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1.
| 1. |
The rock foundation of the Sayano-Shushenskoe dam is inhomogeneous in its seepage characteristics: individual stretches in zones of tectonic crushing of the rock are the most permeable.
| | 2. |
The depth of opening of the rock-concrete contact does not exceed 27 m.
| | 3. |
During 4 years each subsequent filling of the reservoir to the NPL intensified the degree of decompression of the foundation, involving the deep curtain in this process. Signs of cracking of the middle part of the grout curtain were detected.
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It is necessary in the very near future to take measures to suppress seepage through the rock foundation. 相似文献
2.
| 1. |
For design of the antifiltration components in the karstic rock, the entire potentially karstic mass was usually closed off with curtains.
| | 2. |
The constructed complex of antifiltration components, consisting of a grout curtain, concrete-filled karst hollows, and local concrete crosscut walls corresponds to the difficult geologic conditions of the Chain-N'yan massif.
| | 3. |
The adopted work organization, with construction of tunnels cutting across the entire karst mass, simultaneous rock grouting, and more precise determination of the geomorphology made it possible to considerably reduce the proposed volumes and costs of the antifiltration components of the Hoabinh hydraulic development.
| | 4. |
The adopted scheme for providing a working face for the antifiltration measures at El. 133 m was the optimal. It opportunely permitted ensuring readiness of the high-head front for filling the reservoir to El. 112 m in November 1990, and to the NPL at El. 125 m in September 1991.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 6, pp. 29–35, June, 1991. 相似文献
3.
| 1. |
The problem of energy dissipation of the flow remains one of the most important in constructing high-head hydraulic structures with pulsating loads.
| | 2. |
During operation of the world's largest gravity-arch dam of the Sayano-Shushenskoe hydrostation, the energy of the flow being discharged is dissipated by a stilling basin. It was established that the powerful dynamic impulses created in this case originate, among others, from the baffle platform and its foundation. The latter circumstance requires the provision of reliable tightness of the joints between the blocks composing the platform and deep solid transition of the platform with its foundation.
| | 3. |
For the first time in domestic hydrotechnical practice fastening of the platform of the stilling basin by means of advance grouting and prestressed anchors installed to a depth greater than 20 m was mastered on the construction of the Sayano-Shushenskoe dam.
| | 4. |
Works on the manufacture, transport, assembly, tensioning, and testing PSAs were successfully mastered by the Krasnoyarsk enterprise of Gidrospetsstroi. A number of innovations were introduced at the know-how level.
| | 5. |
Passage of the 1992 floodwaters at the elevation of the NPL, after pumping water from the stilling basin, showed the effectiveness of the repair and restoration measures taken, which indicates the correctness of the selected designs, optimal technology, and high quality of the works of Gidrospetsstroi.
| | 6. |
An analysis of the strengthening works for high-head structures under analogous conditions permits recommending the following measures for designing and constructing a stilling basin:
grouting of the foundation in the region of the stilling basin to a depth of 30–40 m; 相似文献
4.
Conclusions
| 1. |
It is necessary to revise urgently SNiP 2.06.05-84x with respect to the designs of dams being constructed in the northern
construction-climatic zone, i.e., to remove all vagueness in understanding the basic design principles.
|
| 2. |
The top of watertight zones of dams should exceed the elevation of the HFL by amounts specified by SNiP. When necessary, in
connection with seasonal freezing and thawing of the upper part of the core, additional measures should be provided for ensuring
local static stability and seepage strength.
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| 3. |
Large dams should be evaluated under the aegis of the National Committee on Large Dams, whose role in this matter must be
increased. It is necessary to establish legislatively the procedure of changing the designs of dams after approving the projects.
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| 4. |
A coordination center processing all information on construction and operation should be created for large dams and dams being
constructed in the northern construction-climatic zone. The best solutions should be recommended for implementation.
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| 5. |
It is necessary to reconstruct the upper part of the dams of the Kureika hydrodevelopment, using above the NPL soils of an
analogous composition for the entire zone of the core with provision of its seepage strength by an additional filter layer
of sorted sand of fractions 0–10 mm. Reconstruction of the dam crests will make it possible not only to obtain additional
power production due to the prism of the reservoir between the NPL and HFL within 150–200 million kWh/yr.
