Determination of Grouped Piles’ Effective Length Based on Numerical Analysis Solution

In recent years, there has been an increasing amount of literature on pile’s effective length. A number of studies have found that the single pile’s effective length could be computed by means of different methods which are unsuitable for grouped piles’ computation. In order to understand how the effective length of piles should be calculated, a series of studies was performed in this paper. On the basis of numerical analysis for grouped piles foundation, the computed results indicate the existence of piles’ effective length. Taking an engineering example as a case, both the finite element analysis and the semi-analytical element analysis are used for analyzing. It is revealed that the influencing factors of grouped piles’ effective length are as follows: the pile-soil modulus ratio, top load distribution area, pile diameter, etc. The grouped piles’ effective length increases gradually with the increasing top load distribution area. Although it is difficult to use an appropriate formula to reflect the influence of various factors on the grouped piles length, different various factors can be considered in the numerical simulation analysis. The influencing factors on the grouped piles’ effective length should be considered synthetically. An example of highway in-situ study makes the grouped piles’ effective length be understood deeply both in theory and practice.