【摘要】 以改性钠羧甲基纤维素加固土法在季冻区边坡水土流失的治理和应用推广为研究背景,基于室内试验,研究冻融循环次数和冻融低温温度对加固黄土和粉砂土体积、抗剪强度、渗透系数和耐久性的影响规律及加固土颗粒及结构在冻融循环过程中的变化。发现在反复冻融循环过程中,加固黄土和粉砂土的体积和渗透系数随循环次数增加而增大,抗剪强度和耐久性随冻融次数的增加而减小;加固黄土和粉砂土12次冻融循环后试样冻胀体积和抗剪强度随冻结温度降低而减小,渗透系数随温度降低而增大,耐久性随温度降低而减小,但减小幅度随温度降低越来越小;加固黄土作为相对细的土冻胀变形更显著,渗透系数变化更明显,而加固粉砂土作为相对粗的土颗粒间胶结作用更弱,黏聚力变化更显著,两者耐久性受冻融循环影响变化规律相似;M-CMC与颗粒间的包裹吸附胶结增强了土壤结构稳定性,使得黄土和粉砂土随水融次数增加试样含水率不断提高,试样体内液态水凝结成冰晶体时的冻胀作用增强,这是加固土团聚粒发生塑性变形甚至断裂变形的主要原因,导致加固土结构损伤劣化,改良性能受到影响;与此同时,由于M-CMC材料的延展性,使得材料与颗粒间胶结具有"弹性"减缓了冻胀损伤,提高加固土的冻融耐久性。更多还原

【Abstract】 A soil stabilization method using modified carboxymethyl cellulose(M-CMC) is developed to control soil loss of slope in seasonal frozen region. A series of laboratory experiments is conducted to study the effect of the number of freeze and thaw cycles and freezing temperatures on the shear strength,infiltration coefficient,structure and durability of stabilized loess and fine silty sand. Results show that the volume and infiltration coefficient of stabilized soil increase with the increasing of number of freeze and thaw cycles,but shear strength decreases. Volume,shear strength and durability decrease with the decreasing of frozen temperature,but infiltration coefficient increases. The volume and infiltration coefficient of stabilized loess changes more significantly compared to that of stabilized fine silty sand experiencing to frozen action. Meanwhile,the internal friction stress of silty sand changes more significantly compared to loess as the cementation of sand is weak. The durability both two stabilized soil shows similar trend. The coated cementation and adsorption between M-CMC and soil particles make a steady structure to increase water binding capacity. Hence,water content of soil specimens increases subjecting to frost heaving and thawing process. The higher sample?s water content is,the more serious plastic deformation and damage between aggregates is. This is the main reason why plastic deformation and even crack are generated for aggregate. Then the structure of stabilized soil is damaged and the properties of soil are affected. However,frost heaving damage from frozen are released and the durability of stabilized soil was held under the elastic connection between M-CMC and particles.更多还原