›› 2018, Vol. 39 ›› Issue (5): 1699-1708.doi: 10.16285/j.rsm.2017.1120

• 基础理论与实验研究 • 上一篇    下一篇

真三轴条件下Q3原状黄土的力学特性

方瑾瑾1,冯以鑫2,朱昌星1   

  1. 1. 河南理工大学 土木工程学院,河南 焦作 454000; 2. 河南理工大学 基建处,河南 焦作 454000
  • 收稿日期:2017-06-05 出版日期:2018-05-11 发布日期:2018-06-12
  • 作者简介:方瑾瑾,女,1984年生,博士,讲师,主要从事黄土力学方面的研究工作。
  • 基金资助:

    河南理工大学博士基金项目(B2018-64)

Mechanical characteristics of Q3 intact loess in true triaxial tests

FANG Jin-jin1, FENG Yi-xin2, ZHU Chang-xing1   

  1. 1. School of Civil Engineering, Henan Polytechnic University, Jiaozhuo, Henan 454000, China; 2. Infrastructure Department, Henan Polytechnic University, Jiaozhuo, 454000, China
  • Received:2017-06-05 Online:2018-05-11 Published:2018-06-12
  • Supported by:

    This work was supported by the Doctoral Foundation of Henan Polytechnic University (B2018-64).

摘要: 为了模拟实际工程中黄土在不排水条件下的破坏,在控制含水率不变条件下,利用非饱和土真三轴仪对不同初始吸力非饱和原状黄土进行了等向固结试验和不同中主应力参数b值的剪切试验,研究了非饱和原状黄土的力学特性。研究结果表明:真三轴等向压缩屈服应力随着初始吸力的增大而增大,吸力随着净平均应力的增大而减小,净平均应力对吸力的影响程度随着初始吸力的增大而增大。不同 值条件下,广义剪应力和净平均应力破坏状态线近似呈平行直线关系,广义剪应力和有效净平均球应力试验点可归一为饱和土的排水剪切破坏状态线;剪切破坏时吸力随着b值的增大基本呈线性增大趋势;孔隙比和净平均应力对数临界状态线近似呈线性平行关系,其斜率比饱和土大,且大于等向压缩屈服前的斜率;非饱和土孔隙比和有效净平均球应力对数临界状态线与饱和土的临界状态线近似呈线性平行关系;不同净围压条件下,不同 值非饱和土与饱和土的破坏状态孔隙比的比值与气体饱和度的试验点分布于1.0~1.2的直线带内,但同一净有效球应力条件下可以归一为一条非线性曲线。

关键词: 非饱和原状黄土, 非饱和土真三轴仪, 吸力, 孔隙比

Abstract: To simulate the failure of loess under undrained condition in the actual engineering, a series of isotropic consolidation and shear tests with different intermediate principal stress ratios b under constant water content is performed on intact loess with various initial suctions by using unsaturated soil true tri-axial apparatus. The mechanical characteristics of unsaturated intact loess are studied. The results show that the isotropic compression yield stress increases with initial suction, suction decreases with the increase of net mean stress, the extent of suction impact of net mean stress increases with increasing of the initial suction. The damage state lines of generalized shear and net average stress are parallel to the linear relationship and the test points of generalized shear and effective net mean spherical stress can be normalized to drainage shear failure state line of saturated soil under different the ratios b. The suction of shear failure increases linearly with the ratio b; void ratio is approximately linear parallel to logarithm of net average stress critical state lines, whose slopes are larger than those of saturated loess and larger than those of isotropic compression before yielding; both void ratio and logarithm of effective net mean spherical stress critical state lines of unsaturated soil are approximately linear parallel to the critical state line of saturated soil. The test points that ratios of damage state void ratios between unsaturated loess and saturated loess and gas saturations are distributed in a linear zone of 1-1.2 under different net confining pressures, but those points can be normalized to a nonlinear curve at the same net effective stress.

Key words: unsaturated intact loess, unsaturated soil true triaxial apparatus, suction, void ratio

中图分类号: 

  • TU 411

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