Experimental Study on Micro-macro Shear Properties of Sand Considering Particle Size
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摘要: 为探究砂土粒径对其抗剪强度的影响，利用应变控制式直剪仪和离散元软件，分别进行了3种不同平均粒径砂的剪切试验，从宏观、细观两个角度对砂展开了剪切特性分析。研究表明：抗剪强度随法向应力和平均粒径的增加而增大，内摩擦角随平均粒径的增加而增大。建立了砂土抗剪强度多元线性预测模型，且模型预测准确。平均粒径的增加致使剪切带厚度增大。剪切带厚度与法向应力关系可用一元二次函数表达。因此，在实际工程施工中，合理采用粒径较大的砂土有利于提高抗剪能力。Abstract: In order to explore the influence of sand particle size on its shear resistance, strain controlled direct shear apparatus and discrete element software were used to conduct shear tests on three kinds of sand with different average particle sizes, and the shear characteristics of sand were analyzed from both macro and micro perspectives. The results show that the shear strength increases with the increase of normal stress and average particle size, and the internal friction angle increases with the increase of average particle size. A multivariate linear prediction model of sand shear strength is established, and the model prediction is accurate. The thickness of shear band increases with the increase of average particle size. The relationship between shear band thickness and normal stress can be expressed by a quadratic function. Therefore, in the actual project construction, reasonable use of sand with larger particle size is conducive to improving the shear capacity.
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Key words:
- sand /
- average particle size /
- shear strength /
- numerical simulation /
- shear band thickness
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表 1 各情况下抗剪强度表
平均粒径d/mm 法向应力σ/kPa 抗剪强度τf/kPa 0.15 50 27.56 100 51.40 150 79.24 200 106.37 0.36 50 29.64 100 55.24 150 82.64 200 115.64 1.22 50 32.64 100 63.25 150 93.70 200 128.53 
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表 2 剪切带厚度L与法向应力σ拟合关系
粒径类型 拟合函数 相关系数R2 dⅠ L = -0.00002 σ2 + 0.015 σ + 16.1 1.000 dⅡ L = -0.00004 σ2 + 0.017 σ + 6.8 0.997 dⅢ L = -0.00002 σ2 + 0.011 σ + 2.7 1.000
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[1] 孔 亮,陈凡秀,李 杰. 基于数字图像相关法的砂土细观直剪试验及其颗粒流数值模拟[J]. 岩土力学,2013,34(10):2971-2978. doi: 10.16285/j.rsm.2013.10.021 [2] BEEN K,JEFFERIES M G. A state parameter for sands[J]. Géotechnique,1985,35(2):99-112. [3] 郝冬雪,岳 冲,陈 榕,等. 常压至高压下中砂剪切特性及应力–剪胀关系[J]. 岩土工程学报,2020,42(4):765-772. doi: 10.11779/CJGE202004021 [4] 刘方成,吴孟桃. 橡胶砂直剪试验的颗粒离散元细观力学模拟[J]. 合肥工业大学学报(自然科学版),2017,40(7):944-951. [5] 李 航,陆 烨,孙 康. 标准砂直剪试验的PFC数值模拟[J]. 上海大学学报(自然科学版),2017,23(5):780-788. [6] 杨忠平,雷晓丹,王 雷,等. 含石量对土石混合体剪切特性影响的颗粒离散元数值研究[J]. 工程地质学报,2017,25(4):1035-1045. doi: 10.13544/j.cnki.jeg.2017.04.018 [7] 张振平,盛 谦,付晓东,等. 基于颗粒离散元的土石混合体直剪试验模拟研究[J]. 应用基础与工程科学学报,2021,29(1):135-146. doi: 10.16058/j.issn.1005-0930.2021.01.012 [8] 李广信. 高等土力学[M]. 北京: 清华大学出版社, 2004. [9] MASSON S,MARTINEZ J. Micromechanical analysis of the shear behavior of a granular material[J]. Journal of Engineering Mechanics,2001,127(10):1007-1016. doi: 10.1061/(ASCE)0733-9399(2001)127:10(1007) [10] JIANG M J,YU H S,HARRIS D. Bond rolling resistance and its effect on yielding of bonded granulates by DEM analyses[J]. International Journal for Numerical & Analytical Methods in Geomechanics,2006,30(8):723-761. [11] FENG Y T,OWEN D. Discrete element modelling of large scale particle systems—I: exact scaling laws[J]. Computational Particle Mechanics,2014,1(2):159-168. doi: 10.1007/s40571-014-0010-y -
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