Shand pr eng, ninham shand, cape town, south africa. Pdf evaluation the hydraulic aspects of stepped labyrinth. Modeling was 10% of design modeling was 1% of construction, estimated to save 2% of construction costsa modeling was required for sitespecific design importance of site considerations for labyrinth design 35% reduction in discharge from standard design modeling was a valuable design tool. Labyrinth spillways, computational fluid dynamics cfd, dams. New labyrinth weirs triple the spillways discharge dam. This paper describes the design and hydraulic model study conducted for a labyrinth weir arrangement proposed for the south heart dam in northern alberta. When the reservoir water level reaches the design elevation, embankment is breached and is washed out by controlled method and flood passes via auxiliary spillway. Experimental investigation of discharge capacity of labyrinth. Due to the complex design of the overflow structure, the labyrinth spillway discharge capacity is af.
The pk weir not often considered, primarily because of the staffs unfamiliarity with this design. A number of hydraulic models have also been tested in order to learn about the design of labyrinth spillways. Reclamation design standards may include exceptions to requirements of these codes and standards. The labyrinth weir is commonly considered for upgrading spillways. A table of hydrologic design criteria giving the spillway design flood, the service spillway design flood and minimum freeboards for various hazard classifications can be found in table 1. Paul tullis, member, asce, nosratollah amanian,z and david waldron abstract. Don pedro spillway flowing for the second time in its history. Usace dam safety program design of spillway upgrades. Case study of a labyrinth weir spillway canadian journal. Hydraulic design and application of labyrinth spillways kathy. A labyrinth spillway is an overflow weir folded in plan view to provide a longer total effective length for a given overall spillway width. This included the overflow approach, labyrinth weir and spillway chute, as shown in figure 3. The capacity of a labyrinth spillway is a function of the total head, the effective crest length, and the crest coefficient.
It does not contain the detailed hydrologic or hydraulic procedures used to synthesize the anticipated storm flow conditions. This collection of publications is the single official repository for official engineering regulations ers, engineering circulars ecs, engineering manuals ems and other official public documents originating from headquarters u. Labyrinth spillways are passive control structures that are commonly implemented in dam projects i. Weirs channels flow magnification hydraulic design. The locations of the labyrinth spillways in this dataset are presented in fig. Weir and other labyrinth structures, energy dissipation is enhanced and, for moderate discharges, any downstream erosion may be much reduced.
Labyrinth spillways are more economical than gated structures. Hydraulic structures, equipment and water data acquisition systems vol. The book begins with a section on the theory of labyrinth weirs and continues with detailed sections on significant factors that affect the discharge characteristics such as crest shape, weir height, and sidewall angle. The walls of the chute were artificially raised in the modelling to enable. Designing labyrinth spillways for less than ideal conditions. Waldron, 1995, design of labyrinth spillways, journal of hydraulic engineering, asce, 12, new york, p.
One drawback of free overflow spillways is their low specific discharge. The design of the wall footings was taken from the quickrwall analysis of the walls as retaining structures. During the computations for principal spillway size, a number of volume checks must be made to assure a proper design. Pdf the design and analysis of labyrinth weirs researchgate. Em 111022400, structural design of spillways and outlet works. The ogee spillway is generally provided in rigid dams and forms a part of the main dam itself if sufficient length is available. Lux and hinchli 1985 accomplished dimensional analysis to get discharge coe cient of labyrinth spillways and presented design curves 2. Engineering and design hydraulic design of spilways 1. The two stage, seven cycle labyrinth spillway is designed to pass 82,000 cfs. Sep 05, 2019 hydraulic design and application of labyrinth spillways. Case study of a labyrinth weir spillway canadian journal of. In order to satisfy these requirements, the several types of the spillways including free overfall or labyrinth spillway design is the best way ouamane and.
Design of labyrinth spillways journal of hydraulic. Hydraulic design and appucatlon of labyrinth spillways by david l. Spillway design flood sdf can be selected using some prescribed guidelines or from a riskbased analysis. An adaptive neural fuzzy inference system anfis model was. Cascade spillway most of the spillways are of overflow types large capacities, higher hydraulic conformities, and adaptable to almost all types of dams. Increase spillway capacity using labyrinth weir sciencedirect. Experimental investigation of discharge capacity of. An approach to optimal design of trapezoidal labyrinth weirs. This numerical model was then calibrated using a 1. Fema workshop issues, remedies and research needs relating to service andor emergency spillways d4 lux, f. Evaluation the hydraulic aspects of stepped labyrinth spillway. Hydraulic design and application of labyrinth spillways.
Introduction a labyrinth weir is a passive control structure that is folded in planview fig. Chapter 50 earth spillway design 210vineh, august 1997 501 chapter 50 earth spillway design 628. Goal tailor spillway excavation to meet rock borrow requirements. The designer is confronted with the use of empirical methods for determining spillway configurations which require careful design and verification by use of a hydraulic model. Compared to creager type weir profiles, labyrinth weirs may divide by a factor of about 3 the spillway lengths required at fill dams or by 2 the upstream head required at any weir.
Theory and modeling for the lake townsend spillway replacement project greg paxson, p. The existing spillway was evaluated using computational fluid dynamics and the design was. An excellent alternative to traditional method of adding another spillway. Modeling was 10% of design modeling was 1% of construction, estimated to save 2% of construction costsa modeling was required for sitespecific design importance of site considerations for labyrinth design 35% reduction in discharge from standard design modeling was a valuable design. Design and construction of a labyrinth pkw spillway at. Figure 1 design suggestion for pkweir type a scale of cross sections is 1.
