岩土力学 ›› 2020, Vol. 41 ›› Issue (S1): 156-162.doi: 10.16285/j.rsm.2019.1349

• 基础理论与实验研究 • 上一篇    下一篇

重塑黄土在不同基质吸力下的真三轴剪切试验

郑方1,邵生俊1, 2,佘芳涛1,袁浩1   

  1. 1. 西安理工大学 岩土工程研究所,陕西 西安 710048;2. 西安理工大学 陕西省黄土力学与工程重点实验室,陕西 西安 710048
  • 收稿日期:2019-08-02 修回日期:2019-12-17 出版日期:2020-06-19 发布日期:2020-06-09
  • 通讯作者: 邵生俊,男,1964 年生,博士,教授,博士生导师,主要从事土动力学与黄土力学方面的研究。E-mail: sjshao@xaut.edu.cn E-mail:zhfshirley@126.com
  • 作者简介:郑方,女,1989年生,博士研究生,主要从事黄土力学与土动力学方面的研究
  • 基金资助:
    国家自然科学基金项目(No.11572245,No.41272320,No.51608442)。

True triaxial shear tests of remolded loess under different matrix suctions

ZHENG Fang1, SHAO Sheng-jun1, 2, SHE Fang-tao1, YUAN Hao1   

  1. 1. Institute of Geotechnical Engineering, Xi’an University of Technology, Xi’an, Shaanxi 710048, China; 2. Shaanxi Key Laboratory of Loess Mechanics and Engineering, Xi’an University, Xi'an, Shaanxi 710048, China
  • Received:2019-08-02 Revised:2019-12-17 Online:2020-06-19 Published:2020-06-09
  • Supported by:
    This work was supported by the National Natural Science Foundation of China(11572245, 41272320, 51608442).

摘要: 为研究重塑黄土在控制吸力真三轴条件下的剪切特性,利用非饱和土固结仪测试了重塑黄土的土?水特征曲线,得到基质吸力与含水率的对应关系。利用真三轴仪对重塑黄土进行了控制基质吸力为50、100、200 kPa的固结排水剪切试验。在剪切试验中同时控制净平均应力为300 kPa,中主应力参数b值分别为0、0.25、0.50、0.75、1.00,试验结果给出大主应变、中主应变和小主应变与偏应力的关系曲线,研究了基质吸力和b值对土体应力?应变响应的影响。结果表明,重塑黄土的抗剪强度随基质吸力的增大而增大,随中主应力参数的b值增大而降低;应力?应变曲线随b值增大逐渐从应变硬化型向理想弹塑型转化;给出的重塑黄土在π平面上的强度破坏线,其随着基质吸力的增大而向外扩展,基质吸力会影响其位置、大小及形状,且重塑黄土不同基质吸力的试验结果与Lade-Duncan破坏准则的预测结果更接近。

关键词: 土?水特征曲线, 重塑黄土, 真三轴仪, 基质吸力, 中主应力参数

Abstract: In order to investigate the shear characteristics of remolded loess under suction-controlled true triaxial condition, firstly, soil-water characteristic curve of remolded loess was tested by using the unsaturated soil oedometer, so the relationship between moisture content and matrix suction of remolded loess was obtained. Then, true triaxial shear tests under consolidated drained conditions of remolded unsaturated loess were carried out with matrix suction of 50, 100 and 200 kPa. In the true triaxial shear tests, the net mean stress was kept at 300 kPa and the intermediate principal stress parameters(b-values) were respectively 0, 0.25, 0.50, 0.75 and 1.00. The relationship curves of major principal strain, intermediate principal strain and minor principal strain versus deviatoric stress from true triaxial test results were given. The effects of matrix suction and intermediate principal stress parameter on the stress-strain response of remolded loess were studied. It could be concluded that the shear strength of remolded loess increased with the increase of matrix suction. And it could be summarized that the shear strength of remolded loess decreased with the increase of intermediate principal stress parameter(b-value). The stress-strain curves gradually transformed from strain-hardening type to ideal elastic-plastic type with the increase of intermediate principal stress parameter(b-value). The strength failure line of the remolded loess on π-plane was given. The failure line expanded outward with the increase of matrix suction. Matrix suction might affect the position, size and shape of the failure line. Besides, the test results of different matrix suction were more similar to those predicted by Lade-Duncan criterion.

Key words: soil-water characteristic curve, remolded loess, true-triaxial apparatus, matrix suction, intermediate principal stress parameter

中图分类号: 

  • TU 444
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