含水率和干密度对三峡库区紫色土膨胀特性的影响  

Effects of Moisture and Dry Density on the Swelling Characteristics of Purple Soil in the Three Gorges Reservoir Area

作　　者：薄纯悦 刘春红[1,2,3] 冷佳欣[1,2] 陈聪 BO Chunyue;LIU Chunhong;LENG Jiaxin;CHEN Cong(College of Geography and Tourism Science,Chongqing Normal University,Chongqing 401331,China;Chongqing Key Laboratory of Surface Process and Ecological Restoration in the Three Gorges Reservoir Area,Chongqing 401331,China;Chongqing Field Observation and Research Station of Surface Ecological Process in the Three Gorges Reservoir Area,Chongqing 401331,China)

机构地区：[1]重庆师范大学地理与旅游学院,重庆401331 [2]重庆师范大学三峡库区地表过程与生态修复重庆市重点实验室,重庆401331 [3]三峡库区地表生态过程重庆市野外科学观测研究站,重庆401331

出　　处：《土壤》2024年第6期1381-1389,共9页Soils

基　　金：国家自然科学基金项目(42107355);重庆市基础研究与前沿探索项目(cstc2018jcyjAX0489);三峡库区地表过程与环境遥感重庆市重点实验室开放基金项目(DBGC201805)资助。

摘　　要：为明晰土壤初始含水率和干密度对紫色土土体膨胀过程机制的影响,选取三峡库区典型紫色土为研究对象,通过室内无荷膨胀试验,采用双因素方差分析、响应面分析,探讨不同初始含水率(5%、10%、15%、20%、25%)、土壤干密度(1.1、1.3、1.5 g/cm3)的紫色土无荷膨胀特征。结果表明:①紫色土无荷膨胀率随时间的变化规律可分为快速膨胀、缓慢膨胀和膨胀稳定3个阶段;②在快速膨胀、缓慢膨胀阶段紫色土无荷膨胀率呈对数增长,采用对数函数对紫色土膨胀时程进行拟合,拟合效果较好(R^(2)均大于0.65);紫色土无荷膨胀率随初始含水率升高而降低,随干密度增加而升高;方差分析表明,土壤初始含水率、干密度及两者交互作用对紫色土无荷膨胀率的影响极显著(P<0.01);响应面关系模型可较好地反映土壤初始含水率、干密度与紫色土无荷膨胀率的关系(R^(2)=0.92);③紫色土膨胀过程与吸水过程具有过程上的一致性,多在吸水初期发生大幅膨胀,紫色土含水率达到稳定状态所需时长均短于土壤膨胀率稳定状态耗时。研究结果可为三峡库区的农业可持续发展和紫色土资源保护提供科学依据。In order to clarify the effects of initial soil moisture and dry density on the expansion process mechanism of purple soil,the typical purple soil was selected in the Three Gorges Reservoir area for indoor unloaded expansion test,two-factor analysis of variance and response surface analysis were used to investigate the unloaded expansion characteristics under different initial moistures(5%,10%,15%,20%,25%)and dry densities(1.1,1.3,1.5 g/cm^(3)).The results showed that:1)The variation of the unloaded expansion rate with time was obvious,which could be divided into three stages:rapid expansion,slow expansion and stable expansion.2)In the stages of rapid and slow expansions,the unloaded expansion rate increased logarithmically,and the semi-logarithmic function was used to fit the expansion time course,and the fitting effect was better(R^(2)>0.65).The unloaded swelling rate decreased with the increase of initial moisture,when the dry density was increased,the unloaded swelling rate increased.The analysis of variance showed that the initial moisture,dry density and their interaction had significant effects on the unloaded swelling rate(P<0.01).The response surface relationship model could better reflect the relationship between the initial moisture,dry density and the unloaded expansion rate(R^(2)=0.92).3)The expansion process was consistent with the water absorption process,and most of them expanded greatly in the initial stage of water absorption.The time reaching to the stable state required was shorter for the moisture than that for soil expansion rate.The results can provide scientific basis for sustainable development of agriculture and protection of purple soil resources in the Three Gorges Reservoir area.

关 键 词：三峡库区 紫色土 无荷膨胀率 初始含水率 干密度 

分 类 号：S157.1[农业科学—土壤学]