利用秸秆灰渣作为添加剂,进行室内改良膨胀土试验,研究改良后膨胀土的三维自由体变化特性及无侧限抗压强度特征。秸秆灰渣以(干质量之比)0%,10%,15%,20%的比例与素膨胀土混合进行击实试验,在最大干密度及最佳含水率条件下进行三维自由体膨胀、膨胀力和无侧限抗压强度3个试验,在液限状态下进行三维自由体收缩试验。根据三维自由体应变及膨胀压力特征,拟合出秸秆灰渣最佳含量的线性方程,得出灰渣的最佳含量为17%。试验结果表明:膨胀土的体应变、塑性指标和膨胀压力随着秸秆灰渣含量的增加而逐渐降低,无侧限抗压强度随着秸秆灰渣的增加逐渐提高;对未养护的试样,秸秆灰渣对无侧限抗压强度影响不明显,而试样养护7 d后的强度提高较为明显。
Laboratory tests were carried out on expansive soil improved with straw ash as additive to research the 3-D free volume change and unconfined compressive strength (UCS) characteristics of expansive soil improved with straw ash. Straw ash content (weight of straw ash/weight of dry soil) at 0%, 10%, 15% and 20% were mixed with expansive soil and then compacted. Tests on the 3-D free volumetric swell strain, vertical swell pressure and unconfined compressive strength were conducted in the presence of maximum dry density and optimum moisture content, and also tests on the volumetric shrinkage strain was conducted in liquid limit state. The linear equation of the optimum content of straw ash was fitted based on the 3-D free volumetric strain and swelling pressure properties of expansive soil, and the optimum content of straw ash was 17%. The test results show that with the increasing of straw ash, the volume strain, plasticity index and swell pressure decreased whereas the UCS increased. There is no remarkable change in the UCS of the samples immediately tested with straw ash, however, curing of 7 days could bring a remarkable increase in the UCS.
[1] 刘特洪. 工程建设中的膨胀土问题[M]. 北京:中国建筑工业出版社,1997:43-44.(LIU Te-hong. Expansive Soils Problems in Engineering Construction[M]. Beijing: China Architecture and Building Press, 1997:43-44.(in Chinese))
[2] 廖世文. 膨胀土与铁道工程[M]. 北京:中国铁道出版社,1984.(LIAO Shi-wen. Expansive Soil and Railway Engineering[M]. Beijing:China Railway Press,1984.(in Chinese))
[3] 徐永福,刘松玉. 非饱和土强度理论及其工程应用[M]. 南京:东南大学出版社,1999:186-187.(XU Yong-fu,LIU Song-yu. Strength Theory for Unsaturated Soils and Its Engineering Application[M]. Nanjing: Southeast University Press, 1999:186-187.(in Chinese))
[4] 张家发,刘晓明,焦赳赳. 膨胀土渠坡兼有排水功能的双层结构防护方案[J]. 长江科学院院报,2009,26(11):37-41.(ZHANG Jia-fa, LIU Xiao-ming, JIAO Jiu-jiu. A Protection Scheme of Double Layers with Drainage Function for Expansive Soil Slopes by Canal[J]. Journal of Yangtze River Scientific Research Institute,2009,26(11):37-41.(in Chinese))
[5] NOWAMOOZ H, MASROURI F. Hydromechanical Behaviour of an Expansive Bentonite/silt Mixture in Cyclic Suction-controlled Drying and Wetting Tests[J]. Engineering Geology,2008,101(3/4):154-164.
[6] SABTAN A. Geotechnical Properties of Expansive Clay Shale in Tabuk,Saudi Arabia[J]. Journal of Asian Earth Sciences 2005,25(5):747-757.
[7] PHANIKUMAR B R. Effect of Lime and Fly Ash on Swell,Consolidation and Shear Strength Characteristics of Expansive Clays: a Comparative Study[J]. Geomechanics and Geoengineering,2009,(4):175-181.
[8] KUMAR M A,PRASADA R G V R. Use of Lime Cement Stabilized Pavement Construction[J]. Indian Journal of Engineering and Materials Sciences,2009,16(4):269-276.
[9] KOONNAMAS P, ANAND J P, SAI K V, et al. Volume Change Behaviors of Expansive Soils Stabilized with Recycled Ashes and Fibers[J]. Journal of Materials in Civil Engineering, 2006,47(3):295-306.
[10]ZHA Fu-sheng, LIU Song-yu, DU Yan-jun, et al. Behavior of Expansive Soils Stabilized with Fly Ash[J]. Natural Hazards,2008,47(3): 509-523.
[11]孙树林,魏永耀,张 鑫. 废弃轮胎胶粉改良膨胀土的抗剪强度研究[J]. 岩石力学与工程学报,2009,28(增1):3070-3075.(SUN Shu-lin,WEI Yong-yao,ZHANG Xin. Research on Shear Strength of Expansive Soils Reinforced with Waste Tire Powders[J]. Chinese Journal of Rock Mechanics and Engineering,2009,28(Sup.1):3070-3075.(in Chinese))
[12]魏永耀,孙树林,郑华章. 膨胀土-胶粉(ESR)抗剪强度与含水量关系试验研究[J]. 工程地质学报,2010,18(4):543-547.(WEI Yong-yao,SUN Shu-lin,ZHENG Hua-zhang. Laboratory Tests on Uniaxial Compressive Strength of Expansive Soil-rubber[J]. Journal of Engineering Geology,2010,18(4):543-547. (in Chinese))
[13]孙树林,郑海清. 碱渣改良膨胀土室内试验研究[J]. 岩土力学,2012,33(6):1608-1612.(SUN Shu-lin,ZHENG Hai-qing. Experimental Research on Expansive Soil Improved by Soda Residue[J]. Rock and Soil Mechanics,2012, 33(6):1608-1612. (in Chinese))
[14]孙树林,张 鑫,魏永耀. 掺绿砂改良膨胀土室内试验研究[J].岩土力学,2012,33(增2):209-212.(SUN Shu-lin, ZHANG Xin,WEI Yong-yao. Experimental Study of Expansive Soil Improved with Granulated Blast Furnace Slag(GBFS)[J]. Rock and Soil Mechanics, 2012,33(Sup.2):209-212. (in Chinese))
[15]AKSHAYA, K S,RADHIKESH P. N. Effect of Marble Dust on Strength and Durability of Rice Husk Ash Stabilised Expansive Soil[J]. International Journal of Civil and Structural Engineering, 2011, 1(4):939-947.
[16]JTJ051—93,公路土工试验规程[S]. 北京:人民交通出版社,1993.(JTJ051—93,Test Method of Soils for Highway Engineering[S]. Beijing:China Communications Press, 1993.(in Chinese))
[17]MITCHELL J K. Fundamentals of Soil Behavior[M]. New York: Wiley ＆ Sons,1993.
[18]查甫生,刘松玉,杜延军. 石灰-粉煤灰改良膨胀土试验[J]. 东南大学学报(自然科学版),2007,37(2):339-341. (ZHA Fu-sheng,LIU Song-yu,DU Yan-jun. Expansive on Improvement of Expansive Clays with Lime-fly,Ash[J]. Journal of Southeast University(Natural Science),2007,37(2):339-341. (in Chinese))
