Correlation between mechanical properties and microstructure parameters of soft dredger fill under the coupling action of consolidation and load

The consolidation condition and load condition have obvious influence on the mechanical characteristics of the dredger fill, and the microstructure characteristics of the soil are the essential factors to determine its macroscopic mechanical properties. In order to study the change rule of the mechanical properties of the dredger fill under different consolidation conditions and load conditions and the correlation between the mechanical properties and the microstructure parameters, the creep tests and microstructural tests of the remodeling and filling soft soil in Tianjin Binhai New Area were carried out under different initial consolidation conditions and load effects. The relationship between macro-mechanical parameters and micro-structural parameters is established by using the grey relational degree theory. The test results show that the stability creep plays an active role in increasing the strength of the dredger fill soft soil. The strength of biased consolidation increases faster than that of unbiased consolidation, and the more sufficient the initial consolidation is, the faster the strength growth is. With the increasing creep time, the equivalent diameter, shape ratio and roundness of particles increase, while the number and circumference of particles and voids, the equivalent diameter, shape ratio and roundness of voids decrease. The shear strength index, C and φ, increase with the increasing equivalent diameter, shape ratio and roundness of particles, but decrease with the increasing number and circumference of particles and voids, the equivalent diameter, shape ratio and roundness of voids. Relevance analysis shows that the equivalent diameter and roundness of particles (pore) are important microstructural parameters that affect the evolution of mechanical properties of the dredger fill. The more sufficient consolidation and creep the dredger fill has, the more stable the adjustment of microstructural parameters is and the higher the strength is.