Reliability Analysis Of Bored Pile Foundation Based On The Random Field Of Geotechnical Parameters

It is assumed that the effect on top of every piles are same when vertically axial load is acting on pile foundation in current design methods. Under the assumption each pile enter the limit state at the same time and the reliability of each pile represent the reliability of the pile foundation. So it is enough to study the reliability of single pile and the result is suitable for the whole pile foundation. At present the research achievements about the reliability of the pile foundation are all obtained based on this assumption.In fact, the reaction on each pile bolck is not equivalent. So each pile doesn't enter the limit state simultaneously and therefore it is necessary to study the reliability of the group piles.In this paper total material of the four high-rise structures near the site is selected and one-dimension stable Gaussian random field is treated as numerical model of geotechnical parameters of pile foundation. Correlative function method and variable function method are used to calculate the relevant range of soil layer. The limit capacity of bored pile is determined by the cone penetration tests(CPT) and the static loading tests and related statistics parameters are also evaluated. Considering the effects of group piles, the action effect is calculated by the settlement of pile foundation and the reliability index of single pile as well as group piles is determined by Monte-carlo method. At last, the resultes are compared with those without adoption of random field model and the reliability of pile foundation under vertical load is systematically studied. The conclusion is that the interaction of piles group-soil-pile cap has great effect on the reliability of the pile foundation.