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The expansion of hydraulic engineering construction in regions with severe climatic conditions has necessitated the development of new design solutions for the watertight membranes of dams of local materials, since, when erecting cutoff wails and cores from clay earths, concrete cutoff wails, and reinforced-concrete membranes, a large amount of imported material is necessary, and working in frost and unfavorable weather is very difficult. The construction of rockflll dams, with a high level of mechanization of the work, remits in greater settlements of the body of the dam and substantial deformations of the watertight membrane, particulariy if made from a rigid material. Following the well-known failure of the reEnforced-concrete cutoff wail at the San Gabriel dam in the USA, the walls were made in several layers, with rows of slabs up to six [1], and more recently, in order to avoid tension on the surface wail or inclined membrane, a proposal was advanced for adopting a profile in the form of a circular or hyperbolic curve, or again a hyperbola, with a depth of curvature equal to the theoretical depth of curvature of the reinforced-concrete coating under the action of the head of water and settlement of the body of the dam [2].The membrane is the most economical structure for the watertight member of a dam, requiring a minimum of material, and exposed to the least deformation during settlement of the body of the dam, but it must satisfy severe requirements as regards reliability, on account of the thinness and flexibility of the whole structure. Collapse of one of the earliest rockfill dams, the Lower Authie in California, cleariy demonstrates the inadequacy of rigid membranes. The membrane was made from two layers of concrete, each 30 cm thick, with a sheet of steel 6.5-8.5 mm thick in between, coated with bitumen and canvas. In 1916, after 19 years service, during the flood period, the membrane burst and the 45.6-m high dam was breached, some parts of the membrane being carried 15 km downstream [1].In order to reduce the rigidity of the membrane, horizontal joints were cut, so that a large part of the head was absorbed by the resistance of the downstream shell of the dam embankment [3]. However, an attempt to give even more mobility to the membrane resulted in proposals for constructing vertical joints also, compensating the nonuniformity of deformations of the individual sections and temperature stresses [4], and even making a reinfo-c ?d concrete membrane of individual free-standing rigid blocks, held only by the resistance of the downstream shell of the dam [5]. This type of complex system of breaks greatly complicates the construction of the membrane and requires reliable sealing of numerous joints. Hence, abroad, there is an increased tendency to achieve flexibility of the watertight structures on earth and rockfill dams by using asphalt concrete and plastics. It is not surprising that American engineers have observed [6] that replacing the reinforced concrete cutoff wall of the Montgomery rockfill dam, s...

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The increasing rate and volume of modern hydraulic construction, especially in the northern and eastern regions of the Soviet Union, require a radical improvement in the designs of hydraulic structures and methods of constructing them. The traditional materials do not always meet the increasedrequirements of modern construction and this raises new problems on the use of polymers, creating of structures on their base, and new methods of conducting hydraulic engineering operations.The chemical industry of the USSR is producing plastics on an ever-larger scale. According to the Five-Year Plan of development of the USSR national economy for [1971][1972][1973][1974][1975], the production of plastics is supposed to increase 'twofold, and of rubbers 1.7 times. However, only a small part of the total production of polymers is used for construction. Plastics are being introduced into hydraulic construction completely insufficiently. This is explained by the comparatively few investigations devoted to finding the possible areas of use of plastics and the inadequate coordination of studies in this field.Most often used in hydraulic construction are epoxy, polyester, phenol formaldehyde, and furfural resins and glass-fber-reinforced plastics on their base, polyethylene, synthetic rubbers, bitumen-polymer composites, etc.( Fig. 1).Anticavitation and anticorrosion protection of structures and hydromechanical equipment is accomplished by polymeric paint and mastic plaster coatings. These coatings are used for anticavitation protection of concrete on the spillway faces of dams, in the spiral cases and draft tubes of hydraulic turbines, and in bottom discharges and mnels. Investigations showed that epoxy mastics and polymer-mortars have a cavitation resistance greater by 2-3 orders than high-strength concrete. Composites based on epoxy resins modified by polyester MGF-9, nitrile and carboxylated rubbers SKN-10A, and SKN-18, thiokols, and other combined plasticizers have the best cavitation properties. Such coatings are placed on the spillway faces, tunnels, bottom outlets, and other structures of the Bratsk, Krasnoyarsk, Nurek, Charvak, and other stations. These coatings are 3-6 times cheaper than metal facings. A special standard has been developed at the B. E. Vedeneev All-Union Research Institute of Hydraulic Engineering 0TNIIG) and research department of the All-Union Planning, Surveying, and Research Institute (Gidroproekt) and is being prepared for publication. According to the investigations of UkrVNIIGiM, the facing of furfural and phenol formaldehyde polymerconcrete proved to be resistant to the abrasive wear by sediments. Such facings are operating successfully on the Sary-Kurgan dam under conditions in which steel facing is worn at a rate of 1.5-2 mmt~jrear.The epoxy paint coatings are, as practice shows, a reliable anticorrosion protection of underground and underwater steel structures. The paint ~FAZhS based on epoxy resin modified by monomer FA is used for protecting the cable lines of the 22rid Party Congress Volga...

Asphalt seals are a reliable method of waterproofing contraction joints of hydraulic structures, especiallywhen subjected to temperature-settlement deformations [1,2]. However, owing to the thermoplasticity of the asphalt filler, it is necessary to have a reliable protection against sharp temperature variations, since under high temperatures the asphalt mastic may flow, and under low temperatures it may lose its plasticity; leading to cracking when the joint is opened or to excess pressure in the seal cavity when the joint is closed. According to a procedure developed for the analysis of asphalt seals of the shaft type [1, p. 81], in order to prevent tension in the asphalt filler under a design temperature of 0~ in a 50-m high dam, it is necessary to place a seal 180x 260 cm in cross section; with a seal measuring 30 x 30 cm, the pressure produced during closing of the joint at a rate of 10 -s cm/sec may reach 45 kg/cm 2. The first attempts to place superficial seals on the structures of the Moscow canal and the Uglichsk hydraulic development by using ordinary asphalt mastic consisting of 30% of BN-III asphalt and 70a/o cement led to destruction of the water-retaining elements of these seals [4, p. 102]. For this reason, the norms SN 123-69 prohibited the use of superficial asphalt seals and permitted the use only of internal, shaft asphalt seals. They have substantial disadvantages: the complex formwork and the difficult concreting operations, the high labor consumption involved, and the impossibility of verifying the quality of the seal preparation before placing the mastic and just after the electric heating system is installed. As a result, in most structures small-section asphalt seals do not operate satisfactorily. (At the Lenin Dnepr and Kama hydroelectric plants, costly and complex repair work was carried out.) At most hydraulic developments built on soft compressible foundations an established practice at the present time is the waterproofing of construction joints with asphalt seals having a cavity measuring 1.5 x 1.2 m (seals used at the Volgostroi). The waterproofing of the joints with asphalt seals 80 x 100 cm in cross section at the Bratsk hydroelectric plant and 60 x 80 cm in cross section at the Plyaviusk hydroelectric plant [3], although sufficiently reliable, was so complicated that at the Krasnoyarsk and Ust'-Ilimsk dams asphalt seals were not used, and the joints were waterproofed with metal compensators.The development, in recent years, of fundamentally new asphalt-polymer waterproofing materials [3] opens up new prospects for the use of superficial asphalt seals under a sharply continental climate [2].At the Sarrans darn in France (1936, height 114.5 m), the joints were waterproofed by means of a reinforcedconcrete beam 1 x 1 m in cross section with an adjacent asphalt seal 7 x 21 m in cross section. Although this seal