Trenchless Execution of Microtunnels for Municipal Infrastructure in Urbanized Site – Conception of a New Solution

The technologies for trenchless execution of mini and microtunnels for an installation of municipal infrastructure in urbanized sites, used at present, are described in the article. The emphasis is laid on uncontrolled methods, in the case of the diameters of installations which do not exceed 200-250 mm and their length not bigger than 30-40 m. Some issues connected with making the installations of this type, using conventional methods, are also presented. A conception of equipment (ground rocket) for an trenchless execution of short-distance microtunnels of the diameter up to 200 mm and the length up to 30 m with an innovative electric drive, developed at the Department of Machinery Engineering and Transport of the AGH in Cracow as an alternative for the solutions applied nowadays, is described. An electric linear motor, whose conception is presented in the article, was installed in the head of the device. The goal of these works was possibility of using new solution of ground rocket without additional equipments for pneumatic supply with compressed air. New concept of proposed ground rocket can be used with feeding directly from the domestic electric network. The device is intended for execution of installation in incoherent and low-compact ground.