Study On The Mechanism And Risk Prediction Of Secondary Tectonic Activation Water Inrush On Pressurized Water

Floor water inrush is mostly caused by the existence of fault structures.During the formation of faults,secondary cracks or oblique cracks sliding along faults often occur near fault zones,which are hidden and difficult to detect.When mining activities are carried out,under the action of mine pressure and confined water pressure,secondary cracks in fault zone and adjacent rock mass are prone to expand,resulting in changes in the permeability of fault structure.Under the action of high confined water,the permeability of fractured zones in faults is enhanced.When secondary fissures develop and extend through the floor failure zone and large faults,water inrush channels are easily formed.The original non-conductive faults may be transformed into water inrush accidents when water inrush faults enter the working face along the water inrush channel.In this paper,the influence of secondary faults on activated water inrush from large faults is studied by theoretical analysis and numerical simulation.and the prediction model of water inrush of bottom plate under the influence of secondary fault was established by Bayes discriminant analysis method.and obtained the following research results:(1)The basic characteristics of fault tectonics are analyzed and summarized.Based on the characteristics of the fault structure of the penetrating coal seam and the theory of elastoplastic mechanics,the mechanical model of the fault activation of the bottom plate is established,and the critical water pressure of the activated coal seam fault activation and the angle of the penetrating rock mass fracture are the most prone to failure.(2)Based on the case analysis of the water inrush of the secondary tectonic floor,the characteristics of the water inrush of the secondary fault plate are summarized,and according to the difference between the secondary fault and the large fault position,the water inrush mechanics analysis of the secondary fault intersecting with the large fault and the apart condition are deduced,and the mechanical criterion of the secondary fault activation is revealed.(3)The numerical model of secondary fault is established by using Flac3D numerical simulation software,and three numerical simulation schemes of different secondary fault inclination,secondary fault and large fault spacing and different aquifer water pressure are selected,and the distribution characteristics and stress distribution characteristics of coal seam bottom plate and tectonic plastic zone are summarized and analyzed,Stress characteristics and pore water pressure variation characteristics of internal monitoring points in large faults,and study on secondary fault activation leading to water inrush in working face.(4)By selecting the mathematical method of Bayes discriminant analysis in multivariate statistical theory,the prediction model of water inrush level of the bottom plate with secondary fault is established,and the prediction accuracy of the sample data return test model is carried out,and the collected mine examples are verified,The results show that the Bayes discriminant analysis model can be effectively applied to the prediction of water inrush on the bottom plate of the secondary fault,and the prediction model has certain.practical application value.