Laboratory investigation of the mechanical properties of coal-rock combined body

  • Zhan-bo ChengEmail author
  • Liang-Hui Li
  • Ya-Ning Zhang
Original Paper


Understanding the behavior of the top-coal caving mining face and immediate roof can be used to enhance buffering effects. The mechanical properties of the coal-rock combined body (CRCB) play a vital role in the performance of overburden load transmittance and support resistance design. We define and derive the relative physical and mechanical parameters of CRCB to illustrate and analyze the influence of coal-rock height ratio (CRHR), coal and rock mass behavior, and interface parameters on CRCB mechanical properties. We conducted uniaxial compression tests to obtain uniaxial compressive strength (UCS), elastic modulus (EM), and the full range of stress–strain curves. Our results show that UCS is positively correlated with EM. However, CRCB EM and UCS decrease with increasing CRHR or effective coal-rock height ratio (ECRHR) and the slope of the curves gradually decreases. CRCB mechanical parameters increase linearly with EM of the coal or rock mass. Although increased coal-rock interface angles (IA) lead to increased CRCB mechanical parameters, the incremental value can be ignored. Sensitive analysis shows that the rank of influential factors on CRCB properties is CRHR/ECRHR > coal strength > rock strength > IA.


Coal-rock combined body Mechanical parameters Uniaxial compressive test Influence factors 



acoustic emission


coal-cement ratio


coal-rock combined body


coal-rock height ratio


coal strength


effective coal-rock height ratio


elastic modulus


fine soil-cement ratio


interface angle


rock strength


top-coal caving mining


uniaxial compressive strength



The authors acknowledge support from the China Scholarship Council (CSC). Many thanks to Baojin Yan for technical guidance in the uniaxial compressive test procedure. We thank the editors and anonymous reviewers for their valuable time and suggestions.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Zhan-bo Cheng
    • 1
    • 2
    • 3
    Email author
  • Liang-Hui Li
    • 1
    • 2
  • Ya-Ning Zhang
    • 1
    • 2
    • 4
  1. 1.School of Energy and Mining EngineeringChina University of Mining and Technology–BeijingBeijingChina
  2. 2.Coal Industry Engineering Research Center of Top-coal Caving MiningBeijingChina
  3. 3.School of EngineeringUniversity of WarwickCoventryUK
  4. 4.Research Institute of Coal Strategy and Planning, Coal Industry Planning InstituteBeijingChina

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