A New Experimental System for Quantifying the Multidimensional Loads on an on-Site Hydraulic Support in Steeply Dipping Seam Mining

  • Y. P. Wu
  • B. S. HuEmail author
  • P. S. Xie
Applications Paper


Model supports are widely used for selecting the type of field support and quantifying the working resistance in coal seam mining. These devices may also be employed for reproducing phenomena induced by human activities, such as advancement of the working face, in three-dimensional physical model experiments. This study investigates the relevance of the currently used model supports and finds that the interactions between the model supports and surrounding rocks are unavoidable; the three-dimensional load characteristics of the model support is also immeasurable. Therefore, first, we design a type of hydraulic-powered model support via a real case study. For this, a series of theoretical analyses is performed and the design criteria are proposed. Second, the model support and an integrated measurement system are developed and compared with previous model supports. The newly developed system has the following advantages: i) adopts a hydraulic loading-control system and hydraulic oil for power; ii) equipped with high-precision displacement-measuring elements and pressure-measuring elements for determining the three-dimensional loads of the support (quantitative values for the model support include the working resistance, lateral pushing force transferred from the adjacent supports, and thrust force from the caving-gangue). Subsequently, the performance of the integrated system is tested, following which the integrated system is used in a three-dimensional physical model experiment of working face 3232 of the Lvshuidong coal mine. It is noteworthy that the integrated system can contribute in obtaining the missing load information and increase the quality of the parameters measured in steeply dipping seam mining.


Steeply dipping coal seams Hydraulic-powered model support Support–surrounding rock interactions Working resistance Three-dimensional physical model experiment 



Number of (model) support at working face


Total number of (model) support


Working resistance of the ith model support in the physical model experiment, kN;


Lateral pushing resultant of the ith model support, kN


Thrust force of the ith model support from the caving-gangue, kN


Lateral pushing force of the ith model support transferred from the upper support, kN


Lateral pushing force of the ith model support transferred from the lower support, kN


Constant of geometric similarity


Working resistance of the ith on-site hydraulic-powered support, kN


Stiffness of the model support, N/mm


Supporting resistance of the ith model support at the end of the resistance increasing phase, kN


Supporting resistance of the ith model support at the initial supporting phase, kN


Weight of the support, kN


Force floor to the support, kN


Support width, m


Support height,m


Component of T along the direction of the working face width, kN


Component of T along the direction of the pseudo-inclined working face length, kN


Inherent toppling force of the support, kN


Frictional coefficient between the support and roof


Frictional coefficient between the support and floor


Frictional coefficient between the support and caving-gangue


Dip angle of the steeply dipping coal seam, (°)


Pseudo dip angle of the steeply dipping working face, (°)


The toppling angle of support caused by relative movement of roof and floor strata, (°)


Distance from Fi to the front of the base, m


Distance from W to the front of the base, m


Critical sliding angle of the model support, (°)


Ratio of the outspread length of broken rock along the pseudo-inclined working face direction to the width of a single support, is dimensionless


Mean density of the overlying strata, Kg/m3


Cover depth of the steeply dipping coal seam, m


Actual working resistance of the model support, kN


Working resistance of the model support, maintaining dynamic stabilization, kN


Working resistance of the model support when the working face advances, kN


Working resistance of the model support when the working face advances and also maintains its dynamic stabilization, kN


Thickness of the main roof, m


Thickness of the immediate roof, m


Pressure of the hydraulic loading system at the outlet end, MPa


Diameter of a prop, mm



This work was financially supported by the Key Program of National Natural Science Foundation of China (Grand No.51634007) and The National Natural Science Foundation of China (Grand No. 51774230). The corresponding author would like to thank the Research Team on Safe and Efficient Mining of Coal Seams with Complex Mining Conditions at Xi’an University of Science and Technology for its financial support provided for his Ph.D. study at TU Bergakademie Freiberg, Germany.


