Hydraulics Structures

S.ThanarajJ/CE/13/03/19

BCASJAFFNA

Content What is Hydraulic Hydraulic Structures The Dam Classification of Dam Purpose of Dam Site selection for a Dam Structure of Dam Failures in Dam

What is Hydraulics?Hydraulics is A topic in

engineering dealing with the mechanical properties of liquids or fluids.

Hydraulic Structure A hydraulic structure is a

structure submerged or partially submerged in any body of water, which disrupts the natural flow of water.

DAM

DamDams are individually unique structures. Irrespective of size and type they demonstrate great complexity in their load response and in their interactive relationship with site hydrology and geology.

Site selection for dam Needs Catchment Area Elevation Soil Type Rainfall Benefits

Design features of dams

• Cut-offs,• Spillway systems, including channels and stilling basins,• Internal drainage systems,• Internal culverts, galleries, etc.,• Foundation preparation, including excavation and grouting• Construction details, • Gates, valves and bottom outlet works, and• River diversion works.

Dam Classification1.Embankment dams

Earth Fill Dams Rock Fill Dams

2. Concrete dams Arch Dams Gravity Dams Buttress Dams

Earth Fill DamsAn earth fill dam is

constructed primarily of selected engineering soils compacted uniformly and intensively in relatively thin layers and at a controlled moisture content.

Principal variants of earth fill and earth fill–rock fill embankment dams

Rock fill embankmentsIn the rock fill embankment the sectionincludes a discrete impervious element of compacted earth fill or a slender concrete or bituminous membrane.

Embankment defect mechanisms and failure modes

Overtopping Internal erosion Seepage Piping Embankment and

foundation settlement Instability

Arch Dam

Buttress Dam

Structure of Concrete Dam (Gravity)

Typical Forces for a Gravity Dam

Concrete dams defect mechanisms and failure modes

Overtopping failure. See page. Landslide failure. Collapse

Cut-offs and control of under seepage

Open trench cut-off

Grouted cut-off Diaphragm cut-

off Upstream blanket

ConclusionIn Civil Engineering, Hydraulic structures are more complicated and huge like Dam/ reservoir Dams are individually unique structures. Two generic groups can be made in terms of

the principal construction material employed.

Dams have interactive relationship with site hydrology and geology

Construction style may vary with purposes Construction and Failure consideration like

seepage, instability, overtopping etc.

References Lecture Notes. The Dam Site. 2015. The Dam Site. [ONLINE] Available at:http

://members.optusnet.com.au/~engineeringgeologist/page18.html. [Accessed 03 December 2015].

Dam Design and Construction, Reservoirs and Balancing Lakes. 2015. Dam Design and Construction, Reservoirs and Balancing Lakes. [ONLINE] Available at: http://www.hydrocoop.org/dam-design-construction-reservoirs-balancing-lakes/. [Accessed 03 December 2015].

Alpsu, I. (1967) Investigation of water losses at May reservoir, in Transactions of

the 9th International Congress on Large Dams, Istanbul, International Commission on Large Dams, Paris, Q34 R27.

Attewell, P.B. and Farmer, I.W. (1976) Principles of Engineering Geology,

Chapman and Hall, London.

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