高速铁路桥梁桥下新建公路工程的安全性分析

新建公路工程下穿既有高速铁路桥梁工程时,公路施工和运营期间的恒载和活载作用会引起既有高速铁路桥梁基础的土层发生竖向和侧向变形,土层变形产生的附加应力引起既有高速铁路桥梁基础产生垂直沉降和水平位移,当上述变形超过规范要求时应重新确定下穿方案。结合某新建高速公路下穿已建成的大西高速铁路桥梁工程,从桥梁承载力、垂直沉降和水平位移等方面分析新建下穿工程引起的土层变形对大西高速铁路桥梁的安全影响,该新建公路工程以路堤占压铁路桥墩承台下穿大西高速铁路时,铁路桥墩桩基础的承载力和沉降均超出规范要求,新建公路工程实施时改为以公路桥的形式下穿大西高速铁路。

Safety Analysis of New Highway Passing under High-speed Railway Viaduct

In the construction and operation stages of highway,the dead-load and live-load may cause vertical and horizontal movement of the soil around the foundations of the existing highs-peed railway viaducts,and the additional stress caused by the soil movement may result in vertical settlement and lateral displacement of adjacent railway viaduct foundations. When the settlement and the lateral displacement excess the specifications,the design shall be otherwise reconsidered. This paper takes a completed viaduct with a highway below in Daxi high-speed railway as an example to analyze the soil movement influence on railway viaduct safety in respect of bearing capacity,horizontal displacement and settlement. The results show that where a highway underpasses railway viaduct with embankment on the railway pier cap,the bearing capacity and settlement of viaduct piles can not meet the stipulated requirements. Such is the case,a highway bridge is used below the railway viaduct.