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doi: 10.1007/BF02376966pmid: N/A
1. The parameters of modern penstocks are increasing constantly, and in this connection the requirements imposed on the materials for their manufacture are increasing. Observance of the technology of manufacture and assembly as an indispensable condition of high-quality construction assumes particular importance. 2. A common feature of present-day plans for assembling penstocks is the trend to a maximum decrease of the cost of constructing a hydroelectric station and shortening its construction time, increase of reliability, and improvement of the operating conditions. The ever-increasing demands for reliability and economy of penstocks, mechanization and automation of operations, and the use of new technology require a further increase in the efficiency of assembly work. 3. In the case of large volumes of assembly operations performed in the construction of outsize penstocks it is expedient to create at the assembly facilities specialized shops equipped with 50-ton bridge cranes and stationary roller stands. If the automatic welding shop does not have bridge cranes, it is necessary to use universal travelling roller stands for automatic welding and inspection of the welded joints. 4. Assembly of the penstock in a tunnel must begin from the end opposite the entrance through which the pipes are delivered. Delivery of the pipes through the tunnel should be done on tracks laid with great accuracy and concreted thus, so that the links are normal immediately to the design position when butted. 5. The elbows, forks, and collectors should be assembled in the tunnel by means of bridge cranes.
doi: 10.1007/BF02376967pmid: N/A
1. In connection with the considerable depth of the underground structures of the Nurek station below the groundwater level, a necessary condition for their rational design and construction is the use of drainage to lower the groundwater level to acceptable values. 2. For the given hydrogeologic conditions, layout, and designs the construction of general drainage in the region of the penstocks (right bank) and local drainage in the spillway and other free-flowing structures is the optimal decision for the creation of drainage of the underground structures. 3. The main type of local drainage for underground free-flowing structures under the construction conditions at the Nurek station is hole drainage, which is distinguished by a high draining capacity, simplicity of installation and restoration, possibility of combining it with grouting operations, and economy. 4. Drainage bands of granular materials, precast members, etc., and pipes for discharging the drainage waters should be positioned in tunnels in rock within the limits of the lining in order to avoid overbreakages and complication of traffic movement. 5. To establish the effectiveness of drainage in underground structures, it is necessary to provide for the installation of appropriate monitoring and measuring devices for determining the level of groundwaters and their presure on the lining and the quantity and quality of the water being drained.
Ostroumov, S.; Lyubitskii, K.; Ilyushin, V.; Sovetova, A.
doi: 10.1007/BF02376968pmid: N/A
1. The installation of temporary runners at high-head hydroelectric stations provides: shortening of the station startup time and reduction in the cost of the starting complex with an absolute effectiveness of additional investments in the temporary structures; reliable operation of the hydropower equipment with minor changes in construction of the turbines; possibility of prolonged investigation and testing of the structures and adjustment of the equipment under conditions of gradual build-up of the heads and capacity. 2. The use of temporary runners guarantees operation of the turbines without erosion of the flow section and vibrations, i.e., without the adverse phenomena that have occurred at a number of hydroelectric stations during temporary operation with reduced heads.
doi: 10.1007/BF02376969pmid: N/A
1. When designing a hydroelectric station in a narrow canyon the main schemes for trimming the slopes and constructing traps and barriers must be issued simultaneously with the standard plans in order to ensure maximum safety during its construction. All safety measures should be taken before the start of construction at the dam site and on the powerhouse. The designs of the main structure should be such that they maximally preserve the natural state of the mountain slopes during excavating, drilling, and blasting. 2. A centralized safety service should be created at the construction site for organizing observations, taking measures to provide safety, and coordinating the sequence of operations. A clear-cut order of conducting simultaneous operations should be worked out, and especially dangerous types of jobs, just as the simultaneous ones, should be performed according to an admittance roster. 3. All workers in the dangerous zone at the site should be taught the basics of cliff climbing and overall safety and personal-safety techniques.
Tolkachnik, S.; Natarius, Ya.; Leshkevich, G.
doi: 10.1007/BF02376973pmid: N/A
1. Results of the investigation show the marked effect of foundation yielding on the modes and frequencies of natural vibrations of structure and accordingly the seismic load on concrete gravity and earth dams. Foundation yielding leads to a decrease of the frequency and change of modes of natural vibrations of such dams. 2. It was established that when Ef/Ed=0.2–1 for concrete gravity dams the yielding of the foundation should be taken into account in dynamic calculations regardless of the slope of the downstream face. This conclusion holds also for earth dams when Ef/Ed=1.0–10.0, as follows from [1]. 3. To extend the conclusions of this investigation to other types of dams, a further investigation of the dynamic behavior of the “foundation-structure” system for a broader class of structures is necessary.
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