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黄金科学技术 ›› 2021, Vol. 29 ›› Issue (3): 355-363.doi: 10.11872/j.issn.1005-2518.2021.03.204

• 采选技术与矿山管理 • 上一篇    

应力—渗流耦合作用下损伤岩石渗流特性

胡建华(),董喆喆,马少维(),秦亚光,徐晓,代转   

  1. 中南大学资源与安全工程学院,湖南 长沙 410083
  • 收稿日期:2020-11-29 修回日期:2021-03-08 出版日期:2021-06-30 发布日期:2021-07-14
  • 通讯作者: 马少维 E-mail:hujh21@126.com;mashaowei@csu.edu.cn
  • 作者简介:胡建华(1975-),男,湖南衡南人,教授,从事高效安全采矿技术与工程稳定性研究工作。hujh21@126.com
  • 基金资助:
    国家自然科学基金项目“深部采动下地质结构体跨尺度时变力学行为试验及机理”(41672298);国家“十三五”重点研发计划课题“深部大矿段多采场时空协同采矿理论与技术”(2017YFC0602901)

Seepage Characteristics of Damaged Rock Under Stress-Seepage Coupling

Jianhua HU(),Zhezhe DONG,Shaowei MA(),Yaguang QIN,Xiao XU,Zhuan Dai   

  1. School of Resources and Safety Engineering,Central South University,Changsha 410083,Hunan,China
  • Received:2020-11-29 Revised:2021-03-08 Online:2021-06-30 Published:2021-07-14
  • Contact: Shaowei MA E-mail:hujh21@126.com;mashaowei@csu.edu.cn

摘要:

地下矿产资源开采过程中,频繁的应力扰动会对深部硬岩造成一定的损伤。硬岩内部孔隙和裂隙在高地应力和高渗透压的状态下迅速扩展贯通,严重威胁岩体工程的安全和稳定性。针对损伤花岗岩开展了一系列应力—渗流耦合试验,结合CT扫描,考虑渗透压、围压和损伤程度等因素的影响,综合分析了损伤岩石在应力—渗流耦合作用下的力学和渗流特性。试验结果表明:随着损伤程度的增加,岩样孔隙及裂隙体积呈现出从平缓增加、稳步增加到急剧增加的变化趋势;在围压相同的情况下,岩样的峰值强度随着渗透压的增加呈线性减小,渗透压对损伤花岗岩的强度具有明显的弱化效应,且弱化程度与围压无关;损伤程度越大,裂隙发育程度越高,渗透率越大,同时,孔隙及裂隙的发育程度可用于表征渗透率的大小。

关键词: 岩石力学, 损伤花岗岩, 应力—渗流耦合, 渗透率, CT扫描, 损伤程度

Abstract:

During the mining of underground mineral resources,the deep hard rock will be damaged by the frequent stress disturbances.Its internal pores and fissures will rapidly expand and penetrate under the state of high ground stress and high osmotic pressure,which seriously threatens the safety and stability of rock mass engineering.The damage degree D is defined by the ratio of axial stress σ to compressive strength σc.Pre-damaged rock samples with different damage degrees (0%,25%,40%,50%,65%,75%,100%) were prepared by uniaxial compression test.A series of stress-seepage coupling tests were carried out for 75% damaged granite.Combined with CT scanning,considering the influence of seepage pressure,confining pressure and damage degree,the mechanical and seepage characteristics of damaged rock under stress-seepage coupling was comprehensive analyzed.The research results show that with the increase of damage degree,the number and size of pore and fracture of rock sample increase significantly,and changes of the volume of pore and fracture of rock sample shows a trend of increase gently and increase steadily to increase sharply.Under the same confining pressure,the peak strength of the rock sample shows a linear decrease with the increase of osmotic pressure,the osmotic pressure has a significant weakening effect on the strength of damaged granite,and the degree of weakening is independent of the confining pressure.The permeability of pre-damaged rock samples is closely related to the volume of pores and fractures.The variation trend of permeability with damage percentage confirms the evolution law of pores in different development stages.The greater the degree of damage,the higher the degree of fracture development and the greater the permeability.At the same time,the permeability can be characterized by the degree of development of pores and fractures.With the same degree of fracture development,the greater the confining pressure,the smaller the permeability.

Key words: rock mechanics, damage granite, stress-seepage coupling, permeability, CT scan, damage degree

中图分类号: 

  • TU45

图1

花岗岩岩样"

表1

花岗岩基本物理力学参数"

参数数值参数数值
密度/(g·cm-32.55黏聚力/MPa27.6
孔隙率/%0.823泊松比0.25
抗压强度/MPa180弹性模量/GPa52.87

图2

花岗岩内部宏观损伤图"

图3

GCTS RTR-1500岩石三轴试验机"

图4

孔隙和裂隙可视化步骤"

图5

试验原理示意图"

表2

渗流—应力耦合试验控制参数"

岩样编号渗透压ΔP/MPa围压σ3/MPa
A11,A12,A13015
A21,A22,A23025
B11,B12,B13415
B21,B22,B23425
C11,C12,C13815
C21,C22,C23825
D11,D12,D131215
D21,D22,D231225

表3

渗流试验控制参数"

岩样编号初始渗透压?P/MPa围压σ3/MPa损伤百分比 /%

E11,E12,E13

E21,E22,E23

2

15

25

25→40→50→65→75
2

图6

不同损伤程度孔隙及裂隙显示图"

图7

孔隙及裂隙体积—损伤程度曲线"

图8

不同渗透压下偏应力—应变曲线"

图9

峰值强度—渗透压拟合曲线"

图10

渗透率—损伤百分比曲线"

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