|
|
|
| Compaction behavior of compacted Maryland expansive soil considering micro-structure effect |
| YUAN Shengyang1，2，3，LIU Xianfeng1，2，4，PAN Gaofeng1，2，JIANG Guanlu1，2 |
| (1. School of Civil Engineering，Southwest Jiaotong University，Chengdu，Sichuan 610031，China；2. Key Laboratory of High-speed Railway Engineering of Ministry of Education，Southwest Jiaotong University，Chengdu，Sichuan 610031，China；3. State Key Laboratory of Geohazard Prevention and Geoenvironment Protection，Chengdu University of Technology，Chengdu，Sichuan 610031，China；4. Xinjiang Institute of Engineering，Urumqi，Xinjiang 860023，China) |
|
|
|
|
Abstract In order to study the evolution of stress status of expansive clay，a series of compaction tests for ML clay had been carried out. The samples with different initial water contents were compacted via a home-made one-dimensional compaction apparatus. The evolutions of suction and deformation of samples were analyzed during the compaction process. It shows that compression index( ) is significantly affected by initial water content. The value of increases with initial water content if the initial water content is smaller than 21.4%，otherwise it keeps almost constant. The initial water content has little effect on the unloading-reloading index( ). Due to the “mechanical wetting”effect，the matric suction gradually decreases during compaction. During the unloading stage，the matric suction increases significantly. For the sample with same initial water content，the increment of matric suction due to unloading effect increases with the degree of saturation. Based on the post-compaction suction，the compaction plane could be divided into parts：the post-compaction suction is not affected by the degree of saturation of samples，and the post-compaction suction increases with degree of saturation. It also clearly shows that soil water retention curve of sample with constant volume is strongly affected by the void ratio. Based on suction，the degree of saturation，average effective stress，modified suction and void ratio，models for soil water retention curve and compaction curve have been established. The predict of suction and volume evolution during the compaction has been carried out.
|
|
|
|
|
|
| [1] NELSON J D，CHAO K C，OVERTON D D，et al. Foundation Engineering for Expansive Soils[M]. [S. l.]：John Wiley and Sons，Inc.，2015：40–53.
[2] FREDLUND D G，RAHARDJO H，FREDLUND M D. Unsaturated Soil Mechanics in Engineering Practice[M]. [S. l.]：John Wiley and Sons，Inc.，2012：731–782.
[3] SHI B，JIANG H，LIU Z，et al. Engineering geological characteristics of expansive soils in China[J]. Engineering Geology，2002，67(1)：63–71.
[4] 李献民，王永和，杨 果，等. 击实膨胀土工程变形特征的试验研究[J]. 岩土力学，2003，24(5)：826–830.(LI Xianmin，WANG Yonghe，YANG Guo，et al. Test study on engineering deformation characteristics of compacted expansive soil[J]. Rock and Soil Mechanics，2003，24(5)：826–830.(in Chinese))
[5] 刘 毅. 高庙子膨润土水化膨胀特性及其微观机理研究[J]. 工程地质学报，2016，24(3)：451–458.(LIU Yi. Investigation on the swelling properties and microstructure mechanism of compacted Gaomiaozi bentonite[J]. Journal of Engineering Geology，2016，24(3)：451–458.(in Chinese))
[6] 王 芳，曹 培，严丽雪. 南水北调中线膨胀土变形特性的试验研究[J]. 水利学报，2014，45(增2)：142–146.(WANG Fang，CAO Pei，YAN Lixue. Study on swelling characteristic of expansive soil in the Middle Route of South-to-North Water Transfer Project[J]. Journal of Hydraulic Engineering，2014，45(Supp.2)：142–146.(in Chinese))
[7] 张 龙，孙德安，刘月妙. 两种高庙子钠基膨润土膨胀特性比较研究[J]. 岩土力学，2016，37(12)：3 447–3 454.(ZHANG Long，SUN De'an，LIU Yuemiao. Comparison between swelling properties of two Gaomiaozi Na-bentonite[J]. Rock and Soil Mechanics，2016，37(12)：3 447–3 454.(in Chinese))
[8] 姚志华，陈正汉，朱元青，等. 膨胀土在湿干循环和三轴浸水过程中细观结构变化的试验研究[J]. 岩土工程学报，2010，32(1)：68–76.(YAO Zhihua，CHEN Zhenghan，ZHU Yuanqing，et al. Meso-structural changes of remolded expansive soils during wetting-drying cycles and triaxial soaking tests[J]. Chinese Journal of Geotechnical Engineering，2010，32(1)：68–76.(in Chinese))
[9] 郑健龙，张 锐. 公路膨胀土路基变形预测与控制方法[J]. 中国公路学报，2015，28(3)：1–10.(ZHENG Jianlong，ZHANG Rui. Prediction and control method for deformation of highway expansive soil subgrade[J]. Chinese Journal of Highway and Transport，2015，28(3)：1–10.(in Chinese))
[10] ALONSO E E，ROMERO E，HOFFMANN C，et al. Expansive bentonite-sand mixtures in cyclic controlled-suction drying and wetting[J]. Engineering Geology，2005，81(3)：213–226.
