Question

What all factors an engineer must consider for designing a retaining wall to retain a soil of height 10m? How those factors are different for a cohesionless soil, a cohesive soil and a saturated soil?

Answer 1

• Materials Of wall , reinforcement .
• Earth pressure.
• siesmic load if applicable .
• Type of wall. The type of wall you choose should be determined by need.
• Drainage. Most retaining walls fail because of pressure against the wall caused by water or soil-moisture build up behind the wall.
• Foundations. A wall is only as good as its foundation and all retaining walls should be built on structurally sound, compacted foundation sub-base material.
  
• Reinforcement .
• Cant. Walls are more stable and structurally secure if they slope back or “lay back” into the retained slope. This amount of variance from true vertical is called “cant” or “batter”.

q 2) solution.

• Cohesive soils :
• The inherant problem with clayey back fill is the development of negative tension zone (drying cracks on clay/wall interface) near top of wall. The crack tends to hold water and causing over turning problem.
• It also have High friction angle and hence exerts relatively higher pressure then non cohesive soil.
• Low permiablity of cohesive soil also increases water pressure on wall.
• Non cohesive soils .
• above problems are nullified.
• saturated soils .
• There is another hydrostatic Pressure of water acting on the wall apart from soil pressure .