on the structure^ with no active backfill pressure opposing it» From 

 the section on wave forcesj, this raoment would be lYjiiOO foot pounds per 



lineal foot of wallo Since this moment is smaller than that due to 

 earth pressures alone^ tiie lifall would be stable against wave attack., 



31 0, Stability's^ ^ l^^Mlg^S^ ^ws-Td o - The weight of the filling material 



per foot of ot avail l-i^ngthi is 



W a Whb (86) 



w>)"re w s the iinsiiturated eel] fill vmit wei<g'i-: 



h ^ the fill height 



b e the average cell width 



so W t- 120 X 13 X 16 g 2i;^,800 pounds per foot 



The Kno-sjn forces for seaward sliding are as shown in Figtire lOU, 



y2.(jo For stability against sliding^, the horizontal force divided 

 by the total weight !m3.st be less than the coefficient of friction 

 mijltiplied by the factor of safety^ Because of the penetration of the 



pilingc, a factor of safety of 1 is satisfactoary,, or 



"^ .MJ^L^ 30o21'5 which is less than the allowable and the wall is 



257800 



stable again-st sliding seawardo 



321 Stability^ Sliding^ ^-itildyTardo =■ The mimerator of the above 

 ■■"'.y!j.3taon ±s smaller '>jh.en a wav~- force of Ujil50 foot pounds per foot ia 

 'nfostituted for S,3U0o Since the denominator remains the samSj, the wall 



': 'yen more stable againat w-;,ve forces than it is against ear-tl"! forces, 



322 1, £££M!L.S3£tiono --- a cell section designed for stability is 

 ohown on FigarelO^T" 



■^"i-^o §J&££l„§l^i!fjL£!ii®-;^ii£i'c!2it^'' " Sheet pile bulkheads may be con- 

 structed where adequate penetration is obtainableo For design computa- 

 tion/-; th*^ following assumptions for- earth force calculations may be made 



i,aj 1 surcharge, load on a fill may be considered to be re- 

 placed by an equivalent height of fill which will produce the same 

 pressure as the siorcharge at its point of application^ 



