共查询到20条相似文献，搜索用时 62 毫秒
1.
| 1. |
The Karman parameter used in dependences on the assignment of the boundary conditions in K- models is determined from the relationship between geometric characteristics of the flow.
| | 2. |
The Launder-Spalding relation|
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2.
| 1. |
An industrial procedure for electrofacing by a powder wire of special composition has been developed to produce a wear-resistant coating up to 5 mm thick on the components of suction dredges. An increase of 4–6 times is achieved in the time to failure of the faced components, while the cost of these operations does not exceed the price of the initial article.
| | 2. |
It is expedient to use the facing procedure to strengthen new components under plant conditions and to restore worn parts at the site where the suction dredges are operated. The Scientific-Production Spetsstal' can perform work on electrofacing with the required materials, equipment, and technical accompaniment, and organize the strengthening of components at the plant.
| | 3. |
The installation of a three-channel suction dredge with effective water protection of components from abrasive wear while eliminating overflow of slurry into the pump and increasing the efficiency of the unit on the whole is proposed. The proposal is recommended for development and implementation.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 3, pp. 10–13, March, 1995. 相似文献
3.
| 1. |
For the first time in Russia a submersible axial-flow dredge pump was developed and tested for installation as a first-stage
pump on dredges to reduce the negative pressure before the hold dredge pump and to increase its positive suction head.
|
| 2. |
The use of the axial-flow dredge pump permits increasing the output of the dredge and depth of excavating the underwater borrow
pit. With respect to power consumption the axial-flow pipe is 2–3 times more economical than ejection.
|
| 3. |
The small mass of the pump permits mounting it on existing dredges without their alteration.
|
| 4. |
Development and perfection of this direction is quite prospective for hydraulicking.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 10, pp. 14–17, October, 1995. 相似文献
4.
| 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
5.
| 1. |
The morphometric method of estimating the geometry of stable canal channels, as based on a deeper physical nature and using the fluvial process theory principle, has become most popular in solving the problem of designing canals in alluvial soil. It can be considered that sufficiently reliable relations have presently been obtained which can be used in practice with consideration of the particular canal operating conditions.
| | 2. |
More detailed investigations of the separate consideration of the transport of bottom and suspended sediments on stability for providing channel stability of canals when vvne are needed for refining the morphometric relations.
| | 3. |
It is necessary to continue investigations of the effect of the sediment concentration of a flow on the velocity structure of the flow and noneroding velocity.
| | 4. |
It is necessary to consider as one of the most important problems of open-channel hydraulics the activation of experimental and theoretical investigations of the three-dimensional turbulent structure of a flow for the purpose of estimating the distributon of local velocities in the flow cross section as a function of the size of the channel and roughness of its walls.
| | 5. |
For dynamically stable canal channels investigations are needed for estimating the roughness coefficient as a function of the channel size , shape, sediment concentration of the flow, and bed-load transport.
| | 6. |
It is necessary to prepare the relevant materials for compiling standard data on the design of dynamically stable canals.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 3, pp. 37–42, March, 1991. 相似文献
6.
| 1. |
Sludge storage ponds can be located on any foundation soils, but economic calculations should be made for selecting the site.
| | 2. |
In the presence of seismic conditions, it is necessary to remove weak soils within the shoulder in order to provide its stability with a steepness of the downstream slope up to m=5. Other methods providing stability of the shoulder can also be used with appropriate technical and economic substantiation.
| | 3. |
The stability and possible liquefaction of soils of the shoulder should be determined only according to the guide Consideration of seismic loads when designing hydraulic structures, which is the only standard with respect to this problem.
| | 4. |
The size of the hydraulic-fill beach is determined on the basis of the particle-size distribution of the slurry.
| | 5. |
The permissible minimum width of the hydraulic-fill beach is determined on the basis of calculating the stability of the shoulder.
| | 6. |
It is necessary to recommend the construction of a siphon intake (discharge) located on the bank of the settling pool, which gives a more reliable and economical solution.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 12, pp. 53–55, December, 1991. 相似文献
7.
