超大型深基坑对高速铁路桥墩稳定性影响分析

随着近邻高速铁路沿线房地产的开发,建筑基坑施工有可能影响到高速铁路桥梁、路基的稳定性,为了减小基坑开挖产生的不利影响,确保高速铁路行车安全,通过大型有限元软件计算以及现场位移、水位等实时检测手段进行稳定性分析,同时,研究了深基坑开挖及抽水过程对高速铁路桥梁桩基变形的影响规律及范围。结果显示,基坑自身的稳定性及其降水后的水位位置,对高速铁路桥梁桥墩的水平位移有着重要影响,且这种影响关系是复杂的,影响范围较大,因此,不能仅以基坑与高速铁路的距离是否在20m以上作为安全标准,而应根据基坑深度、大小以及需要降水的程度,结合其与高速铁路距离、地层土质力学参数等因素,综合评价其对高速铁路的影响。

Stability Analysis of Bridge Piers of High-speed Railway Affected by Adjacent Extra Large and Deep Foundation Pit

With the development of real estate adjacent to high-speed railway,the excavations of building foundation pits are likely to adversely affect the stability of bridges and subgrades of high-speed railways.In this paper,in order to reduce the adverse effects arising from excavation of foundation pits and ensure operation safety of high-speed railways,several means were utilized to analyze the stability of high-speed railway,such as finite element software calculation,field monitoring on pier displacement and water level.At the same time,the influence on the deformation of bridge pile foundation of high-speed railway and the influenced area,which were caused by deep foundation pit excavating and water pumping,were also studied.The results show that the stability of foundation pit itself and water level after being lowered have significant influence on the horizontal displacement of the bridge piers of high-speed railway; and this influence is complex,concerning a wide range.Therefore,it is suggested in this paper that the safety standard should not be based only on whether or not the foundation pit is 20 meters away from the high-speed railway; in fact,the influence on high-speed railway caused by foundation pit excavation should comprehensively be evaluated in view of excavation depth and size as well as the degree of water lowering,together with the consideration of the distance to the high-speed railway,the soil stratum mechanical parameters and other factors.