黄土地区高速铁路桥梁设计

Design of High Speed Railway Bridges in Loess Area

中卫至兰州客运专线沿线多为黄土地区,地形起伏较大,地质条件复杂,在黄土深沟陡坡上进行桥梁设计是本线的一大难题。文章结合中兰客运专线的地形地质特征,重点从桥梁布设原则、墩台刷方边坡稳定性、桩基自由桩长的确定及桥台设置等方面,对本线黄土深沟陡坡地段桥梁设计进行了深入阐述。针对湿陷性黄土的工程地质特性,分别对非自重湿陷性黄土和自重湿陷性黄土提出了桩基负摩阻力的取值范围,研究了桩侧负摩阻力的计算深度和m值的计算原则,修正了现行《铁路桥涵地基和基础设计规范》对湿陷性黄土地区基础沉降的计算方法,并简要介绍了黄土地区桥梁基础施工的注意事项和应采取的相关工程措施,为类似地区桥梁工程的设计与施工提供了实用经验。

Along Zhongwei-Lanzhou Passenger Dedicated Line,it is covered with loess areas,which is accompanied with big topographic relief and complicated geological conditions,so bridge design on the loess ditch slope is a big problem to this line. By analyzing the characteristics of bridge design on the loess deep groove of steep slope area,combining with the landform features of Zhongwei- Lanzhou Passenger Dedicated Line,this thesis gives a deep exposition of the bridge design of the on loess ditch slope area. It is focused on the setting of bridge,the stability of brush abutment slope,the free pile length and the set of abutment,etc. According to the engineering geological characteristics of collapsible loess,respectively to self weight collapse and non-weight collapse,the value scope of negative skin friction resistance of pile foundation has been put forward,the calculation of negative skin friction and the principle of M value calculation are studied in depth, and the current foundation settlement computing method of specification of railway bridges in collapsible loess area has been corrected. This paper briefly introduces the attention and measures of pile foundation in construction. The conclusion provides reference for engineering design and construction of bridge in similar areas.