Research on damage law of surrounding rock of large drop faults and prevention and control of floor water inrush during roadway excavation in Xinyi Coal Mine
In order to analyze the surrounding rock damage law when Xinyi Coal Mine centralized trackway crosses the large drop fault and its impact on water inrush in the floor aquifer,we used FLAC3D finite difference software to construct numerical calculation model to ana-lyze the development of plastic zone and the distribution law of floor damage between the fault and the floor mudstone aquifer with the roadway excavation.The results show that,as the distance between the roadway excavation and the fault zone becomes closer,the stress dis-tribution in the fault zone has the characteristics of both pressure reduction and pressure increase coexisting,among them,the distribution in the direction of the floor shows a pattern of pressure reduction near the lower plate position and pressure reduction first and then pres-sure increase near the upper plate position.When the roadway excavation face is 4～6 m away from the fault,the fault zone generates the displacement,which indicates that the fault has been activated;the plastic zone is gradually expanding along the fault zone,presenting a distribution feature of the roof,floor,two sides and four directions extension.The excavation effect shows the maximum plastic zone in the direction of the floor,with a range of 10 m.The activation of faults and the expansion of plastic zones have formed a water inrush channel along the fault in the floor.Therefore,technical measures for controlling the stability of fault zones and floor rock layers through grouting reinforcement have been proposed.Research has shown that after grouting reinforcement,an effective waterproof layer is formed,which im-proves the stability of rock layers in the fault area and is conducive to the prevention and control of floor aquifer.
faultsFLAC3Dnumerical simulationplastic zone distribution
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