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ПОСОБИЕ (гидротехнич строительство) 174.doc
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5. Answer the following questions.

  1. What does the stability of gravity dams depend on?

  2. What do gravity dams use to resist the horizontal force of the water?

  3. Are gravity dams usually straight or rectangular in plan?

  4. May they be slightly curved or convex?

  5. The shape of the gravity dam resembles a square, doesn’t it?

  6. What does horizontal pressure depend on?

  7. Is water exerting no pressure at the surface of the reservoir?

  8. Is water exerting minimal pressure at the bottom of the reservoir?

  9. What is the base of a concrete gravity dam equal to?

  10. Is good impervious foundation essential for the gravity dams?

  11. What is the classification of gravity dams?

  12. What type of a gravity dam is more widely used?

  13. What type of a gravity dam is more economical to construct?

  14. What must be done before the construction work in a river channel can be started?

  15. What is the flow diverted to one side of the channel by?

  16. What happens when the work on the lower side of the dam is completed?

  17. What must be excavated to solid rock before any concrete will be poured?

  18. What is sealed with concrete or grout after excavation?

  19. Why is a grout curtain placed near the heel of the dam?

  20. What does the size of blocks depend on?

  21. Are block poured alternately?

  22. Why are individual sections sprinkled with water?

  23. When are the lateral surfaces of each section painted with an asphaltic emulsion? Why?

  24. What is provided between sections? Why?

  25. Are metal water stops also placed in the vertical or horizontal construction joints near the upstream face?

  26. Do inspection galleries permit access to the interior of the dam?

  27. When are inspection galleries formed?

  28. What may these galleries be necessary for?

  29. When may cracks develop?

  30. What may be used to avoid cracks?

  31. Can you name the most famous gravity dams in the world?

6. Make a plan of the text and then write a short summary of it.

7. Match the meanings of the terms with their definitions.

outlet, valve, inspection, joint, cracks, interior, gate, maintenance

  1. _______ slides across an opening, often folding into a smaller space as it is opened.

  2. _______ is a device which allows air or liquid to enter, or be prevented from entering.

  3. _______ are long narrow spaces.

  4. _______ is the process of looking at carefully in order to discover information, especially about quality or correctness.

  5. _______ is the process of keeping (a road, machine, building, etc.) in good condition.

  6. _______ is a way, especially a pipe or hole for liquid or gas to go out.

  7. _______ is the inside part of something.

  8. _______ is a place where two things are fixed together.

8. Choose the odd word.

  1. to liberate / to restrict / to discharge / to release / to free

  2. to preserve / to protect / to attack / to defend

  3. to permit / to allow / to let / to admit / to prohibit

  4. access / exit / path / entrance / entry / admission

  5. surface / covering / exterior / top / inside

  6. to form / to build / to destroy / to create / to make / to construct

  7. to accumulate / to leak / to seep / to escape / to pass / to discharge