鄱阳湖湖相深厚软土工程地质特性研究
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摘要
在横跨鄱阳湖某工程勘察中发现,江西省鄱阳湖都昌—庐山湖心岛屿一带,存在厚达50~60 m的湖相软土,具有特殊的工程特性。利用理学DMAX-3C(Cu Ka,Ni滤光)、高倍光学显微镜、环境扫描电镜(ESEM)等对鄱阳湖软土的地质成因和空间分布规律进行探讨,分析了其矿物组成、化学成份、物理力学性质、胀缩特性及其击实后的膨胀性和承载强度等进行了试验研究。研究发现鄱阳湖软土主要以伊利石、高岭石、绿泥石等粘土矿物为主,分布上交互特征;微观结构上以原生空隙为主,水平向空隙的渗透性优于垂直向,粘粒呈胶结状;其原状膨胀性并不明显、压实后膨胀性增加。在天然和加载条件下,抗剪强度随着固结程度的增加逐渐增大。这些试验结果对鄱阳湖软土地基上的工程建设具有参考意义。
In exploring the project reconnaissance across Poyang Lake,we find that there is a layer of soft lake soil in Poyang Lake as thick as 50 ~ 60 m along Duchang-Lushan eyot,which has special engineering characteristics. Employing DMAX-3 C( Cu Ka,Ni filter),high power optical microscope and environmental scanning electron microscope( ESEM) experiment,we study the geological formation and spatial distribution regularity of soft soil at Poyang Lake,analyzing its mineral composition,chemical composition,physical and mechanical properties,swell-shrink characteristics and its expansibility and the compaction in the bearing strength. The study shows that the soft soil at Poyang Lake mainly includes illite,kaolinite,chlorite and other clay minerals. The microstructure is dominated by the primary space,and the permeability of horizontal direction is better than that of vertical direction and the clay is cemented. The swelling property of the original clay is not obvious,but it increases after it is compacted. Under natural and loading conditions,the shear strength increases gradually with the increase of consolidation degree. The results of these experiments are of reference to the construction of the soft soil foundation of Poyang Lake.
In exploring the project reconnaissance across Poyang Lake,we find that there is a layer of soft lake soil in Poyang Lake as thick as 50 ~ 60 m along Duchang-Lushan eyot,which has special engineering characteristics. Employing DMAX-3 C( Cu Ka,Ni filter),high power optical microscope and environmental scanning electron microscope( ESEM) experiment,we study the geological formation and spatial distribution regularity of soft soil at Poyang Lake,analyzing its mineral composition,chemical composition,physical and mechanical properties,swell-shrink characteristics and its expansibility and the compaction in the bearing strength. The study shows that the soft soil at Poyang Lake mainly includes illite,kaolinite,chlorite and other clay minerals. The microstructure is dominated by the primary space,and the permeability of horizontal direction is better than that of vertical direction and the clay is cemented. The swelling property of the original clay is not obvious,but it increases after it is compacted. Under natural and loading conditions,the shear strength increases gradually with the increase of consolidation degree. The results of these experiments are of reference to the construction of the soft soil foundation of Poyang Lake.
引文
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[2]霍雨.鄱阳湖形态特征及其对流域水沙变化响应研究[D].南京:南京大学,2011.
[3]陈炳贵,欧阳平,黄梅.3S技术支持下鄱阳湖区地质构造调查分析[J].地球物理学学报,2007,22(5):1666-1672.
[4]杨晓东,吴中海,张海军.鄱阳湖盆地的地质演化、新构造运动及其成因机制探讨[J].地质力学学报,2016,22(3):667-1685.
[5]郑军,阎长虹,夏文俊,等.江办盱眙特殊软土的工程地质特性研究[J].地质论评,2011,32(11):3487-3496
[6]阎长虹,夏文俊,董平,等.长江中下游地区软土工程地质特征及其成因类型分析[J].工程地质学报,2007,15(2):142-146.
[7]周建,邓以亮,曹洋,等.杭州饱和软土固结过程微观结构试验研究[J].中南大学学报:自然科学版,2014,45(6):1998-2006.
[8]周晖,房营光,李勇.珠三角软土微观结构试验分析[J].科学技术与工程,2009,9(18):5397-5404.
[9]曹洋,周建,严佳佳.考虑循环应力比和频率影响的动载荷下软土微观结构研究[J].岩土力学,2014,35(3):735-744.
[10]Mirzababaei M,Mohamed M,Miraftab M.Analysis of Strip Footings on Fiber-Reinforced Slopes with the Aid of Particle Image Velocimetry[J].Journal of Materials in Civil Engineering,2016,29(4):04016243.
[11]曾铖.软土微观结构特征及其随固结变化的试验分析[D].广州:华南理工大学,2011.
[12]刘慧明.闽东南沿海软土物理力学性质研究[D].福州:福州大学,2005.
[13]周晖.珠江三角洲软土分布特征及成因的地质与水文环境分析[J].广东土木与建筑,2014,7:36-40.
[14]孟庆山,汪稔,刘观仕.动力固结后饱和软土三轴剪切性状的试验研究[J].岩石力学与工程学报,2005,24(22):4025-4030.
[15]王煜霞,许波涛.软土固结系数确定方法的研究及应用[J].岩土工程技术,2010,24(5):217-221.
[16]Rohayu Che Omar,Rashid Jaafar.The characteristics and engineeing properties of soft soil at cyberjaya[C]//Geological Society of Malaysia Annual Geological Conference,Pulau Pinang,Malaysia,2000.
[17]李西斌,谢康和,陈福全.考虑软土流变特性和应力历史的一维固结与渗透试验[J].水利学报,2013,44(1):18-25.
[18]庄迎春.软土非单调压缩固结试验与理论研究[D].杭州:浙江大学,20005.
[19]陈艺南,谈清,殷红岩,等.江苏连云港地区滨海相软土地质特性研究[J].岩土工程技术,2001,25(4):29-33.