Dynamic characteristics of combined coal rock based on RSM-BBD
XIE Beijing
LUAN Zheng
LI Heng
WU Bowen
LI Xiaoxu
CHENG Changhao
Abstract：The inherent instability of deep coal rock masses and coal-rock composite bearing structures significantly contributes to coal rock dynamic disasters in mines.An experimental investigation into the dynamic response behavior of composite coal-rock was carried out by conducting impact loading experiments using a separated Hopkinson pressure bar system with a 50 mm diameter.The study analyzed the effects of factors like strain rate(A:50-350 s-1),lateral confining pressure(B:4-16 MPa),and compression ratio(C:1-4).Sub-sequently,a response surface experimental design with three factors and levels was developed using Design Expert12 software to analyze the impacts of individual factors and factor interactions on dynamic compressive strength σ and energy consumption rate k.Finally,a su-perposition damage constitutive model was formulated based on principles such as superposition theory and Weibull distribution.The res-ults indicate that the mechanical properties of coal rock are notably affected by both individual factors and the interaction between factors.Specifically,the influence of single factors on σ and k follows the order A＞C＞B,while the impact of factor interactions on σ is ranked as AC＞AB＞BC,and on k as AB＞AC＞BC.The coal components within composite coal rock primarily undergo shear failure,leading to the de-velopment of macroscopic cracks in regions with lower ratios of rock components.Furthermore,the strength distribution of ternary com-posite coal rock demonstrates regional characteristics.The strength hierarchy of composite coal rock,from lowest to highest,follows this sequence:coal component non-interface area,coal component interface area,low component rock interface area,low component rock non-interface area,high component rock interface area,and high component rock non-interface area.The developed damage constitutive mod-el effectively portrays the dynamic response relationship of composite coal rock,demonstrating a fitting coefficient of at least 0.97 between the theoretical and experimental curves.These research findings offer valuable insights for investigating the phenomenon of dy-namic and static load superposition in the mining face during operations and for disaster prevention and control.
Keywords：combined coal rockresponse surface methodologySHPBdestructive instabilityconstitutive model
Publication Date：2025-02-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：15( 109-123 )