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Introduction: In this work, we aim to explore numerically the behavior of beam energetic particles in the Divertor Tokamak Test (DTT), a superconductive device equipped with a Neutral Beam Injection (NBI) system capable of injecting neutrals up to 510 keV. Method: We explore beam ionization and beam slowing down for different DTT plasma scenarios. Numerical simulations are performed using the ASCOT suite of codes, including a wide-range scan of plasma density and beam injection energy. For different plasma conditions, we estimate shine-through losses, including the heat fluxes on the first wall thanks to dedicated particle tracing simulations. Orbits of newly-born fast ions are characterized by means of the constant of motion phase space, showing how trapped energetic particles' population and prompt losses change with plasma density and NBI energy. Results and discussion: Slowing down simulations show that NBI injection at 510 keV is well coupled to DTT plasmas. DTT NBI will be one of the sources of auxiliary ion heating, with an absorbed power ratio of up to ∼50% depending on plasma and beam parameters. At low plasma densities, energetic particle confinement is less efficient, and NBI power and/or energy reduction is expected. [ABSTRACT FROM AUTHOR]

Collecting detailed hydrogeological data before, during, and after remediation campaigns is essential for effective management and monitoring of contaminated sites. As in-situ remediation injection treatment becomes more popular, recording the hydraulic response during these events offers an opportunity to collect detailed data on hydrogeological parameters. Often, multiple injections are performed in a grid pattern over an area targeted for treatment, essentially serving as spatially distributed and high-frequency inverse pumping tests. This information, which is often overlooked, can be assimilated into numerical models for enhanced site characterization and improved forecasts of management actions. However, the high pressures during injections often result in hydraulic fracturing. These events can represent temporary or permanent changes in aquifer properties and should be considered when assimilating injection response data into a model to reduce the risk of introducing parameter bias. Four groundwater models were developed for a contaminated site in Sweden, treated with in-situ injections in 2017. The models were designed to evaluate strategies for assimilating injection response data, including alternative weighting schemes and the use of time-varying parameters around injection points to account for hydraulic fracturing during injections. Results show that assigning a higher weight to observations recorded during injections, compared to records of ambient head, combined with the use of time-varying parameters, yielded the best results with the lowest risk of underestimating predictive uncertainty. A subsequent data worth analysis revealed that injection response data provided detailed insights into aquifer properties in the injection zone that were not available from ambient head data alone. [ABSTRACT FROM AUTHOR]

Inflatable steel-tube rock bolts are useful as they can introduce a pull-out resistance immediately after installation and do not cause a loss of frictional force under the existing groundwater environment. The anchoring mechanism and pull-out resistance of the inflatable steel tube has been basically explained through theoretical studies. The contact behaviour between the tube and borehole rock is essentially geometrically non-linear and elasto-plastic, which cannot be properly considered in theoretical approaches. In this study, the contact behaviour of inflatable steel-tube rock bolts was investigated through a novel modelling based on the contact theory. A validating representative model test for an inflatable steel-tube rock bolts was performed and successfully reproduced through the contact modelling method. It was revealed that the contact behaviour differs significantly differ from theoretical assumptions. Parametric analyses were carried out to investigate the effect of influencing factors such as the diameter ratio, the elastic modulus and maximum installation pressure, which cannot be considered in the theoretical model. It was found that the state of full inflation is the stress turning point where the general tube behaviour changes from mainly plastic to elastic. The maximum contact stress was obtained immediately before full inflation. [ABSTRACT FROM AUTHOR]

Earthquake-induced liquefaction is likely to cause uplift displacements of underground structures and excessive settlements of surface structures. While these two phenomena have been investigated separately in the literature, the case of a shallow tunnel buried adjacent to a surface structure in liquefiable ground has not yet been thoroughly studied. In this paper, the OpenSees platform is employed to numerically model two centrifuge tests on the structure–soil–structure interaction in saturated Hostun sand. The PM4Sand constitutive model is calibrated to capture the non-linear behaviour of the liquefiable ground. Overall, the numerical simulations are in good agreement with the centrifuge test data. The excess pore pressure build-up, the acceleration response of the Hostun sand ground, the uplift of the tunnel and the settlement of the surface structure are simulated with adequate accuracy. Then, the validated numerical models are used to investigate further the structure–soil–structure interaction in liquefiable ground, with a special emphasis placed on the variation of the relative density of the sand, and a parametric analysis is conducted on the responses of the tunnel and the surface structure. [ABSTRACT FROM AUTHOR]

