Investigation On The Support Technology Of Gob-side Entry Retaining And Its Ground Pressure In Inclined Coal Seam

The development and application of goaf roadway retention technology have brought great breakthroughs to the technology and economy of safe and efficient production in coal mines.The application of goaf roadway retention technology eliminates the section pillar,effectively improves the coal production rate and reduces the tunneling cost.Goaf roadway retention technology has been widely used in near horizontal coal seam,but the surrounding rock stress,strain and ore pressure in goaf roadway retention along inclined coal seam are different from those in near horizontal coal seam.The stability of goaf roadway retention is more affected by coal seam dip Angle and mining movement,so the support technology needs to adapt to goaf roadway retention along inclined coal seam.Taking the 11841 working face of Tangjiahe coal mine as the object,this paper studies the surrounding rock movement rule of gob roadway along inclined coal seam,retaining roadway support technology and retaining roadway ore pressure development rule,providing reliable basis for safe and efficient mining of inclined coal seam without pillar.The main research contents and results are as follows:(1)According to the characteristics of overburden strata on the working surface of11841 in Tangjiahe coal mine,the deformation law of surrounding rock is analyzed.According to the technical characteristics of the roadway along the goaf along the roof unloading,the mechanical principle of the roadway along the goaf along the roof unloading is analyzed,and the mechanical model of the roadway along the roof unloading based on the short cantilever beam is established.(2)The design parameters of the support inside and beside the roadway along the goaf were calculated,and the support scheme inside the roadway was determined,that is,the combined support form of full-thread and other strong resin bolt+metal net+steel ladder+anchor cable was adopted,and the temporary strengthening support measures for the dynamic pressure affected section were adopted by the hydraulic single pillar.Strike prestressed anchor beam,11#I-steel point column and metal anchor net supporting bidirectional shaped energy roof pre-splitting blasting cutting pressure relief technology to protect the roadway.(3)By FLAC^3D,the supporting plan under the condition of different lane,different locations of the stress distribution and displacement of roadway deformation and the plastic zone are numerically simulated,the results show that the bottom slab of the lower end support in the working face is destroyed seriously and subjected to great horizontal stress,which is easy to produce slip instability and large roadway deformation.The support of inclined coal seam along gob in roadway can meet the support requirements of roadway and ensure normal use of roadway and safe production of working face.(4)The mining pressure monitoring scheme is designed to monitor the related parameters of the roadway along goaf,such as the two sides moving amount,the roof and floor moving amount,the roof separating amount and the roof pressure,etc.The monitoring results show that the supporting technology proposed in this paper has a good effect.