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.
|
| 2. |
Underwater coastal borrow pits in the shallow-water zone can be used for direct dredging of soil.
|
| 3. |
In the absence of sand borrow pits, fine-grained loamy sand soils can be used for hydraulic filling the construction sites.
|
| 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.
|
| 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
8.
Conclusions
| 1. |
Theoretical investigations and bench tests on a pump model made it possible to obtain the setting geometry that ensures extremely
good power characteristics for pumps having large setting flow areas.
|
| 2. |
It is recommended to use wear-resistant white chromium-manganese cast iron for components in the setting of the GrT-4000/71
soil pump, which is intended for the transfer of sandy-gravelly soils with a lump size no greater than 60 mm.
|
| 3. |
Use of a dual-cup rubber shaft seal is recommended to improve the operational reliability of the pump.
|
| 4. |
To extend the longevity and improve the reliability of the drive of the soil pump, it is proposed to use a bearing with a
set of spring that lower the axial forces on the bearing.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 2, pp. 31–37, February, 1999. 相似文献
9.
| 1. |
It has been shown that in canals of rectangular cross-sectional shape, the vector of the full turbulence stresses forms with the flow direction an angle equal to 65°, and the value of this angle does not depend on the distance to the solid boundary.
| | 2. |
It was demonstrated that the shearing stresses are proportional to the vector of the full turbulence stresses and that the proportionality coefficient is constant.
| | 3. |
We established the type of relation of the velocity gradient with respect to the vector of the full turbulence stresses, which is correct to the limit of the external layer in canals with rectangular cross-sectional shapes.
| | 4. |
A new equation is proposed for calculation of the velocity gradient in canals by means of the vector of full turbulence stresses.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 5, pp. 39–42, May, 1994. 相似文献
10.
Conclusions
| 1. |
Biolocation as a nondestructive method of flaw detection of hydraulic structures and their earth foundations is of practical
interest and can solve a number of problems of hydrotechnical, power, industrial, and civil construction along with other
traditional geological and geophysical methods.
|
| 2. |
Areal biophysical profiling (biolocation) considerably reduces the cost of archaeological investigations in the flooding zone
of reservoirs and without digs permits establishing the internal structure of an archeological object, and the use of resonators
of various materials (ceramic, copper, iron, precious metals) permits obtaining information about the affinity of the archaeological
memorial to a particular historical epoch and thereby establishing its historical significance and material value.
|
| 3. |
By means of biolocation we can establish vertical circulation of geoenergy in geopathogenic zones, determine the location
of “dead” sections, and solve social problems with respect to neutralization of the harmful effect of geopathogenic zones
on human health and on the environment.
|
| 4. |
Detection of geopathogenic zones permits a reliable prediction of karst and piping processes in earth masses of the foundations
of buildings and structures and taking timely measures to neutralize them.
|
| 5. |
From the increased productivity of biocenoses and biological activity of substances and minerals we can establish centers
of methane formation in the soil stratum and take a systems approach to the solution of problems related to the ecology of
large cities and environmental protection, including at sites of hydrodevelopments and other power facilities.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 10, pp. 38–43, October, 1997. 相似文献
11.
Conclusions
| 1. |
It was proved that the coefficient in front of the existing formulas for determing the critical sediment concentration of
flows are not constant, and their values depend on the sediment concentration of the flow
in accordance with dependence (12).
|
| 2. |
A new dependence (13) for calculating the critical sediment concentration of a flow was obtained on the basis of processing
numerous existing on-site investigations.
|
| 3. |
The regime of motion of suspended fine sediments (d≤0.25 mm) in tranquil open-channel flows occurs according to dependence
(13).
|
| 4. |
Formula (13) can be recommended for practical use when calculating the critical sediment concentration in canals, settling
basins, and other streams transporting fine natural suspended material.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 1, pp. 20–23, January, 1997. 相似文献
12.
