为了研究靖远大厚度黄土在浸水条件下的水分入渗规律和自重湿陷变形特征，在中兰铁路沿线的靖远北站黄土自重湿陷场地进行了不打注水孔的现场浸水试验，监测并分析了地表及地下湿陷变形、试坑周围裂缝、含水率和土中竖向应力变化情况，对水分扩散规律、自重湿陷特性和土中竖向应力变化规律进行了研究，并对地区修正系数β0值和浸润角进行了探讨。结果表明：体积含水率变化分为浸水稳定（2个）、快速增加（1个）和缓慢增加（1个）共4个阶段；浸水过程中，水分在21 m处竖向入渗加快、径向扩散减缓，湿润峰最终形态呈现为椭圆状。根据探井和钻孔含水率测试结果，推算出浸润角最大为41°。该场地黄土自重湿陷过程历经剧烈湿陷、缓慢湿陷和固结稳定3个阶段。试验结束时共计发展了13圈环状裂缝，裂缝最远处距试坑边缘26 m。根据室内试验和现场测试结果，建议地区修正系数沿土层深度进行修正，0～10 m内β0值取1.05，10～27 m内β0值取0.95。在地表至21 m深度范围内，地基土浸水饱和且湿陷充分，土中竖向应力沿深度呈线性增加，土中竖向应力接近饱和自重应力，21 m以下的地基土未能充分湿陷，土中竖向应力逐渐减小。该研究成果可应用于中兰铁路后期的建设，并为该地区其他工程建设提供参考。大厚度黄土地基

In order to study the water infiltration and self-weight collapsedeformation characteristics of Jingyuan loess with large thickness under thecondition of immersion

a field immersion test without water injection holeswas carried out in the self-weight collapse loess site of Jingyuan NorthStation along the Zhongwei-Lanzhou Railway. The surface and undergroundcollapsible deformation

cracks

water content and vertical stress in the soilaround the test pit were monitored and analyzed. The water diffusion

self-weight collapsible characteristics and vertical stress in the soil werestudied

and the regional correction coefficient β0 value and wetting angle were discussed. The resultsshowed that: the change of volumetric water content was divided into fourstages: immersion stability (2)

rapid increase (1) and slow increase (1). Inthe immersion process

the vertical infiltration of water was accelerated andthe radial diffusion was slowed down at 21 m

and the final shape of thewetting front was presented as elliptical. According to the water content testresults of exploratory wells and boreholes

the maximum wetting angle was calculatedto be 41°. The self-weight collapse process of loess in the site went throughthree stages: severe collapsibility

slow collapsibility and consolidationstabilization. At the end of the test

a total of 13 ring cracks weredeveloped

and the farthest point of the cracks was 26 m from the edge of the test pit. Accordingto the indoor test and field test results

it was suggested that the regionalcorrection coefficient should be corrected along the depth of the soil layer

and the β0 value was taken as 1.05 within 0−10 m and 0.95 within 10−27 m. In the depthrange from the surface to 21 m

the foundation soil was saturated and fullycollapsed. The vertical stress in the soil increased linearly along the depth

and the vertical stress in the soil was close to the saturated self-weightstress. The foundation soil below 21 m failed to collapse entirely

and thevertical stress in the soil decreased gradually. The research results could beapplied to the later construction of Zhongwei-Lanzhou Railway and provide areference for other regional engineering projects.large-thickness loess foundation