79 



act at one-third of the height (H) of the wall from the 

 base. The overturning moment then is 



To obtain the proper length of the base to resist this 

 overturning moment, and to prevent crushing or settle- 

 ment of the earth under the toe, 



2 ( W+lvA ) M 



where L equals distance of the resultant center of gravity 

 of the wall and earth on the heel, from the end of the heel, 

 and ft equals the bearing power of the foundation bed. If 

 the foundation bed is liable to serious s.-t tl.Mn.Tit. the position 



of /'J uiid-r tht- maximum normal enrth thrust Is found, and 

 the toe extended until P2 cuts the base in the middle. This 



