石灰改良膨胀土工程主要特性试验研究-以广西南宁地区膨胀土路堤为例  

Study on the Engineering Mechanical Properties of Lime-modified Expansive Soil Under the Wetting-drying Cycles

作　　者：王小芳 程谦恭 李俊 刘文方 WANG Xiaofang;CHENG Qiangong;LI Jun;LIU Wenfang(School of Civil Engineering,Sichuan University of Science ＆ Engineering,Zigong 643000,China;Faculty of Geosciences and Enviromnental Engineering,Southwest Jiaotong University,Chengdu 610031,China;Sichuan Province University Key Laboratm7-of Bridge Non-destruction Detecting and Engineering Computing,Zigong 643000,China)

机构地区：[1]四川理工学院土木工程学院,四川自贡643000 [2]西南交通大学地球科学与环境工程学院,成都610031 [3]桥梁无损检测与工程计算四川省高校重点实验室,四川自贡643000

出　　处：《四川理工学院学报（自然科学版）》2018年第5期81-87,共7页Journal of Sichuan University of Science & Engineering(Natural Science Edition)

基　　金：国家自然科学基金(41530639;41372292);四川省安全生产科技项目(aj20170601105926)

摘　　要：研究干湿循环作用下石灰改良膨胀土的工程主要特性对其工程应用具有重要意义。以广西南宁铁路枢纽动车运用所的石灰改良膨胀土路堤为研究对象,基于室内离心模型实验仪器,设计降雨-加热系统,通过三次干湿循环试验,分析路堤模型在干湿循环过程中土压力、吸力、含水率、温度等工程主要特性的变化规律。研究结果如下:(1)经过三次干湿循环后,路堤边坡并没有发生明显变形与破坏。(2)在加热蒸发阶段,土压力随时间减小、吸力随时间增加;在降雨入渗阶段,土压力随时间增大、吸力随时间降低。(3)含水率在蒸发阶段随时间减少,降雨阶段随时间增加;埋深越浅,含水率的变化幅度越大。(4)土层温度在加热蒸发阶段变化较大,降雨对其影响不大。(5)土水特征曲线显示吸力在蒸发阶段随含水率的降低而增加,在降雨阶段随含水率的升高而减小;脱湿和吸湿两阶段的土水特征曲线不重合。It is of great significance to study the engineering characteristics of lime-modified expansive soil under dry and wet circulation. Taking the lime-modified expansive soil embankment of Gualgxi Nanning Railway Hub Station as the research object, based on the laboratory centrifuge model experimental instrument, the rainfall heating system is designed, and through three dry and wet cycle tests, the variation law of soil pressure, suction, moisture content and temperature during dry and wet circulation of embankment model is analyzed. The research results are shown as follows ： （ 1 ） After three dry and wet cycles, there is no obvious deformation and failure of embankment slope. （2） In the heating evaporation stage, the earth pressure decreased with time, while the suction increased. At the stage of rainfall infiltration, the earth pressure increased with time, while the suction decreased. （3）The moisture content decreased with time in evaporation stage and increased in rainfall stage; The shallower the buried depth, the larger the variation range of water eontentis. （4）The temperature changed greatly in the stage of heating and evaporation, but rainfall has little effect on it. （5）The soil-water characteristic curve showed that the suction increased with the decrease of water content in evaporation stage and decreased with the increase of it in rainfall stage. The characteristic curves of soil-water in the two stages of dehumidification and moisture absorption did not coincide.

关 键 词：石灰改良膨胀土 工程力学特性 离心模型试验 干湿循环 

分 类 号：U416.167[交通运输工程—道路与铁道工程]