Dynamic analysis of gas permeable blasting mat as geometrically nonlinear system with unilateral constraints

摘要

Blasting mat is used to prevent flyrock accidents, decrease environmental impacts and expand the range of projects where blasting operations could be carried out. Transformable gas permeable blasting mat is made from worn out tires of heavy trucks bound together with chains, ropes or cables. Dynamic model of blasting mat is proposed in this research. It is represented by concentrated masses interacting with unilateral foundation and by elastic weightless incompressible elements. The problem solving involves combination of two types of nonlinearity: geometrical nonlinearity associated with large displacements and contact nonlinearity which emanates from the fact that contact region changes due to deformation of the elements. Explosive loading is simulated by instantaneous impulses applied at different times to different masses. The system behavior under various sequences of explosions is of special interest. Numerical experiments showed that axial forces in elastic elements and maximum flight height of the masses depend on detonation sequence of the blast holes. Employed mathematical model was verified by full-scale experiment.