岩土力学 ›› 2022, Vol. 43 ›› Issue (1): 97-109.doi: 10.16285/j.rsm.2021.0612

• 基础理论与实验研究 • 上一篇    下一篇

高地应力卸荷条件下错动带塑性变形 规律与硬化特征

段淑倩1, 2,高坡1,江权2,周扬一3,徐鼎平2   

  1. 1. 郑州大学 土木工程学院,河南 郑州 450001;2. 中国科学院武汉岩土力学研究所 岩土力学与工程国家重点实验室,湖北 武汉 430071; 3. 东北大学 深部金属矿山安全开采研究中心,辽宁 沈阳 110819
  • 收稿日期:2021-04-21 修回日期:2021-09-22 出版日期:2022-01-10 发布日期:2022-01-06
  • 通讯作者: 江权,男,1978年生,博士,研究员,主要从事岩石力学与地下工程方面的研究。E-mail: qjiang@whrsm.ac.cn E-mail:shuqianduan@zzu.edu.cn
  • 作者简介:段淑倩,女,1991年生,博士,副教授,主要从事岩石力学与工程方面的研究
  • 基金资助:
    国家自然科学基金青年科学基金项目(No. 51909241);河南省高等学校重点科研项目(No. 19A560006);岩土力学与工程国家重点实验室开放基金项目(No. Z017011)

Plastic deformation and hardening characteristics of the staggered zone under high in-situ stress unloading conditions

DUAN Shu-qian1, 2, GAO Po1, JIANG Quan2, ZHOU Yang-yi3, XU Ding-ping2   

  1. 1. School of Civil Engineering, Zhengzhou University, Zhengzhou, Henan 450001, China; 2. State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei 430071, China; 3. Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines, Northeastern University, Shenyang, Liaoning 110819,China
  • Received:2021-04-21 Revised:2021-09-22 Online:2022-01-10 Published:2022-01-06
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (51909241), the Scientific Research Key Project Fund of Colleges and Universities of Henan Province (19A560006) and the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences (Z017011).

摘要: 为阐明高地应力地下工程开挖卸荷条件下错动带变形破坏的塑性规律与硬化特征,通过一系列不同围压、不同加卸荷应力路径下的三轴试验,着重研究了不同加卸荷应力路径下的错动带塑性变形规律;基于试验结果,在应力空间进一步探究了等效塑性功、等效塑性应变、塑性体应变等内变量作为硬化参数的应力路径相关性,并提出应力路径无关的硬化参量修正公式。研究结果表明:(1)高地应力下错动带的变形力学特性存在着明显的应力路径效应,在相同卸荷应力路径下,高围压会抑制错动带试样环向塑性变形的发展;在相同初始围压下,卸轴压卸围压应力路径下错动带试样的塑性体积残余应变(6%)明显大于其余卸荷应力路径(2%~4%);不同应力路径对错动带塑性体积变形的促进作用为卸轴压卸围压应力路径>恒轴压卸围压应力路径>增轴压卸围压应力路径;(2)错动带在不同卸荷路径变形破坏过程中,其塑性体应变、等效塑性应变、等效塑性功等内变量均存在一定的应力路径相关性,因而在错动带的弹塑性分析中,直接将以上任何一个状态参量作为其硬化参数并假定其与应力路径无关是不准确的。为此,提出等效塑性功修正方法,发现当修正等效塑性功公式中反映错动带材料特性的参数ns = ?0.4时,修正等效塑性功具有明显的应力路径无关性,更适宜作为高地应力卸荷条件下错动带的硬化参数来描述其卸荷塑性应变硬化特征。揭示的错动带塑性力学特性可进一步深化高地应力卸荷条件下错动带的变形破坏认识,为实际工程中错动带的破坏机制分析和支护控制提供理论依据。

关键词: 错动带, 高地应力, 卸荷, 塑性变形, 硬化特征

Abstract: To clarify the plastic law and hardening characteristics of deformation and failure of staggered zone under high in-situ stress unloading conditions with excavation in underground engineering, a series of triaxial tests under different confining pressures and different loading and unloading stress paths was conducted. The plastic deformation laws of the staggered zone under different loading and unloading stress paths were deeply investigated. Based on the results of the experiments, the dependency of stress path of internal variables such as the equivalent plastic work, the effective plastic strain and the plastic volumetric strain as hardening parameters were further explored in the stress space. Meanwhile, a modified formula for hardening parameters with the independency of stress path was proposed. The results showed that 1) The effect of stress path was significant on the deformation properties of staggered zone under high in-situ stress. The high initial confining pressure would inhibit the development of the circumferential plastic deformation of samples with the staggered zone under the same unloading stress path. And the plastic volumetric residual strain (6%) of samples with the staggered zone under the stress path of unloading axial pressure and confining pressure was significantly greater than that of other unloading stress paths (2%-4%) under the same initial confining pressure. The promoting effects of different stress paths on the plastic volumetric deformation of the staggered zone were as follows. The promoting effect of the stress path of unloading axial pressure and unloading confining pressure was the strongest, that of the stress path of constant axial pressure and unloading confining pressure was the second strong, and that of the stress path of loading axial pressure and unloading confining pressure was the weakest. 2) There were a certain of the dependency of stress path of its internal variables such as plastic volumetric strain, effective plastic strain and equivalent plastic work during the deformation and failure process of the staggered zone in different unloading stress paths. Therefore, it is not accurate to directly take any of the above state parameters as the hardening parameters and assume that it is independent of the stress paths in the elastic-plastic analysis of staggered zone. Therefore, a modified method of the equivalent plastic work was proposed. It was found that when the parameter ns reflecting the material properties of staggered zone was equal to ?0.4, the modified equivalent plastic work had the obvious independency of stress path, which was more appropriate for describing the unloading plastic strain hardening characteristics of the staggered zone under high in-situ stress unloading conditions. The plastic mechanical characteristics of the staggered zone revealed in this paper can further deepen the understanding of deformation and failure of the staggered zone under high in-situ stress unloading conditions, and provide a theoretical basis for the analysis of the failure mechanism and support control of the staggered zone in practical engineering.

Key words: staggered zone, high in-situ stress, unloading, plastic deformation, hardening characteristics

中图分类号: 

  • TU 470
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