Characterizing large-scale weak interlayer shear zones using conditional random field theory

The shear behavior of large-scale weak intercalation shear zones(WISZs)often governs the stability of foundations,rock slopes,and underground structures.However,due to their wide distribution,undulating morphology,complex fabrics,and varying degrees of contact states,characterizing the shear behavior of natural and complex large-scale WISZs precisely is challenging.This study proposes an analytical method to address this issue,based on geological fieldwork and relevant experimental results.The analytical method utilizes the random field theory and Kriging interpolation technique to simplify the spatial uncertainties of the structural and fabric features for WISZs into the spatial correlation and variability of their mechanical parameters.The Kriging conditional random field of the friction angle of WISZs is embedded in the discrete element software 3DEC,enabling activation analysis of WISZ C2 in the underground caverns of the Baihetan hydropower station.The results indicate that the activation scope of WISZ C2 induced by the excavation of underground caverns is approximately 0.5e1 times the main powerhouse span,showing local activation.Furthermore,the overall safety factor of WISZ C2 follows a normal distribution with an average value of 3.697.

Interlayer shear of nanomaterials:Graphene–graphene,boron nitride–boron nitride and graphene–boron nitride

In this paper, the interlayer sliding between graphene and boron nitride （h-BN） is studied by molecular dynamics simulations. The interlayer shear force between h-BN/h-BN is found to be six times higher than that of graphene/graphene, while the interlayer shear between graphene/h-BN is approximate to that of graphene/graphene. The graphene/h- BN heterostructure shows several anomalous interlayer shear characteristics compared to its bilayer counterparts. For graphene/graphene and h-BN/h-BN, interlayer shears only exit along the sliding direction while interlayer shear for graphene/h-BN is observed along both the translocation and perpendicular directions. Our results provide significant insight into the interlayer shear characteristics of 2D nanomaterials.

Interlayer friction behavior of molybdenum ditelluride with different structures

The interlayer friction behavior of two-dimensional transition metal dichalcogenides(TMDCs)as crucial solid lubricants has attracted extensive attention in the field of tribology.In this study,the interlayer friction is measured by laterally pushing the MoTe_(2)powder on the MoTe_(2)substrate with the atomic force microscope(AFM)tip,and density functional theory(DFT)simulations are used to rationalize the experimental results.The experimental results indicate that the friction coefficient of the 1T'-MoTe_(2)/1T'-MoTe_(2)interface is 2.025×10^(−4),which is lower than that of the 2H-MoTe_(2)/2H-MoTe_(2)interface(3.086×10^(−4)),while the friction coefficient of the 1T'-MoTe_(2)/2H-MoTe_(2)interface is the lowest at 6.875×10^(−5).The lower interfacial friction of 1T'-MoTe_(2)/1T'-MoTe_(2)compared to 2H-MoTe_(2)/2H-MoTe_(2)interface can be explained by considering the relative magnitudes of the ideal average shear strengths and maximum shear strengths based on the interlayer potential energy.Additionally,the smallest interlayer friction observed at the 1T'-MoTe_(2)/2H-MoTe_(2)heterojunction is attributed to the weak interlayer electrostatic interaction and reduction in potential energy corrugation caused by the incommensurate contact.This work suggests that MoTe_(2)has comparable interlayer friction properties to MoS_(2)and is expected to reduce interlayer friction in the future by inducing the 2H-1T'phase transition.