Simplified bounding curves based elastoplastic model for lateral and cyclic response of caisson-soil system

This paper proposes a simplified constitutive model employing bounding curves to evaluate the lateral and cyclic characteristics of the caisson-soil system. The Bouc-Wen constitutive law is commonly preferred for analysing lateral and cyclic responses in the caissons. However, ambiguity arises in determining the values of Bouc Wen model parameters as they do not represent physical interpretation, which makes it challenging to decide on the value of model parameters from experimental or field tests. To overcome this limitation, this study provides a simplified constitutive model that offers an enhanced physical interpretation, effortless calibration, site-specific adaptability, versatile formulation, and the capability to capture the nonlinearity and hysteresis characteristics of the response of the caisson-soil system using just four parameters. Validation against literature data demonstrates the accuracy of the proposed constitutive law in capturing the hysteretic nonlinear behaviour of the caisson-soil system under both monotonic and cyclic loading conditions. The proposed constitutive law has potential applications in other foundation and soil-structure interaction problems, in which bespoke calibration of a simplified model can lead to a more efficient design.