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An elastoplastic numerical model for calculating the consolidation settlement of wide embankment on soft ground is established using PLAXIS finite element software to investigate the settlement behaviour of soft ground under the wide embankment. The distribution rules are analysed and compared to narrow embankments, such as surface settlements of ground and embankment, lateral displacement of soft ground at the foot of embankment slope and excess pore pressure in soft ground. The influence rule of elastic modulus of soft ground on the settlement of soft ground under wide embankment is discussed. The results show that the settlement distributions of wide and narrow embankments on soft ground are “W” and “V” shapes, respectively. The maximum settlement of wide embankment is near the foot of the embankment slope, which is unequal to the settlement at the centreline of the embankment. The lateral displacement distribution rules of soft ground are both “belly” shaped at the foot of two types of embankments slope. However, the lateral displacement of the wide embankment is larger in each corresponding stage. During the construction period, the excess pore pressure in the soft ground under the wide embankment is much higher than that of the narrow embankment, so the post-construction consolidation time of the wide embankment is longer. Moreover, the macroscopic settlement rule of the wide embankment is still the same with the increase of elastic modulus of soft ground.

Particle breakage and the corresponding change of morphology are two key factors governing the mechanical behavior of calcareous sands in offshore geotechnical engineering constructions. To reveal the characteristics of these two factors, oedometer tests on calcareous sands have been performed in this study. The materials were sampled from the South China Sea with a homogenous composition but different particle size ranges and relative densities. In these tests, the dynamic imaging analysis (DIA) by Microtrac PartAn3D and acoustic emission (AE) techniques were employed to investigate the evolution of particle morphology and characteristics of AE signaling associated with the material deformations, respectively. The compressive deformation of calcareous sands was mainly induced by the particle rearrangement and particle breakage which are effectively irreversible plastic deformations. The irregular particle shape has led to strong interparticle filling and interlocking effects, which affected the particle slippage and rearrangement significantly during the deformation. The intensity and type of AE-triggering micro-mechanical behaviors were characterized by AE ringdown counts (RDC) and peak frequency, respectively. The RDC values concentrated primarily in the compression stage and increased rapidly under the normal stress of 400–3200 kPa. The RDC values increased with the increase of particle size but decreased with the increase of initial relative density. The compressive deformation and breakage characteristics of calcareous sands are consistent with the existing acoustic emission laws. National Natural Science Foundation of China (grant Nos. 41877260 and 41877267), UK Engineering and Physical Sciences Research Council (EPSRC) New Investigator Award (grant EP/V028723/1), and the open funding of the State Key Laboratory of Geomechanics and Geotechnical Engineering (No. Z019004).

The paper examines the stress–strain behaviour of densely compacted sand tested at pressures up to 80 MPa in one-dimensional compression and 7.2 MPa confining pressure in triaxial tests. Tests were performed at temperatures up to 100 °C. The testing relates to a proposal by Atomic Energy of Canada Limited to fill containers of waste nuclear fuel with a crushed quartz sand to provide additional stiffness. No significant effects of temperature were encountered in either isotropic compression or triaxial shear.Key words: sand, compression, shear strength, temperature, pressure.