Grouting reforming method for pre-elevation angle of working face in"three soft"coal seam
Grouting technology can effectively transform the mechanical properties of the soft coal seam,and it is also an ef-fective means to control the deformation and damage of the working face of the"three soft"coal seam.In order to solve the problem of 1508 working face falling with mining in Chenghe Coal Mine,three different grouting materials are selected to carry out strength test and effective diffusion range test,and a simulation software is used to solve the change law of over-support stress and displacement in 1508 working face.The results show that:through three groups of diffusion radius test,it can be obtained that the large cementitious material diffusion radius will lead to good adhesion,the stability of the slurry af-ter diffusion is good,its diffusion radius is 142.75 cm.The test shows that the cementitious material grouting effect is the best,and after grouting the peak of the stress in front of the face will be shifted forward,which will greatly reduce the support pressure of the working face hydraulic support,which is conducive to the control of the roof of the working face.By compa-ring the change laws of displacement before and after reinforcement,the settlement peak is reduced by 98.76 mm,and the position of the settlement peak is shifted forward by 653.02 mm.The study provides the parameter basis for the application of the"three-soft"coal seam working face's super-advance grouting renovation technology.
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