Since acoustic emission(AE)could be produced because of sand particle crushing and/or sliding, more and more researchers have been exploring the potential of applying AE technique to localize such interactions on sand. In this paper, drained triaxial compression tests incorporating with an array of eight AE sensors were conducted on saturated dense coral sand under different constant loading rates, aimed at locating the shear band by AE source location technique. Like the back analysis of earthquake epicenter, the source location and the generation time of the AE event were calculated based on the principle of Time Difference of Arrival (TDOA) and an assumed constant wave velocity of 1500 m/s. Results showed that the AE sources were concentrated into an inclined band in the post-peak region, which was consistent with the appearance of the shear band developed in the specimens.

Based on the analysis of isotropic compression behavior of clay affected by cohesion, the parameter considering cohesion is introduced into logarithmic function to describe the isotropic compressibility of normally consolidated cohesive clay. Combining with the coordinate translation method, the UH model considering cohesion effects is established in translational stress space. The proposed model can describe mechanical behavior of overconsolidated cohesive clay, including isotropic compression, shear yielding and critical state. Meanwhile, it has the same form in translational stress space as the UH model in real stress space and can be easily extended. Comparison with existing test results shows that the model can reasonably describe the basic mechanical behavior of cohesive clays.

In order to investigate the effects of preparation methods of specimens on liquefaction properties of two kinds of sandy soils, a series of cyclic undrained triaxial tests was performed on the sandy soils under the different conditions in grain size distribution and compaction thickness. Test specimens were prepared by the moist-tamping method. Test results showed that liquefaction resistances were influenced by the thickness of the compaction layer, and its tendency was changed depending on the grain size distribution and compaction degree, Dc. In addition, it was found that a difference in initial moisture content has an influence on deformation properties during cyclic loadings.

Stability of landslide dam is of great concern worldwide. Geomaterials of a landslide dam, a natural dam, are usually at unsaturated state, which requires a saturated/unsaturated constitutive model to describe the hydro-mechanical behavior of the landslide dam materials (LDM). Study (Xiong et al. (2018)) has been done on the failure mechanism under seepage loadings both in model tests and numerical simulations, while the element behavior of LDM is still unclear. In this paper, large-scale saturated triaxial compression tests under undrained condition, water retention test and unsaturated triaxial compression test under undrained/unvented condition were conducted on four kinds of LDM. Results of saturated large-scale triaxial tests show the shear stress ratio at critical state with a gap-graded mixture is the largest, which indicates the landslide dam made of this material is the most stable. Water retention curve (WRC) of LDM is obtained in water retention tests. Hysteresis of WRC varies with different grain size distributions. Unsaturated triaxial test results in four different LDM show that the strength of the materials increases with the increase of suction and mean net stress, and the same tendency in the change of the volumetric strain can be observed.

In order to better simulated the anisotropy of granular materials, the anisotropic state variable was introduced into the micropolar hypoplastic constitutive model, and the simulation of biaxial compression tests were carried out. The influences of fabric on the width and inclination of the shear band were studied by the FEM and DEM. The following results were found. With the increase of anisotropic state variables, at the same vertical strain, the width and inclination of the shear band remained basically unchanged and the element rotation angle at the same position was increased.