This paper presents a surrogate-based Bayesian approach for updating the ground parameters within an application of the observational method in sequential excavation method (SEM) construction. A three-dimensional (3D) finite-difference model is used in the forward analysis to simulate SEM construction explicitly considering 3D multi-face excavation effects and ground–structure interaction. The polynomial-chaos Kriging (PCK) method was employed to provide a surrogate for the 3D finite-difference model to alleviate the cost of probabilistic analysis. The uncertain geotechnical parameters are updated during SEM construction through a progressive Bayesian updating procedure. Time-series observations of multiple types of measurements are used to form the likelihood function. The posterior distributions of the uncertain parameters are derived from the affine invariant ensemble sampling (AIES) algorithm. The proposed framework is illustrated through application to data from the Regional Connector Transit Corridor (RCTC) crossover cavern project constructed in downtown Los Angeles. The uncertainties of the geotechnical parameters were substantially reduced. The posterior estimations indicate higher elastic modulus and cohesion of the Fernando formation than what was assumed before the construction. The updated predictions of the ground surface, subsurface and structural deformations showed improvement in agreement with the field measurements through the continuous updating process. [ABSTRACT FROM AUTHOR]

The milled shape of point blades is one of the main factors causing structural problems with railway points (also known as turnouts or switches). Choosing the right type of milling for point blades can improve train running performance. Based on wheel–rail system dynamics, a vehicle–points dynamic model with various milling methods was established, from which a selection and evaluation method for milling was proposed. The service performance of four milling types was compared and combined with point blade robustness to provide a comprehensive evaluation. It was found that a small rate of railhead width change for an oblique tangent point blade resulted in better running performance of trains. The oblique secant point blade caused an abrupt change in the rail layout, which reduced train running steadiness. The railhead widths of longitudinal secant and longitudinal secant–oblique tangent point blades increased quickly, and the corresponding dynamic responses were at an intermediate level. The proposed selection and evaluation method for milling types took into account the dynamic characteristics and structural durability of the points. It will be beneficial in selecting an appropriate milling type for points blades according to their service requirements. [ABSTRACT FROM AUTHOR]

Integral bridges are preferred on infrastructure schemes as they have lower maintenance costs than a conventional jointed bridge. A key aspect of integral bridge design is the assessment of long-term passive resistance that develops in the abutment backfill due to seasonal movements of the superstructure. This resistance is currently defined by an intermediate earth pressure coefficient termed K*, and is typically evaluated using the limit equilibrium (LE) approach prescribed in BSI PD-6694-1:2011+A1:2020. This paper adopts the alternative numerical design approach and investigates the development of K* behind full-height abutments using soil–structure interaction (SSI) modelling in Plaxis-2D software. The study demonstrates that mobilised passive resistance is primarily a function of backfill and structural stiffnesses, and that the current LE approach does not capture the backfill resistance profile correctly. The effectiveness of the SSI method was verified by comparison to the LE method. The current study provides an SSI methodology that is an efficient design approach, and which is suitable for a wide variety of integral bridge arrangements beyond the current LE method applicability. [ABSTRACT FROM AUTHOR]

Two-dimensional discrete-element modelling was adopted to study the engineering and fundamental aspects of shear band formation in reverse faulting through sandy soils of varying densities. The employed discrete-element methodology was verified with experimental centrifuge results. From an engineering perspective, the results showed that the shear bands formed due to a reverse fault consisted of multiple ruptures formed at the different fault throws. These ruptures may deviate towards the hanging or footing wall depending on the faulting angle. The distortion zone outcropping location was captured by the W/H ratio at the 1% normalised fault throw (h/H) step. Various micro and macro aspects of shear banding, such as porosity, coordination number and strong contact forces within the localised areas along the shear bands, were studied. Moreover, a link was established between the micro and macro events occurring inside the shear bands. The results showed that the wedge pressure formed between the shear band and back-thrust rupture in a fault with a dip angle smaller than 45° significantly affected the back-thrust formation and micro–macro parameters in the shearing region. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the influence of particle breakage on the dynamics and deposition of rockslides. A rigid-body finite element formulation incorporating bond beam element is proposed to model rock breakage behaviors. This approach enables simulations of particle fragment rolling, collisions between adjacent pieces, and impacts of pieces with the bedrock. Numerical analyses were conducted considering the variations in volumes, breakage modes, breakage efficiency, and the friction coefficient of bedrock surfaces. Simulation results demonstrate a negative linear correlation between the runout distance and the volume of rock blocks. Incorporating fragmentation effects, this study reveals that the breakage efficiency of maternal rock blocks significantly influences the energy dissipation process and the downslope movement of rockslides. Despite variations in breakage modes leading to distinct deposit configurations, run-out distances remain basically consistent. Analysis of block contributions from various source locations indicates that the longitudinal spreading of the deposit primarily depends on blocks distributed on the periphery of the rock mass. [ABSTRACT FROM AUTHOR]

