The quantification of the moistening deformation for wetting-sensitive unsaturated loess is of direct interest in regions implementing geotechnical engineering. Many constitutive models are available for describing the stress–strain behavior of unsaturated soils. However, few constitutive models directly describe moistening deformation. In this study, two types of triaxial tests were carried out on undisturbed loess. A triaxial compression test was conducted to determine the shear strength boundary of a specimen, and a triaxial moistening test with different stress ratios was used to study the moistening deformation law. The volumetric strain caused by moistening was used as the hardening parameter. A humidity variable was defined as the moisture level, and this parameter could reflect the moistening degree. The experimental rule and plastic theory were combined to establish the constitutive model. The model could directly calculate the deformation amount caused by moistening under different stress states. The model is applicable to the loess in the Guanzhong area in the Chinese Loess Plateau.

From 2011 to 2013, a mega project, known as the Gully Land Consolidation Project (GLCP), was implemented in the hilly gully region atop China’s Loess Plateau. However, the GLCP involved large-scale slope excavation and gully backfilling that changed the local geological environment, which led to serious geohazards, such as erosion, soil salinization, and dam failure. In this study, various geohazards caused by the GLCP in the Gutun watershed (GTW) were investigated by combined remote sensing analysis, geophysical exploration, and field surveys, and the relationships between the hazards were also explored. According to the achieved results, increased soil erosion with an average doubling from 2018 to 2020 is widely distributed in the GTW. Furthermore, 195 areas containing clear evidence of salt precipitates were observed in some of the newly created arable lands, especially downstream of the dam. This was mainly attributed to the high water table, evaporation, and soluble salt concentration of the loess. Fifty-nine newly built silt dams, primarily located in the branch channels and at the gully mouth of the Gutun channel, broke in 2020. The osmotic damage and softening caused by the combined effect of the incomplete compaction of the dam body and concentrated heavy rainfall were the main reasons of the dam breaks. The different types of disasters in the GTW after the implementation of the GLCP show a strong spatial relationship that follows the surface water flow path and forms a disaster chain consisting of slope erosion, silt dam breaks, and the soil salinization of near-dam farmlands downstream. This disaster chain amplifies disaster risks and losses. These findings can guide the improvement of the GLCP and inform geohazard mitigation strategies in areas impacted by the GLCP.

The water sensitivity and structural characteristics of collapsible loess are two typical factors that significantly influence its mechanical behaviors. This paper presents a simple and practical elastic-plastic model based on the modified Cam-Clay model to well capture the essential behavior of unsaturated intact loess. The model employs deviator stress and spheric stress as the stress variables, with the water content serving as the moisture variable. The critical state surface of the model can be determined by utilizing the shear strength parameters of unsaturated soil under axisymmetric stress conditions. An initial yield surface equation is established by incorporating structural strength into the elliptical yield surface equation, which is used to determine the starting point for elastic-plastic deformation calculations under different humidity and stress combinations. The model comprises several parameters, each of which has a clear physical interpretation and can be conveniently obtained through conventional triaxial tests. The validity of the model for unsaturated intact loess is confirmed through a comparison with the stress–strain relationship of unsaturated intact loess in the axisymmetric stress state. This work has the potential to significantly enhance our ability to predict and mitigate potential geotechnical disasters, such as foundation deformation under axisymmetric conditions and slope stability problems under non-axisymmetric conditions. Ultimately, the application of this model could contribute to the safety and stability of infrastructure and construction projects in loess regions.

This paper presents the acoustic analysis of a three-dimensional cylindrical shell model under electromagnetic vibration, a critical factor affecting the performance of electric motors in various applications such as automotive, aerospace, and industrial systems. The study provides a multidisciplinary approach that integrates electromagnetics, structural vibration, and acoustics, solved using the fast multipole boundary element method (FMBEM). The results summarize the validation of the analytical models and numerical simulations, offering insights into effective vibration reduction methods. The conclusions indicate that the 3-D numerical analysis using FMBEM aligns well with the analytical solution for the sound pressure in the exterior acoustic domain of the cylindrical shell model. The paper contributes valuable insights for the design of low-noise motors and the control of electromagnetic vibration and noise in electric motors.