Advertisement

Journal of Central South University

, Volume 25, Issue 12, pp 2979–2991 | Cite as

Geotechnical characterization of red shale and its indication for ground control in deep underground mining

  • Dong-yi Wang (王栋毅)
  • Xi-bing Li (李夕兵)
  • Kang Peng (彭康)Email author
  • Chun-de Ma (马春德)
  • Zhen-yu Zhang (张振宇)
  • Xiao-qian Liu (刘晓茜)
Article
  • 4 Downloads

Abstract

Geotechnical properties of red shale encountered in deep underground mining were characterized on both laboratory and field scale to reveal its unfavorably in geoenvironment. Its constituents, microstructure, strength properties and water-weakening properties were investigated. In situ stress environment and mining-induced fractured damage zone after excavation were studied to reveal the instability mechanism. The results show that red shale contains swelling and loose clayey minerals as interstitial filling material, producing low shear strength of microstructure and making it vulnerable to water. Macroscopically, a U-shaped curve of uniaxial compressive strength (UCS) exists with the increase of the angle between macro weakness plane and the horizon. However, its tensile strength reduced monotonically with this angle. While immersed in water for 72 h, its UCS reduced by 91.9% comparing to the natural state. Field sonic tests reveal that an asymmetrical geometrical profile of fractured damage zone of gateroad was identified due to geological bedding plane and detailed gateroad layout with regards to the direction of major principle stress. Therefore, red shale is a kind of engineering soft rock. For ground control in underground mining or similar applications, water inflow within several hours of excavation must strictly be prevented and energy adsorbing rock bolt is recommended, especially in large deformation part of gateroad.

Key words

red shale soft rock deep mining geotechnical characterization ground control 

深部红页岩地质特性及其巷道掘进地压控制技术

摘要

软岩是一种对地质工程有危害的岩体。本文主要研究在深部开采时红页岩的实验室与实际应用 中的地质特性。通过成分分析,显微结构,强度特性等测试,尤其是水软化实验,揭示在原岩应力环 境中或开采扰动下特定巷道中红页岩的失稳机理。实验结果表明,红页岩在失稳时具有膨胀性,抗剪 强度变低,遇水易软化且失去粘土矿物作为充填介质的特性。随着软弱面与水平线的夹角不断增大, 在单轴抗压强度图像上可明显见到其曲线呈U 型,红页岩的失稳模式与这个角有很大的关联。强度实 验中红页岩的抗拉强度随这个角度的增大而单调减小,抗剪强度也比完整红页岩的低。当使用摩尔库 伦强度理论时,内聚力也会随这个角度的增大而减小。红页岩在浸水72 h 后,单轴抗压强度比原始状 态的减少91.9%。通过现场声发射实验,由于层理面的存在,当巷道沿主应力方向布置时会观察到一 个明显的不对称断裂面。根据研究与实验结果,红页岩为地质软岩,在深部开采地压控制或相同地质 情况下应严格控制水流量,在变形较大的巷道中使用预应力锚杆。