Hydrological simulations and predictions are vital aspects of hydrological change research. Accurate predictions of hydrological factors such as stage and discharge are essential for water resources planning, reservoir dispatching and operation, shipping management and flood control. River discharge forecasting during flood seasons is an important issue in water resources planning and management. To improve the calibration accuracy and stability of the stage–discharge relationship model, the feasibility of integrated algorithms for studying the stage–discharge relationship was explored. A random forest (RF) algorithm based on a neural network (NN) was developed using a framework of integrated algorithms. First, the Levenberg–Marquardt (LM) algorithm was used to optimise the weight updating process of a back-propagation (BP) NN and improve the convergence speed. Then, the LM-BP algorithm was used as a decision tree to build an RF algorithm. The model was tested using hydrological data from Hongqi station on the Dadu River in China in the flood season. Results for the classical model, BP NN model, LM-BP NN model and optimised algorithm model were evaluated based on the mean absolute error (MAE), mean square error (MSE) and mean absolute percentage error (MAPE). The performance indicators showed that the optimised algorithm model (MAE = 3.13 m3/s, MSE = 19.28 m3/s and MAPE = 1.8%) was superior to the other models and showed high accuracy and good stability in flood-season flow forecasting. [ABSTRACT FROM AUTHOR]

By decreasing the entrained air flow discharge and improving the hydraulic characteristics of vertical shaft spillways, Marguerite-shaped inlets (MSIs) can mitigate the effects of swirling flow surrounding their inlet. The hydraulic and hydrodynamic characteristics of flow around MSIs under orifice flow regime were numerically investigated, applying different geometrical parameters. This inlet configuration can decrease the strength of swirling flow and increase the flow discharge through the shaft. The finite-volume method and the re-normalisation group k–ε turbulence model were employed to solve the governing equations of motion in a cylindrical coordinate system and a two-phase air–water flow on the water free-surface. Increasing the height and length of the blades of the MSIs was found to increase the area of the barriers against swirling flow, weaken the swirling flow strength, engender a more uniform flow and lower the water free-surface level. Extremely long or high blades, however, resulted in an intense collision of the flow with the spillway and increased the water free-surface level and the swirling flow strength at the MSI. [ABSTRACT FROM AUTHOR]

To explain induced polarization, membrane polarization is often referred to as a relevant process taking place in granular media – particularly, when narrow pore throats are present. This polarization effect is based on the membrane-like behaviour of pore throats caused by the presence of an usually negative charge on the pore surface, that influences charge transport in the pore fluid. Existing analytical, 1D models describe the pore system as a series of cylindrical pores with different radii and lengths. The polarization response is calculated by solving the Poisson–Nernst–Planck system for the current densities of one single anion and one single cation species representing the charge transport in the electrolyte and the diffuse layer at the pore surface. To include charge transport in the Stern layer, cations in the Stern layer have so far simply been considered by increasing the concentration of the diffuse layer cations. As we know from numerical modelling, this approach fails to predict the polarization response when the Stern layer is significantly charged. Here, we present a new semi-analytical model that treats the Stern-layer cations as a separate ion species and allows the Stern layer to polarize individually. To validate our new model, we compare it to the previously used analytical model and numerical simulations for different relative charges in Stern- and diffuse layer. We also use electrostatic surface-complexation models for two mineral surfaces (quartz and montmorillonite) to simulate the response of real geologic material under varying chemical conditions. This work is a step forward for considering realistic pore properties in induced-polarization modelling. [ABSTRACT FROM AUTHOR]

