Research into the application of undrained analysis with critical state soil mechanics approach for the design of a quay wall

Abstract

The design and construction of quay walls are processes that exist for many centuries and have become more complex and challenging in current engineering practice. For the design of quay walls a number of guidelines and design codes have been developed over the years. These give the requirements that a quay wall structure should meet, but do also provide some guidance in which steps to take in order to arrive at a proper final design. The relevance of undrained soil behavior, described using critical state soil mechanics, for the analysis of quay wall stability is yet unknown. The main objective of this research is to investigate the possibilities to use the alternative design approach for modelling soil behavior in the design processes of a quay wall. For this, three case studies have been elaborated. The three case studies represents soil profiles consisting 1) predominantly sandy soils, 2) normally consolidated clay and 3) overconsolidated clay. The differences between the analyses and outcomes of the conventional approach and the new approach have been compared for each case study. Based on the quantitative results of case study 1 and 3, the difference in outcome between the conventional and alternative design approaches is between 0 and 10% for both displacements and sectional forces. The outcome of case study 2 is not in line with the results of case 1 and 3. Based on the results of the first case study with sandy soil profile, the alternative design approach applied in this report is not a valid option for the design of a quay wall due to the absence of undrained soil conditions.
For a soil profile consisting clay, the magnitude of preconsolidation of the soil plays an important role. For the alternative design approach, increasing values of pre-loading results in decreasing values of sectional forces and displacements of the wall. This effect is stronger in comparison to the conventional design approach. In further research the aim should be to increase the reliability of the alternative design approach. This can be done by using in-situ measurements of the displacements of the wall to validate if the model represents the reality accurately.