关键词

红页岩 软岩 深部开采 地质特性 地压控制 水软性 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. [1]
    LI X B, WENG L. Numerical investigation on fracturing behaviors of deep-buried opening under dynamic disturbance [J]. Tunn Undergr Space Technol, 2016, 54(4): 61–72.CrossRefGoogle Scholar
  2. [2]
    LI X B, LI C J, CAO W Z, TAO M. Dynamic stress concentration and energy evolution of deep-buried tunnels under blasting loads [J]. Int J Rock Mech Min Sci, 2018, 104(4): 131–146.Google Scholar
  3. [3]
    LI X B, WANG S F, WANG S Y. Experimental investigation of the influence of confining stress on hard rock fragmentation using a conical pick [J]. Rock Mech Rock Eng, 2018, 51(1): 255–277.MathSciNetCrossRefGoogle Scholar
  4. [4]
    HE M. Latest progress of soft rock mechanics and engineering in China [J]. Rock Mech and Geotech Eng, 2014, 6(4): 165–179.CrossRefGoogle Scholar
  5. [5]
    KANJI M A. Critical issues in soft rocks [J]. Rock Mech Geotech Eng, 2014, 6(3): 186–195.CrossRefGoogle Scholar
  6. [6]
    JOHNSTON I W. Geomechanics and the emergence of soft rock technology [J]. Aust Geomech, 1991, 21(12): 3–26.Google Scholar
  7. [7]
    BROWN E T. Rock characterization testing and monitoring, ISRM suggested methods [M]. Pergamon, Oxford, 1981.Google Scholar
  8. [8]
    YANG X L, ZHANG J H, JIN Q Y, MA J Q. Analytical solution to rock pressure acting on three shallow tunnels subjected to unsymmetrical loads [J]. Journal of Central South University, 2013, 20(2): 528–535.CrossRefGoogle Scholar
  9. [9]
    HE Xian, XU Chao, PENG Kang, HUAN Gun. Simultaneous identification of rock strength and fracture properties via scratch test [J]. Rock Mech Rock Eng, 2017, 50(8): 2227–223.CrossRefGoogle Scholar
  10. [10]
    HE M, JING H, SUN X. Soft rock engineering mechanics [M]. Beijing: Science Press, 2002. (in Chinese)Google Scholar
  11. [11]
    CIANTIA M O, CASTELLANZA R, CROSTA G B, HUECKEL T. Effects of mineral suspension and dissolution on strength and compressibility of soft carbonate rocks [J]. Eng Geol, 2015, 184: 1–18.CrossRefGoogle Scholar
  12. [12]
    LI X, WANG S, WANG S. Experimental Investigation of the influence of confining stress on hard rock fragmentation using a conical pick [J]. Rock Mechanics & Rock Engineering, 2018, 51(1): 255–277.MathSciNetCrossRefGoogle Scholar
  13. [13]
    YOSHINAKA R, TRAN T V, OSADA M. Mechanical behavior of soft rocks under triaxial cyclic loading conditions [J]. Inter J Rock Mech Min Sci, 1997, 34(3, 4): 3–4.Google Scholar
  14. [14]
    COVIELLO A, LAGIOIA R, NOVA R. On the measurement of the tensile strength of soft rocks [J]. Rock Mech Rock Eng, 2005, 38(4): 251–273.CrossRefGoogle Scholar
  15. [15]
    ULUSAY R, ERGULER Z A. Needle penetration test: Evaluation of its performance and possible uses in predicting strength of weak and soft rocks [J]. Eng Geol, 2012, 149(2): 47–56.CrossRefGoogle Scholar
  16. [16]
    PENG Kang, LI Xi, WANG Ze. A numerical simulation of seepage structure surface and its feasibility verifying [J]. Journal of Central South University, 2013, 20(5): 1326–1331.CrossRefGoogle Scholar
  17. [17]
    AYDAN Ö, SATO A, YAGI M. The inference of geo-mechanical properties of soft rocks and their degradation from needle penetration tests [J]. Rock Mech and Rock Eng, 2014, 47(5): 1867–1890.CrossRefGoogle Scholar
  18. [18]
    CORTHÉSY R, LEITE M H, GILL D E, GAUDIN B. Stress measurements in soft rocks [J]. Eng Geol, 2003, 69(3, 4): 381–397.CrossRefGoogle Scholar
  19. [19]
    TAHERI A, TANI K. Characterization of a sedimentary soft rock by a small in-situ triaxial test [J]. Geotech Geol Eng, 2010, 28(3): 241–249.CrossRefGoogle Scholar
  20. [20]
    CHANG Q, ZHOU H, XIE Z, SHEN S. Anchoring mechanism and application of hydraulic expansion bolts used in soft rock roadway floor heave control [J]. Inter J Min Sci Tech, 2013, 23(3): 323–328.CrossRefGoogle Scholar
  21. [21]
    SHEN B. Coal mine roadway stability in soft rock: A case study [J]. Rock Mech Rock Eng, 2013, 47(6): 2225–2238.CrossRefGoogle Scholar
  22. [22]
    KANG H P, LIN J, FAN M J. Investigation on support pattern of a coal mine roadway within soft rocks—A case study [J]. Coal Geol, 2015, 140(2): 31–40.CrossRefGoogle Scholar
  23. [23]
    ZHOU H, ZHANG C, LI Z, HU D, HOU J. Analysis of mechanical behavior of soft rocks and stability control in deep tunnels [J]. Rock Mech Geotech Eng, 2014, 6(3): 219–226.CrossRefGoogle Scholar
  24. [24]
    DONG L J, SHU W W, LI X B, ZHANG J M. Quantitative evaluation and case studies of cleaner mining with multiple indexes considering uncertainty factors for phosphorus mines [J]. J Clean Prod, 2018, 183(3): 319–334.CrossRefGoogle Scholar
  25. [25]
    LI X B, DU J, GAO L, HE S Y, GAN L, SUN C, SHI Y. Immobilization of phosphogypsum for cemented paste backfill and its environmental effect [J]. J Clean Prod, 2017, 156(7): 137–146.CrossRefGoogle Scholar
  26. [26]
    DONG L J, ZOU W, LI X B, SHU W W, WANG Z W. Collaborative localization method using analytical and iterative solutions for microseismic/acoustic emission sources in the rockmass structure for underground mining [J]. Eng Fract Mech, 2018, 5(2):1–18. DOI: https://doi.org/10.1016/j.engfracmech. 2018.01.032.Google Scholar
  27. [27]
    DONG L J, SUN D Y, LI X B, DU K. Theoretical and experimental studies of localization methodology for AE and microseismic sources without pre-measured wave velocity in mines [J]. IEEE Access, 2017, 5(9): 16818–16828.CrossRefGoogle Scholar
  28. [28]
    HE Xian, XU Chao, PENG Kang, HUAN Gun. Simultaneous identification of rock strength and fracture properties via scratch test [J]. Rock Mechanics and Rock Engineering, 2017, 50(8): 2227–2234.CrossRefGoogle Scholar
  29. [29]
    MA Nian, HOU Chao. Mining pressure theory and application of mining roadway [M]. Beijing, China: China Coal Industry Publishing House, 1995. (in Chinese)Google Scholar
  30. [30]
    ULUSAY R, HUDSON J A. The complete ISRM suggested methods for rock characterization, testing and monitoring: ISRM Turkish national group, Ankara, Turkey [J]. Bull Eng Geol Environ, 2009, 68: 287–288.CrossRefGoogle Scholar

Copyright information

© Central South University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Dong-yi Wang (王栋毅)
    • 1
  • Xi-bing Li (李夕兵)
    • 1
  • Kang Peng (彭康)
    • 2
    • 3
    Email author return OK on get
  • Chun-de Ma (马春德)
    • 1
  • Zhen-yu Zhang (张振宇)
    • 2
    • 3
  • Xiao-qian Liu (刘晓茜)
    • 2
  1. 1.School of Resources and Safety EngineeringCentral South UniversityChangshaChina
  2. 2.State Key Laboratory of Coal Mine Disaster Dynamics and ControlChongqing UniversityChongqingChina
  3. 3.College of Resources and Environmental ScienceChongqing UniversityChongqingChina

Personalised recommendations