Comparative analysis of analytical and numerical calculation methods for soil improvement by rigid inclusions

Abstract

In recent decades a soil improvement technique of foundation soft soils by inserting or constructing rigid inclusions has been developed. Its main application is in compressible soils under large fills or foundations of structures, optimizing the construction time and decreasing settlements considerably. Along with the development of the method, various codes and standards in different countries in Europe have been published as guidelines for analysis of rigid inclusions and different elements that make up the technique such as load transfer platform, etc. Considering the increased use of finite element modelling in different geotechnical problems, in this paper a comparison of analytical and numerical calculation methods of rigid inclusions is presented. Load transfer platform is analyzed for its different thicknesses and various separations between inclusions that defines the ranges in which analytical methods approach numerical modelling. The interaction between the soft soil and rigid inclusion for estimating ground settlements is also studied. Considering different soil stiffness, the comparison of settlements obtained by analytical and numerical methods has been done. Furthermore an analysis of the variation of the neutral point depth with the change of soft soil stiffness is performed by finite elements. This depth is decisive in the calculation of the total length of the rigid inclusion.