Artificial Neural Network Prediction of Airport Pavement Moduli Using Interpolated Surface Deflection Data

Establishing the structural integrity of an airport pavement is crucial to assess its remaining life and implement strategies or priorities for action. In this context, the elastic modulus represents an effective indicator of the condition of the pavement which can be calculated through back-calculation procedures starting from surface deflections, obtained from a non-destructive test (such as the Heavy Weight Deflectometer). Nevertheless, the conventional inverse engineering analysis involves the use of an axial-symmetric pavement finite-element program able to evaluate stiffness values exclusively at the deflection measuring points. This study presents an alternative methodology for spatial modelling of the load- bearing capacity of the runway surface pavement layer from deflection data measured at specific points, using Shallow Artificial Neural Networks. The search of the optimal neural model hyperparameters has been addressed through a Bayesian Optimization procedure and a 5-fold cross-validation has been implemented for a fair performance evaluation, given the limited number of deflection measures available. Once the optimal model has been defined, the measured surface deflection data were linearly interpolated and resampled gridding data were used as a new input matrix of the neural model to predict the expected value of elastic moduli at non-sampled points on the runway. The optimal BO model has returned very satisfactory results with a value of Pearson Coefficient R averaged over 5-fold equal to 0.96597 and of Mean Squared Error averaged over 5-fold equal to 0.01849. In such a way, a contour map of the runway stiffness has been drawn, to provide a support tool for the planning of intervention priorities.

Nonlinear EHD Instability of Two-Superposed Walters’ B Fluids Moving through Porous Media

The current work examines the application of the viscous potential flow to the Kelvin-Helmholtz instability (KHI) of a planar interface between two visco-elastic Walters’ B fluids. The fluids are fully saturated in porous media in the presence of heat and mass transfer across the interface. Additionally, the structure is pervaded via a uniform, normal electrical field in the absence of superficial charges. The nonlinear scheme basically depends on analyzing the linear principal equation of motion, and then applying the appropriate nonlinear boundary-conditions. The current organization creates a nonlinear characteristic equation describing the amplitude performance of the surface waves. The classical Routh–Hrutwitz theory is employed to judge the linear stability criteria. Once more, the implication of the multiple time scale with the aid of Taylor theory yields a Ginzburg–Landau equation, which controls the nonlinear stability criteria. Furthermore, the Poincaré–Lindstedt technique is implemented to achieve an analytic estimated bounded solution for the surface deflection. Many special cases draw upon appropriate data selections. Finally, all theoretical findings are numerically confirmed in such a way that ensures the effectiveness of various physical parameters.

Comparative experimental research on falling ball test method and K30 plate load method on foundation of different structures

In highway and railway foundation projects, the mechanical properties of foundation materials are one of the main indicators of construction process control. The elastic modulus of foundation directly affects road surface deflection and must be tested. The falling ball test method and the K30 plate load method are widely used in engineering, In order to explore the relationship between the two methods and guide the engineering application, the falling ball test method and the K30 plate load method are applied to homogeneous materials (homogeneous fine-grained material layers) and layered materials(Old foundation).Through comparative test, we found that there is a strong correlation between the falling ball test method the K30 plate load method in some scenarios,which can be used for mutual reference in engineering experiments.

The Ekman spiral for piecewise-uniform viscosity

We re-visit Ekman's (1905) classic problem of wind-stress-induced ocean currents to help interpret observed deviations from Ekman's theory, in particular from the predicted surface current deflection of 45∘. While previous studies have shown that such deviations can be explained by a vertical eddy viscosity varying with depth, as opposed to the constant profile taken by Ekman, analytical progress has been impeded by the difficulty in solving Ekman's equation. Herein, we present a solution for piecewise-constant eddy viscosity which enables a comprehensive understanding of how the surface deflection angle depends on the vertical profile of eddy viscosity. For two layers, the dimensionless problem depends only on the depth of the upper layer and the ratio of layer viscosities. A single diagram then allows one to understand the dependence of the deflection angle on these two parameters.

The Ekman spiral for piecewise-uniform diffusivity

We re-visit Ekman's (1905) classic problem of wind-stress induced ocean currents to help interpret observed deviations from Ekman's theory, in particular from the predicted surface current deflection of 45 degrees. While previous studies have shown that such deviations can be explained by a vertical eddy viscosity varying with depth, as opposed to the constant profile taken by Ekman, analytical progress has been impeded by the difficulty in solving Ekman's equation. Herein, we present a solution for piecewise-constant eddy viscosity which enables a comprehensive understanding of how the surface deflection angle depends on the vertical profile of eddy viscosity. For two layers, the dimensionless problem depends only on the depth of the upper layer and the ratio of layer viscosities. A single diagram then allows one to understand the dependence of the deflection angle on these two parameters.