Numerical analysis of evolution of the unsaturated soil micro-structure with capillary action during compression
-
摘要:
研究非饱和土微结构的动态演化规律对认识非饱和土宏观物理力学行为的本质有重要意义。然而目前岩土学界对此尚不清楚。文章提出利用毛细水算法进行非饱和土压缩数值试验，研究其宏观变形过程中土水作用与孔隙的演变规律。首先参考黄土骨架颗粒的形态和优势颗粒的大小，建立了540 μm×400 μm理想的非饱和土微观结构模型；其次利用毛细水模型计算某一含水率下水分分布及毛细力，并将此毛细力施加于土粒之间；然后施加外荷载，对含水率为5%、10%、18%的3个模型土样进行压缩模拟。模拟结果表明：模拟获得的压缩曲线与同工况试验曲线表现出了相同的变化规律，表明该模拟一定程度上能够反映土体在压缩过程中的宏观变形特征；在压缩过程中，随土体的变形，饱和度和基质吸力分别呈上升和下降趋势，且变化程度与含水率有关，表现为含水率越高，饱和度涨幅越大，而基质吸力却在土样干燥和近饱和时降幅较大；土体孔隙结构的演化形式与体积含水率有关，低含水率时孔隙以收缩变形为主，高含水率时以大孔隙压密为更小类型的孔隙为主。模拟结果可作为实验结果的有益补充，加深对土体宏观变形行为的认识。
Abstract:Using numerical method to investigate the evolution of micro-structure in unsaturated soil is helpful to explain their physical mechanical. However, the evolution of micro-structure in unsaturated soil is not clear. For this reason, the capillary method is proposed to simulate compression test of unsaturated soil for analyzing soil-water interaction and evolution of pore spaces. In this research, an ideal micro-structure soil model of 540 μm×400 μm is established according to the shape and size of skeleton particles of loess. The capillary method is used to calculate the capillary water distribution and capillary force under different water content(5%, 10%, 18%), and the force then acts on the wetting surface among particles. The loading is applied to the soil sample. The compression test of unsaturated soil is simulated in this research. The simulation results show that the characteristics of compression curve are in good agreement with the experiment data, indicating that the numerical test can reflect the unsaturated soil deformation behavior under the condition of compress. Moreover, the saturation increases and matric suction decreases with the compression of the soil; the saturation increases most at high water content; the matric suction decreases least at middle water content; the deformation pattern is related with the moisture, namely, the pores are mainly shrunk at low water content while mainly disintegrated at high water content. The simulation results are a very useful supplement to laboratory test to explore the deformation mechanism of unsaturated soil.
-
-
表 1 模型参数表
Table 1. Parameters in the model
单元 密度
/（g∙cm−3）弹模
/GPa泊松比 摩擦角
/（°）黏聚力
/kPa接触角
/（°）表面张力
/（mN∙m−1）土颗粒 2.65 10.0 0.30 30.0 0.0 10.0 72.75 样盒 8.96 108.0 0.32 0.0 0.0 179.0 0.00 
下载: 导出CSV
-
[1] LI X, ZHANG L M. Characterization of dual-structure pore-size distribution of soil[J]. Canadian Geotechnical Journal,2009,46(2):129 − 141. doi: 10.1139/T08-110
[2] TANAKA H, SHIWAKOTI D R, OMUKAI N, et al. Pore size distribution of clayey soils measured by mercury intrusion porosimetry and its relation to hydraulic conductivity[J]. Soils and Foundations,2003,43(6):63 − 73. doi: 10.3208/sandf.43.6_63
[3] XIE W L, LI P, ZHANG M S, et al. Collapse behavior and microstructural evolution of loess soils from the Loess Plateau of China[J]. Journal of Mountain Science,2018,15(8):1642 − 1657. doi: 10.1007/s11629-018-5006-2
[4] WANG J D, LI P, MA Y, et al. Change in pore-size distribution of collapsible loess due to loading and inundating[J]. Acta Geotechnica,2020,15(5):1081 − 1094. doi: 10.1007/s11440-019-00815-9
[5] YU B, FAN W, FAN J H, et al. X-ray micro-computed tomography (μ-CT) for 3D characterization of particle kinematics representing water-induced loess micro-fabric collapse[J]. Engineering Geology,2020,279:105895. doi: 10.1016/j.enggeo.2020.105895
[6] 姚志华, 陈正汉, 李加贵, 等. 基于CT技术的原状黄土细观结构动态演化特征[J]. 农业工程学报,2017,33(13):134 − 142. [YAO Zhihua, CHEN Zhenghan, LI Jiagui, et al. Meso-structure dynamic evolution characteristic of undisturbed loess based on CT technology[J]. Transactions of the Chinese Society of Agricultural Engineering,2017,33(13):134 − 142. (in Chinese with English abstract) doi: 10.11975/j.issn.1002-6819.2017.13.018