An analysis of the experience in the Soviet Union and in foreign countries with conveyor transportation in the mining industry,
as well as with use of conveyors in hydraulic construction shows that the introduction of conveyor transportation in the field
of construction of embankment dams in this country, for delivery of earth-rock material from quarries, as well as for carrying
raw materials to concentrating plants processing nonmetallic minerals, will make it possible.
| 1) |
To reduce substantially the personnel nees.
|
| 2) |
To lower significantly the transportation costs for delivery of earth-rock materials to construction sites and to concentrating
plants processing nonmetallic mateirals (rubble, gravel, and sand);
|
| 3) |
To reduce the need for trucks, by replacing them with conveyors;
|
| 4) |
To increase the rate of delivery of earth-rock materials from quarries for dam, construction and, consequently, to reduce
the times of completion.
|
| 5) |
To reduce the volume of housing, cultural-welfare, and auxiliary-subsidiary construction in owing to the lower needs for personnel
in conveyor transportation;
|
| 6) |
To eliminate the need for constructing a large number of roads with rigid pavements for large-capacity dump trucks;
|
| 7) |
To raise the technical level of the earth-rock work.
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相似文献
13.
| 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:
|
| – |
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
14.
| 1. |
An on-site examination of the damageability of polymer-film skins and measurements of the seepage leakage made it possible to estimate the apparent permeability coefficient of such skins with relatively small damageability P<=0.05% by=" the=" quantity=">–3, m/day.
| | 2. |
Maximum damageability of polymer-film skins is formed due to the use of machines — bulldozers leveling the soil of the protective layer and vehicles delivering these soils.
| | 3. |
Introduction of mechanisms making it possible to place the protective layer of soil on the film element without traveling on the skin makes it possible to substantially reduce the damageability of polymer-film skins and their permeability.
| | 4. |
A reduction of damageability and permeability of polymer-film skins can be achieved by improving its construction and, in particular, by introducing bituminous and geotextile pads covering the film element of the skin on top and below, introduction of a second layer of film covering, and also by providing a drainage system of the protective layer.
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Deceased. 相似文献
15.
| 1. |
Modified wood is an effective substitute of the laminated wood lining of bearing bushings for vertical pump units.
| | 2. |
An investigation of modified wood showed that this material in some indices (friction coefficient and wear resistance) is better than laminated wood.
| | 3. |
Since there is no mass manufacture and centralized supply of modified wood, it is possible to create a technological department for its production.
| | 4. |
Organization of the department does not require capital expenditures and special accommodations.
| | 5. |
Machining of the wood is performed on ordinary metal-cutting machines with the use of the tools used when machining laminated woods.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 7, pp. 33–35, July, 1991. 相似文献
16.
| 1. |
In certain cases of constructing dams salt-containing soils serve as their foundation.
| | 2. |
Under these conditions reliable operation of the structures can be provided only by developing special engineering measures to control dissolution.
| | 3. |
All existing methods of protecting saliferous foundation soils of hydraulic structures from dissolution can be divided into passive, active, and combined.
| | 4. |
The combined methods should be considered the most effective for preventing removal of salts from foundation soils by the seepage flow.
| | 5. |
Large-scale field investigations of the work of the combined method of protecting saliferous foundation soils of the planned Lower Kafirnigan hydro development showed its high effectiveness even in the case of complex engineering-geological conditions at the construction site.
| | 6. |
Individual elements of the set of dissolution protective measures investigated under field conditions can be used in hydrotechnical and hydropower construction practice.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 10, pp. 10–14, October, 1994. 相似文献
17.
