Technical and economic indices of reinforced-concrete lock structures

Abstract

LOCK STRUCTURES UDC 627.45.003.1 V. I. Sevast'yanov Large locks are characterized by quite large volumes of concrete (Table 1). All modern large locks in the USSR are constructed of reinforced concrete, the only exceptions being double-lane six-chamber Perm locks, whose chamber walls are made of metal sheet piling.Single-lift locks with a head to 23 m are presently being designed and constructed on soft soils (Votkin, Saratoy, Lower-Kamk, Cheboksary) and up to 42 m on rock foundations (Ust'-Kamenogorsk, Dniepr-II t/ydroelectric station, Perevoloksk) almost exclusively in place of multiple chamber locks and locks with separate reaches (Perm, Gor'kii, locks of the V. I. Lenin and 22nd Party Congress Volga hydroelectric stations). It is presumed that singlelift locks with a high head (50-60 m) will be built at the hydro developments on Siberian rivers. Research and development for such high-head locks are already being carried out. The analysis presented here gives an idea of the trends in the area of lock design and construction.Lock Supply System. The following trends are observed in the design of the supply systems of medium-head locks: expansion of the limit of use of the head supply (increase of head and chamber length) and positioning of the galleties in the bottom of the lock chambers with a supply distribution system. The lock-head systems have a number of construction and economic advantages: absence of longitudinal galleries in the chambers and upper lock heads, almost complete absence of thin-walled openwork reinforced-concrete structures, and the possibility of increasing the rate of concrete placement and shortening the construction time. These qualities of locks with a head filling system gave rise to the trend of expanding their use for ever higher heads: up to H = 17 m, Pakhomovsk lock, on the V. I. Lenin Volga-Baltic waterway, mad for the targe chambers of the Saratov lock (H = 15 m). However, the experience of operating locks with a head filling system showed that the lockage effects on the ships under real conditions were much more severe than foreseen by the design according to laborabory investigations. To improve the lockage conditions the operating personnel had to extend the time of filling, which reduced the traffic capacit 7 of the locks. At the Second All-Union Joint Conference on Ship Locks and Canals, held in Kiev in October, 1968, the attention of research and development organizations was called to the need to explain the causes of these discrepandes and to the broader use of locks with head filling. One of the possible causes of the indicated discrepandes may be aeration of the flow, which is not reproducible on models. Therefore, lock-head filling via bypass galleries in the case of high heads should be preferred to filling from under the lift gates.