Dynamic Analysis of Blast Procedure in Tunneling

Static analysis of tunnels in rock generally neglects the load imposed by blasting during tunnel driving. Today, the influence of time on the redistribution of stresses is largely limited to the rock’s rheology, whereby these are extremely slow load functions. It is precisely the extremely short effect of the blasting load that exerts an additional force on the rock and superposes on the loading from stress redistribution in the destroyed excavation zone. The result is an irreversible change of the rock properties immediately behind the face with a major import on further static analysis. This loosening caused by blasting, that has been a known factor to design engineers for many years, was often used to advocate mechanical tunneling without it being possible to quantify its influence.