基础理论与实验研究

非饱和压实土率相关变形特征与时效模型

展开
  • 1. 湘潭大学 岩土力学与工程安全湖南省重点实验室,湖南 湘潭 411105;2. 同济大学 地下建筑与工程系,上海 200092; 3. 中南林业科技大学 工程流变学湖南省重点试验室,湖南 长沙 410004
王智超,男,1980年生,副教授,博士后,主要从事岩土流变学的研究工作。

收稿日期: 2015-04-03

  网络出版日期: 2018-06-09

基金资助

国家自然科学基金(No.51308485,No.51108397);湖南省自然科学基金资助项目(No.12JJ4006);湖南省重点试验室开放基金(No.14HNKLER01)。

Rate-dependent deformation characteristics and time-dependent constitutive model of unsaturated compacted clay

Expand
  • 1. Hunan Provincial Key Laboratory of Geomechanics and Engineering Safety, Xiangtan University, Xiangtan, Hunan 411105, China; 2. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China; 3. Hunan Provincial Key Laboratory of Engineering Rheology, Central South University of Forestry and Technology, Changsha, Hunan 410004, China

Received date: 2015-04-03

  Online published: 2018-06-09

Supported by

This work was supported by the National Natural Science Foundation of China (51308485, 51108397), the Natural Science Foundation of Hunan Province of China (12JJ4006) and the Open Foundation of Hunan Provincial Key Laboratory of Engineering Rheology (14HNKLER01).

摘要

为研究高填方路堤压实土率相关变形特征,对不同压实度的非饱和压实土分别开展了不同加载速率以及不同围压条件下的CD三轴剪切试验,探讨了不同工况下压实土的剪切强度指标;借助GDS饱和土静态三轴仪的围压控制器来间接测定非饱和压实土体变的途径。试验结果表明:压实土强度及变形特征具有明显的时间相依性,加载速率越大,压实土的抗剪强度越高,超固结变形特性越强,抗剪强度指标黏聚力c值增幅较大、内摩擦角 值增幅较小;低围压下,压实土呈应变软化及剪胀变形,且压实度越高,应变软化及剪胀变形越显著,c值增加明显、 值增加缓慢。采用基于下负荷面的弹黏塑性本构模型对路基压实土的率相关变形特征进行表征,预测结果与试验数据吻合良好,表明该模型适用于高填方路堤长期沉降分析。

本文引用格式

王智超 ,金 刚 ,吴晓峰 ,邓旭华 ,董 辉, . 非饱和压实土率相关变形特征与时效模型[J]. 岩土力学, 2016 , 37(3) : 719 -727 . DOI: 10.16285/j.rsm.2016.03.014

Abstract

To investigate the rate-dependent deformation characteristics of subgrade compacted clay of high-filled embankment, a series of CD triaxial shear tests on the unsaturated compacted clay with different compaction degrees is carried out under different loading rates and confining pressures, and the shear strength parameters under different working conditions are examined. A method is proposed for indirectly measuring the volume change of unsaturated compacted clay, i.e. using the confining pressure controller of GDS saturated static triaxial system to obtain the volume change. The experimental results show that the strength and deformation of compacted clay shows significant time-dependent characteristics. At the greater loading rate, the shear strength is higher and the over-consolidated properties are stronger, and the value of cohesion c increases more quickly but the value of the internal friction angle increases more slowly. Under low confining pressure, compacted clay shows dilatant and softening behavior. As the compacting degree increases, shear dilatancy and strain softening become more and more pronounced, shear strength index c increases quickly, whereas increases slowly. An elastic-viscoplastic constitutive model based on the subloading yield surface is adopted to describe the rate-dependent deformation characteristics of the over-consolidated compacted clay. The predictions of the proposed model are in good agreement with the experimental data, showing that the proposed model is suitable for analyzing the long-term settlement of high-filled embankment.
文章导航

/