Font Size: a A A

Study On Prevention And Control Of Rock Burst By Water Injection With Composite Wetting Agent

Posted on:2022-02-26Degree:MasterType:Thesis
Country:ChinaCandidate:Z J QinFull Text:PDF
GTID:2481306314988779Subject:Environmental Engineering
Abstract/Summary:PDF Full Text Request
Rock burst is one of the most harmful environmental geological disasters in the process of coal mining.Coal seam water injection technology has become one of the most effective and widely used methods of rock burst prevention and control because it can effectively wet coal,reduce coal dust,displacing gas,and prevent rock burst.In the practical engineering of coal seam water injection,the surface tension of the solution is usually reduced by adding surfactant to improve the water injection effect.However,with the mining of deep coal seam,the ground stress of coal seam increases and the permeability decreases,and the water injection of coal seam with surfactant cannot effectively wet the coal,so as to achieve the purpose of preventing rock burst.Based on the above problems,this paper proposes a composite wetting agent composed of traditional surfactants and chelating agent sodium iminodisuccinate(IDS),giving full play to the advantages of both,changing the physical and mechanical properties of coal,enhancing the wettability of coal and improving the effect of coal seam water injection.The properties of surfactant monomer solution were studied by measuring the surface tension and contact angle of different mass concentrations of solution.The surfactant was compounded with chelating agent tetrasodium iminodisuccinate(IDS).Through the surface tension,contact angle and the change of oxygen-containing functional groups on the surface of coal,the optimum formula of composite wetting agent for coal seam water injection was determined as follows:chelating agent tetrasodium iminodisuccinate(IDS)and fatty alcohol polyoxyethylene ether(JFCS),the mass concentration of both was 0.05%,and the compound ratio was 1:1.The physical and mechanical properties of coal after the action of composite wetting agent were measured.The results show that the composite wetting agent can improve the moisture content of coal,reduce the uniaxial compressive strength(σc)and the impact energy index(KE),and increase the dynamic failure time(DT),thereby reducing the impact tendency of coal and achieving the purpose of preventing and controlling rock burst.Based on the instability theory of rock burst disturbance,the mechanism of water injection with composite wetting agent to prevent and control rock burst is analyzed.The results show that the composite wetting agent can dissolve the minerals in coal,change the physical and mechanical properties of coal samples,and reduce the impact tendency index(K),the internal friction angle(φ)and the uniaxial compressive strength(σc),so as to improve the critical softening radius(ρcr)and the critical load(Pcr)when rock burst occurs in roadways,and reduce the risk of rock burst.At the same time,according to the actual engineering situation of 703 working face in Hongyang No.3 Mine,the field water injection scheme is designed.Adding composite wetting agent into coal seam water injection can effectively enhance the wetting effect of coal,change the physical and mechanical properties of coal,reduce the impact tendency of coal,improve the water injection effect,and provide technical support for the prevention and control of rock burst.
Keywords/Search Tags:composite wetting agent, coal seam water injection, physical and mechanical properties, rock burst
PDF Full Text Request
Related items