The exponential growth of electrical resistivity tomography (ERT) methods for exploring the subsurface at large depths widened the applicability of the self-potential (SP) method, a passive geoelectrical technique suitable for a variety of purposes like mapping ore bodies or inferring fluid flow in the subsurface. Several new-generation resistivity meters have been designed to continuously log the electric potentials thus allowing for the identification of weak amplitude signals and resulting in deeper inversion models. In such approaches, long SP time-series are collected but are totally ignored as only marginal intervals are retained and analysed in the ERT procedure. The discarded SP records could be valuable although not collected using the traditional methodology, based on a reference electrode. We present an SP forward modelling feasibility study of different array techniques, based on numerical finite-element methods. The SP has been modelled in a variety of electrical settings to assess the imaging potentials of non-conventional (i.e. sparse gradient and full sparse gradient) arrays in comparison to traditional (i.e. fixed-base and the leapfrog) arrays. The analytic signal amplitude (ASA) algorithm was employed to compare numerical modelling results obtained from the different type of arrays, highlighting the great potentials of non-conventional arrays for the recognition of several sources of SP anomalies. The ASA maps, presenting a single peak centred over the targets, can significantly help in identifying the source anomalies for all the analysed array techniques. The cost-effectiveness along with the imaging capability of these non-conventional arrays constitute important benefits that could be exploited resulting in a systematic inclusion of SP analysis when collecting deep ERT data using distributed systems. [ABSTRACT FROM AUTHOR]

Electrical resistivity tomography inversion often encounters uncertainty stemming from two primary sources: epistemic uncertainty, arising from imperfect underlying physics and improper initial approximation of model parameters, and aleatory variability in observations due to measurement errors. Despite the widespread application of electrical resistivity tomography in imaging, the resistivity distribution of subsurface structures for various hydro-geophysical and engineering purposes, the assessment of uncertainty is seldom addressed within the inverted resistivity tomograms. To explore the combined impact of epistemic and aleatory uncertainty on resistivity models, we initially perturb the observed data using non-parametric block-wise bootstrap resampling with an optimal choice of the block size, generating different realizations of the field data. Subsequently, a geostatistical method is applied to stochastically generate a set of initial models for each bootstrapped data set from the previous step. Finally, we employ a globally convergent homotopic continuation method on each bootstrapped data set and initial model realization to explore the posterior resistivity models. Uncertainty information about the inversion results is provided through posterior statistical analysis. Our algorithm's simplicity enables easy integration with existing gradient-based inversion methods, requiring only minor modifications. We demonstrate the versatility of our approach through its application to various synthetic and real electrical resistivity tomography experiments. The results reveal that this approach for quantifying uncertainty is straightforward to implement and computationally efficient. [ABSTRACT FROM AUTHOR]

The analysis of the splitting signature of XKS phases is crucial for constraining seismic anisotropy patterns, especially in complex subduction settings such as outward-dipping double subduction. A natural example of this is found in the Central Mediterranean, where the Apennine and the Dinaride slabs subduct in opposite directions, with the Adriatic plate separating them. To assess the capability of XKS-splitting analysis in revealing anisotropic seismic properties, such as fast polarization directions and shear wave anisotropy (in per cent), we use three-dimensional numerical geodynamic models combined with texture evolution simulations. In these models, two identical outward-dipping oceanic plates are separated by a continental plate. Using the full elastic tensors – directly derived from the texture evolution simulations – we compute anisotropic seismic properties and synthetic teleseismic waveforms. From these waveforms synthetic observables are determined, including apparent splitting parameters (fast polarization directions and delay times) and splitting intensities. Based on these observables, we (1) derive models for a single anisotropic layer (one-layer model), (2) identify regions with significant depth-dependent anisotropic seismic properties, and (3) perform inversions at selected locations in terms of two anisotropic layers (two-layer model). We consider two geodynamic models: one with a strong (M1) and one with a weak (M2) continental plate. Model M1 exhibits significant retreat of the subducting plates with no horizontal stretching of the continental plate, whereas Model M2 shows less retreat, substantial horizontal stretching, and detachment of the subducting plates. These different subduction styles result in distinct flow and deformation patterns in the upper mantle, which are reflected in the anisotropic seismic properties. In Model M1, the fast polarization directions below the continental plate are predominantly trench-parallel, whereas in Model M2, they are mostly trench-normal. In most regions of both models, the one-layer models are sufficient to resolve the anisotropic seismic properties, as these properties are nearly constant with depth. However, for both models, we identify some isolated regions – primarily near the tips of the subducting plates and beneath the continental plate – where fast polarization directions exhibit significant variations with depth. Inverting the apparent splitting parameters in these regions yields multiple two-layer models at each location that excellently fit the observables. However, their anisotropic seismic properties can vary significantly, and not all these two-layer models adequately approximate the true depth variations. This ambiguity can be partially reduced by selecting two-layer models in which the summed shear wave anisotropy closely matches that of one of the one-layer models, as these models better capture the true variations. [ABSTRACT FROM AUTHOR]

