不同初始含水量和容重条件下紫色土坡耕地埂坎土壤膨胀特征  

Soil Expansivity of Bund Soil under Various Initial Moisture Contents and Bulk Densities on Purple-soil Sloping Farmlands

作　　者：邱健 韦杰[1,2] 李进林 QIU Jian;WEI Jie;LI Jin-lin(Chongqing Key Laboratory of Remote Sensing of Surface Processes and Environment in the Three Gorges Reservoir Area,Chongqing Normal University,Chongqing 401331,China;Chongqing Field Scientific Observatory of Surface Ecological Processes in the Three Gorges Reservoir Area,Chongqing 401331,China;Chongqing Institute of Green and Intelligent Technology,Chinese Academy of Sciences,Chongqing 400714,China)

机构地区：[1]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 [2]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 [3]中国科学院重庆绿色智能技术研究院,重庆400714

出　　处：《土壤通报》2025年第1期117-126,共10页Chinese Journal of Soil Science

基　　金：重庆师范大学博望学者领军人才项目资助。

摘　　要：【目的】探究不同初始含水量、容重下紫色土坡耕地埂坎土壤膨胀特征,为埂坎管护措施优化提供依据。【方法】选取三峡库区典型紫色土坡耕地埂坎为研究对象,模拟试验不同初始含水量、容重下埂坎土壤吸水膨胀过程,分析初始含水量、容重对埂坎土壤膨胀量、无荷膨胀率、膨胀速率、膨胀量变化率的影响。【结果】(1)紫色土坡耕地埂坎土壤膨胀量时间曲线可划分为快速线性膨胀(I)、缓慢非线性膨胀(II)、膨胀稳定(III)三个阶段。线性膨胀速率变化范围为0.33%h-1~30.09%h-1,初始含水量越小,线性膨胀速率越快;初始容重越大,线性膨胀速率越慢,线性膨胀阶段历时越长。无荷膨胀率、线性膨胀速率的变化幅度随初始容重升高而增大,随初始含水量升高而减小。(2)同一初始容重下,无荷膨胀率和各阶段膨胀速率均与初始含水量呈显著负相关(P<0.01);同一初始含水量下,线性膨胀速率与初始容重呈显著负相关(P<0.01),线性膨胀阶段持续时长与初始容重呈显著正相关(P<0.01)。无荷膨胀率变化范围为1.25%~16.15%,低初始含水量(100 g kg^(-1))时,无荷膨胀率随土壤初始容重增大而增大,初始含水量超过150 g kg^(-1)后,无荷膨胀率随初始容重增大呈先增(容重1.2~1.4 g cm^(-3))后减(容重1.5~1.7 g cm^(-3))的趋势变化。(3)无荷膨胀率、线性膨胀速率受初始含水量和初始容重的交互作用影响显著(P<0.01),随着初始含水量和初始容重同时升高,无荷膨胀率、线性膨胀速率总体呈降低趋势变化。【结论】适量增大紫色土埂坎土壤容重配合水土保持措施提升埂坎土壤水分含量,可控制土壤膨胀潜势。[Objective]This study investigates the expansive characteristics of bund soil in purple-soil sloping farmlands under varying initial moisture contents and bulk densities,aiming to provide a scientific basis for optimizing bund management and protection measures.[Method]The research focused on typical bund soil from purple-soil sloping farmlands in the Three Gorges Reservoir Area.A series of simulation experiments were conducted to examine the water absorption and expansion processes of bund soil under different initial moisture contents and bulk densities.The effects of these factors on expansion height,unloaded expansion rate,expansion rate,expansion change rate and other parameters were analyzed.[Results]①The expansion time curve of bund soil can be divided into three stages:rapid linear expansion(I),slow nonlinear expansion(II),and stable expansion(III).The linear expansion rate varied from 0.33%h-1 to 30.09%h-1.Lower initial moisture content led to faster linear expansion rates,while higher initial bulk density resulted in slower linear expansion rates and longer durations.The range of variation in unloaded expansion rate and linear expansion rate increased with higher initial bulk density but decreased with higher initial moisture content.②Under the same initial bulk density,the unloaded expansion rate and expansion rate were significantly negatively correlated with initial moisture content(P<0.01).Conversely,under the same initial moisture content,the linear expansion rate was significantly negatively correlated with initial bulk density(P<0.01).The duration of the linear expansion stage was significantly positively correlated with initial bulk density(P<0.01).The unloaded expansion rate ranged from 1.25%to 16.15%.When initial moisture content was low(100 g kg^(-1)),the unloaded expansion rate increased with increasing initial bulk density.However,when initial moisture content exceeded 150 g kg^(-1),the unloaded expansion rate initially increased(bulk density 1.2-1.4 g m^(-3))and then decreased(bulk den

关 键 词：坡耕地埂坎 土壤膨胀性 土壤水分 土壤容重 

分 类 号：S157.1[农业科学—土壤学]