YAO Zhihua, CHEN Zhenghan, LI Jiagui, et al. Meso-structure dynamic evolution characteristic of undisturbed loess based on CT technology[J]. Transactions of the Chinese Society of Agricultural Engineering, 2017, 33(13): 134-142. (in Chinese with English abstract) doi: 10.11975/j.issn.1002-6819.2017.13.018
[7] 陈正汉, 方祥位, 朱元青, 等. 膨胀土和黄土的细观结构及其演化规律研究[J]. 岩土力学,2009,30(1):1 − 11. [CHEN Zhenghan, FANG Xiangwei, ZHU Yuanqing, et al. Research on meso-structures and their evolution laws of expansive soil and loess[J]. Rock and Soil Mechanics,2009,30(1):1 − 11. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-7598.2009.01.001
CHEN Zhenghan, FANG Xiangwei, ZHU Yuanqing, et al. Research on meso-structures and their evolution laws of expansive soil and loess[J]. Rock and Soil Mechanics, 2009, 30(1): 1-11. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-7598.2009.01.001
[8] SHI G H, GOODMAN R E. Two dimensional discontinuous deformation analysis[J]. International Journal for Numerical and Analytical Methods in Geomechanics,1985,9(6):541 − 556. doi: 10.1002/nag.1610090604
[9] 江强强, 焦玉勇, 宋亮, 等. 降雨和库水位联合作用下库岸滑坡模型试验研究[J]. 岩土力学,2019,40(11):4361 − 4370. [JIANG Qiangqiang, JIAO Yuyong, SONG Liang, et al. Experimental study on reservoir landslide under rainfall and water-level fluctuation[J]. Rock and Soil Mechanics,2019,40(11):4361 − 4370. (in Chinese with English abstract)
JIANG Qiangqiang, JIAO Yuyong, SONG Liang, et al. Experimental study on reservoir landslide under rainfall and water-level fluctuation[J]. Rock and Soil Mechanics, 2019, 40(11): 4361-4370. (in Chinese with English abstract)
[10] 邬爱清, 丁秀丽, 陈胜宏, 等. DDA方法在复杂地质条件下地下厂房围岩变形与破坏特征分析中的应用研究[J]. 岩石力学与工程学报,2006,25(1):1 − 8. [WU Aiqing, DING Xiuli, CHEN Shenghong, et al. Researches on deformation and failure characteristics of an underground powerhouse with complicated geological conditions by dda method[J]. Chinese Journal of Rock Mechanics and Engineering,2006,25(1):1 − 8. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-6915.2006.01.001
WU Aiqing, DING Xiuli, CHEN Shenghong, et al. Researches on deformation and failure characteristics of an underground powerhouse with complicated geological conditions by dda method[J]. Chinese Journal of Rock Mechanics and Engineering, 2006, 25(1): 1-8. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-6915.2006.01.001
[11] 张国新, 金峰. 重力坝抗滑稳定分析中DDA与有限元方法的比较[J]. 水力发电学报,2004,23(1):10 − 14. [ZHANG Guoxin, JIN Feng. Comparison of stability of gravity dams by discontinuous deformation analysis and finite element method[J]. Journal of Hydroelectric Engineering,2004,23(1):10 − 14. (in Chinese with English abstract) doi: 10.3969/j.issn.1003-1243.2004.01.003
ZHANG Guoxin, JIN Feng. Comparison of stability of gravity dams by Discontinuous Deformation Analysis and Finite Element Method[J]. Journal of Hydroelectric Engineering, 2004, 23(1): 10-14. (in Chinese with English abstract) doi: 10.3969/j.issn.1003-1243.2004.01.003
[12] 张国新, 李广信, 郭瑞平. 不连续变形分析与土的应力应变关系[J]. 清华大学学报(自然科学版),2000,40(8):102 − 105. [ZHANG Guoxin, LI Guangxin, GUO Ruiping. Stress strain relationship for soil using discontinuous deformation analysis[J]. Journal of Tsinghua University (Science and Technology),2000,40(8):102 − 105. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-0054.2000.08.027
ZHANG Guoxin, LI Guangxin, GUO Ruiping. Stress strain relationship for soil using discontinuous deformation analysis[J]. Journal of Tsinghua University (Science and Technology), 2000, 40(8): 102-105. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-0054.2000.08.027
