Study On Roof Damage And Instability Control In Goaf Of Sedimentary Bauxite Mine

The sedimentary bauxite mines in Shanxi are generally layered and layer-like.The direct roof is Shanxi-style clay ore.Due to the low compression and shear strength of the clay ore body,it does not have bearing capacity.The thickness of the bauxite body is used as the top layer.The reserved bauxite is thin,and the roof is susceptible to various damages such as weathering damage,joint damage,blasting damage,etc.,gradually losing the existing supporting capacity,which in turn induces the collapse of the goaf,causing serious casualties and serious economic losses.Disaster accidents.Therefore,carrying out research on roof damage and instability and control of goaf in bauxite mine has important research significance for reducing engineering geological disasters in bauxite mines.In this paper,the goaf roof of a bauxite mine was taken as the research object,on the basis of on-site investigation,based on the damage mechanics and material mechanics related theory,constructs a mechanical model of the goaf roof,studied the weathering damage,joint damage and blasting of the roof Under the effect of cumulative damage,the safety thickness of the protective top layer,the limit exposed area of the roof and the safety factor,the control measures for roof damage and instability were proposed.The main work of the thesis was as follows:(1)A field investigation of a sedimentary bauxite mine was conducted to obtain an overview of the basic engineering of the mine and to clarify the damage of the roof of the goaf.Based on this,the internal and external factors affecting the damage and instability of the roof of the goaf were studied in detail.(2)A simplified mechanical model of the roof was constructed,and the effects of weathering damage and joint damage were considered on the basis of traditional research.The formulas for the safe thickness of the top layer and the limit exposed area of the roof were derived.The effect of the crack surface diameter on the exposed area of the roof.(3)The simplified mechanical model of the roof was constructed,considering the effects of erosion damage and joint damage,the safety thickness of the bauxite top layer under erosion damage and the limit exposed area of the roof under joint damage were studied,which wer the parameters of the roof structure of the mine goaf design provides theoretical guidance.(4)On the basis of on-site investigation and theoretical research on roof damage and instability,the roof instability control measures such as optimization of roof structure parameters,determination of safe mining window period,improvement of blasting method and filling of mined-out area are proposed.The research results of this paper provide theoretical guidance for the roof structure design and roof instability control of bauxite underground stope,and have certain engineering application value.