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Rainfall-induced unsaturated wetting deformation has been one of the main sources of postconstruction deformations of rockfill structures. An experimental study is presented of the unsaturated wetting deformation characteristics of a weakly weathered granite rockfill under different triaxial stress conditions and rainfall intensities investigated by a modified triaxial apparatus equipped with the newly developed rainfall simulator. Results show that the wetting deformation of rockfill materials occurs at a relatively small water content; when the rockfill reaches a critical wetting point (i.e., the effective water content), additional water does not produce more deformations. It is shown that the tested rockfill material has an effective water content of Key words: rockfill material, unsaturated, wetting deformation, rainfall infiltration La deformation par mouillage non sature induite par les pluies a ete l'une des principales sources de deformations postconstruction des structures en enrochement. Une etude experimentale est presentee sur les caracteristiques de deformation par mouillage non sature d'un enrochement granitique faiblement altere sous differentes conditions de contraintes triaxiales et d'intensites de pluie, etudiees par un appareil triaxial modifie equipe d'un simulateur de pluie nouvellement developpe. Les resultats montrent que la deformation par mouillage des materiaux d'enrochement se produit a une teneur en eau relativement faible ; lorsque l'enrochement atteint un point de mouillage critique (c'est-a- dire la teneur en eau effective), l'ajout d'eau ne produit pas davantage de deformations. Il est demontre que le materiau d'enrochement teste a une teneur en eau effective de Mots-cles : materiau d'enrochement, non sature, deformation par mouillage, infiltration des precipitations, 1. Introduction Rockfill, usually obtained by exploiting natural rocks, has beenseidely used as the main building material in earth-rockfill dams, airport and railway foundations, and other common projects in geotechnical [...]

In this study, a spherical CrCoFeNiMn high-entropy alloy (HEA) powder with uniform size was prepared using gas atomization. High-quality CrCoFeNiMn HEA coatings were then applied to a 316L stainless steel substrate using prepowdered laser cladding. The main focus of the study is on the phase structure composition and stability, microstructure evolution mechanism, mechanical properties, and wear resistance of CrCoFeNiMn HEA coatings. The results show that the CrCoFeNiMn HEA coatings prepared using gas atomization and laser melting techniques have a single FCC phase structure with a stable phase composition. The coatings had significantly higher diffraction peak intensities than the prepared HEA powders. The coating showed an evolution of columnar and equiaxed crystals, as well as twinned dislocation structures. Simultaneously, the microstructure transitions from large-angle grain boundaries to small-angle grain boundaries, resulting in a significant refinement of the grain structure. The CrCoFeNiMn HEA coating exhibits excellent mechanical properties. The microhardness of the coating increased by 66.06% when compared to the substrate, the maximum wear depth was reduced by 65.59%, and the average coefficient of friction decreased by 9.71%. These improvements are mainly attributed to the synergistic effects of grain boundary strengthening, fine grain strengthening, and twinning and dislocation strengthening within the coating. [ABSTRACT FROM AUTHOR]

The transient dynamics analysis of the new driving drum is carried out by using ANSYS,its maximum equivalent stress cloud pictures and maximum principal stress time history in different work conditions are obtained. The rain-flow counting,the load extrapolation and superposition of the maximum equivalent stress time history of the dangerous area of the driving drum are carried out by using Rainflow module in n Code Glyph Works. Based on the relative theory of fatigue life prediction,stress life module is used to analyze the fatigue life and fatigue sensitivity of the driving drum. The damage histogram of the driving drum and the minimum fatigue life curves of the driving drum under the different inputted parameters are obtained. The results show that the driving drum has a good mechanical property,the minimum fatigue life of the driving drum is about 783 days to meet use requirements. The overload and residual stress have obvious influence on the fatigue life of the driving drum.

The finite element analysis software ANSYS is applied to conduct the finite element analysis of the driving drum,and the stress and deformation conditions are obtained. According to the result,the structure redesign and lightweight research of the driving drum are carried out,and the lightweight results are verified.Finally,the multi-objective optimization design of the driving drum is carried out by using optimization module of ANSYS Workbench,which provides a theoretical basis for the optimization and improvement of the driving drum structure.

Based on a force analysis, an expression is derived to describe the critical Shields number for incipient motion of uniform cohesionless sediment particles on a riverbank slope in terms of flow parameters, outflow seepage, and physical and mechanical properties of sediments. Parametric studies were conducted to investigate quantitatively the effects of hydraulic gradient of seepage, slope angle, and flow direction on the critical Shields number. The results show that the critical Shields number decreases with an increase in the hydraulic gradient. Where bank collapse is concerned, the most dangerous direction of hydraulic gradient of outflow seepage is at an angle equal to the effective internal angle of friction of the sediment mass with respect to slope surface. At a certain value of hydraulic gradient, the critical Shields number decreases with increasing slope angle. Open flow becomes more erosive when the current direction changes from horizontally parallel with the riverbank line to turning downward. CE Database subject headings: River bank erosion; Sediment; Motion; Seepage; Shear stress.