两种重塑土样的结构性差异试验分析
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摘要
结构性是土体的固有属性,对土体的物理力学和工程性质有强烈影响。天然黏土普遍具有结构性,重塑土样因为制样方法不同也具有不同程度的结构性。在结构性的试验研究中常常需要使用具有一定结构性的重塑土样。为了探讨制样方法对重塑土样结构性的影响,在实验室内制备了2种尺寸形状、土壤材料、干密度和含水率均相同,但饱和方法不同的重塑土样,并通过单轴压缩和加卸载试验分析和比较了2种土样在均匀性和结构性方面的差异。试验发现:未经真空抽气饱和的土样,其单轴压缩平行试验的重复性较好,土样的压缩曲线具有较明显的结构性特征;真空抽气饱和会对土样产生一定限度的随机扰动,使土样的均匀性变差、结构性变弱。
Natural clays are generally structural clays,and reconstituted soil samples also have some structural characteristics due to different sample preparation processes. Structural reconstituted soil samples are usually used in laboratory studies,and the sample preparation conditions have great influences on samples' structural characteristics.Two kinds of reconstituted soil samples( with the same size,soil type,dry density,and moisture content,yet with different saturation methods) were prepared and the structural characteristics were analyzed by uniaxial compression and uniaxial loading-unloading compression tests. It was found that vacuum suction saturation could weaken the structures and uniformities of reconstituted soil samples,and the soil samples without vacuum suction saturation had very good initial uniformity and typical structural characteristics.
Natural clays are generally structural clays,and reconstituted soil samples also have some structural characteristics due to different sample preparation processes. Structural reconstituted soil samples are usually used in laboratory studies,and the sample preparation conditions have great influences on samples' structural characteristics.Two kinds of reconstituted soil samples( with the same size,soil type,dry density,and moisture content,yet with different saturation methods) were prepared and the structural characteristics were analyzed by uniaxial compression and uniaxial loading-unloading compression tests. It was found that vacuum suction saturation could weaken the structures and uniformities of reconstituted soil samples,and the soil samples without vacuum suction saturation had very good initial uniformity and typical structural characteristics.
引文
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[11]罗爱忠,邵生俊,陈昌禄,等.黄土湿载结构性本构模型的数值实现[J].长江科学院院报,2016,33(2):74-79.
[2]龚晓南,熊传祥,项可祥,等.黏土结构性对其力学性质的影响及形成原因分析[J].水利学报,2000,(10):43-47.
[3]李作勤.有结构强度的欠压密土的力学特性[J].岩土工程学报,1982,4(1):34-45.
[4]张诚厚.两种结构性黏土的土工特性[J].水利水运科学研究,1983,(4):65-71.
[5]顾正维,孙炳楠,董邑宁.黏土的原状土、重塑土和固化土渗透性试验研究[J].岩石力学与工程学报,2003,22(3):505-508.
[6]何开胜,沈珠江.天然沉积黏土的结构性调查[J].东南大学学报(自然科学版),2002,32(5):818-822.
[7]齐吉琳,马巍.冻融作用对超固结土强度的影响[J].岩土工程学报,2006,28(12):2082-2086.
[8]王立忠,丁利,陈云敏,等.结构性软土压缩特性研究[J].土木工程学报,2004,37(4):46-53.
[9]王杏杏,尚军,夏锦红,等.重塑土和原状土的应力状态和屈服准则[J].广西大学学报(自然科学版),2016,41(1):196-202.
[10]罗爱忠,邵生俊,陈昌禄,等.基于综合结构势的结构性黄土双硬化参数模型[J].长江科学院院报,2013,30(9):59-63.
[11]罗爱忠,邵生俊,陈昌禄,等.黄土湿载结构性本构模型的数值实现[J].长江科学院院报,2016,33(2):74-79.