由石蜡基相变材料和煤渣改良的粉砂土的冻融性能  

Freeze-thaw properties of silty sand modified by paraffin-based phase change materials and cinder

作　　者：唐少容[1,2,3] 杜鹏[1] 李昊天 殷磊 TANG Shaorong;DU Peng;LI Haotian;YIN Lei(College of Civil and Hydraulic Engineering,Ningxia University,Yinchuan 750021,China;Ningxia Research Center of Technology on Water-saving Irigation and Water Resources Regulation,Ningxia University,Yinchuan 750021,China;Engineering Research Center for Efficient Utilization of Water Resources in Modern Agriculture on Arid Regions,Ningxia University,Yinchuan 750021,China)

机构地区：[1]宁夏大学土木与水利工程学院,宁夏银川750021 [2]宁夏大学宁夏节水灌溉与水资源调控工程技术研究中心,宁夏银川750021 [3]宁夏大学旱区现代农业水资源高效利用教育部工程研究中心,宁夏银川750021

出　　处：《中国粉体技术》2024年第1期123-131,共9页China Powder Science and Technology

基　　金：宁夏自然科学基金项目,编号:2021AAC03021;宁夏高等学校一流学科建设项目,编号:NXYLXK2021A03。

摘　　要：【目的】针对季节冻土区渠道的衬砌结构因冻融作用而受损的现状,同时为了解决石蜡基相变材料(phase change materials, PCM)的泄露,并满足煤渣的再利用需求,研究石蜡基PCM和煤渣对土体冻融性能的影响。【方法】以粉砂土为研究对象,选取石蜡基PCM和煤渣作为改良剂,制备石蜡基PCM改良土和石蜡基PCM-煤渣改良土;通过冻融循环作用下的体积变化率试验、无侧限抗压强度试验,微观结构及潜热研究土体的体积和无侧限抗压强度的变化。【结果】石蜡基PCM能抑制粉砂土的冻融变形,质量分数为8%时2种改良土的体积变化率最小;随着冻融循环次数的增加,土体的无侧限抗压强度均降低,降低速率先大后小;循环次数相同时,加入煤渣的改良土的无侧限抗压强度均大于未加入煤渣的;冻融循环9次后,石蜡基PCM质量分数为10%的石蜡基PCM改良土的无侧限抗压强度最低;2种改良土的结构比粉砂土更密实、稳定;潜热的吸收或释放延缓了土体冻融过程。【结论】将石蜡基PCM和煤渣共同掺入粉砂土,能控制土体的冻融变形且效果稳定,改善土体的冻融性能,减轻季节冻土区输水渠道衬砌结构的冻害,提高煤渣的利用率。Objective In view of the current situation the lining structure of farmland water transmission channel is frequently damaged due tofreeze-thaw cycles in areas with seasonal frozen soil.To solve the leakage problem of paraffin-based phase change materials(PCM)and meet the recycling demand of cinder in local thermal power plants,paraffin-based PCM and cinder are added into the channel soil as additives and the primary focus is on studying the mechanism of improving the freeze-thaw performance of soil.Additionally,the impact of the latent heat effect of paraffin-based PCM on temperature field within seasonally frozen soil is also analyzed.Methods The silty sand collected from a channel in Ningxia was used as the research object.Paraffin-based PCM and cinder were selected as the improver to prepare two distinct types of improved soil:paraffin-based PCM improved soil and paraffin-based PCM-cinder improved soil.Through the volume change rate test and unconfined compressive strengh test under the freeze-thaw cycle,the volume change rate and unconfined compressive strength of silty sand and the improved soil were analyzed.Besides,an analysis of the microstructure and latent heat changes of the improved soil before and after the freeze-thaw cycle was also conducted.This comprehensive approach allowed for a thorough investigation into the combined effects of paraffin-based PCM and cinder on the freeze-thaw properties of the improved soil.Results and Discussion The freeze-thaw deformation of silty sand can be inhibited by PCM.However,the volume change of paraffin-based PCM improved soil lacks stability with the increase of the freeze-thaw cycles.When the mass fraction of paraffin-based PCM is 8%,the volume change rate of the two improved soils is the smallest.Cinder can reduce the leakage of paraffin-based PCM,and the volume change rate of paraffin-based PCM decreases with the increase of the content of paraffin-based PCM.In contrast the adsorption effect of cinder on the paraffin-based PCM gradually decreases with the incr

关 键 词：石蜡基相变材料 煤渣 改良土 粉砂土 冻融性能 

分 类 号：TU445[建筑科学—岩土工程] TB4[建筑科学—土工工程]