Study On Water Resistance And Compressive Properties Of 9-6 Collapse Column Pre And Post Injection In Hemei No.9 Mine

9-6 collapse column was exposed within the scope of 3103 working face in Hemei No.9 Mine.The water pressure of the ash aquifer in this area is about 7.88 MPa.When3103 working face passes through the collapse column area,the exposed area is large,At the same time,the disturbance to coal seam roof and floor rock formations is relatively large,as well as the collapsed column.There is a risk of water inrush through the collapsed column.Therefore,in order to ensure the safety of mine production,it is necessary to carry out research on the original water-conductivity of 9-6 collapsed column,to clarify the water resistance and compression performance of the collapsed column after grouting.This paper is guided by the professional knowledge of geology,hydrogeology,rock mechanics and other disciplines,and takes 9-6 collapse column of Hemei No.9Mine as the research object.Water resistance and compressive properties of 9-6collapse column pre and post injection by collecting,arranging and analyzing relevant data and using the combination of qualitative and quantitative methods such as field investigation,XRD mineral composition test,permeability test,water chemical property test,swelling test and mechanical property test,etc.The following research results were obtained:1)The 9-6 collapsed column develops in the coal seam occurrence range as an irregular elliptical shape with a short axis length of 47 m and a long axis length of 141 m.The collapse column expands downward at a dip angle of about 75° and develops irregularly.The column is a mixed structure of soft rock and hard rock.The cylinder surface is uneven on the section.The central axis of the collapsed column is slightly bent and skewed,which is not perpendicular to the rock layer.The collapsed column is developed at a height of 270 m at least.2)The 9-6 column has poor original water conductivity and weak waterabundance overall.However,the column located in the area and the area to the east of3103 Lower Bottom Pumping is seriously broken,with relatively good waterabundance.At the same time,the stratified water volume of the collapsed column shows a trend of increasing gradually from top to bottom.In the collapsed column,the original conductivity height of the ash water is high and there are a few vein-like fractures with strong water conductivity.The mining disturbance will also increase the water conductivity of the collapsed column,so the threat of water inrush is greater.3)After grouting,the crushed section of 9-6 collapsed column has enhanced the compressive performance,the integrity and impermeability.It has become a relatively water-resistant section,and its seepage resistance strength is 1.5 times greater than the hydrostatic pressure of ash aquifer.However,the mechanical strength of the grouting body is still lower than the complete mudstone.The research results of the thesis can be used to guide the safe production of mines.The relevant rock mechanics parameters of the collapsed column after grouting which is obtained from the paper can be used to the simulation and calculation of the feasibility about working face passing through the collapsed column;the permeability results of collapsed columns after grouting which is obtained from the paper can be used to guide the retention of water-proof coal(rock)columns.The paper has 53 pictures,14 tables,and 101 references.