  1. 1.
    Xu G (2015) Experimental and theoretical study on hydraulic support in working face and its relationship with roof subsidence. J China Coal Soc 40:1485–1490Google Scholar
  2. 2.
    Wang GF, Pang YH (2016) Shield-roof adaptability evaluation method based on coupling of parameters between shield and roof strata. J China Coal Soc 41:1348–1353Google Scholar
  3. 3.
    Wang GF, Pang YH (2015) Relationship between hydraulic support and surrounding rock coupling and its application. J China Coal Soc 40:30–34Google Scholar
  4. 4.
    Qian MG, Miao XX, He FL et al (1996) Mechanism of coupling effect between supports in the workings and the rocks. J China Coal Soc 21:40–44Google Scholar
  5. 5.
    Liu CY (1998) Study on stiffness of support and surrounding rock system of mining face. Gr Press Strat Control 3:2–4Google Scholar
  6. 6.
    Wang HW, Wu YP, Cao PP et al (2015) Large scale loadable 3D-simulation tests on mining steeply dipping seam. J China Coal Soc 40:1505–1511Google Scholar
  7. 7.
    Singh GSP, Singh UK (2010) Prediction of caving behavior of strata and optimum rating of hydraulic powered support for longwall workings. Int J Rock Mech Min Sci 47:1–16CrossRefGoogle Scholar
  8. 8.
    Yun DF, Cheng WD et al (2017) Monitoring strata behavior due to multi-slicing top coal caving longwall mining in steeply dipping extra thick coal seam. Int J Min SciTechnol 27:179–184CrossRefGoogle Scholar
  9. 9.
    Islavath SR, Deb D, Kumar H (2016) Numerical analysis of a longwall mining cycle and development of a composite longwall index. Int J Rock Mech Min Sci 89:43–54CrossRefGoogle Scholar
  10. 10.
    Wang GF (2014) Theory system of working face support system and hydraulic roof support technology. J China Coal Soc 39:1593–1601Google Scholar
  11. 11.
    Wu YP, Hu BS, Wang HW et al (2017) Mechanism of flying gangue-caused disasters in longwall mining of steeply dipping seam. Meitan Xuebao/J. China Coal Soc 42:2226–2234. Google Scholar
  12. 12.
    Ju Y, Zheng Z, Xie H et al (2017) Experimental visualisation methods for three-dimensional stress fields of porous solids. Exp Tech 41:1–14CrossRefGoogle Scholar
  13. 13.
    Lai XP, Shan PF, Cao JT et al (2016) Simulation of asymmetric destabilization of mine-void rock masses using a large 3D physical model. Rock Mech Rock Eng 49:487–502CrossRefGoogle Scholar
  14. 14.
    Guo WB (2015) Stability of coal wall and interaction mechanism with support in fully mechanized working face with great mining height, [Ph. D. Thesis][D]. Xuzhou: China University of Mining and. TechnologyGoogle Scholar
  15. 15.
    Yang PJ (2009) Research on the relationship between two-leg sublever caving shield support and surrounding rocks and adaptability[Ph. D. Thesis][D]. Xuzhou: China University of Mining and. TechnologyGoogle Scholar
  16. 16.
    Jia L, Pei B, Liang B et al (2015) Development and application of support resistance monitoring device in similar simulation experiment. J Liaoning Tech Univ 34:432–437Google Scholar
  17. 17.
    Kong L, Jiang F, Wang C (2010) Study of reasonable working resistance of support in fully-mechanized sublevel caving face in extra-thick coal seam. Chinese J. rock. Mech Eng 29:2312–2318Google Scholar
  18. 18.
    Liu C, Li H, Jiang D (2017) Numerical simulation study on the relationship between mining heights and shield resistance in longwall panel. Int J Min Sci Technol 27:293–297CrossRefGoogle Scholar
  19. 19.
    Dan JJ, Shi HY, Bao SS et al (2012) The hydraulic support parameter design in lean coal seam and numerical simulation about the relation hydraulic support and surround rock. J. Coal. Sci Eng 37:313–318Google Scholar
  20. 20.
    Wu F, Liu C, Li J (2014) Combination hydraulic support stability of working face in large inclined and “three-soft” thick seam. J Min Saf Eng 31:721–732Google Scholar
  21. 21.
    Roshko A (1961) Experiments on the flow past a circular cylinder at very high Reynolds number. J Fluid Mech 10:345. CrossRefGoogle Scholar
  22. 22.
    Lai XP, Shan PF, Cai MF et al (2015) Comprehensive evaluation of high-steep slope stability and optimal high-steep slope design by 3D physical modeling. Int J Miner Metall Mater 22:1–11. CrossRefGoogle Scholar
  23. 23.
    Wang JA, Jiao JL (2016) Criteria of support stability in mining of steeply inclined thick coal seam. Int J Rock Mech Min Sci 82:22–35. CrossRefGoogle Scholar
  24. 24.
    Xie SR, Sun YJ, He SS et al (2016) Distinguishing and controlling the key block structure of close-spaced coal seams in China. J South African Inst Min Metall 116:1119–1126. CrossRefGoogle Scholar
  25. 25.
    Oster C.J.: Schanzlin E.H.: Hydraulic control system 1–2 (1953)Google Scholar
  26. 26.
    Whyte C, Stojadinovic B (2016) Use of a high-precision digital displacement encoder for hybrid simulation of seismic. Response of stiff specimens. Exp Tech 40:677–688CrossRefGoogle Scholar
  27. 27.
    Yun DF, Wu YP (2001) Research into principle and method on readjusting high angle full-mechanized coalface to false forward slant. J. Liaoning Tech. Univ.:2Google Scholar
  28. 28.
    Chai J, Liu Q, Liu J et al (2018) Optical fiber sensors based on novel polyimide for humidity monitoring of building materials. Opt Fiber Technol 41:40–47. CrossRefGoogle Scholar
  29. 29.
    Wu YP (2006) Keys to dynamic equations of system R-S-F and determination on working resistance of face support in steeply dipping seam mining. J China Coal Soc 31:736–741Google Scholar
  30. 30.
    Qi T, Feng G, Li Y et al (2015) Effects of fine gangue on strength, resistivity, and microscopic properties of cemented coal gangue backfill for coal mining. Shock Vib 2015:1–11. CrossRefGoogle Scholar
  31. 31.
    Xie GX, Chang JC, Yang K (2009) Investigations into stress shell characteristics of surrounding rock in fully mechanized top-coal caving face. Int J Rock Mech Min Sci 46:172–181. CrossRefGoogle Scholar
  32. 32.
    Basarir H, Ferid Oge I, Aydin O (2015) Prediction of the stresses around main and tail gates during top coal caving by 3D numerical analysis. Int J Rock Mech Min Sci 76:88–97. CrossRefGoogle Scholar

Copyright information

© The Society for Experimental Mechanics, Inc 2019

Authors and Affiliations

  1. 1.School of Energy and Mining EngineeringXi’an University of Science and TechnologyXi’anChina
  2. 2.Key Laboratory of Western Mine Exploitation and Hazard PreventionMinistry of EducationXi’anChina

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