石灰改良膨胀土压缩特性及力学特性研究  

Study on compression characteristics and mechanical properties of lime modified expansive soil

作　　者：龚锦林 柳厚祥 王真 GONG Jinlin;LIU Houxiang;WANG Zhen(Hunan Provincial Research Institute of Transportation Science Co.,Ltd.,Changsha 410000,China;School of Civil Engineering,Changsha University of Science&Technology,Changsha 410114,China)

机构地区：[1]湖南省交通科学研究院有限公司,湖南长沙410000 [2]长沙理工大学土木工程学院,湖南长沙410114

出　　处：《交通科学与工程》2022年第4期35-40,共6页Journal of Transport Science and Engineering

摘　　要：为研究石灰改良膨胀土的力学性能,针对石灰改良膨胀土在不同石灰掺量和养护时间情况下的压缩性能、侧限抗压强度及抗剪强度进行试验分析。研究结果表明:随着石灰掺量及养护时间的增加,石灰改良膨胀土的压缩系数均呈现先增加后稳定的变化趋势。当石灰掺量为2%时,石灰改良膨胀土的压缩系数从0.78 MPa减小至0.18 MPa;当石灰掺量超过6%时,其压缩系数的减小幅度很小。石灰改良膨胀土的无侧限抗压强度随石灰掺量的变化呈指数分布。当养护时间为1 d,石灰掺量分别为2%、4%、6%、8%时,其无侧限抗压强度分别增加至311.9、206.9、177.8和104.8 kPa。在不同养护时间内,改良膨胀土黏聚力、内摩擦角均随着石灰掺量的增加而快速增大,且黏聚力、内摩擦角随石灰掺量的变化均呈指数分布。在养护初期,改良膨胀土的黏聚力及内摩擦角快速增加,而随着养护时间的增加,石灰逐渐絮凝,导致产生的絮凝产物含量不再增加,从而使其黏聚力及内摩擦角增长变缓。该结果可为石灰改良膨胀土的工程应用提供参考。To investigate the mechanical properties of the lime-treated expansive clay,the experimental analysis of compressive properties,unconfined compressive strength and shear strength was performed on he lime-treated expansive clay with different lime content and curing time.The study showed that the compression coefficient of lime-modified expansive soil showed a trend of increasing first and stabilizing eventually with the increase of lime dosing and curing time.The change of unconfined compressive strength of improved expansive soil increases exponentially with the increase of lime content.When the samples were cured for 1 d,the lime content is 2%,4%,6%and 8%,the unconfined compressive strength increases to 311.9,206.9,177.8 and104.8 kPa,respectively.Both the cohesion and internal friction angle of the modified expansive soil increase rapidly wiithin the curing period.Those increases exponentially at early stage of curing.However,the growth rate slows down with the increase of curing time,as the lime gradually flocculates,causing the content of produced flocculation product to stop increasing.The results can provide reference for the engineering application of limeimproved expansive soil.

关 键 词：道路路堤 石灰改良膨胀土 力学特性 指数函数 

分 类 号：U416.1[交通运输工程—道路与铁道工程]