[13] 郭培玺, 林绍忠. 粗粒料力学特性的DDA数值模拟[J]. 长江科学院院报,2008,25(1):58 − 60. [GUO Peixi, LIN Shaozhong. Numerical simulation of mechanical characteristics of coarse granular materials by discontinuous deformation analysis[J]. Journal of Yangtze River Scientific Research Institute,2008,25(1):58 − 60. (in Chinese with English abstract) doi: 10.3969/j.issn.1001-5485.2008.01.015
GUO Peixi, LIN Shaozhong. Numerical simulation of mechanical characteristics of coarse granular materials by discontinuous deformation analysis[J]. Journal of Yangtze River Scientific Research Institute, 2008, 25(1): 58-60. (in Chinese with English abstract) doi: 10.3969/j.issn.1001-5485.2008.01.015
[14] 郭龙骁, 张常亮, 杨德广, 等. 黄土单向固结试验微观非连续变形分析[J]. 长江科学院院报,2017,34(3):80 − 84. [GUO Longxiao, ZHANG Changliang, YANG Deguang, et al. Discontinuous deformation analysis with microstructural model for axial odometer test of loess[J]. Journal of Yangtze River Scientific Research Institute,2017,34(3):80 − 84. (in Chinese with English abstract) doi: 10.11988/ckyyb.20151103
GUO Longxiao, ZHANG Changliang, YANG Deguang, et al. Discontinuous deformation analysis with microstructural model for axial odometer test of loess[J]. Journal of Yangtze River Scientific Research Institute, 2017, 34(3): 80-84. (in Chinese with English abstract) doi: 10.11988/ckyyb.20151103
[15] ZHANG R, LI J Q. Simulation on mechanical behavior of cohesive soil by Distinct Element Method[J]. Journal of Terramechanics,2006,43(3):303 − 316. doi: 10.1016/j.jterra.2005.05.006
[16] SHEN Z F, JIANG M J, THORNTON C. Shear strength of unsaturated granular soils:Three-dimensional discrete element analyses[J]. Granular Matter,2016,18(3):1 − 13.
[17] 李强, 李同录, 乔志甜, 等. 非饱和土粒间毛细作用的微观不连续变形分析[J]. 工程地质学报,2021,29(3):834 − 842. [LI Qiang, LI Tonglu, QIAO Zhitian, et al. Microscopic discontinuity deformation analysis of capillary in unsaturated soil[J]. Journal of Engineering Geology,2021,29(3):834 − 842. (in Chinese with English abstract)
LI Qiang, LI Tonglu, QIAO Zhitian, et al. Microscopic discontinuity deformation analysis of capillary in unsaturated soil[J]. Journal of Engineering Geology, 2021, 29(3): 834-842. (in Chinese with English abstract)
[18] 高世桥, 刘海鹏. 毛细力学[M]. 北京: 科学出版社, 2010
GAO Shiqiao, LIU Haipeng. Capillary mechanics[M]. Beijing: Science Press, 2010. （in Chinese）
[19] 王丽琴, 邵生俊, 王帅, 等. 原状黄土的压缩曲线特性[J]. 岩土力学,2019,40(3):1076 − 1084. [WANG Liqin, SHAO Shengjun, WANG Shuai, et al. Compression curve characteristic of undisturbed loess[J]. Rock and Soil Mechanics,2019,40(3):1076 − 1084. (in Chinese with English abstract)
WANG Liqin, SHAO Shengjun, WANG Shuai, et al. Compression curve characteristic of undisturbed loess[J]. Rock and Soil Mechanics, 2019, 40(3): 1076-1084. (in Chinese with English abstract)
[20] 蔡宗鹏. 原状黄土的增湿变形强的及土水特征试验研究[D]. 西安: 西安理工大学, 2016
CAI Zongpeng. Experimental study on the humidification deformation strength and soil water characteristics of undisturbed loess[D]. Xi’an: Xi’an University of Technology, 2016. （in Chinese with English abstract）
[21] 金娟. 侧限条件下原状黄土的增减湿变形特性及土水特征[D]. 西安: 西安理工大学, 2015
JIN Juan. Deformation characteristics and soil-water characteristics of undisturbed loess under confining conditions[D]. Xi’an: Xi’an University of Technology, 2015. （in Chinese with English abstract）
[22] 曹亮, 刘文白, 李晓昭, 等. 侧限压缩下砂土的细观力学特性及其形态分析[J]. 地质论评,2011,57(4):591 − 599. [CAO Liang, LIU Wenbai, LI Xiaozhao, et al. Micro mechanical properties and shape analysis of sands employing confined compression tests[J]. Geological Review,2011,57(4):591 − 599. (in Chinese with English abstract)
CAO Liang, LIU Wenbai, LI Xiaozhao, et al. Micro mechanical properties and shape analysis of sands employing confined compression tests[J]. Geological Review, 2011, 57(4): 591-599. (in Chinese with English abstract)
-
图(10)
表(1)
计量
- 文章访问数: 1533
- PDF下载数: 57
- 施引文献: 0