季冻区草炭土直剪特性研究
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摘要
选取吉林省敦化市江源镇的半纤维草炭土和高分解草炭土,通过室内快剪和固结快剪试验,分析了季冻区纤维草炭土直剪特性及其力学机理。结果表明:草炭土快剪试验的法向应力与峰值剪应力的关系曲线呈线性,符合摩尔-库伦定律。固结快剪试验的法向应力与峰值剪应力的关系曲线以法向应力200 kPa为分段转折点,呈两段直线形式;基于摩尔-库伦强度准则建立了相应分段函数,得到了符合草炭土固结快剪规律的表达式。所得直剪特性及强度参数可为季冻区草炭土路基稳定性评价参数取值提供参考。
Hemic turfy soil and sapric turfy soil were selected from Jiangyuan Town, Dunhua City, Jilin Province as samples to analyze their direct shear characteristics and mechanical mechanism in seasonal frozen region by indoor fast shear and consolidated-fast shear experiments. The test results demonstrated that the relation curve between normal stress and peak of the shear stress was linear that conforming to Mohr-Coulomb criterion. The relation curve was a two-section line with a turning point at normal stress 200 kPa. Based on the Mohr-Coulomb criterion, the piecewise function was established, and the improved formula in accordance with the change rule of turfy soil was obtained. The obtained direct shear characteristics and strength parameters can be used as reference for the parameters valuing of subgrade stability evaluation in seasonal frozen region.
Hemic turfy soil and sapric turfy soil were selected from Jiangyuan Town, Dunhua City, Jilin Province as samples to analyze their direct shear characteristics and mechanical mechanism in seasonal frozen region by indoor fast shear and consolidated-fast shear experiments. The test results demonstrated that the relation curve between normal stress and peak of the shear stress was linear that conforming to Mohr-Coulomb criterion. The relation curve was a two-section line with a turning point at normal stress 200 kPa. Based on the Mohr-Coulomb criterion, the piecewise function was established, and the improved formula in accordance with the change rule of turfy soil was obtained. The obtained direct shear characteristics and strength parameters can be used as reference for the parameters valuing of subgrade stability evaluation in seasonal frozen region.
引文
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[16] 崔凯,秦晓同.粗颗粒含量对川西地区混合土压缩特性的影响[J].中国公路学报,2019,32(2):59-66.
[17] 方薇.一种非饱和土的非线性抗剪强度包络壳模型[J].岩石力学与工程学报,2018,37(11):2601-2609.
[2] 徐燕,佴磊,胡忠君.季冻区草炭土工程地质特性研究[J].人民长江,2011,42(10):17-20
[3] Amuda A G,Sahdi F,Hasan A,et al.Measurement of amorphous peat shear strength in the direct shear box at high displacement rates [J].Geotechnical and Geological Engineering,2019,37(2):1059-1072.
[4] Hendry M T,Barbour S L,Martin C D.Evaluating the effect of fiber reinforcement on the anisotropic undrained stiffness and strength of peat[J].Journal of Geotechnical and Geoenvironmental Engineering,2014,140(9):1-11.
[5] Hendry M T,Sharma J S,Martin C D,et al.Effect of fibre content and structure on anisotropic elastic stiffness and shear strength of peat[J].Canadian Geotechnical Journal,2012,49(4):403-415.
[6] Mesri G,Ajlouni M.Engineering properties of fibrous Peats[J].Journal of Geotechnical and Geoenvironmental Engineering,2007,133(7):850-866.
[7] Mansor S H B,Zainorabidin A B.Stress-strain Behavior of parit Nipah peat[J].InCIEC 2014,2015,515-523.
[8] Boylan N,Long M.Evaluation of peat strength for stability assessments[J].Proceedings of the Institution of Civil Engineers-Geotechnical Engineering,2014,167(5):421-430.
[9] 桂跃,付坚,侯英杰,等.高分解度泥炭土直剪抗剪强度特性及机理[J].河海大学学报(自然科学版),2016(5):418-426.
[10] American Society for Testing and Materials.ASTM D2974-14 Standard test methods for moisture,ash,and organic matter of peat and other organic soils[S].West Conshohocken:American Society for Testing and Materials,2000.
[11] American Society for Testing and Materials.ASTM D1997-91( 2008) Standard Test Method for Laboratory Determination of the Fiber Content of Peat Samples by Dry Mass [S].West Conshohocken:American Society for Testing and Materials,1997.
[12] 公路土工试验规程:JTG E40-2007 [S].北京:人民交通出版社,2010.
[13] Kovalenko N P,Anisimov N N.Investigation of the shear strength of peats[J].Soil Mechanics and Foundation Engineering,1977,14(1):36-37.
[14] Craig R F.Craig′s soil mechanics seventh edition [M].New York:Spon Press,2004.
[15] Wood M D.Geotechnical Modelling[M].London:Taylor & Francis Ltd,2004.
[16] 崔凯,秦晓同.粗颗粒含量对川西地区混合土压缩特性的影响[J].中国公路学报,2019,32(2):59-66.
[17] 方薇.一种非饱和土的非线性抗剪强度包络壳模型[J].岩石力学与工程学报,2018,37(11):2601-2609.