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| STRAIN-HARDENING MECHANISMS AND METHODS FOR DETERMINING STRENGTH PARAMETERS OF MUNICIPAL SOLID WASTE |
| LI Junchao1，2，ZHU Bin1，2，LIAN Baoqin1，2，WANG Lei1，2，KE Han1，2，CHEN Yunmin1，2 |
| (1. MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering，Zhejiang University，Hangzhou，Zhejiang 310058，China；2. Institute of Geotechnical Engineering，Zhejiang University，Hangzhou，Zhejiang 310058，China) |
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Abstract A series of triaxial shear tests on municipal solid waste(MSW) with the maximum vertical strain of approximately 50% were carried out by a modified triaxial apparatus. The test results show that MSW samples failed under large-strain condition and the failure strain decreases with the increasing of the landfill depth. The basic and reinforced phases of MSW were separated and triaxial consolidated drained(CD) shear tests were carried out on each phase. The results show that the stress-strain curves of both basic and reinforced phases have the strain-hardening characteristics. The structural formation and reinforcement effect of the organic fibers in basic phase were described through sieving and microscopic observation on granule groups. Then CD tests of several granule groups were carried out and the results demonstrate that every group has a strain-hardening stress-strain curve except the group with particle diameter smaller than 0.075 mm. The stress-strain curves of the basic phase before and after burned were compared，showing that the organic fibers will not play the reinforcement effect until a certain value of strain is reached. Fiber fracture and slipping along the interface seem to exist during shearing. Finally，based on the results of triaxial shear tests，methods for determining the shear strength parameters of triaxial consolidated undrained shear(CU) and CD tests were discussed respectively.
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Received: 26 March 2013
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| [1] QIAN X D，KOERNER R M，GRAY D H. Geotechnical aspects of landfill design and construction[M]. New Jersey：Prientice-Hall Inc.，2001.
[2] GRISOLIA M，NAPOLEONI Q，SIRINI P，et al. Geotechnical behaviour of sanitary landfill based on laboratory and in-situ tests[C]// Proceedings of the 15th Conference of Geotechnics of Torino. Torino：Societa` Ingegnerie Architetti in Torino，1991.
[3] JESSBERGER h l，kOCKEL R. Determination and assessment of the mechanical properties of waste materials[C]// Proceedings Sardinia 93，4th International Landfill Symposium. Cagliari，Italy：[s.n.]，1993：1 383–1 392.
[4] CAICEDO B，GIRALDO E，YAMIN L，et al. The landslide of Dona Juana landfill in Bogota[C]// Proceedings of the 4th international congress on environmental geotechnics(4th ICEG). Riode Janeiro，Brazil：[s.n.]，2002：171–175.
[5] MACHADO S L，CARVALHO M F，VILAR O M. Constitutive model for municipal solid waste[J]. Journal of Geotechnical and Geoenvironmental Engineering，2002，128(11)：940–951.
[6] 朱俊高，施建勇，严 蕴. 垃圾填埋场固体废弃物的强度特性试验研究[C]// 第一届全国环境岩土工程与土工合成材料技术研讨会论文集合. 杭州：浙江大学出版社，2002：192–196.(ZHU Jungao，SHI Jianyong，YAN Yun. Experimental study on the strength behavior of solid waste[C]// Proceedings of the 1st Chinese Symposium on Geoenvironmental and Geosynthetics. Hangzhou：Zhejiang University Press，2002：192–196.(in Chinese))
[7] VILAR O M，CARVALHO M F. Mechanical properties of municipal solid waste[J]. Journal of Testing and Evaluation，2004，32(6)：1–12.
[8] 冯世进. 城市固体废弃物静动力特性及填埋场的稳定性分析[博士学位论文][D]. 杭州：浙江大学，2005.(FENG Shijin. Static and dynamic strength properties of municipal solid waste and stability analysis of landfill[Ph. D. Thesis][D]. Hangzhou：Zhejiang University，2005.(in Chinese))
[9] GOMES C，LOPES M L，LOPES M G. A study of MSW properties of a Portugese landfill[C]// Proceedings of International Workshop on Hydro-physico-mechanics of Landfills. Grenoble，France：[s.n.]，2005.
