Today there is a high demand for transport tunnels in Brazil, where the lack of logistical infrastructure is highlighted by the crowding of vehicles on highways and the congestion of trains on existing networks. The solution is overcoming the topographical relief complexities in urban centers and railway networks. This article deals with one of the tools for solving these problems: the fire plan for controlled rock blasting when opening tunnels and their portals, especially when the work of art is built under restricted conditions; geographic location, rock mass structural and mechanical characteristics, stress states arising from depth or induction from previously existing structures, interference with other transport routes, etc. in addition to all aspects inherent to blasting, such as vibration propagation, explosive force, and other parameters to be considered in its application. It should be noted, in this dimensioning, the use, among others, of the Line Drilling technique.
The big problem with the use of explosives in rock blasting in urban areas is due to the phenomenon of vibrations caused by explosives, and they are the same ones that cause the rocks to rupture and their simultaneous fragmentation. To avoid any structural damage to neighboring buildings, depending on the values of velocity and frequency of particle vibration achieved, or the occurrence of unwanted overbreak of the rock itself, it is imperative to exercise care in the blasting.
For rock cuts in tunnels, roads, and railways, it is of greater importance that the remaining rock is of high quality to minimize block falls, rock failure, or excessive maintenance work.
To determine a blast design that does not produce undesirable effects on the environment, one must know, therefore, the characteristics of the explosives used, the structural characteristics and mechanical properties of rock masses, the state of active stresses, the speeds of vibration of material particles around them and the frequencies with which such vibrations occur. All these data can be obtained by monitoring, field surveys, and performing representative experimental tests and blasts that are well-planned and executed.
