hebei Province was planned to under-cross Beijing-Shanghai high speed railway and the existing Beijing-Shanghai railway. The area features high water table, mostly silty clay soil with small permeability coefficient. In order to achieve the successful connection of the framed bridge jacked under-crossing the existing Beijing-Shanghai railway with the reserved Beijing- Shanghai high-speed railway overpass, to minimize the impact of construction on Beijing-Shanghai high-speed railway, effective sealing measures, construction program refinement, optimization and other methods were adopted to ensure the smooth jacking of the framed bridge in place, to reduce the impact on high-speed rail in the control range. From the design aspect, long enough and deep waterproofing curtains were set along the railway embankment, four sides of work pits were closed by sealing curtains, in the process of the bridge jacking, water stopping and other measures were adopted timely, with very good sealing effect achieved, which ensured the water level near the railway embankment maintained without change, and also the stability of the embankment.