BGS238 PROFESSIONAL SKILLS FOR APPLIED GEOCSIENTISTS

SCHOOL OF EARTH & ENVIRONMENTAL SCIENCES Engineering Geology of Dams

Engineering Geology of DamsBrain-storm the various geological and engineering aspects of dam construction.

1

Engineering Geology of Dams What is the purpose of a dam? Do you need to extend your list above to include aspects to do with the reservoir area?

Engineering Geology of DamsWhat will influence the positioning of the dam?

2

Engineering Geology of DamsHow can we work out how big (how high) the dam needs to be?

Engineering Geology of DamsNature of Valley Chord Height Ratio

Gorges

Less than 3

Narrow Valleys

Between 3 - 6

Wide Valleys

Greater than 6

Flat Country Plains

Embankments used to create reservoir volume. Eg. Near Heathrow

Modified from Walter, R. C. S (1962) Dam Geology.

3

Engineering Geology of DamsTypes of DamArch or Buttress Dam

Gravity Dam

Embankment Dam

Engineering Geology of DamsTypes of dam Principal design factors

Gravity

Stability derived from self-weight. Ground anchors can be used to increase stability. Masonry or concrete. Used in narrow to wide valleys with Chord / height ratio 5 to 8 eg Vyrnwy (Wales) =7 and the Three Gorges dam in China

Buttress

Reinforced concrete buttresses used to transfer thrust to foundation. Used in very wide valleys eg Errochy =10 and Shira =15 (Scotland)

Arch dam

Stability derived from the curved shape of the dam transferring the forces to the abutments. Reinforced concrete, can be thick (chord/height ratio of 3 5) or thin skinned (c/h< 3, radius