Analysis of Methods to Determine Compressed Layer's Thickness in Calculating Foundation Settlements

There are mainly two methods to determine compressed layer thickness in calculating foundation settlements,control strain method and control stress method.Through comparing results of foundation settlement calculated by using the two methods,it is found that control strain method is not reasonable in determining compressed layer.And it resulted from the reason that the thickness of compressed layer determined by control strain does not put relationship with additional stress under foundation.The method to determine the thickness of compressed layer is suggested.