[10] ITOH T，TOWHATA I，KAWANO Y. Mechanical properties of municipal waste deposits and ground improvement[C]// Proceedings of the 16th International Conference on Soil Mechanics and Geotechnical Engineering. Osaka，Japan：[s.n.]，2005：2 273–2 276.
[11] ZEKKOS D. Evaluation of static and dynamic properties of municipal solid waste[Ph. D. Thesis][D]. Berkeley：Department of Civil and Environmental Engineering，University of California，2005.
[12] 孙秀丽. 城市固体废弃物变形及强度特性研究[博士学位论文[D]. 大连：大连理工大学，2007.(SUN Xiuli. Characterization of deformation and strength for municipal solid waste[Ph. D. Thesis][D]. Dalian：Dalian University of Technology，2007.(in Chinese))
[13] ZHAN L T，CHEN Y M，LING W A. Shear strength characterization of municipal solid waste at the Suzhou landfill，China[J]. Engineering Geology，2008，97(3/4)：97–111.
[14] REDDY K R，HETTIARACHCHI H，PARAKALLA N S，et al. Geotechnical properties of fresh municipal solid waste at Orchard Hills Landfill，USA[J]. Waste Management，2009，29(2)：952–959.
[15] KARIMPOUR-FARD M，MACHADO S L，SHARIATMADARI N，et al. A laboratory study on the MSW mechanical behavior in triaxial apparatus[J]. Waste Management，2011，31(8)：1 807–1 819.
[16] 陈云敏，高 登，朱 斌. 城市固体废弃物的复合指数应力–应变模型及其应用[J]. 岩土工程学报，2009，31(7)：1 020–1 029.(CHEN Yunmin，GAO Deng，ZHU Bin. Composite exponential stress-strain model of municipal solid waste and its application[J]. Chinese Journal of Geotechnical Engineering，2009，31(7)：1 020–1 029.(in Chinese))
[17] KOCKEL R. Scherfestigkeit von mischabfall im hinblick auf die standsicherheit von deponien.[Ph. D. Thesis][D]. Schriftenreihe des Lehrstuhls für Grundbau und Bodenmechanik，Ruhr-Universität Bochum，Heft 24，1995. (in German)
[18] SHARIATMADARI N，MACHADO S L，NOORZAD A，et al. Municipal solid waste effective stress analysis[J]. Waste Management，2009，29(12)：2 918–2 930.
[19] 连宝琴. 城市固体废弃物大应变三轴试验研究[硕士学位论文[D]. 杭州：浙江大学，2012.(LIAN Baoqin. Study on large strain triaxial tests of municipal solid waste[M. D. Thesis][D]. Hangzhou：Zhejiang University，2012.(in Chinese))
[20] BRAY J D，ZEKKOS D，KAVAZANJIAN E，et al. Shear strength of municipal solid waste[J]. Journal of Geotechnical and Geoenvironmental Engineering，2009，135(6)：709–722.
[21] BAREITHER C A，BENSON C H，EDIL T B. Effects of waste composition and decomposition on the shear strength of municipal solid waste[J]. Journal of Geotechnical and Geoenvironmental Engineering，2012，138(10)：1 161–1 174.
[22] HOSSAIN M S，GABR M A，ASCE F. The effect of shredding and test apparatus size on compressibility and strength parameters of degraded municipal solid waste[J]. Waste Management，2009，29(9)：2 417–2 424.
[23] HOSSEININIA E S，FARZANEH R. A simplified two-phase macroscopic model for reinforced soils[J]. Geotextiles and Geomembranes，2010，28(1)：85–92.
[24] COOP M R. The mechanics of uncemented carbonate sands[J]. Geotechnique，1990，40(4)：607–626.
[25] SKEMPTON A W. Effective stress in soils，concrete and rocks[M]. London：[s.n.]，1961：4. |
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2014, Vol. 33 
