f Soil investigation by radar techniques: first experiments by the Italian telecommunications operating company

Every year SIP, the Italian Telecommunications operating Company, performs thousands of kilometers of excavation, mainly open, for cable installation . Three kinds of excavation machinery are used : traditional, special and microtunnelling machines . In all cases preliminary investigations are needed before actual digging commences in order to détermine the position of any utilitys (pipes and cables) in the excavation cross section, not only in order to avoid damaging them, but also to plan the optimal excavation lay-out (for instante the road side less laden with pipes). Such investigations, useful in the case of traditional digging methods, become essential when using special or microtunelling machines, which characteristically breakthrough any utility in their path .