摘要
[目的]砾石是影响土壤孔隙和水分入渗的重要因素,明确砾石通过改变哪些土壤孔隙特征进而影响水分入渗具有重要意义。[方法]以西南喀斯特地区砾石含量高的石灰土为研究对象,采用CT扫描和室内一维土柱入渗试验,对比分析2种砾石粒径(2.0~5.0,5.0~12.5 mm)和5种砾石含量(0,10%,20%,30%,40%)条件下的土壤孔隙特征及水分入渗特性,并使用结构方程模型探究土壤孔隙特征与入渗特性之间的耦合关系。[结果](1)含砾石土壤的大孔隙度、孔隙连通率、孔隙形状因子、孔隙表面积和孔隙体积均高于无砾石土壤;且当砾石含量为20%和30%时,孔隙连通率与孔隙形状因子和无砾石土壤之间存在显著性差异(p<0.05);(2)砾石改善土壤入渗性能,粒径为2.0~5.0 mm时,砾石含量从10%到40%的稳定入渗率分别是无砾石土壤的4.02,5.00,2.88,5.14倍,累积入渗量分别是1.67,1.76,2.49,2.39倍;粒径为5.0~12.5 mm时,土壤稳定入渗率分别是无砾石的2.20,2.67,4.78,2.78倍,累积入渗量分别是1.42,1.75,2.46,2.02倍。(3)在结构方程模型中砾石含量与孔隙连通率、孔隙等效直径呈正相关关系,孔隙连通率对稳定入渗率的影响最大,孔隙等效直径对累积入渗量的影响最大。[结论]砾石含量主要通过增加土壤孔隙连通率和孔隙等效直径促进水分入渗,研究结果可为深入认识西南喀斯特地区含砾石土壤的水文过程提供科学依据与理论参考。
[Objective]Gravel is an important factor affecting soil porosity and water infiltration.Therefore,it is of great significance to determine the specific soil porosity characteristics that are impacted by gravel-induced changes.[Methods]Taking lime soil with high gravel content in southwest karst area as the research object,CT scanning and one-dimensional soil column infiltration test were used to compare and analyze the soil pore characteristics and water infiltration characteristics under two gravel particle sizes(2.0~5.0 and 5.0~12.5 mm)and five gravel contents(0,10%,20%,30%,40%).The structural equation model was used to explore the coupling relationship between soil pore characteristics and infiltration characteristics.[Results](1)The macroporosity,pore connectivity,pore shape factor,pore surface area and pore volume of gravel-bearing soil are higher than those of gravel-free soil.When the gravel content was 20%and 30%,there was significant difference between pore connectivity and pore shape factor(p<0.05).(2)Gravel improved soil infiltration performance,with stable infiltration rates of gravel content from 10%to 40%being 4.02,5.00,2.88 and 5.14 times higher than those of gravel-free soils,and cumulative infiltration being 1.67,1.76,2.49 and 2.39 times higher,respectively,for particle sizes ranging from 2.0 to 5.0 mm.When the particle size was 5.0~12.5 mm,the stable infiltration rate was 2.20,2.67,4.78 and 2.78 times of that without gravel,and the cumulative infiltration amount was 1.42,1.75,2.46 and 2.02 times of that without gravel,respectively.(3)In the structural equation model,gravel content was positively correlated with pore connectivity and pore equivalent diameter.Pore connectivity had the greatest influence on the steady infiltration rate,and pore equivalent diameter had the greatest influence on the cumulative infiltration rate.[Conclusion]Gravel content promotes water infiltration mainly by increasing soil pore connectivity and pore equivalent diameter.The research results can provide scientific bas
作者
黄光灵
王星
徐勤学
敖利满
秦湛博
张帅普
HUANG Guangling;WANG Xing;XU Qinxue;AO Liman;QIN Zhanbo;ZHANG Shuaipu(Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area,Guilin University of Technology,Guilin,Guangxi 541006,China;The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control,Guilin University of Technology,Guilin,Guangxi 541006,China;Guangxi Institute of Hydraulic Research,Nanning 530023,China)
出处
《水土保持学报》
CSCD
北大核心
2024年第4期312-321,334,共11页
Journal of Soil and Water Conservation
基金
广西重点研发计划项目(桂科AB22035058)
国家自然科学基金项目(42067014,51769005)。
关键词
砾石
CT
土壤孔隙
入渗
结构方程模型
rock fragments
CT
soil pores
infiltration
structural equation model
