无黏性粗粒土直接剪切试验的强度尺寸效应

发布时间：2018-05-20 08:02

本文选题：无黏性土 + 尺寸效应　；参考：《四川大学学报(工程科学版)》2016年S1期

【摘要】：为研究无黏性粗粒土直接剪切试验的强度尺寸效应,采用相同试样尺寸直剪仪对不同最大粒径无黏性粗粒土进行直剪试验。试验土料最大粒径分别为40、20、10、5和2 mm,各组土料具自相似质量分形结构以保证土料孔隙特征相同,并采用预先植入竖直锡丝的方法测量剪切带宽度。结果表明:随最大粒径增大,剪切带宽度和强度增大,且当最大粒径大于试样高度的1/20时,产生明显的强度尺寸效应现象;咬合力c和内摩擦角φ随试样高度与最大粒径比值的增大而减小,且与其对数呈明显的线性关系;随最大粒径增大,强度尺寸效应逐渐明显的原因为剪切带内颗粒数减少,颗粒间接触力强力链容易形成。
[Abstract]:In order to study the strength and size effect of the direct shear test of non-viscous coarse grained soil, the direct shear test of different maximum diameter non-viscous coarse grained soil was carried out by using the same sample size direct shear apparatus. The maximum particle size of the tested soil is 40 ~ 20 ~ 10 ~ 5 mm and 2 mm respectively. Each group of soil has self-similar mass fractal structure to ensure that the pore characteristics of soil are the same, and the width of shear band is measured by pre-implantation of vertical tin wire. The results show that the shear band width and strength increase with the increase of the maximum particle size, and when the maximum particle size is greater than 1 / 20 of the sample height, the strength size effect is obvious. The occlusal force c and the internal friction angle 蠁 decrease with the increase of the ratio of specimen height to the maximum particle size, and there is an obvious linear relationship with the logarithm of the sample, and with the increase of the maximum particle size, the size effect of strength becomes obvious gradually because the number of particles in the shear band decreases. The strong chain of contact force between particles is easy to form.
【作者单位】：四川大学水力学与山区河流开发保护国家重点实验室水利水电学院;华电金沙江上游水电开发有限公司;
【基金】：国家自然科学基金资助项目(50909068)
【分类号】：TU411

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