非充分补水条件下冬灌区压实黄土的冻融变形特性
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摘要
结合宁夏的气候和黄土区域特点,以压实度和饱和度为因素,设计正交试验方案,用维持饱和度不变的一维单向冻融试验方法,研究压实黄土在非充分补水条件下的冻胀和融沉特性,分析其作用规律,建立冻胀率、融沉系数与饱和度、压实度及冻融循环次数间的关系模型.结果表明,非充分补水条件下,压实黄土的冻胀率和融沉系数均随冻融循环次数的增加而增大,在约12次时趋于稳定,且冻融循环效应随压实度或饱和度的增大而提高.冻胀率随饱和度的增大而增大,随压实度变化的规律与冻融循环次数有关,在7次冻融循环内随压实度的增大而减小,之后随压实度的增大而增大.融沉系数随压实度的增大而减小,随饱和度的增大而增大.压实度和饱和度对压实黄土的冻融变形影响显著,均是重要的影响因素.建立的关系模型预测结果准确,可用于预测非充分补水条件下压实黄土的冻融变形.
Combining with the features of loess area and climate of Ningxia,the article designs orthogonal experiment program by taking degrees of compaction and saturation as factors,studies compacted loess' frost heaving and melting features under non-sufficient water-supplying condition with the method of one dimensional unidirectional freeze-thaw test which keeps the saturation constant,analyzes the law of function,and establishes the relation model among frost heaving ratio &thaw-settelment coefficient and saturability &compactness,and freeze-thaw cycles times.The result shows that,the frost heaving ratio and thaw-settelment coefficient of compacted loess enlarge as the addition of freeze-thaw cycles times under the condition of non-sufficient water-supplying,which tends to be stable at the 12 th times,free-thaw cyclical effect enhances as the enlargement of compactness or saturability,and frost heaving ratio rises as the enlargement of saturability,which is connected to compactness variation law and the frost-thaw cycle times that reduces as the rise of compactness within 7 frost-thaw cycle times and increases as the enlargement of compactness afterwards.The thaw-settelment coefficient decreases as the increase of frost heaving ratio,and rises as the increase of saturability.Both compactness and saturability have obvious influence on the freeze thawing deformation of compacted loess and are important influencing factors.The established relational model predicts the outcome precisely,which can be used for the prediction of compacted loess' frost-and-thaw deformation under non-sufficient water-supplying condition
Combining with the features of loess area and climate of Ningxia,the article designs orthogonal experiment program by taking degrees of compaction and saturation as factors,studies compacted loess' frost heaving and melting features under non-sufficient water-supplying condition with the method of one dimensional unidirectional freeze-thaw test which keeps the saturation constant,analyzes the law of function,and establishes the relation model among frost heaving ratio &thaw-settelment coefficient and saturability &compactness,and freeze-thaw cycles times.The result shows that,the frost heaving ratio and thaw-settelment coefficient of compacted loess enlarge as the addition of freeze-thaw cycles times under the condition of non-sufficient water-supplying,which tends to be stable at the 12 th times,free-thaw cyclical effect enhances as the enlargement of compactness or saturability,and frost heaving ratio rises as the enlargement of saturability,which is connected to compactness variation law and the frost-thaw cycle times that reduces as the rise of compactness within 7 frost-thaw cycle times and increases as the enlargement of compactness afterwards.The thaw-settelment coefficient decreases as the increase of frost heaving ratio,and rises as the increase of saturability.Both compactness and saturability have obvious influence on the freeze thawing deformation of compacted loess and are important influencing factors.The established relational model predicts the outcome precisely,which can be used for the prediction of compacted loess' frost-and-thaw deformation under non-sufficient water-supplying condition
引文
[1]严晗,王天亮,刘建坤.粉砂土反复冻胀融沉特性试验研究[J].岩土力学,2013,34(11):3159-3165.
[2]杨成松,何平,程国栋,等.冻融作用对土体干容重和含水率影响的试验研究[J].岩石力学与工程学报,2003,22(S2):2695-2699.
[3] VIKLANDER P.Permeability and volume changes in till due to cyclic freeze/thaw[J].Canadian Geotechnical Journal,1998,35(3):471-477.
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[5]张莲海,马巍,杨成松.冻融循环过程中土体的孔隙水压力测试研究[J].岩土力学,2015,36(7):1856-1864.
[6]许健,牛富俊,牛永红,等.冻结过程路基土体水分迁移特征分析[J].重庆大学学报:自然科学版,2013,36(4):150-158.
[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):230-233.
[8]张国军,陆立国.影响衬砌渠道冻胀破坏严重的关键因素[J].中国农村水利水电,2012(9):105-108.
[2]杨成松,何平,程国栋,等.冻融作用对土体干容重和含水率影响的试验研究[J].岩石力学与工程学报,2003,22(S2):2695-2699.
[3] VIKLANDER P.Permeability and volume changes in till due to cyclic freeze/thaw[J].Canadian Geotechnical Journal,1998,35(3):471-477.
[4]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):1919-1925.
[5]张莲海,马巍,杨成松.冻融循环过程中土体的孔隙水压力测试研究[J].岩土力学,2015,36(7):1856-1864.
[6]许健,牛富俊,牛永红,等.冻结过程路基土体水分迁移特征分析[J].重庆大学学报:自然科学版,2013,36(4):150-158.
[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):230-233.
[8]张国军,陆立国.影响衬砌渠道冻胀破坏严重的关键因素[J].中国农村水利水电,2012(9):105-108.