1 前言 宝中线黄土分布较广,泾河、颉河流域至六盘山间,湿陷性黄土厚达10～30 m。DK173+000～DK212+800线路沿泾河、颉河左岸的漫滩及一级阶地上走行,地形平坦开阔,部分地段地形略有起伏,冲沟发育,其上部为冲积黄土质砂粘土,下部为砂粘土。从涵渠地质钻探资料分析,部分涵洞基础置于黄土质砂粘土上,呈灰黄色夹褐色,土质均匀,具有孔隙、虫穴,硬塑、中密,具有自重湿陷性,土质基本承载力较低[σ]=80～120 kPa。 小桥涵基础置于湿陷性黄土地基上,设计时分别采用强夯和三七灰土换填加固地基等处 1 Foreword Loess Plateau is widely distributed in the Loess Plateau. The thickness of collapsible loess in the Jinghe and Jiehe Watershed ranges from 10 to 30 m. DK173 +000 ~ DK212 +800 line along the Jinghe River, the left bank of Jiehe floodplain and a terrace on the ground, the terrain is flat and open, some terrain slightly ups and downs, gully development, the upper part of the alluvial loess sand, the lower part Sandy clay. According to the geological drilling data of culverts, part of the culverts are placed on loess sand with gray-brown color and brown soil with uniform soil quality, with pores, insect holes, hard plastic and medium density, with self-weight collapsible and basic soil bearing capacity Lower [σ] = 80 to 120 kPa. The foundation of small bridge and culvert is placed on the collapsible loess foundation. During design, the ground and foundation are filled with strong ram and sanskrit