我国煤矿整体失稳型冲击地压类型、发生机理及防治

Types,occurcenec mechanism and prevention of overall istability induced rockbursts in China coal mines

  • 摘要: 整体失稳型冲击地压是近年来我国深部煤矿开采过程中发生的一种新的冲击地压类型,其释放能量和破坏性远大于常见的局部冲击地压。采用现场调查、理论分析、现场监测等方法,对我国煤矿3起典型整体失稳型冲击地压事故的工程特征和冲击显现特征进行分析,将当前我国整体失稳型冲击地压分为孤岛工作面整体失稳型冲击地压、大巷煤柱整体失稳型冲击地压和底煤整体滑移失稳型冲击地压3类。分别建立了3类整体失稳型冲击地压发生机理的力学模型,提出了3类整体失稳型冲击危险的评估方法和防治对策,揭示了3类整体失稳型冲击地压的发生机理。其中孤岛工作面整体失稳型冲击地压的发生机理为孤岛工作面上覆岩层自重和两侧采空区转移载荷叠加形成的总应力超过了孤岛工作面整体承载能力时,孤岛工作面中部弹性整体失稳破坏诱发冲击地压灾害;底煤整体滑移失稳型冲击地压发生机理为工作面超前支承压力超过底煤发生冲击和滑移的临界应力时,底煤冲击和滑移同时发生,形成底煤整体滑移失稳型冲击地压;大巷煤柱整体失稳型冲击地压发生机理为大巷煤柱在自重应力、构造应力和巷道开挖、卸压转移应力等叠加作用下应力高度集中,当应力集中程度超过煤柱整体承载能力时,煤柱中部弹性核发生整体失稳冲击,导致煤柱两侧大巷均发生严重冲击破坏。由于我国深部矿井开采条件复杂,实际生产过程中还会遇到很多具有隐蔽性的整体失稳型冲击类型,因此在现场冲击地压防治工作中,需要加强对这些隐蔽性整体失稳型冲击风险的判识和防治工作。研究结果对类似条件下的工作面安全开采具有一定的借鉴意义。

     

    Abstract: The overall instability induced rockburst is a new type of rockburst in the process of deep coal mining in China in recent years,and its released energy and destructiveness are far greater than the common local rock burst.By using the methods of field investigation,theoretical analysis and field monitoring,based on the analysis of the engineering characteristics and rockburst appearance features of three overall instability induced rockburst accidents in China’s coal mines,the overall instability induced rockburst in China is classified into three categories,namely the overall instability induced rockburst in island working face,the overall instability induced rockburst in main roadway and the overall instability induced rockburst in bottom coal.Regarding those three types,the mechanical mechanism models of three types of overall instability induced rockburst were established.Then,the rockburst risk assessment method and prevention countermeasures of three types of overall instability induced rockburst were proposed.Finally,the mechanism of the three types of overall instability induced rockburst was presented.The occurrence mechanism of the overall instability induced rockburst in the isolated working face is that when the total stress formed by the superposition of the self weight of the overlying strata and the transfer load on both sides of the goaf exceeds the overall bearing capacity of the isolated working face,the overall instability failure of the elastic core in the middle of the island working face induces the rock burst disaster.The occurrence mechanism of the overall sliding instability induced rockburst in bottom coal is that when the abutment pressure of the working face exceeds the critical stress of rockburst and slip of bottom coal,meanwhile incurring the rockburst and slip of bottom coal,forming the whole sliding unstable rockburst of bottom coal.The mechanism of overall instability induced rockburst of main roadway coal pillar is that the stress of main roadway coal pillar is highly concentrated under the superposition of self weight stress,structural stress,roadway excavation,and pressure relief transfer stress,etc.When the stress concentration exceeds the overall bearing capacity of coal pillar,the elastic core in the middle of the coal pillar will have an overall instability impact,leading to serious impact damage on both sides of the coal pillar.Due to the complex mining conditions in deep mines,a variety of concealed overall instability rockbursts can be found during the mining process.Therefore,to prevent rockbursts,it is necessary to strengthen the risk identification and prevention of such concealed overall instability rock bursts.The research results have certain reference significance for the safe mining of working face under similar conditions.

     

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