The Islamic university - Gaza Faculty of Engineering Civil Engineering Department Principles of foundation Engineering Chapter 7 Lateral earth pressure Engr. Safaa Abu El-Aish

Types of lateral earth pressure: At rest soil pressure: Active soil pressure: Passive soil pressure:

At rest soil pressure: At any distance (z) below the ground surface, the lateral earth pressure ( ) equals: : At rest pressure coefficient, For normally consolidated If there is water table we have to add the effect of water pressure to the lateral pressure: The coefficient of lateral earth pressure for the water =1 for any case. To find the at rest forces:

The water stress diagram is a triangle starts from (0.00) to the value of

Lateral earth pressure At rest soil pressure Active soil pressure Straight back fill RankinColumb Inclined back fill RankinColumb Passive soil pressure

Rankin Active soil pressure:

Ranking passive soil pressure :

Note: For retaining wall design, the active soil pressure is assumed as follow (Modified Active soil pressure)

EXAMPLE 1:

Example) A 3m length wall as shown below, Determine the ranking passive soil pressure per unit length of the wall.

Rankin soil pressure for inclined backfill: Passive: Active:

Passive: Active:

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