Safety prediction method for shear failure of underground structure caused by demolition blasting of dangerous bridge

The invention provides a safety prediction method for shear failure of an underground structure caused by demolition blasting of a dangerous bridge. The safety prediction method comprises the following steps that the height and width of a blasting bridge floor, and the height of a bridge pier are determined; the mass of the bridge floor within the unit width is determined; the action time and themaximum impact load between the bridge floor and the ground after the bridge floor is in contact with the ground are determined; the buried depth of an underground pipeline and the nearest horizontaldistance from the central axis of the bridge floor are determined, and the nearest horizontal distance and the pile length from a pile foundation to the central axis of the bridge floor are determined; the generated horizontal normal stress, vertical normal stress and shear stress, and the subjected maximum principal stress, minimum principal stress and maximum shear stress tau1, max and tau2, maxat the pipeline and the pi