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Translated from Gidrotekhnicheskoe Stroitel’stvo. No. 3, pp. 41–45, March. 1998. 相似文献
5.
| 1. |
Intense passage of the sediment deposits washed from the upstream stretches of the reservoir through the cut was observed. In the cut itself or in the immediate vicinity of its outlet, 13,000 m3 of sediments was deposited, the remainder was discharged by the through-flow into the downstream pool.
| | 2. |
The cut made was not curvilinear in plan as was intended, and therefore its expected intensive erosion by the flow did not occur. The exception was the inlet stretch of the cut, where its erosion and widening by about 10 m occurred.
| | 3. |
An increase of the cross-sectional area of the reservoir due to the cut leads to some decrease of the level of the flushing flow in the main channel and increases its slope on the upstream stretch of the reservoir, increasing the flow velocity and effectiveness of erosion of the sediments. Furthermore, the directions of the flow velocities partially changed in the region of the cut, which intensified the effect of erosion of the sediments.
| | 4. |
Gradual erosion of the island of sediment deposits cut off by the cut from the left-bank mass of sediments was observed during flushing and subsequent operation of the reservoir.
| | 5. |
It is better to use diesel dredges for making cuts, which, with their self-contained power supply makes it possible to operate on any stretch of the reservoir at a sufficient distance from the bank.
| | 6. |
The cost effectiveness of combined removal of sediments can be estimated by comparing the cost of conducting it with the cost of removing sediments by hydraulicking as the cheapest of the presently known methods. For conditions of the Chiryurt reservoir the effectiveness was 0.9 ruble/m3 of sediments being removed for the particular flushing under consideration.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 8, pp. 34–37, August, 1989. 相似文献
6.
| 1. |
For short revetmentsl
r/l
j<1.5, the=" vertical=" component=" of=" the=" fluctuation=" instantaneous=" bottom=" velocity=" has=" a=" considerable=" effect=" on=" the=" depth=" of=" the=" scour=" pocket.="> | | 2. |
The results of investigating the velocity structure of the flow obtained on erodible models with a length of the revetment less than 1.5l
j and limited time of the experiment do not reflect the actual kinematics of the flow in the pocket in the case of completely stabilized scouring.
| | 3. |
For the velocity-squared region of resistance of the channel and revetment lengths less than 1.5l
j, as well as for the transition region of resistance and revetment length less than 2l
j, it is necessary to carry out artificial lowering of the bottom of the lower pool to obtain the kinematic characteristics of the flow corresponding to stabilized scouring.
| | 4. |
For a revetment length equal to or greater than 2l
j, the results of investigating the kinematic structure of the flow obtained on the model can be transferred to the prototype without correction.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 12, pp. 42–45, December, 1991. 相似文献
7.
| 1. |
For locks with a head not exceeding 1.5 of the initial depth in the chamber it is most expedient to use the simplest supply systems of the lock-head type with filling from under the gate.
| | 2. |
For heads exceeding the initial depth in the chamber by more than 1.5 times, prevention of the entrainment of air by the flow filling the chamber should be provided. Preference should be given to the scheme with bypass submerged culverts in the upstream head, eliminating air entrainment.
| | 3. |
An analysis of the laboratory and onsite data shows that complication of the culvert supply systems from a certain level is not paid back by an acceleration of ship passage and improvement of ship mooring. Thus, for locks with a head on the chamber up to 40 m it is recommended to use a scheme with not more than four outlet sections (schemes 4 and 6 in Fig. 5). The ship mooring conditions for such schemes practically do not limit the chamber filling speed.
| | 4. |
An additional supply system can be used for accelerating the filling of high-head locks. The regime of the combined operation of main and additional supply systems is selected by model investigations.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 2, pp. 38–41, February, 1989. 相似文献
8.
Conclusions
| 1. |
In the upper reservoir of the Zagorsk PSS there are standing waves of a complex frequency spectrum having a virtually undamped
character.
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| 2. |
The excess of the level of the crest of the upper reservoir embankment of the PSS should be selected with consideration of
not only waves caused by meteorological factors but also the presence of standing waves.
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| 3. |
The standard systems of measuring the upper pool level of the PSS should provide for averaging the measurements.
