柔性加筋土复合体力学性能试验
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摘要
为了研究柔性加筋土复合体的基本力学特性,分别对无纺土工布加筋砂、土工格栅加筋砂、"土工布+纤维"综合加筋砂和"土工格栅+纤维"综合加筋砂制作的多组试样完成了一系列组合工况下的无侧限抗压试验.得到以下主要结论:1)土工布的强度和加筋层间距应与砂的密度相匹配,此时,两者协同工作性最好,加筋砂土极限强度高,破坏应变大;2)相同情况下,"土工布+纤维"综合加筋砂的强度比土工布加筋砂的高,但当砂的密度和加筋层间距都较小时,强度提高不显著;3)应变较大时,土工格栅加筋砂的强度明显低于土工布加筋砂的强度,这可能是格栅与砂土的刚度差异过大以致格栅-土界面产生了相对滑动所致;4)纤维的掺入既提高了"土工格栅+纤维"综合加筋砂的强度,又提高了其承受大变形的能力.
In order to study the mechanical properties of flexible geosynthetic-reinforced soil complex,a series of unconfined compression tests were conducted in laboratory.The test samples were made up of sand reinforced respectively with nonwoven geotextile,geogrid,both geotextile and fiber,or both geogrid and fiber.Each sample varied in either the number of reinforcement inclusions or the density of sand.Based on the analysis of the test results,some conclusions are drawn as follows.1) There is an appropriate match among the geotextile strength,the reinforcement spacing and the sand density.The samples making according to such match have not only high compressive strengths but also large failure compressive strains.2) Sand reinforced with both geotextile and fiber has a higher compressive strength than that of one reinforced only by geotextile at the same conditions;but only a little difference between them while both the sand has a relatively low density and the reinforcement spacing is small.3) While the compressive strain is larger,the compressive strength of the geogrid-reinforced sand is much lower than that of geotextile-reinforced sand,which is perhaps due to the large difference between the geogrid and the sand in tensile stiffness resulting in sliding at the geogrid-soil interface.4) Compared with the geogrid-reinforced sand,the sample reinforced with both geogrid and fiber has a higher compressive strength at low compressive strain and a larger failure compressive strain due to the fiber inclusions.
In order to study the mechanical properties of flexible geosynthetic-reinforced soil complex,a series of unconfined compression tests were conducted in laboratory.The test samples were made up of sand reinforced respectively with nonwoven geotextile,geogrid,both geotextile and fiber,or both geogrid and fiber.Each sample varied in either the number of reinforcement inclusions or the density of sand.Based on the analysis of the test results,some conclusions are drawn as follows.1) There is an appropriate match among the geotextile strength,the reinforcement spacing and the sand density.The samples making according to such match have not only high compressive strengths but also large failure compressive strains.2) Sand reinforced with both geotextile and fiber has a higher compressive strength than that of one reinforced only by geotextile at the same conditions;but only a little difference between them while both the sand has a relatively low density and the reinforcement spacing is small.3) While the compressive strain is larger,the compressive strength of the geogrid-reinforced sand is much lower than that of geotextile-reinforced sand,which is perhaps due to the large difference between the geogrid and the sand in tensile stiffness resulting in sliding at the geogrid-soil interface.4) Compared with the geogrid-reinforced sand,the sample reinforced with both geogrid and fiber has a higher compressive strength at low compressive strain and a larger failure compressive strain due to the fiber inclusions.
引文
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[8]Tatsuoka F,Koseki J,Tateyama M,et al.Seismicstability against high seismic loads of geosynthetic re-inforced soil retaining structures[C]//Proceedings of6th International Conference on Geosynthetics,Atlan-ta,2007:103-142.
[9]刘华北.水平与竖向地震作用下土工格栅加筋土挡墙动力分析[J].岩土工程学报,2006,28(5):594-599.
[10]Lee K Z Z,Wu J T H.A synthesis of case histories onGRS bridge supporting structures with flexible facing[J].Geotextiles and Geomembranes,2004,22(4):181-204.
[11]Helwany S M B,Wu J T H,Kitsabunnarat A.Simu-lating the behavior of GRS bridge abutments[J].Journal of Geotechnical and Geoenvironmental Engi-neering,2007,133(10):1299-1240.
[12]包承纲.土工合成材料界面特性的研究和试验验证[J].岩石力学与工程学报,2006,25(9):1735-1744.
[13]包承纲.土工合成材料应用原理与工程实践[M].北京:中国水利水电出版社,2008.
[2]Wu J T H.Lateral earth pressure against the facing ofsegmental GRS walls[C]//ASCE.Geosynthetics inReinforcement and Hydraulic Applications(GSP 165),Denver,Colorado,USA:ASCE,2007:165-175.
[3]Adams M T,Schlatter W,Stabile T.Geosynthetic re-inforced soil integrated abutments at the Bowman RoadBridge in Defiance County,Ohio[C]//ASCE.Geo-synthetics in Reinforcement and Hydraulic Applica-tions(GSP 165),Denver,Colorado,USA:ASCE,2007:119-129.
[4]Adams M T,Ketchart K,Wu J T H.Mini pier exper-iments geosynthetic reinforcement spacing and strengthas related to performance[C]//ASCE.Geosyntheticsin Reinforcement and Hydraulic Applications(GSP165),Denver,Colorado,USA:ASCE,2007:98-106.
[5]Phanikumar B R,Prasad R,Singh A.Compressiveload response of geogrid-reinforced fine,medium andcoarse sands[J].Geotextiles and Geomembranes,2009,27:183-186.
[6]Hu Y C,Song H,Zhao Z J.Experimental study onbehavior of geotextile-reinforced soil[C]//Wang Y H,Yi P,An S,et al.Critical Issues in TransportationSystems Planning,Development,and Management.Harbin,China:ASCE,2009:2393-2402.
[7]Hu Y C,Song H,Zhou J,et al.Compressive per-formance of geogrid-reinforced granular soil[C]//WeiH,Wang Y H,Rong J,et al.Integrated Transporta-tion Systems Green.Intelligent.Reliable,Beijing,China:ASCE,2010:3126-3132.
[8]Tatsuoka F,Koseki J,Tateyama M,et al.Seismicstability against high seismic loads of geosynthetic re-inforced soil retaining structures[C]//Proceedings of6th International Conference on Geosynthetics,Atlan-ta,2007:103-142.
[9]刘华北.水平与竖向地震作用下土工格栅加筋土挡墙动力分析[J].岩土工程学报,2006,28(5):594-599.
[10]Lee K Z Z,Wu J T H.A synthesis of case histories onGRS bridge supporting structures with flexible facing[J].Geotextiles and Geomembranes,2004,22(4):181-204.
[11]Helwany S M B,Wu J T H,Kitsabunnarat A.Simu-lating the behavior of GRS bridge abutments[J].Journal of Geotechnical and Geoenvironmental Engi-neering,2007,133(10):1299-1240.
[12]包承纲.土工合成材料界面特性的研究和试验验证[J].岩石力学与工程学报,2006,25(9):1735-1744.
[13]包承纲.土工合成材料应用原理与工程实践[M].北京:中国水利水电出版社,2008.
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