CHANGES IN TECHNICAL CONDITION Of UTILITY TUNNELS AFTER LONG-TERM OPERATION AND JUSTIFICATION OF EFFECTIVE SOLUTIONS OF UNDERGROUND SUPPORTING STRUCTURES

Abstract

Urgency of problem. Modern city is a very large energy and information entity and its opertion is impossible without utility lines. The above-ground
installation of those contradicts the requirements of the city's transport, safety and aesthetics. Location below the level of the day surface of city requires the
arrangement of complex underground structures.
With the development of Kyiv, the so-called utility tunnels were built in new areas of the city in the 50-70s of last century. Currently, most of them are
characterized by significant deterioration of the main engineering structures and that is why deterioration degree should be defined and decisions on
reconstruction of utility tunnels should be made. An example of solution of such problems is scientific and technical support of reconstruction of the Chokolivskyi utility tunnel in the Solomyansky district of Kyiv.
Purpose of the research is to establish deterioration degree of main engineering structures of utility tunnel and to present of priority measures aimed at ensuring further operation of the tunnel. A secondary purpose is to propose the use of large reinforced concrete pipes for micro tunneling.
Task of the research is to create an array of scientifically proved information on changes in size and physical and mechanical characteristics of structural
materials. The assessment of such changes is verified calculations of structures with real dimensions and mechanical characteristics.
Research methods are experimental and analytical.
Main results set out in the paper were obtained in scientific and technical support of reconstruction of the tunnel. Inspections have been performed, existing defects and damages have been identified and documented and technical condition of the structures has been assessed. On the basis of previous authors’ research on large reinforced concrete pipes for micro tunneling and putting of those into production together with LLC "Kyivpidzemshlyakhbud", it is
proposed to use these pipes in construction of utility tunnels. At the same time, the goal of eliminating the carbonization of concrete, corrosion of reinforcement and extending service life of utility tunnel should be achieved.