Investigation Of The U-steel Support Technology In The Soft-rock Main Roadway In Jie Bangou Coal Mine

All of the northern main haulage roadway, orbital roadway and return-air roadway are typical soft-rock roadways, and their surrounding rock are mostly constituted by mudstone and sandy mudstone.Large roof convergence, large squeezing volume, large floor deformation and even roof falling are induced because of the soft surrounding rock, these definitely draw potential dangers for the security of coal mining.In this thesis, the northern main orbital roadway is selected as the object to investigate the stability of soft-rock roadway in terms of field survey, theoretical analysis, experimental test, numerical simulation and industrial test.Experiments have been conducted to test the mechanical characters of roadway surrounding rock. With the analysis of microstructure, field measurements, theoretical analysis of fracture evolution law and conformation law of road surrounding rock According to the surrounding rock deformation and failure of the extent of damage of surrounding rock in different sections of different branch support scheme, and using FLAC3 D numerical calculation software of the supporting scheme, finally established the roadway deformation is controlled the optimal supporting scheme.The support mechanism and mechanical characteristics of the using U- steel plastic support are investigated by theoretical analysis, and then the software of FLAC3 D is used to interpret the influence of wall backfilling on the support performance of U- steel support. It reveals that the plastic zone and the stress of rib are distinctly affected by the strength of backfilling material, whereas the influence on the stress of roof is on inversed condition. Investigation into the deformation process and the relation between the shrinking slippage of support in specific loading condition and the pre-tension of clamp are conducted by the experimental compressive test. The results reveals the anti-sliding capacity is in linear correlation with the pre-tension of clamp, and asymmetric deformation is induced even when the U-shaped support is in symmetric loading condition.Industrial tests show that the optimized support scheme has a good effect on deformation and failure of surrounding rock, the deformation of roadway is decreased, and the safety production is satisfied.