Study on the mechanism of burst water of mine floor fault under dynamic and static loads
Fault burst water is one of the major disasters in mine production.For the spatial location relationship between water-bearing fault and protective layer in mine floor,the mechanical model of fault burst water under the joint action of dynamic and static load,excavation unloading and pressurized water is established by using fracture mechanics theory,the formula of critical water pressure calculation for fault activation is derived,and the influencing factors of critical water pressure are analyzed.The results show that:the critical water pressure decreases with the increase of fault length,decreases with the increase of unloading coefficient,increases with the increase of lateral pressure coefficient,and increases with the increase of friction coefficient;the changes of critical water pressure with fault angle and dynamic load are more complicated,and the dynamic load will promote or inhibit the activation of fault;fault activation is a necessary condition for the occurrence of sudden water in the mine floor;the distance H between fault penetration and protection layer not penetrated is a sufficient condition for the occurrence of sudden water in the floor.The minimum safe thickness H of the unpenetrated section of the protection layer of the broken floor is deduced,and the reasonableness and reliability of the theoretical deduction are verified by a set of geological data.
fault burst waterstress intensity factorcritical water pressuresafety distance
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