The Research On The Ultimate Bearing Capacity Of Gravel Pile

The theories and methods of calculation of the ultimate bearing capacity of gravelpile are varied. The calculation methods of the ultimate bearing capacity of gravel pileinclude the calculation methods of Brauns(1978), Hughes&Withers(1974), WongH.Y.(1975),passive earth pressure, the cylindrical cavity expansion theory and so on.Among those, the Brauns is simple in calculations, clear in ideas.Although the calculation method of Brauns is used by the most designers,It is on the safe side which disregards the self-weight of the pile and the soil aroundand of which the form of failure surface is not perfect. So it’s necessary to take theself-weight of the pile and the soil into consideration and modified the form of failuresurface as to get more economic and social benefits in engineering constructions.On the base of Brauns, the issue makes some relative modifications throughanalysis and calculation:①Deriving the theoretical formula of the ultimate bearing capacity of gravel pilewhich considers the self-weight of both soil and pile;②Deriving the relationship between the ultimate bearing capacity of gravel pileand the radius of the pile, the undrained shear strength, and the approximate formulaas well;③Making comparison between the theoretical formula which is modified and thedata of engineering construction, and concludes that the modified Brauns method isbetter in the conditions that the soil has a smaller undrained shear strength;④Changing the plane of rupture into logarithmic spiral surface and derives therelative theoretical calculation formula.