[11] 丁振洲，郑颖人，李利晟. 膨胀力变化规律试验研究[J]. 岩土力学，2007，28(7)：1 328–1 332.(DING Zhenzhou，ZHENG Yingren，LI Lisheng. Trial study on variation regularity of swelling force[J]. Rock and Soil Mechanics，2007，28(7)：1 328–1 332.(in Chinese))
[12] 周葆春，孔令伟，郭爱国. 不同水化状态下的压实膨胀土应力–应变–强度特征[J]. 岩土力学，2012，33(3)：641–651.(ZHOU Baochun，KONG Lingwei，GUO Aiguo. Stress-strain-strength behaviour of compacted expansive soil under different hydration states[J]. Rock and Soil Mechanics，2012，33(3)：641–651.(in Chinese))
[13] TARANTINO A，DE COL E. Compaction behaviour of clay[J]. Géotechnique，2008，58(3)：199–213.
[14] ALONSO E E，VAUNAT J，GENS A. Modelling the mechanical behaviour of expansive clays[J]. Engineering Geology，1999，54(1)：173–183.
[15] FITYUS S G，SMITH D W. The development of a residual soil profile from a mudstone in a temperate climate[J]. Engineering Geology，2004， 74(1)：39–56.
[16] LIU X F，BUZZI O P，YUAN S Y，et al. Multi-scale characterization of the retention and shrinkage behaviour of four natural Australian soils[J]. Canadian Geotechnical Journal，2016，53(5)：1–17.
[17] YUAN S，LIU X，SLOAN S W.，et al. Multi-scale characterization of swelling behaviour of compacted Maryland clay[J]. Acta Geotechnica，2016，11(4)：789–804.
[18] MENDES J，BUZZI O. New insight into cavitation mechanisms in high-capacity tensiometers based on high-speed photography[J]. Canadian Geotechnical Journal，2013，50(5)：550–556.
[19] GENS A，ALONSO E E，SURIOL J，et al. Effect of structure on volumetric behaviour of compacted soil[C]// Proceeding of 1st International Conference on Unsaturated Soils. Rotterdam：Balkema， 1995：83–88.
[20] LI Z M. Compressibility and collapsibility of compacted unsaturated loessial soils[C]// Proceeding of 1st International Conference on Unsaturated Soils. Rotterdam：Balkema，1995：139–144 .
[21] ROMERO E，GENS A，LLORET A. Water permeability，water retention and microstrucutre of unsaturated compacted boom clay[J]. Engineering Geology，1999，54(1/2)：117–127.
[22] GALLIPOLI D，WHEELER S J，KARSTUNEN M. Modelling the variation of degree of saturation in a deformable unsaturated soil. Geotechnique，2003，53(1)：105–112.
[23] WHEELER S J，SHARMA R S，BUISSON M S R.(2003). Coupling of hydraulic hysteresis and stress-strain behaviour in unsaturated soils. Geotechnique，2003，53(1)：41–54.
|
|
|
|
2021, Vol. 40 
