长江科学院院报 ›› 2019, Vol. 36 ›› Issue (1): 88-94.DOI: 10.11988/ckyyb.20170764

• 岩土工程 • 上一篇    下一篇

基于场应变的充填体与围岩组合模型循环加卸载试验研究

王志国1,2, 李柱营1,2, 李跃龙1,2   

  1. 1.华北理工大学 矿业工程学院,河北 唐山 063009;
    2. 华北理工大学 河北省矿业开发与安全工程实验室,河北 唐山 063009
  • 收稿日期:2017-07-03 出版日期:2019-01-01 发布日期:2019-01-17
  • 作者简介:王志国(1969-),男,河北香河人,教授,博士,硕士生导师,主要从事采矿与岩石力学方面的教学与研究工作。E-mail:wzg@ncst.edu.cn
  • 基金资助:
    河北省自然科学基金项目(E2015209260);河北省钢铁冶金联合研究基金项目(E2018209351);河北省高等学校科学技术研究重点项目(ZD2017060)

Cyclic Loading and Unloading Test on Fracture Mechanism of Combined Model of Surrounding Rock and Backfill Based on Field Strain

WANG Zhi-guo1,2,LI Zhu-ying 1,2, LI Yue-long1,2   

  1. 1.College of Mining Engineering, North China University of Science and Technology, Tangshan 063009,China;
    2.Key Laboratory of Mining Industry Development and Safety of Hebei Province, North ChinaUniversity of Science and Technology, Tangshan 063009, China
  • Received:2017-07-03 Online:2019-01-01 Published:2019-01-17

摘要: 为模拟研究充填采场围岩破裂演变机理,设计了充填体与围岩组合模型,采用RLW-3000微机控制剪切蠕变试验机对不同种类岩石模型试样进行了不同侧压力条件下的循环加卸载试验;通过VIC-3D非接触全场应变系统同步监测模型试样损伤破坏过程,基于试验过程中应变场的演变,对组合模型破裂机理进行了分析。研究表明:充填体能够增强围岩的完整性及强度;组合模型的破裂经历了一个扩容的过程;不同侧压下循环加卸载应力-应变曲线形成多塑性滞回环,岩性越软滞回现象越显著;应变场在低循环荷载时近似均匀场,高荷载时在加载非均匀场与卸载均匀场之间变换,渐呈应变局部化特征;张拉应变区首先出现在强度比较低的充填体区域,并随荷载增大逐渐向两侧的围岩移动,充填体与围岩变形具有时空非同步性与破坏形式差异;不同种类围岩破坏形式不同,强度较低的呈剪切破坏,强度较高的则为拉伸破坏。结果表明场应变演变可较好地表征充填采场围岩破裂过程。

关键词: 充填体, 围岩, 应变场, 组合模型, 循环加卸载, 破裂机理

Abstract: A combined model of surrounding rock and backfill was designed to simulate the failure evolution of backfilled mining stope. Cyclic loading and unloading tests were conducted on model specimens of three different rocks (marble, granite, and basalt) by using RLW-3000 microcomputer-controlled shear creep test machine under varying lateral pressure; VIC-3D non-contact full-field strain measurement system was employed to simultaneously monitor the damage process and failure of the combined model. Analysis result demonstrates that backfill enhances the integrity and strength of surrounding rock; the combined model undergone a volume dilatation process. The stress-strain curves of the loading and unloading in every cyclic loading process are non-coincident, forming plastic hysteresis loops which becomes more remarkable with the increase of rock’s softness. Strain field approximates uniform field under low cyclic load, while changes between non-uniform field of loading and uniform field of unloading under the condition of high load, exhibiting features of strain localization. Tensile strain firstly appeared in the region of backfill body of low strength, and gradually moves towards two sides of surrounding rock with the climbing of loading. The deformation and failure of backfill body and surrounding rock are asynchronous in spatial-temporal evolution with different failure modes. The failure mode varies with surrounding rock type: rock of low strength exhibits shear failure, and rock of high strength, tensile failure. The results suggest that the evolution of strain field could well reflect the fracture process of the combined model of surrounding rock and backfill.

Key words: filling body, surrounding rock, strain field, combined model, cyclic loading and unloading, fracture mechanism

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