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| 4. |
To eliminate nonproductive water losses through leaks of the close gate apparatus of the PSS units and increased power losses
in the SC regime, it is advisable to provide for the installation of preturbine gates at newly planned PSSs.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 10, pp. 39–42, October, 1999. 相似文献
9.
The concrete dam and rock foundation of the Zeya hydroelectric station after operating for 6 years, during which the reservoir was filled to the NPL and in some years somewhat exceeded it, is in a satisfactory state. | 2. |
The behavior of the dam under the effect of the operating loads and climatic factors correspond to the design assumptions.
| | 3. |
The indices of the state of the Zeya buttress dam give grounds to state that dams of the given type are prospective for use under conditions of a harsh climate.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 5, pp. 9–13, May, 1993. 相似文献
10.
| 1. |
Modeling of the processes of the interaction between outlet works and their foundation during passage of a flow by means of a model of the structure isolated from the channel, the flexibility index of which is less than unity, should be considered most correct, making it possible to completely reveal the mechanism of the effect of the flow on the structure and the reaction of the model of the foundation.
| | 2. |
Construction of the model as a primary detector made it possible to determine the main force parameters of the effect of the hydraulic jump on the basin and the frequency characteristics of the process of interaction of the basin and foundation.
| | 3. |
The character of oscillations of the basin model depends only on the method of supporting the model on the elastic foundation, and therefore for important structures it is necessary to model the base by trial and error.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 7, pp. 24–26, July, 1991. 相似文献
11.
| 1. |
A pressure dangerous with respect to cavitation is observed in those places where the vortex core closely approaches the conduit wall (there are places where with formal conversion to the prototype vacuums m H2O are observed, actually the absolute values will be close to the vaporization pressure).
| | 2. |
Delivery of air to ducts for the given spillway design reduces but does not remove the dangerous vacuum on the conduit walls.
| | 3. |
Large vacuums are recorded both over the length of the outlet conduit and in the dissipation chamber.
| | 4. |
The most effective (of those investigated) means of eliminating the vacuum on the conduit wall and in the dissipation structure are the installation of longitudinal ribs and transverse diaphragms in the outlet tunnel and delivery of air to the end of the swirler and dissipation chamber.
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Deceased. 相似文献
12.
| 1. |
It is necessary to correlate the value of the noneroding velocity with the time of flood passage. If canals are planned in regions where comparatively brief summer floods are dominant, the value of the noneroding velocity should be taken equal to 3 m/sec since by the start of the flood the grass cover will have time to develop and reach maximum strength. If the canals are to be constructed in regions where spring floods are dominant, for example, in the northwestern regions of the country, then the noneroding velocity should be taken equal to 1.5 m/sec, since by the start of the flood the grass carpet does not have time to develop and become stronger.
| | 2. |
In the absence of a constant runoff in the canal, for example, drainage canals, it is necessary to revet the bottom and side slopes with grass carpets.
| | 3. |
In the presence of a constant moistening is made from traditional materials, in the zone of alternate moistening and above it, it is necessary to revet the slopes within reinforced grass carpet.
| | 4. |
In a hydraulic calculation of canals with revetment of the bottom and side slopes with grass carpet, it is necessary to determine the roughness coefficient from the graph of n=f(VR, i). In a hydraulic calculation of wide overgrown channels and in calculation of the movement of the flow over floodplain stretches of rivers free from shrubs and trees, it is necessary to determine the roughness coefficient from the graph of n=f(Vh, i).
| | 5. |
Calculation of canals with nonuniform roughness (rigid revetment and revetment by grass carpets) must be carried out on the basis of relations of uniform flow by means of a generalized roughness coefficient.
