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Based on the analysis of hydrodynamics and sediment transport in the Pearl River Estuary, key techniques for modelling depositional and erosional patterns with physical model are detected. According to the exploration of distinct sediment characteristics and regional setting in Modaomen Estuary, Huangmao Sea and Lingding Bay, different modelling techniques were presented, which aids in the improvement of model results. Since the complex sediment transport process with fluvial and marine hydrodynamics in estuarine regions, key technologies in sediment experiments, including the synchronous simulation of tidal current and wave, automatic control of sediment adding system, were introduced. Additionally, by characterizing the sediment transport and key technical issues in the region, simulations and verifications of currents, waves, and sediments were carried out. Furthermore, the application of physical model in the simulation of sediment erosion and accretion with the impact of the Hong Kong-Zhuhai-Macao Bridge construction were displayed. The results indicated that the model can satisfy the similarity of flow movement and sediment siltation, which provides an important technical support for project construction.

The mechanical properties of frozen soil are complicated due to their complex components and sensitivity to temperature, water content and pressure. This study conducts triaxial compressive tests to experimentally investigate the mechanical properties of frozen silt under different confining pressures and at temperatures of − 2.0, − 4.0, − 6.0 and − 8.0 °C. Constitutive models, which are used to describe the response behaviors of natural and artificial materials under different loading and environmental conditions, were used as the bases for the description of the mechanical behavior of this frozen silt under external loads. After introducing continuous damage and statistics theories, a statistical damage constitutive model was proposed to reproduce the deformation of frozen silt. The Weibull distribution function was used in the model to describe the propagations of micro-voids and micro-cracks during loading process. The validity of this model was verified by comparing its modeling predictions with the experimental results. It was found that the predictions by this model agree well with the corresponding experimental data.

Triaxial compressive tests of frozen silt were carried out under confining pressures from 0.0 to 14.0 MPa at the temperatures of −2, −4 and −6 °C. A strength criterion based upon experimental results is presented by the combination of extended Lade–Duncan strength function fπ(θ) in π-plane and fp–q(p) in p–q-plane. In order to describe the deformation characteristic of frozen silt, an elastoplastic constitutive model in generalized plastic mechanics has been proposed for the nonlinear behavior of frozen silt, such as the pressure melting and crushing phenomena, strain softening/hardening characteristics and dilatation, etc., by employing an elliptical yield surface, together with a non-associated flow rule for the compressive mechanism, and two parabolic yield surfaces, together with non-associated flow rules for the shear mechanism. The validity of the model is verified by comparing its modeling results with the results of triaxial compressive tests. It is found that the stress–strain curves predicted by this model agree well with the corresponding experimental results both under low and high confining pressures.