循环前后不同颗粒粒径下sandwich形加筋土筋土界面单调直剪特性
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摘要
采用3种不同颗粒粒径石英砂作为sandwich加筋土中薄砂层,使用大型直剪仪分别对不同薄砂层厚度的sandwich形加筋土进行了单调直剪、循环剪切及循环后直剪试验.试验结果表明:在单调直剪和循环后直剪过程中,不同颗粒粒径下都存在一个最优厚度,使筋土界面内剪应力最大,且颗粒粒径越大,最优薄砂层厚度越大;在循环剪切过程中,随着颗粒粒径增大,界面强度呈先增大后减小的趋势;相比单调直剪结果而言,在循环后的直剪过程中筋土界面的峰值剪应力更大,体积变更小.
With three different particle sizes of quartz sand as a part of fill material,direct shear tests, cyclic shear tests and post-cyclic direct shear tests were performed using a large-scale direct shear device under different thicknesses of sand. The results indicate that, in the direct shear and post-cyclic direct tests, peak shear stress of the interface reach a maximum value with the optimal thickness of thin sand layer under different particle sizes. The optimal thickness of thin sand layer interface increases with the increase of particle. In the cyclic shear tests, the maximum shear stress of interface also show a trend from increase to decrease with the increase of sand particle size. The peak shear stress of interface increases and the volume change decreases in the post-cyclic direct shear tests as compared to the direct shear tests.
With three different particle sizes of quartz sand as a part of fill material,direct shear tests, cyclic shear tests and post-cyclic direct shear tests were performed using a large-scale direct shear device under different thicknesses of sand. The results indicate that, in the direct shear and post-cyclic direct tests, peak shear stress of the interface reach a maximum value with the optimal thickness of thin sand layer under different particle sizes. The optimal thickness of thin sand layer interface increases with the increase of particle. In the cyclic shear tests, the maximum shear stress of interface also show a trend from increase to decrease with the increase of sand particle size. The peak shear stress of interface increases and the volume change decreases in the post-cyclic direct shear tests as compared to the direct shear tests.
引文
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[16]刘飞禹,林旭,王军,等.循环剪切作用对格栅与砂土界面剪切特性的影响[J].中国公路学报,2015,28(2):1-7.
[2]Liu C N,Ho Y H,Huang J W.Large scale direct shear tests of soil/PET-yarn geogrid interfaces[J].Geotextile and Geomembranes,2009,27(6):19-30.
[3]Vangla P,Madhavi L G.Effect of particle size of sand and surface asperities of reinforcement on their interface shear behavior[J].Geotextiles and Geomembranes,2015,44(3):254-268.
[4]Sayeed M M A,Ramaiah B J,Rawal A.Interface shear characteristics of jute/polypropylene hybrid nonwoven geotextiles and sand using large size direct shear test[J].Geotextiles and Geomembranes,2014,42(1):63-68.
[5]Jewell R A,Milligan G W E,Dubois D.Interaction between soil and geogrids[J].Thomas Telford,1985:19-29.
[6]徐超,孟凡祥.剪切速率和材料特性对筋-土界面抗剪强度的影响[J].岩土力学,2010,31(10):3101-3106.
[7]刘飞禹,林旭,王军.砂土颗粒级配对筋土界面抗剪特性的影响[J].岩石力学与工程学报,2013,32(12):2575-2582.
[8]郑俊杰,苗晨曦,谢明星,等.界面特性及填料粒径影响格栅加筋性能的离散元研究[J].岩土工程学报,2013(8):1423-1428.
[9]Moraci N,Cardile G.Influence of cyclic tensile loading on pullout resistance of geogrids embedded in a compacted granular soil[J].Geotextiles and Geomembranes,2009,27(6):475-487.
[10]冯大阔,张建民.初始静剪应力对粗粒土与结构接触面循环力学特性的影响[J].岩土力学,2012,33(8):2277-2282.
[11]Giuseppe M,Antonio M,Vito N G.Cyclic shear stress degradation and post-cyclic behaviour from sand-steel interface direct shear tests[J].Canadian Geotechnical Journal,2007,44(7):739-752.
[12]徐超,石志龙.循环荷载作用下筋土界面抗剪特性的试验研究[J].岩土力学,2011,32(3):655-660.
[13]Abdel-Rahman A H,Ibbrahim A M.Soil/geogrid behavior subjected to cyclic loading[C]//Advances in Geotechnical Engineering.2011:3087-3096.
[14]Abdi M R,Arjomand M A.Pullout tests conducted on clay reinforced with geogrid encapsulated in thin layers of sand[J].Geotextiles and Geomembranes,2011,29(6):588-595.
[15]Abdi M R,Sadrnejad S A,Arjomand M A.Clay reinforcement using geogrid embedded in thin layers of sand[J].International Journal of Civil Engineering,2009,7(4):224-235.
[16]刘飞禹,林旭,王军,等.循环剪切作用对格栅与砂土界面剪切特性的影响[J].中国公路学报,2015,28(2):1-7.