Conclusions
| 1. |
When searching for the optimal steel percent needed for providing the bearing capacity of a specimen, it is necessary to take
into account the factor of reinforcement arrangement in the soil.
|
| 2. |
It is seen from the dependences γcd*=f(ζ) obtained for specimens with various steel percent that with an increase of the factor of reinforcement arrangement in
soil ζ the work conditions factor decreases, which makes it possible to introduce the given factor in formula (1) for determining
γcd*.
|
| 3. |
The lining of the model must be regarded as an element increasing the bearing capacity of the reinforced earth model.
|
| 4. |
In the case of a discontinuous and continuous lining the bearing capacity of the models (with the same steel percent) is higher
than that of models with a flexible lining.
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Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 3, pp. 19–21, March, 1998 相似文献
18.
| 1. |
A comparison of laboratory and on-site data on a determination of the maximum range of oscillations at the end of a direct hydraulic jump when waves enter it from a chute with the results of calculations by theoretical formulas (1), (2), and (3) confirms the applicability of one of these formulas (2) for superrapid flow and flow transitional from superrapid to rapid.
| | 2. |
The stilling basin generates secondary waves, reaching half of the depth of the basin d with respect to its height. With submergence of the basin from the lower pool, the range of variations of the level increases additionally by 2.0–2.5 times.
| | 3. |
On the apron behind the stilling basin, the drop of waves is insignificant, since the wave transformation coefficient at distance (40–90)hn, where hn is the natural depth, remains equal to
.
| | 4. |
The periods and lengths of the waves transformed in the stilling basin decrease with increase of discharge and Froude number Fr0 and approach in value the wave periods.
| | 5. |
Formulas (6) and (10) were obtained for calculating the maximum amplitude of oscillations of the free surface and maximum depth at the crest of oblique waves on the narrowing sections of the wave chutes and they were checked experimentally, which proved the applicability of these formulas for calculating a nonstationary oblique hydraulic jump.
| | 6. |
The proposed empirical formulas (12)–(17) can be recommended for an approximate evaluation of the parameters of the largest first waves on the narrowing stretch.
| | 7. |
Under these conditions, the use of a stilling basin as an energy dissipator of a superrapid flow is not rational, since not dissipation but generation of secondary waves is observed in it.
When designing narrowing sections of chutes, it is necessary to take into account an increase of depth of the oblique jump with passage of roll waves. 相似文献
19.
Conclusions
| 1. |
Gidrospetsproekt should design the groundwater system.
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| 2. |
One contractor should drill the wells and operate the groundwater-lowering system.
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| 3. |
In connection with the geological conditions, the wells should be of very high quality, for which own enrichment of the filter
material (sand of the blanket) and strict control during drilling the wells are necessary.
|
| 4. |
It is efficient to drill the wells by a 1BA-15V rig with a tool with backwashing.
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| 5. |
With respect to piles of the penstock foundation: Drilling the holes for the piles should be done only with casings. To organize
24-h work for increasing productivity. Works on forming the pile heads should be done immediately after concreting the pile.
The piles should be tested after each change in the geological conditions.
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| 6. |
With respect vertical drainage: the wells should be of high quality, with an enormous safety margin.
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Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 10, pp. 29–33, October, 1999. 相似文献
20.
| 1. |
The energy-storage hydroelectric station (ESHES) can provide a 1.5–2-fold increase in peak capacity with a simultaneous threefold
decrease in daily fluctuations of the water level in the lower pool.
|
| 2. |
A decrease in the length of the concrete structures located in the river channel (especially the length) of the powerhouse)
reduces the consumption of concrete for the ESHES in comparison with the HES, which compensates for the cost of constructing
the additional structures of the ESHES.
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| 3. |
Unlike the HES, the ESHES operates in a sharp-peak regime and also during passage of flood waters.
|
| 4. |
Contrarotating pump-turbines are best suited for an ESHES because of various combinations of heads on its turbine and pump
parts.
|
| 5. |
With increase in the speed of multistage hydraulic machines their placement depth decreases and the cost of the powerhouse
is reduced.
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