非补水条件下同心压实黄土的冻融特性
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摘要
为揭示宁夏压实黄土在非补水条件下的冻融特性,结合当地地域特点,设计正交试验方案,采用封闭系统一维单向冻融试验方法,研究了宁夏压实黄土的冻胀融沉变形随压实度、饱和度和冻融循环次数变化的规律;建立了冻胀率、融沉系数与压实度、饱和度和冻融循环次数的关系模型。结果表明:非补水条件下,冻融循环对压实黄土的冻融变形有明显影响;饱和度越大,影响越明显。饱和度<40%时,试样表现为冻缩融胀现象;且压实度越大,冻缩融胀越明显。冻胀率与融沉系数均随压实度的增大而减小,随着饱和度的增大非线性增大。压实度和饱和度对冻融变形的影响非常显著;尤其是饱和度的影响,饱和度由40%增加至85%,冻胀率最大增量约5%。建立的冻胀率和融沉系数的模型显著性高,与各因素有很好的相关性,可用于预测封闭系统非补水条件下压实黄土的冻融变形。
In order to reveal the freeze-thaw characteristics of compacted loess in Ningxia under non water supply conditions,combined with the characteristics of local area,the orthogonal experimental scheme was designed,and the one-dimensional unidirectional freeze-thaw test method used closed system. The variation of freeze-thaw deformation was studied,relation model between frost heaving ration,thawing settlement coefficient and saturation,compaction,freeze-thaw cycles was established. The results show that under non water supply conditions,the freeze-thaw cycle has a significant effect on the freeze-thaw deformation of compacted loess. When the saturation is less than 40%,the sample shows the phenomenon of freeze-shrinkage,the frost heave ratio and the thawing coefficient decrease with the increase of compaction degree,and increase nonlinearly with the increase of saturation,compactness and saturation the effect of degree on freeze-thaw deformation is very significant,especially the effect of saturation. The saturation increases from 40% to 85%,the maximum increase of frost heave rate is about 5%.The established model of frost heaving rate and melting coefficient is highly significant,which can be used to predict the freeze-thaw deformation of compacted loess under the condition of no water supply with closed system.
In order to reveal the freeze-thaw characteristics of compacted loess in Ningxia under non water supply conditions,combined with the characteristics of local area,the orthogonal experimental scheme was designed,and the one-dimensional unidirectional freeze-thaw test method used closed system. The variation of freeze-thaw deformation was studied,relation model between frost heaving ration,thawing settlement coefficient and saturation,compaction,freeze-thaw cycles was established. The results show that under non water supply conditions,the freeze-thaw cycle has a significant effect on the freeze-thaw deformation of compacted loess. When the saturation is less than 40%,the sample shows the phenomenon of freeze-shrinkage,the frost heave ratio and the thawing coefficient decrease with the increase of compaction degree,and increase nonlinearly with the increase of saturation,compactness and saturation the effect of degree on freeze-thaw deformation is very significant,especially the effect of saturation. The saturation increases from 40% to 85%,the maximum increase of frost heave rate is about 5%.The established model of frost heaving rate and melting coefficient is highly significant,which can be used to predict the freeze-thaw deformation of compacted loess under the condition of no water supply with closed system.
