基础理论与实验研究

不同应力路径下土石混填体变形力学特性大型三轴试验研究

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  • 1.长沙理工大学 水利工程学院,湖南 长沙 410076;2.湖南大学 土木工程学院,湖南 长沙 410082; 3.长沙市规划设计院有限责任公司,湖南 长沙 410007
王江营,男,1985年生,博士,讲师,主要从事岩土体变形力学特性等方面的研究工作。

收稿日期: 2015-07-22

  网络出版日期: 2018-06-09

基金资助

国家自然科学基金(No. 51508039,No. 51078137);湖南省教育厅科技项目(No. 15C0049)。

Large-scale triaxial tests on deformation and mechanical behavior of soil-rock aggregate mixture under different stress paths

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  • 1. School of Hydraulic Engineering, Changsha University of Science and Technology, Changsha, Hunan 410076, China; 2. College of Civil Engineering, Hunan University, Changsha, Hunan 410082, China; 3. Changsha Planning & Design Institute Co., Ltd., Changsha, Hunan 410007, China

Received date: 2015-07-22

  Online published: 2018-06-09

Supported by

This work was supported by the National Natural Science Foundation of China (51508039 and 51078137) and the Science Program of Education Department of Hunan Province of China (15C0049).

摘要

为更加全面地掌握土石混填体的变形、力学特性,采用大型三轴剪切仪分别在常规路径、等应力比路径和等p路径下对不同含石量的土石混填体进行了一系列试验研究。试验结果表明,在低围压下土石混填体的应变软化特征并不明显,其黏聚力普遍较低,而内摩擦角则较高,随试样的含石量从25%增加到70%,其内摩擦角和变形模量亦会随之增加。土石混填体在常规路径和等p路径下的应力-应变关系曲线比较相似,其所求得的抗剪强度指标亦比较接近;而等应力比路径下的应力-应变关系曲线的形态和发展过程均与之存在明显差别。土石混填体在常规路径下具有低压剪胀和高压剪缩的特性,含石量越高,低压剪胀性越明显,反之,则高压剪缩性更为显著;等应力比路径下试样的体积应变与轴向应变之间近似呈线性关系,其斜率随应力比增加而减小;等p路径下试样则是以剪胀性为主,尤其在平均主应力较低时更为显著。

本文引用格式

王江营 ,曹文贵 ,蒋中明 ,赵志鹏, . 不同应力路径下土石混填体变形力学特性大型三轴试验研究[J]. 岩土力学, 2016 , 37(2) : 424 -430 . DOI: 10.16285/j.rsm.2016.02.015

Abstract

To understand the deformation and mechanical behavior of soil-rock aggregate mixture, a series of large-scale triaxial tests is conducted under different stress paths (conventional, constant stress ratio and constant p paths). The experimental results indicate that the strain softening of soil-rock aggregate mixture is insignificant under the low-confining pressure condition; the soil cohesion is generally low and the internal friction angle is relatively high. The internal friction angle and deformation modulus increase as the rock content increases from 25% to 70%. The stress-strain curves of soil-rock aggregate mixture are similar under the conventional stress path and the constant p path. Their shear strength indices are also similar. However, the form and development process of stress-strain curves under constant stress ratio path are significantly different. The specimen presents dilatation under low confining pressure and shrinkage at high confining pressure under conventional stress path. The higher the rock content, the more significant the dilatation under low confining pressure is. Conversely, the more significant the shear shrinkage under high confining pressure is. The relationship of volumetric strain and axial strain is linear under constant stress ratio path, and its slope decreases with the increase of stress ratio (q/p). The soil-rock aggregate mixture generally exhibits dilatation in constant p path tests, which is especially significant under low average principal stress.
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