There are an infinite number of possible labyrinth weir configura. Draft, subject to revision millsite dam spillway rehabilitation design report 1 introduction the existing millsite dam spillway is not in compliance with current utah dam safety standards for passage of the inflow design flood, a 24hour usu local probable maximum flood. Bureau of reclamation march 2010 design standards no. This paper provides an extensive overview of all factors affecting the performance of labyrinth spillways and presents a design procedure. This study was adopted a new concept to enhance performance of stepped spillway towards more dissipation of kinetic energy along chute face through increases interlocking surface areas between the mainstream and trapping cavity recirculation vortices. Debris and maintenance of labyrinth spillways 505 study overview labyrinth spillways numerous owners and dam safety officials were contacted to compile their experiences regarding labyrinth weirs, woody debris, and maintenance. This manual provides guidance for the hydraulic design of spillways for flood control or multipurpose dams. In order to complete this module, you will need access to the national engineering manual, practice standard 378, and tr60 refer to the. A labyrinth spillway and a fish ladder left of the hope mills dam in north carolina. Table 1 labyrinth weir design parameters design aspect value. Design manual for rcc spillways and overtopping protection prepared by urs greiner woodward clyde por tland cement association. Bureau of reclamation january 1984 water resources research laboratory official file copy.
This paper describes aspects of the design and construction of a new auxiliary spillway, incorporating a labyrinth weir and collapsible safety screens, for an existing cyclopean masonry dam. The design, including physical model studies, and construction of this scheme are described here. Labyrinth spillway begins to operate at 14500 year flood. Following previous experience of a piano key weir spillway which had been installed at the goulours dam, edf decided to adopt this concept for the upgrading of flood discharge works at the saintmarc dam. Most are for spillways with design discharges of between 100 and 1 000 m 3 s with walls under 4 m high and with. Design procedure of labyrinth weirs and piano key weirs were outlined and each one applied in five different existing projects. Load combinations for spillway stilling basin walls.
The labyrinth spillway will include three apexes that protrude into the reservoir with a height of 19. Other spillway types include an ogee crest which overtops a dam, a side channel that wraps around the topography of a dam and a labyrinth which uses a zigzag design to increase the sill length for a thinner design and increased discharge. Numerical simulation of turbulent ow over labyrinth. Either stone foundation or slop or built slop terminal and lateral walls to keep the sizes of spillway control erosion of. To aid the design process and give more confidence in the weir rating curve ahead of physical modelling, a cfd model was created. Lack of adequate freeboard and concerns over ability of a masonry spillway to pass the design flood were resolved by providing a labyrinth weir and replacing the masonry spillway. Labyrinth weirs provide an effective means to increase the spillway discharge capacity of dams and are often considered for renovation projects required due to an increase in expected flood inflow to the reservoir of an existing dam. Pdf the capacity of a labyrinth spillway is a function of the total head, the effective crest length, and the crest coefficient. Millsite dam spillway rehabilitation design report 3 spillway structural design the new spillway was designed as a series of retaining walls using quickrwall structural design software. Design of labyrinth spillways, asce, journal of hydraulic engineering, vol. Due to their hydraulic efficiency, labyrinth weirs are often a favourable design option to increase flow capacity e. The crest coefficient depends on the total head, weir height, thickness, crest shape, apex configuration, and the angle of the side legs. Apr 25, 2020 hydraulic design and application of labyrinth spillways.
The design of a labyrinth weir and modeling criteria is also covered. Optimal design of labyrinth spillways using metaheuristic. Labyrinth design is particularly beneficial when spillway width is fixed, us water surface elevation is restricted and large discharge must be passed. A standard creager type profile has a unit flow in m 3 s per metre length of spillway close to 2. Pdf optimal design of labyrinth spillways using metaheuristic. Spillway definition, types of spillways and classification. The hyrum dam auxiliary labyrinth spillway geometry was selected for this comparison see table 1 for dimensions. Jul 18, 20 as there is also much air entrainment in flows from p. States falling within the snowmelt zone in the 48 contiguous states must make a check for snowmelt runoff volume as well as tenday precipitation. Comparisons were made with linear weirs, it was concluded that labyrinth and piano key weirs increase the. The crest coefficient depends on the total head, weir height, thickness. Shand encyclopedia of life support systems eolss the choice of a spillway type depends on a number of factors including the dam type.
Design and construction of a labyrinth pkw spillway at saint. Pdf optimal design of labyrinth spillways using meta. Labyrinth weirs, high headwater ratio, physical models, numerical models, spillways. Hydraulic design and application of labyrinth spillways kathy frizell david l. A spillway is a structure used to provide the controlled release of flows from a dam or levee into.
Load combinations for spillway approach channel walls. The focus of the present study is that on the optimization of the shape of the labyrinth spillway through the minimization of the construction costs because the use of it is a suitable solution in the rehabilitation process of existing reservoirs. This study was adopted a new concept to enhance performance of stepped spillway towards more dissipation of kinetic energy along chute face through increases. Dec 04, 2014 level set simulation of a labyrinth spillway. Iii design of spillways and outlet works for dams m. The new spillway will consist of a reinforced concrete labyrinth spillway with a discharge chute similar to the existing chute. The fi nal design is shown in figure 4 and comprised the design parameters shown in table 1. The labyrinth weir geometry was optimised to maximise effi ciency by minimising depth of water fl ow over the weir within the existing spillway width of 30 m and with a base level of r. The crest of the spillway is shaped to conform to the lower nappe of a water sheet flowing over an aerated sharp crested weir. This manual applies to all headquarter us army corps of elements and all field operating activities fda having responsibility for the design of civil work projects. The focus of the present study is that on the optimization of the shape of the labyrinth spillway through the minimization of the construction costs because the use of.
1041 1188 865 619 1468 486 859 1370 1393 1537 1313 187 558 122 558 27 1167 1504 577 46 1128 542 1470 623 826 1463 1272 1350 565 441 653 461