Rehbann's / Poncelets Theory

Rebhann (1871) gave this graphical procedure for locating the slip plane and determining the total active earth pressure according to Coulomb’s wedge theory.

 

Procedure:-

1) Draw A retaining wall having height H i.e. AB
2) Draw three lines Ground Line (ß @ with horizontal)
                                  Failure Line ∅ 
                                  Earth pressure line Ψ 
3) Through point A Draw a line parallel to Ψ line which cuts BD line at point C.
4) Through C draw perpendicular line CE which cuts an arc at E.
5) Join BE line consider BE as a radius and B as a center draw an arc through E 
     which cuts at point F on BD line. Through F draw a line parallel to Ψ line which 
     cuts line AD at point G.
6) Consider GF as a radius and F is a centre. Draw an arc through G which cuts BD
     at point H. Join GH to form a triangle GHF.
7) Consider GI is a height of triangle that is x. Through point B draw a line BG called Failure Plane.
8) Hence Active Earth Pressure is calculated as = (丫) (A) (△ GHF) 
                                                                                  = 1/2 (HF) (x) (丫).

     In this way we can find Active Earth Pressure using Rehbann/Poncelet Theory.

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