ANALYSIS OF CONSTRUCTIVE MEASURES FOR STRENGTHENING THE LOWER BEEFS OF HYDROTECHNICAL STRUCTURES OF TRANSPORTATION CONSTRUCTION FROM CULVERTS

Abstract

Introduction. Road culverts are one of the most massive hydraulic structures of transport construction in Ukraine. The bottom beef of such structures works in difficult operating conditions: with significant unevenness of the distribution of specific costs; high kinetics of the discharge flow and its saturation with sediments, floating garbage; small flooding of the diversion channel, etc. The main difficulty of the problem lies in the fact that a two-dimensional flow takes place in the area of free spreading, and in the area of quenching of excess kinetic energy, this two-dimensional flow turns into a three-dimensional turbulent flow, which makes it practically impossible to obtain a theoretical solution for the movement of water in the lower bay of hydrotechnical structures . The need to improve the structures of the lower bief of hydraulic structures of transport construction from road culverts is urgent, taking into account that the existing approaches do not lead to the desired positive results. Problems. From the literature analysis, it was established that the strengthening of the lower biefs of hydraulic structures of transport construction from road culverts is an important component for the durability of the structure itself and its proper functioning. Goal. It consists in the analysis of constructive measures to strengthen the lower banks of hydraulic structures of transport construction from road corrugated metal culverts. The results. An analysis of the main approaches to strengthening the lower beams of hydraulic structures of transport construction from road culverts was carried out. The analysis of the calculation of the structural elements of active type energy extinguishers was performed. Conclusions. To date, there are two most common approaches to the solution of the problem of fixing the lower biefs of hydraulic structures of transport construction from road culverts: complete rejection of the arrangement of energy extinguishing structures, which causes a significant shift of the erosion gap from the road embankment; or the use of jet-type energy quenchers (of the water well type formed by a ledge or wall), breakers or dispersants of various types. However, both approaches do not completely solve the problem of extinguishing the energy of the water flow behind the structures of road culverts. The method of hydraulic calculations of ordinary concrete (conditionally smooth) pipes and metal corrugated pipes (with increased roughness of the inner surface) is performed according to the same method, the difference is only in the constants used in the calculation: roughness coefficient, friction slope, depth at the entrance to the pipe, etc. d., which in turn indicates the need for additional calculations and experimental studies. In addition, the existing methods of calculation for the optimization of the structures of energy quenchers in the lower biefs need experimental clarification.