1. SHEET PILE WALLS  generally used for retaining shallow heights of soil  wharfs, key walls  temporary structures for excavation (eg. dredging)

2. From McCarthy, 6 th Edition

3. Cantilever Sheet Pile Walls sssstability depends on passive resistance developed below the lower soil surface ffffailure is by rotation about a point O near bottom of wall Depth of embedment, d d Active E.P. O Passive E.P. fixity

4. aaaa fixing moment is provided by the extra depth below point O to prevent rotation GGGGenerally, design is based on a simplified but equivalent approach: the fixity provided previously is replaced by a resisting force, R at point C which is just below point O d Active E.P. C Passive E.P. R

5. Danish Rules aaaa factor of safety, FP is applied to the passive resistance in front of the wall ttttake moments about C to calculate d tttthen, increase d by 20% (empirical) ffffinally, check that the passive resistance provided by the extra 20% is > R, where R = PH

6. Free Earth Support DDDDetermine the depth of embedment, d by taking moments about A (MA = 0, apply FP) FFFFind tension, T from FH = 0 (don’t apply FP) CCCConstraints: failure wedges must not overlap b > ½da d Active E.P. Passive E.P. T no fixity A tie rod anchor wall 45° +  /2 45° -  /2 b dada