单探针热脉冲法对红壤土失水过程的监测  

Monitoring of red soil dehydration process by single probe heat pulse method

作　　者：韦昊延 耿宁 成静清 孔琼菊 胡优 李敏 WEI Haoyan;GENG Ning;CHENG Jingqing;KONG Qiongju;HU You;LI Min(Key Laboratory of Poyang Lake Water Resources and Environment of Jiangxi Province,Jiangxi Academy of Water Science and Engineering,Nanchang 330029,China;Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas of Ministry of Education,Northwest A&F University,Yangling 712100,China)

机构地区：[1]江西省水利科学院江西省鄱阳湖水资源与环境重点实验室,江西南昌330029 [2]西北农林科技大学旱区农业水土工程教育部重点实验室,陕西杨凌712100

出　　处：《水资源与水工程学报》2024年第5期201-208,共8页Journal of Water Resources and Water Engineering

基　　金：江西省鄱阳湖水资源与环境重点实验室开放基金项目(2021SKSH07);国家自然科学基金项目(42307392);国家重点研发计划项目(2021YFD1900700)。

摘　　要：实现土壤失水过程的原位监测,对红壤区水土资源管理、自然灾害预警及防灾减灾具有重要意义。热脉冲法是目前土壤水热特性原位测量的常用方法,但红壤土失水时极易产生裂缝,单探针热脉冲法能否准确测定失水过程目前尚不清楚。通过室内模拟土壤从饱和到干燥的连续失水过程,用时域反射法(TDR)作为标准对照,验证热脉冲方法测定土壤失水过程的准确性,并评估土壤裂缝产生后对单探针热脉冲法的影响。结果表明:随着土壤失水,土壤热导率K值由1.8 W/(m·K)减小到1.1 W/(m·K),热扩散率α值由1.0×10^(-8)m^(2)/s增加到3.0×10-8 m 2/s,比热容C值由1.8×108 J/(kg·K)减小到0.4×10^(8)J/(kg·K);接触热导率H值随着土壤失水具有台阶状变化特征,与土壤含水率变化速率的转折相吻合;与TDR测定结果相比,MAE和RMSE值分别为1.66和1.94 cm 3/cm^(3),R^(2)值为0.96;单探针热脉冲法能提供可靠的红壤土失水过程测定结果,且H值的变化能指征土壤裂隙的产生,可为土壤干湿循环过程、边坡和堤坝稳定性的动态监测提供技术和理论支撑。The in-situ monitoring of soil dehydration process is of great significance for soil and water resources management,natural disaster warning,and disaster prevention and reduction in red soil areas.The heat pulse method is commonly used for in-situ measurement of soil water and thermal characteristics;however,cracks are likely to occur when red soil loses water,it is still unclear whether the single probe heat pulse method can accurately monitor the dehydration process.This study simulated the continuous dehydration process of soil from saturation to drying by laboratory experiments,and used time-domain reflection(TDR)method as a standard to verify the accuracy of heat pulse method in monitoring soil dehydration process.In the meantime,the influence of soil crack generation on the performance of single probe heat pulse method was evaluated.The results showed that with soil dehydration,the soil thermal conductivity(K)decreased from 1.8 to 1.1 W/(m·K),the thermal diffusion rate(α)increased from 10×10^(-9)to 30×10^(-9)m^(2)/s,and the specific heat capacity(C)decreased from 180×106 to 40×10^(6)J/(kg·K).In addition,the contact thermal conductivity(H)exhibited a step-like variation characteristic with soil dehydration,which was consistent with the turning points of soil water content change rate,and the H value indicated the formation of soil cracks.Compared with the results of TDR,the MAE and RMSE values of the soil water content during the dehydration process monitored by the single probe heat pulse method were 1.66 and 1.94 cm^(3)/cm^(3),respectively,with a R^(2)value of 0.96.The findings indicate that the single probe heat pulse method can provide reliable results for monitoring the dehydration process of red soil,and the variation of H value have an indicative significance for the generation of soil cracks.This method can provide a technical and theoretical support for the dynamic monitoring of soil wetting and drying cycle process,as well as slope and dam stability.

关 键 词：红壤土 失水过程 热脉冲方法 含水率 单探针 

分 类 号：S152.8[农业科学—土壤学]