作者：王家琛1, 朱鸿鹄*1,2, 王静1, 曹鼎峰3, 苏立君2, Narala Gangadhara Reddy1,4
1.南京大学地球科学与工程学院,江苏 南京 210023;
2.中国科学院山地灾害与地表过程重点实验室,四川 成都 610041;
3.中山大学土木工程学院,广东 广州 510275;
4.印度理工学院布巴内斯瓦尔分校基础设施学院,印度 布巴内斯瓦尔 752050
摘要：毛细阻滞效应是多层、不同粒径非饱和土入渗过程中的一个自然现象。为了探究多层土水分入渗的毛细阻滞过程,设计了室内模型试验,采用主动加热光纤法（AHFO法）对多层土的水分迁移进行试验,并结合频域反射法（FDR法） 和直接观测法作为验证。试验结果表明：相较于FDR法和直接观测法,AHFO法对降雨入渗所产生的毛细阻滞现象具有较好的观测效果,可观测出水分运移的更多细节;运用FDR法,对AHFO传感器进行原位标定,曲线拟合精度R2均大于0.93,具有较高的体积含水率监测准确度;毛细阻滞层对降雨入渗具有明显的阻滞效应,即存储屏障上部入渗和减少水分向下部水体渗出。相关研究结论为毛细阻滞现象研究以及土壤水分场监测提供了一种新的监测方法。
关键词 ：毛细阻滞, 主动加热光纤法, 砂土模型试验, 降雨入渗
Laboratory model tests on capillary barrier infiltration using actively heated fiber optic method
WANG Jia-chen1, ZHU Hong-hu1,2, WANG Jing1, CAO Ding-feng3, SU Li-jun2, Narala Gangadhara Reddy1,4
1. School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China
2. Key Lab. of Mountain Hazards and Earth Surface Processes, Chinese Academy of Sciences, Chengdu 610041, China
3. School of Civil Engineering, Sun Yat-sen University, Guangzhou 510275, China
4. School of Infrastructure, Indian Institute of Technology Bhubaneswar, Bhubaneswar 752050, India
Abstract：The capillary barrier effect is a natural phenomenon during the infiltration of unsaturated soil layers with different particle sizes. In order to test the capillary barrier effect of multi-layer soils, laboratory model tests are designed. Subsequently, the actively heated fiber optic (AHFO) method is used to test the water migration of the model tests, and the direct observation method and the frequency domain reflection (FDR) technology are used for verification. The analysis of test shows that compared with the direct observation method and the FDR method, the AHFO method has a better observation effect on the capillary barrier phenomenon caused by rainfall infiltration, and can observe more details of water movement as well. The FDR method is used to perform the in-situ calibration of the AHFO sensor, and the curve-fitting accuracy R2 is greater than 0.93, indicating a high accuracy of volume water content monitoring. The capillary barrier layer has a significant retarding effect on rainfall infiltration, that is, infiltration water can be saved at the storage barrier which can also reduce seepage to the layer under the barrier. The research results may provide a new method for the research on capillary barrier effect and the monitoring of water content distribution.
Key words： capillary barrier actively heated fiber optic method sand model experiment rainfall infiltration
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