Module-IElements of Dam Engineering

Hoover Dam, USAColorado river

Three Gorges DamChina, Yangtze river

Elements of Dam Engineering

Classification of Dam -Earth Dam -Concrete or Gravity Dam - Gravity - Arch dam - Buttress dam - Factors for site sel. Dam - Factor for sel. Type of dam

Spillway -Types - Spillway gates

Dam:A dam is an impervious structure constructed across river and which store the water at U/S. OrA structure built across a River, Stream, and Tributaries for storing water at its upstream side and create a reservoir by help of major axis is called hydraulic structure for Storage such as Dam.

Classification of Dam

1)Based on their use i) Storage Dam ii) Diversion Dam iii) Detention Dam

2) Based on Hydraulic Design i) Over Flow Dam ii) Non-Over Flow Dam

3) Based on Structural Design1)Gravity Dam2) Arch Dam3)Buttress Dam4)Embankment Dam

4) Based on the material used i) Rigid Dam ii) Non- Rigid DAM

Concrete Dam or Gravity DamIt is categorized as rigid dam because it made by the rigid material

Embankment DamIt is most ancient type of dams that can be built by naturally available materials.

1) Earth Dam

i) Homogeneous type

ii) Zoned type

ii) Diaphragm type

2) Rock fill Dam

3) Combined Earth & Rock fill Dam

Concrete Dam or Gravity DamIt is categorized as rigid dam because it made by the rigid material

Advantages of Gravity Dam:1) Strong & Stable2) Overflow spillway, Pass flood3) Any height4) Not sudden failure5) Suitable at heavy downpore6) Less maintenance cost

Disadvantages of Gravity Dam:1) Sound rock foundation2) Higher cost3) Skill labour & Mechanics4) Diff. to rise the height latter5) More time to construction

Arch DamIt is curved concrete dam

Advantages of Arc Dam:1) Suitable deep gorges & Length small2) Built on moderate/weak foundation3) Thickness less than height4) Less cost compare gravity dam

Disadvantages of Arc Dam:1) Skill labour & Mechanics cost2) Construction time large3) Strong abutment4) Not Suit if solid rock not available

Buttress DamButtress dam consists of a continuous inclined U/S face supported by D/S buttress at regular interval

Advantages of Buttress Dam:1) Less materials2) Week foundation3) Buttress support again overturning & sliding

Disadvantages of Buttress Dam:1) More form work2) Constant maintenance and supervision3) Life less

Selection of site for a Dam1) Foundation2) Topography3) Reservoir4) Catchment Area5) Spillway6) Construction Material7) Communication8) Environmental Condition

Factor governing the selection of type of dam1) Topography - V Shape - U Shape2) Geology and Foundation Condition -Solid Rock -Gravel - Silt & Fine Sand - Clay - Non-Uniform3) Availability of materials for Construction4) Spillway size and location5) Roadway6)Length and height of dam7) Life of the dam8) Earthquake

SpillwaySpillways are important auxiliary works of dam, provided to dispose the surplus water from the dam which can not store in the dam otherwise it may overtroped

Location of SpillwayA spillway is located either within the body or totally away from the main dam as independent structure

Requirements of a Spillway1) Sufficient capacity2) Safe disposal of water3) Hydraulically and structure sufficient4) Hard bound surface5) Spillway should accompanied by energy dissipation work

Component part of Spillway1) Control Structure2) Discharge Channel3) Energy Dissipaters4) Entrance and outlet channels

Types of Spillway1) Free overflow and straight drop spillway

2) Ogee or overflow spillway

3) Chute or Open channel or through Spillway

4) Side channel Spillway

5) Siphon spillway

Energy Dissipation Below Spillway

1) Hydraulic Jump

2) Ski jump bucket

Spillway Crest Gates

1) Dropping Shutters or Flash boards

2) Radial gauge or Tainter gates

3) Drum gate

Prepared by, Dr. Dhruvesh

Patel

Prepared by, Dr. Dhruvesh

Patel

Source: www.google.comSincere thanks to Mahajan Publishing house for photographs and supplement materials.

www.drdhruveshpatel.com

www.drdhruveshpatel.com