| 靖远地区大厚度黄土地基浸水湿陷过程及土中竖向应力特征试验研究 |
| |
| 引用本文： | 刘德仁,安政山,徐硕昌,王旭,张转军,金芯,张严.靖远地区大厚度黄土地基浸水湿陷过程及土中竖向应力特征试验研究[J].岩土力学,2023,44(1):268-278. |
| |
| 作者姓名： | 刘德仁 安政山 徐硕昌 王旭 张转军 金芯 张严 |
| |
| 作者单位： | 1. 兰州交通大学 土木工程学院，甘肃 兰州 730070；
2. 兰州交通大学 道桥工程灾害防治技术国家地方联合工程实验室，甘肃 兰州 730070 |
| |
| 基金项目： | 国家自然科学基金资助项目(No. 41662017)。 |
| |
| 摘 要： | 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21m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26m。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，0～10m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，21m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...
|
| 关 键 词： | 大厚度黄土地基 浸水试验 湿陷变形 地区修正系数β0 水分扩散 土中竖向应力 |
| 收稿时间： | 2022-03-28 |
Experimental study on immersion collapsibility process and vertical stress characteristics of large thickness loess foundation in Jingyuan area |
| |
| LIU De-ren,AN Zheng-shan,XU Shuo-chang,WANG Xu,ZHANG Zhuan-jun,JIN Xin,ZHANG Yan.Experimental study on immersion collapsibility process and vertical stress characteristics of large thickness loess foundation in Jingyuan area[J].Rock and Soil Mechanics,2023,44(1):268-278. |
| |
| Authors: | LIU De-ren AN Zheng-shan XU Shuo-chang WANG Xu ZHANG Zhuan-jun JIN Xin ZHANG Yan |
| |
| Institution: | 1. School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou, Gansu 730070, China; 2. National and Provincial Joint Engineering Laboratory of Load & Bridge Disaster Prevention and Control, Lanzhou Jiaotong University, Lanzhou, Gansu 730070, China |
| |
| Abstract: | In order to study the water infiltration and self-weight collapse
deformation characteristics of Jingyuan loess with large thickness under the
condition of immersion, a field immersion test without water injection holes
was carried out in the self-weight collapse loess site of Jingyuan North
Station along the Zhongwei-Lanzhou Railway. The surface and underground
collapsible deformation, cracks, water content and vertical stress in the soil
around the test pit were monitored and analyzed. The water diffusion,
self-weight collapsible characteristics and vertical stress in the soil were
studied, and the regional correction coefficient β0 value and wetting angle were discussed. The results
showed that: the change of volumetric water content was divided into four
stages: immersion stability (2), rapid increase (1) and slow increase (1). In
the immersion process, the vertical infiltration of water was accelerated and
the radial diffusion was slowed down at 21 m, and the final shape of the
wetting front was presented as elliptical. According to the water content test
results of exploratory wells and boreholes, the maximum wetting angle was calculated
to be 41°. The self-weight collapse process of loess in the site went through
three stages: severe collapsibility, slow collapsibility and consolidation
stabilization. At the end of the test, a total of 13 ring cracks were
developed, and the farthest point of the cracks was 26 m from the edge of the test pit. According
to the indoor test and field test results, it was suggested that the regional
correction 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 depth
range from the surface to 21 m, the foundation soil was saturated and fully
collapsed. The vertical stress in the soil increased linearly along the depth,
and the vertical stress in the soil was close to the saturated self-weight
stress. The foundation soil below 21 m failed to collapse entirely, and the
vertical stress in the soil decreased gradually. The research results could be
applied to the later construction of Zhongwei-Lanzhou Railway and provide a
reference for other regional engineering projects. |
| |
| Keywords: | large-thickness loess foundation water immersion test collapse deformation regional correction coefficient β0 water diffusion vertical stress in soil |
|
| 点击此处可从《岩土力学》浏览原始摘要信息 |
| 点击此处可从《岩土力学》下载免费的PDF全文 |
|
