Analysis of methods of disintegration of plain and reinforced concrete in process of reconstruction and re-equipping of hydraulic developments

Abstract

In the last few years sharp problems have arisen in connection with reconstruction of hydraulic developments built during the pre-and postwar years, intended for increase in the capacity of hydroelectric plants, improvement of their operating reliability, and restoration of structures damaged in the process of prolonged operation. For reconstruction, as a rule, in addition to the need for replacing the hydropower, hydromechanical, and electromechanical equipment because of obsolescence and physical wear, in many cases it is necessary to change the configuration of the internal passages of a hydroelectric plant, its repair with full or partial replacement of the metal liners, and repair of individual, heavily loaded elements of the components of basic structures, in particular: spillays, penstocks, concrete in the zone of variable water level, etc. Installation of modern electrical engineering equipment calls, in many cases, for changes in the planning of auxiliary rooms, by removing different walls or floors.At the present time, design, preparatory, and in several cases basic construction-erection work is being carried out for In the engineering practice of this country, such work is not of a massive nature, and until recently it was carried out basically by hand, using pneumatic drills, concrete breakers, and other similar tools. This calls for substantial time expenditures (according to the ENiP Norms and Rules, the demolition of 1 m 3 of reinforced concrete requires up to 40 manhours, the actual time expenditures being even higher). Moreover, prolonged work with manual pneumatic tools adversely affects human health. Taking into account the massive nature of reinforced concrete demolition work in the process of reconstruction and repair of hydraulic developments, as well as the short periods established for the carrying out of this work, the need has arisen for mechanization of these processes, using Russian and foreign experience with similar work or with work in related branches, in particular in rock excavation.