The Preparation And Performance Research For Mining Self-Expansion Hole Sealing Material

Gas extraction is the most basic and effective way of coal mine gas control since 1950s.But the vast majority of mines in China are substandard gas extraction efficiency.One of the most critical factors of gas extraction is hole sealing quality and it depends on the hole sealing material.This paper makes mine gas extraction drilling hole sealing material as research object,in view of the existing long setting time of hole sealing material,low early strength,easy cracking and other issues,to compound formula of hole sealing material and determination of the related performance testing.First,give priority to cement and compound gyp and calcium oxide and bentonite and silica and other additives,developed a new type of mining self-expansion hole sealing material,through the experimental research on those component to get 8 groups.On this basis,the linear weighting method is adopted for the 8 groups formula preparation into hole sealing material expansion rate,permeability,bleeding rate,1d compressive strength,the flow time were measured and the weighted ranking.Results show that the formula A has biggest gains weight,namely A formula for the optimal matching,cement,gyp and calcium oxide,bentonite,silica and fiber were 46.5%,30%,20%,30%,5.5%and 0.2%.Then,by using X ray diffractometer and synchronous thermal analyzer analysis respectively analysis formula A crystal of hydration products and hydration products of decomposition,XRD spectrum of different ages and the types of hydration products,so as to master its early strength mechanism of rapid setting.On the one hand,the interaction of components,the hydration process of get promotion,ettringite is generated and even cross each other and form a stable skeleton structure.On the other hand,inhibition the hydration speed of expansive agent,reduce the crack produces,and produced by silica to fill tiny cracks,the overall hydration products was swelled and density,strengthen the skeleton.On the penetration of expanding hole sealing material properties and mechanical properties were studied.The results show that the permeability decreased with the increase of age and gradually stable.Under the condition of different gas pressure,with the increase of gas pressure the permeability present the tendency of increase with the smaller before,the lowest permeability when 0.5 MPa to 0.6 MPa;Under different confining pressure,the permeability decreases with the increase of confining pressure.The static compressive strength than ordinary cement,increase significantly.After 1 d is 3.22 times than ordinary cement and compressive strength of 28 d is 1.59 times,with the strength of the stable performance.Using SHPB experimental system for impact uniaxial compression experiment,and acknowledged the experimental waveforms,stress strain curve after processing data,show that material has obvious strain hardening characteristics.Finally,using the self-expansion hole sealing material on the mine gas extraction in five rounds for drilling experiment and field application effect shows that the material hole sealing has outstanding advantages,after using,a single gas extraction concentration is increased by 3%～35%than ordinary cement and is a kind of a broad application future and promotion value of new mine hole sealing materials.