引文
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8潘鹏,郝佳兴,崔自治,等.冬灌区黄土压缩性的反复冻融效应[J].广西大学学报(自然科学版),2017,42(1):214-218Pan Peng,Hao Jiaxing,Cui Zizhi,et al.Effect of repeated freezingthawing on compressibility of loess in winter irrigation area[J].Journal of Guangxi University(Natural Science),2017,42(1):214-218
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10王天亮,卜建清,王扬,等.多次冻融条件下土体的融沉性质研究[J].岩土工程学报,2014,36(4):625-632Wang Tianliang,Bu Jianqing,Wang Yang,et al.Thaw subsidence properties of soils under repeated freeze-thaw cycles[J].Chinese Journal of Geotechnical Engineering,2014,36(4):625-632
11 Viklander P.Permeability and volume changes in till due to cyclic freeze-thaw[J].Canadian Geotechnical Journal,1998,35(3):471-477
12倪万魁,师华强.冻融循环作用对黄土微结构和强度的影响[J].冰川冻土,2014,36(4):922-927Ni Wankui,Shi Huaqiang.Influence of freezing-thawing cycles on micro-structure and shear strength of loess[J].Journal of Glaciology and Geocryology,2014,36(4):922-927
2穆彦虎,马巍,李国玉,等.冻融作用对压实黄土结构影响的微观定量研究[J].岩土工程学报,2011,33(12):1919-1925Mu Yanhu,Ma Wei,Li Guoyu,et al.Quantitative analysis of impacts of freeze-thaw cycles upon microstructure of compacted loess[J].Chinese Journal of Geotechnical Engineering,2011,33(12):1919-1925
3肖东辉,冯文杰,张泽.冻融循环作用下黄土孔隙率变化规律[J].冰川冻土,2014,36(4):907-912Xiao Donghui,Feng Wenjie,Zhang Ze.The changing rule of loess's porosity under freezing-thawing cycles[J].Journal of Glaciology and Geocryology,2014,36(4):907-912
4张泽,马巍,张中琼,等.球形模板压入仪在冻土长期强度测试中的应用[J].岩土力学,2012,33(11):3516-3520Zhang Ze,Ma Wei,Zhang Zhongqiong,et al.Application of spherical template indenter to long-term strength tests for frozen soil[J].Rock and Soil Mechanics,2012,33(11):3516-3520
5张世民,李双洋.青藏粉质黏土冻融循环试验研究[J].冰川冻土,2012,34(3):625-629Zhang Shimin,Li Shuangyang.Experimental study of the Tibetan silty clay under freeze-thaw cycles[J].Journal of Glaciology and Geocryology,2012,34(3):625-629
6杨成松,何平,程国栋,等.冻融试验对土中含水量分布的影响(英文)[J].冰川冻土,2004(增刊1):50-55Yang Chengsong,He Ping,Cheng Guodong,et al.Freeze-thaw experiment influence on moisture content distruction of soil(English)[J].Journal of Glaciology and Geocryology,2004(S1):50-55
7潘鹏,李剑,郝佳兴,等.宁夏饱和黄土的冻胀融沉特性[J].科学技术与工程,2016,16(18):230-233Pan Peng,Li Jian,Hao Jiaxing,et al.Frost heaving and thawing settlement characteristics of saturated loess in Ningxia[J].Science Technology and Engineering,2016:16(18):230-233
8潘鹏,郝佳兴,崔自治,等.冬灌区黄土压缩性的反复冻融效应[J].广西大学学报(自然科学版),2017,42(1):214-218Pan Peng,Hao Jiaxing,Cui Zizhi,et al.Effect of repeated freezingthawing on compressibility of loess in winter irrigation area[J].Journal of Guangxi University(Natural Science),2017,42(1):214-218
9崔自治,潘鹏,李剑,等.冬灌区黄土的反复冻融效应[J].工业建筑,2017,47(增刊3):515-519Cui Zizhi,Pan Peng,Li Jian,et al.Effects of repeated freezing and thawing on loess in winter irrigation zone[J].Industrial Construction,2017,47(S3):515-519
10王天亮,卜建清,王扬,等.多次冻融条件下土体的融沉性质研究[J].岩土工程学报,2014,36(4):625-632Wang Tianliang,Bu Jianqing,Wang Yang,et al.Thaw subsidence properties of soils under repeated freeze-thaw cycles[J].Chinese Journal of Geotechnical Engineering,2014,36(4):625-632
11 Viklander P.Permeability and volume changes in till due to cyclic freeze-thaw[J].Canadian Geotechnical Journal,1998,35(3):471-477
12倪万魁,师华强.冻融循环作用对黄土微结构和强度的影响[J].冰川冻土,2014,36(4):922-927Ni Wankui,Shi Huaqiang.Influence of freezing-thawing cycles on micro-structure and shear strength of loess[J].Journal of Glaciology and Geocryology,2014,36(4):922-927