Influence of different roof key block broken structures on stability of surrounding rock in gob-side entry
In practical engineering,roadways and broken roofs usually have three structural characteristics of different spatial positions:roadway is located below the broken roof fracture line;roadway is located inside the broken roof fracture line;roadway is located outside the broken roof fracture line.By FLAC3D simulating the deformation and mechanical characteristics of the key block structure before and after roadway excavation,the spatio-temporal evolution law of the interaction between the key block roof and the surrounding rock under the three structures was obtained.The results show that the influence of the broken roof on the surrounding rock pressure of the three spatial structures types is gradually reduced.When the roadway is located below the fracture line of the key block,the supporting pres-sure of the coal pillar side is the largest.When the roadway is located inside the fracture line of the key block,the side supporting pres-sure of the coal pillar is slightly lower than that of the former,but both of them have the risk of single slope shear failure,and the sup-porting pressure range of the coal wall side of such roadway is the largest,and the stress superposition area of the floor will cause a large range of floor heave.When the roadway is located outside the fracture line of the broken roof,the median key block is in a completely caving state,and the mechanical transfer mechanism to the vertical direction of the roadway surrounding rock is weakened,and the sur-rounding rock is the most stable.
gob-side entrykey blockroof brokensurrounding rock stability
万方数据
维普
