Coupling Numerical Analysis Method for Primary and Secondary Consolidation of Soft Soil Foundation

Abstract

Soft clay is widely distributed in our country, and this type of soil usually has the character of large compressibility and poor permeability, so the foundation composed mainly of soft clay is prone to primary and secondary consolidation coupling settlement deformation after the completion of construction. In this paper, secondary consolidation deformation is redefined in the improved time logarithmic coordinate system, and the calculation formula of secondary consolidation deformation is given. Then an extended unified hardening model is introduced, and by applying this model, the effect of time can be transformed to the increment of equivalent stress. The numerical governing equations are established in combination with the seepage consolidation theory. Thus the coupling analysis of primary and secondary consolidation of soft clay foundation can be realized. By means of a finite element case analysis and verification of subgrade construction and post-construction deformation, it is found that the effective calculation of primary and secondary consolidation deformation can be accomplished smoothly based on the extended unified hardening model, and meanwhile the permeability coefficient and secondary consolidation parameters are able to effectively control the primary consolidation deformation and secondary consolidation deformation of soft clay foundation. The research is valuable to develope the prediction method of soft clay foundation deformation and improve the prediction accuracy of soft clay foundation deformation in engineering, and it is of great significance to solve complex geotechnical engineering problems.