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A method of hydraulic calculation of canals with revetment by grass carpets with presentation of an algorithm and calculation examples was developed from the results of the studies. 相似文献
13.
| 1. |
The means of engineering protection of the foundation of the structure from seepage specified by the design of the dam of the S-Sh HES provided an effective reduction of the head on the upstream stretch of the underground contour. In this case, the value of the uplift on the base of the dam does not exceed the design values, and the discharges in the drainage devices remain below the values specified by calculation.
| | 2. |
The seepage inhomogeneity of the dam foundation is comparatively large and has an ordered character, which was not taken into account in the seepage calculations. Modeling of such an object requires the fabrication of three-dimensional models.
| | 3. |
During staged filling of the reservoir, noticeably abrupt changes in the permeability of the permeable medium occurred along with slowly developing processes of an increase of fracture porosity corresponding to a general increase of the head on the structure. Such sharp changes occurred during filling of the reservoir at a rate greater than 2 m/day.
| | 4. |
A tendency toward a decrease of the effectiveness of the curtain and drainage device is noted with the course of time. The causes of this, as is seen, are decompression of the contact zone related to seasonal variations of the stress-strain state of the medium in the region of transition of the dam with the foundation rocks and intense deposition of sediments in the drain wells.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 8, pp. 32–36, August, 1990. 相似文献
14.
| 1. |
Provision for stability of slopes is one of the main problems in designing plains PSHS.
| | 2. |
The reasons for occurrence and a chain reaction of development of landslide phenomena on the south slope of the area of basic structures of the Zagorsk PSHS were peculiarities of its engineering-geological structure that were not properly taken into account in designing and carrying out construction work.
| | 3. |
For the purpose of stabilizing the landslide slope, a system of engineering measures was developed and implemented, including a change in the configuration and structure of the right-bank abutment of the upper-basin levee to the water intake, construction of a banquette, filling of a counterbanquette, draining of moraine loams, grading of the slope, surface water diversion, and monitoring of the state of the slope and elements of the antilandslide protection.
| | 4. |
Data from full-scale observatins indicate the effectiveness of the antilandslide measures that were performed and a state of the slope corresponding to criteria for the hydro development's safe operation.
| | 5. |
Innovative elements of the system of measures to stabilize the south landslide slope of the Zagorsk PSHS are:
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| – |
the complex nature of measures, providing for the optimum set of criteria with respect to reliability, technological efficiency, construction time, and cost of adjusted expenditures;
| | – |
minimization of one-time and total excavation for the banquette, providing for the least disruption of the slope in the process of construction;
| | – |
draining of moraine loams, which has no known analog;
| | – |
the use of an ejector unwatering system, which provides for minimum adjusted expenditures on construction and operation of the drainage system.
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Deceased. 相似文献
15.
| 1. |
Investigations showed that when constructing dams of fine-grained silty soils by hydraulic filling, it is expedient to use the technology of layerwise placement of soil with consolidation of each layer.
| | 2. |
Dependences are given for calculating the thickness of the layers and period of consolidation of the soil on the basis of investigations of the dynamics of the hydrophysical properties of these soils in relation to technological factors.
| | 3. |
Dependences are also proposed for predicting the density of the hydraulic-filled soil during construction, as well as the distribution of soil in the profile of the structure.
| | 4. |
A method is proposed for calculating the technological parameters, in particular, the rate of construction of hydraulic-fill structures, calculating the size and number of the hydraulic-fill plots referred to one dredge, and prediction of the seepage discharge into the foundation of the dams during their hydraulic filling.
| | 5. |
The proposed calculation methods make possible a more substantiated approach to the design of hydraulic-fill structures of fine-grained silty soils and technology of their construction.
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Translated from Gidrotekhicheskoe Stroitel'stvo, No. 6, pp. 5–9, June, 1990. 相似文献
16.
Conclusions
| 1. |
The water-power resources of small rivers in the Volga basin are significant: the economic potential of the WPR of these rivers
is more than 20% of the production of electric power by the hydroelectric plants in the basin.
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| 2. |
Use of the water-power resources of the small rivers in the basin will create a significant nature-preserving effect: thus,
the number of releases of polluting substances by thermal electric plants into the atmosphere will diminish by 92,100 tons/year,
and the releases of polluted water by 11,100 tons/year.
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| 3. |
The production of electric power by hydroelectric plants on small rivers of the basin will increase the reliability of electric
supply to rural consumers, owing to which shortages of electric power will be reduced by 13.1 million kWh/year.
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| 4. |
The effectiveness of capital expenditures for utilization of the WPR of the small rivers is rather high: considering the nature-preserving
effect, the increase in reliability of electric supply, and an increase recreational potential, the payback time may be 5.8
years; this is significantly shorter than the operating period of the hydroelectric plants (30–40 years).
