Study on Surrounding Rock Structure Evolution Characteristics and Roof Control Techniques of the Retained Roadway Formed by Roof Cutting in Inclined Coal Seams

Figure 8

The single hydraulic prop and its constitutive model. (in the figure, ε₃ and ε₄ refer to the deformation induced by the liquid leakage from a single prop, with ε₃ = ε₄; ε₅ and E₅ separately denote the elastic deformation and the elastic modulus of single props; σ₄ and σ₅ refer to the support forces provided by single props, with σ₄ = σ₅; σ₃ denotes the increment of the support force caused by delay of liquid leakage of single props; and σ denotes the total support force provided by single props, giving σ = σ₄ + σ₃ = σ₅ + σ₃.)