Study on constitutive model of marine soft soil based on disturbed state concept

Abstract

Marine soft soils are widely distributed in near-coastal areas and pose significant risks to the stability of structures due to their unique mechanical properties. While researchers worldwide have used various theoretical constitutive models and scientific methods to investigate the mechanical properties of marine soft soils, no attempts have been made to establish a mechanical model based on the concept of disturbed state for marine soft soils. In this paper, based on the concept of disturbed state, we utilize triaxial and creep test methods, apply the Duncan tensor modulus to describe the relatively complete state of marine soft soil, and modify the Cambridge model to characterize the fully adjusted state. Additionally, we derive the disturbance function to establish the intrinsic model for the disturbed state of marine soft soil. The model's accuracy is verified by comparing its predictions with experimental test results. Subsequently, the model is applied to engineering cases and compared with numerical simulation results. The study shows that the results from the disturbed state constitutive model are consistent with the experimental data and can effectively be used to assess the foundation bearing capacity of marine soft soil layers. The development of the constitutive model based on the concept of disturbed state offers a new theoretical framework and calculation method for studying the mechanical properties of marine soft soil in near-coastal regions.

Keywords: Constitutive model; Disturbed state concept; Geotechnical tests; Marine soft soil; Numerical calculation.

Fig. 1

Triaxial compression test and creep test.

Fig. 2

Schematic diagram of loading for creep test.

Fig. 3

Stress-strain relationship curve of triaxial compression test of marine soft soil.

Fig. 4

ε-t curves of marine soft soil under different water content conditions.

Fig. 5

Workflow of the Python implementation.

Fig. 6

Comparative analysis of stress-strain relationship curves of marine soft soil specimens.

Fig. 7

Numerical calculation model.

Fig. 8

Cloud diagram of stress-strain and equivalent plastic strain induced by concrete structure of municipal building with temporary pile load in marine soft ground layer.