Aimed at the ill-conditioned problem of Biot’s consolidation finite element method (BCFEM)

both orthogonal test and dimensional analysis method are used to study the ill-conditioning regularity and its influencing factors. The influencing factors such as the average size of finite element

the length of timestep

the compressibility of soil and the permeability of soil are taken into account. Two groups of independent similarity criteria are proposed

on the basis of which

two novel dimensionless variables are obtained to analyze the variation of the condition number of BCFEM coefficient matrix. Through the parametric study of an illustrative case

the results show that the average size of finite element

the length of timestep

the compressibility of soil and the permeability of soil are in the order of priority of sensitivity. The smaller the averaged size of finite element

the worse the ill-conditioning situation of BCFEM. With the increase of the presented dimensionless variables

the ill-conditioning number shows a tendency to increasing

etc. The conclusions are helpful to study the ill-conditioned problem of BCFEM.