郑西铁路客运专线路基防排水技术研究

Research on Technology of Water Control and Drainage for Subgrade of Zhengzhou-Xi'an Passenger Dedicated Line

研究目的:郑西铁路客运专线沿线的黄土广泛分布,湿陷性黄土区段占全线总长度的65%,湿陷程度从轻微(Ⅰ级)到严重(Ⅳ级),涵盖了我国湿陷性黄土的全部类型。在这样复杂的工程地质地段修建高速铁路,具有极大的不确定性和挑战性。因此,郑西铁路客运专线开工建设前期,根据沿线黄土丘陵、伊河和洛河二级阶地、黄土塬、黄河二级阶地、渭河二级阶地等不同地貌单元特点,选择典型的试坑浸水试验场地,在充分浸水条件下,查明湿陷性黄土在大面积浸水条件下的影响范围,并为地基处理和防排水设计提供试验资料。研究结论:通过试验研究表明:8个现场浸水试验场地完全浸水后的浸润线斜率在1.3～6.0之间;试坑外15 mm湿陷变形量发生位置距浸水试坑边的水平距离自东向西逐渐增大,为6～15 m;防排水措施距路肩的水平距离为0.2～0.5倍的湿陷性黄土层厚度,设计深度在DK233～DK250段、DK250～DK321段和DK321～DK356段分别为0.32H-1.60a、1.53H-3.40a、0.88H-1.75a。

Research purposes： Loess exists widely in the area along the Zhengzhou-Xi＇an Passenger Dedicated Line,with length of collapsible loess section accounting for 65% of the total railway length.The collapsible loess covers all types of loess in China,with degrees from Grade to Grade Ⅳ.Construction of high-speed railway in such a area with complex geological condition faced the much uncertainty and challenges Therefore,at the early stage of construction,the soaking tests were done in the typical test pits according to the different topographical features of the loess plateau,the second-order terraces of Yi River and Luo River,the loess tableland,the second-order terraces of the Yellow River and the Wei River,so as to seek the influence range of collapsible loess under condition of soaking in large floor for the purpose of providing the tested data for foundation treatment and design of water control and drainage.Research conclusions：The tests and researches showed the saturation-line rates of 8 soaking test fields under fully soaking were between 1.3 ～ 6.0.The horizontal distance between the area where the collapsible deformation happened and the side of soaking test pit increased gradually to 6-15 m from east to west out of the test pit of 15 mm.The horizontal distance between the area where the waterproof measures were taken and the shoulder was 0.2 ～0.5 times of the loess layer＇s thickness.The design depths were 0.32H-1.60a,1.53H-3.40a and 0.88H-1.75a separately for the areas of DK 233-DK 250,DK 250-DK 321 and DK 321-DK 356.