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 5, pp. 46–49, May, 1997. 相似文献
17.
| 1. |
An analysis of the data of on-site observations in 1990–1993 showed that after a fourfold rise of the water level in the reservoir of the Sayano-Shushenskoe dam, a tendency toward stabilization of most monitored parameters characterizing the static behavior of the structure was noted.
| | 2. |
The increase of the irreversible component of radial displacements, tilts, and stresses in concrete slowed. The opening at the rock-concrete contact during seasonal rises of the upper pool level is gradually stabilizing, and the depth of opening (from the upstream face) is not increasing. Although the seepage discharges through the foundation during the last four years increased, the rate of increase decreased by the end of the indicated period.
| | 3. |
An increase of drainage discharges and a change in the piezometric heads (sometime anomalous) with the same upper pool levels indicate continuing changes in the stress state in the dam foundation, which is causing the formation of cracks in the rock mass.
| | 4. |
The magnitude and character of the change in stresses in the arch abutments and strains in the rock mass of the bank abutments indicate that the actual yielding of the banks was greater than was assumed in the design.
| | 5. |
Opening of horizontal joints and cracks on the upstream face within the 50-m zone from the contact during seasonal rises of the UPL to the NPL is continuing. Here a tendency toward penetration of the opening into the depths of the concrete mass is observed. The character of variation of the cantilever stresses at the upstream face in recent years indicates opening of horizontal joints and cracks at elevations higher than 50 m from the base of the structure.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 10, pp. 42–45, October, 1994. 相似文献
18.
Conclusions
| 1. |
The expediency of hydraulic-fill grading of marshy coastal territories and city dumps for housing construction and recreation
park and beach zones was proved practically.
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| 2. |
Underwater coastal borrow pits in the shallow-water zone can be used for direct dredging of soil.
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| 3. |
In the absence of sand borrow pits, fine-grained loamy sand soils can be used for hydraulic filling the construction sites.
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| 4. |
To operate dredges on large water areas under conditions of violent wind-wave action, it is necessary to work out a special
works organization plan taking into account the preservation of supply lines, machines, and crew during a storm and under
ice conditions in the winter.
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| 5. |
The possibility of using the ash of heat and power plants for engineering grading of a marshy territory for housing construction
on a pile foundation was proved.
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Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 9, pp. 29–33, September, 1997. 相似文献
19.
Model studies of the hydraulic operating conditions of an eddy tunnel outlet with an inclined shaft showed that:
| – |
for regimes without delivery of air into the flow core with swirler parameterA=1.1 and with delivery of air for all values ofA, submergence of the outlet section of the conduit in the lower pool noticeably affects the size of the core and promotes
the formation of a hydraulic jump zone along the tunnel;
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| – |
insignificant (in value) submergences of the exit section of the tunnel have little effect on the discharge capacity of the
outlet (their differences is Δ=1.4% forA=0.6, Δ=2.71% forA=1.1, and submergence even increases the discharge of the outlet Δ=0.8% forA=0.83).
|
| – |
delivery of air into the flow core has little effect on the discharge capacity of the structure, with the exception of the
layout with a swirler withA=0.6 (Δ=4.31% forA=0.6, Δ=0.5%, and Δ=0.9% forA=1.1);
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| – |
considerable vacuums are observed for regimes without air in the flow core, the absolute values of which with increase ofA drop intensely from Hfc=−4.5 m to Hfc=−0.3m;
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| – |
delivery of air into the flow core markedly reduces the vacuums in it and their values are close to zero;
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| – |
with increase of swirler parameterA the area occupied by the flow at the end of the tunnel decreases;
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| – |
regimes without delivery of air into the flow core are the most favorable with respect to the conditions of the pressure distribution
on the conduit walls;
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| – |
submergence on the downstream side does not lead to an increase of pressure on the conduit walls if the vacuum in the flow
core increases simultaneously with this.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 11, pp. 41–44, November, 1997. 相似文献
20.
Conclusions
| 1. |
Destruction of the concrete of the dam in the transition section between the spillway face and stilling basin occurred because
of changes in the technology of carrying out the concreting operations.
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| 2. |
The crack in the dividing pier of the overflow dam occurred because of the wrongly selected profile of the foundation and
substantial change in its stress state force and after construction.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 3, pp. 32–33, March, 1999. 相似文献
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