非线性连续卸荷路径下黄土的强度与变形特性研究
DOI:
作者:
作者单位:

西安交通大学

作者简介:

通讯作者:

中图分类号:

基金项目:

国家自然科学基金项目(面上项目,重点项目,重大项目)


Study on strength and deformation characteristics of loess under nonlinear continuous unloading path
Author:
Affiliation:

Xi’an Jiaotong University

Fund Project:

  • 摘要
  • |
  • 图/表
  • |
  • 访问统计
  • |
  • 参考文献
  • |
  • 相似文献
  • |
  • 引证文献
  • |
  • 资源附件
  • |
  • 文章评论
    摘要:

    竖向卸荷状态下黄土的强度变形特性对挖方区边坡失稳研究有重要的理论意义,本文从工程应用角度出发基于伯努利方程改进了室内直剪仪,即利用水箱代替砝码进行加、卸载,研究了非线性连续卸荷路径下黄土的强度变形特性。研究发现:非线性连续卸荷路径下土体剪应力-位移曲线与未卸荷状态不同,具体表现在非线性连续卸荷过程中剪应力不仅与剪切位移有关也与卸荷比(R)有关;剪应力(τ)-剪切位移(δ)空间中,同一初始固结压力下,试样在卸荷比(R)较小时剪应力-剪切位移曲线与未卸荷时基本重合,当卸荷比(R)增大到一定值后,剪应力-剪切位移曲线出现软化现象,且卸荷速率越大,软化越明显;同时非线性连续卸荷工况下,抗剪强度与初始固结压力有关,随着初始固结压力的增加,卸荷引起的超固结效应明显增强;基于Mohr-Coulumb强度准则,采用指数衰减的数学模型可以较好的描述非线性连续卸荷过程中强度参数的演化规律。

    Abstract:

    The strength and deformation of loess under vertical unloading state have important theoretical significance for the study of slope instability in excavation area. From the perspective of engineering application, this paper improves the indoor direct shear apparatus based on Bernoulli equation, which uses water tank instead of weight to load and unload. The strength and deformation of remolded loess under nonlinear continuous unloading path are studied.It is found that the shear stress-displacement curve of the soil under the nonlinear continuous unloading path is different from those under the non-loading state, which is reflected that the shear stress in the process of nonlinear continuous unloading is related not only to the shear displacement but also to the unloading ratio (R). In the shear stress (τ)-shear displacement (δ) space, under the same initial consolidation pressure, the shear stress-shear displacement curve of the sample is basically coincident with that without unloading when the unloading ratio (R) is small. When the unloading ratio (R) increases to a certain value, the shear stress-shear displacement curve appears softening, and the greater the unloading rate, the more obvious the softening is. At the same time, under nonlinear continuous unloading conditions, the shear strength is related to the initial consolidation pressure. With the increase of the initial consolidation pressure, the over-consolidation effect caused by unloading increases significantly. Based on Mohr-Coulumb strength criterion, the mathematical model of exponential decay can be used to describe the evolution of the strength parameters in the process of nonlinear continuous unloading.

    参考文献
    相似文献
    引证文献
引用本文
分享
文章指标
  • 点击次数:
  • 下载次数:
  • HTML阅读次数:
  • 引用次数:
历史
  • 收稿日期:2019-06-24
  • 最后修改日期:2019-09-23
  • 录用日期:2019-09-24
  • 在线发布日期:
  • 出版日期: