Prediction model of dynamic load coefficient for shallow-buried heterogeneous geological and single key stratum working faces and its engineering verification

ZHANG Chuanjiu; YI Junjie; WANG Wei; CHENG Jingyi

doi:10.13225/j.cnki.jccs.2025.0693

Abstract：The shallow-buried coal seams in the Shendong mining area exhibit significant geological heterogeneity.When the traditional method based on an average dynamic load coefficient is used for hydraulic support selection,it fails to ac-curately reflect the actual load distribution,which may result in inappropriate design of working resistance,induce in-stability of the support-surrounding rock system,and restrict safe and efficient mining.Taking the 22309 working face of Halagou Coal Mine as the engineering background,this study aims to reveal the controlling mechanism of geological het-erogeneity on the dynamic load coefficient and to establish a prediction model suitable for such conditions,providing a theoretical basis for rational hydraulic support selection.Field measurements and theoretical analysis were combined in the research.The influence of bedrock thickness and burial depth in different sections on the dynamic load coefficient was analyzed,and the adaptability differences of hydraulic supports under varying geological conditions were evaluated.Based on the energy equivalence principle and the geological characteristics of"shallow-buried,single key stratum,"the re-leased energy from the rotation of the fractured key stratum was treated as the dynamic load source.A dynamic load coef-ficient prediction model(DP model)integrating burial depth,advancing length,and bedrock thickness was established,and the Levenberg-Marquardt algorithm was applied to identify the model parameters.The results indicate that the dy-namic load coefficient of the 22309 working face presents a stepped distribution,with 1.10 in the first section and 1.21 in the second section,leading to a 5.5%higher safety valve opening rate in the latter.The prediction errors of the DP model for the two sections were 8.95%and 1.59%,respectively,with prediction accuracy improvements of 8.14%and 4.86%compared with the traditional method.When applied to the 22315 working face,the predicted dynamic load coefficient was 1.202,with only 0.98%error relative to the measured value.The required support resistance was calculated as 10165.2 kN,and the ZY12000/25/50D hydraulic support was selected accordingly.Field monitoring confirmed the stable opera-tion of the support system.The DP model can accurately predict the distribution of dynamic load coefficients in shallow-buried coal seams under heterogeneous geological conditions using commonly available geological parameters.It has clear physical significance,achieves high prediction accuracy,and overcomes the limitations of the traditional average method.