A mechanism for water inrush due to the floor instability and destruction is analyzed.According to the cusp catastrophe characteristics of water inrush from floor,using the method for the mechanics and energy balance and applying catastrophe theory,a catastrophic model for floor water inrush is established.According to the model,applying the cusp catastrophic theory the mechanics mechanism of water inrush is analyzed from key stratum of floor.Satisfying the sufficient mechanics condition for key stratum ins...