The existence of pores, cracks and cleavage in rocks results in significant non-linear elastic phenomena. One important non-linear elastic characteristic is the deviation of the stress–strain curve from the linear path predicted by Hooke's law. To provide a more accurate description of the non-linear elastic characteristics of rocks and to characterize the propagation of non-linear elastic waves, we introduce the Preisach–Mayergoyz space model. This model effectively captures the non-linear mesoscopic elasticity of rocks, allowing us to observe the stress–strain and modulus–stress relationships under different stress protocols. Additionally, we analyse the discrete memory characteristics of rocks subjected to cyclic loading. Based on the Preisach–Mayergoyz space model, we develop a new non-linear elastic constitutive relationship in the form of an exponential function. The new constitutive relationship is validated through copropagating acousto-elastic testing, and the experimental result is highly consistent with the data predicted by the theoretical non-linear elastic constitutive relationship. By combining the new non-linear elastic constitutive relationship with the strain–displacement formula and the differential equation of motion, we derive the non-linear elastic wave equation. We numerically solve the non-linear elastic wave equation with the finite difference method and observe two important deformations during the propagation of non-linear elastic waves: amplitude attenuation and dispersion. We also observe wave front discontinuities and uneven energy distribution in the 2D wavefield snapshot, which are different from those of linear elastic waves. We qualitatively explain these special manifestations of non-linear elastic wave propagation. [ABSTRACT FROM AUTHOR]

The 1934 M w 8.2 Bihar–Nepal earthquake was one of the devastating earthquakes, which made seismologists realize the importance of proper seismic hazard analysis and design aspects in India. The event occurred way before proper seismic networks were implemented and hence there are no recorded ground motions available for this event. This study, thus aims to generate possible ground motions for the 1934 M w 8.2 Bihar–Nepal event. The complex geographical features, ambiguous source information and lack of ground motion data make the simulation and validation of ground motions very difficult. In this regard, the broad-band (BB) ground motions are simulated and validated for the most recent well-documented Himalayan event, that is, the 2015 M w 7.9 Nepal earthquake in order to calibrate the model and simulation methodology. For this purpose, the computational model is presented for a region of 1000 km × 670 km (longitude 80–89 °E and latitude 23–30 °N) in the Indo-Gangetic Basin to simulate the low-frequency (LF) ground motions using spectral element method. These deterministically simulated LF ground motions are combined with stochastically simulated high-frequency (HF) ground motions based on an improved seismological model. The seismic moment and dimensions of the rupture plane are used to generate ten samples for the finite fault source model having different slip distribution along the rupture plane as a random field. The BB ground motions (0.01–25 Hz) are obtained by merging LF and HF ground motions in the time domain by matching them at a frequency of ∼0.3 Hz. Such BB results are simulated at a grid of stations and at locations where modified Mercalli intensity (MMI) values are available. The estimated MMI values and the observed MMI values are compared to emphasize the efficacy of the model. The maximum PGA estimated from the simulated ground motions in horizontal and vertical directions are observed to be 0.48 g and 0.4 g. Further, 5 per cent damped response spectra and spectral amplification are analysed concerning the sediment depth of the Indo-Gangetic Basin. The results from the study can serve as inputs for dynamic analysis and the design of earthquake-resistant structures across different locations in the Indo-Gangetic Basin. [ABSTRACT FROM AUTHOR]

We propose a frequency-domain finite-element (FDFE) method to model the 2-D P–SV waves propagating in porous media. This specific finite-element method (FEM) is based on the framework of variational principles, which differs from previously widely used FEMs that rely on the weak formulations of the governing equations. By applying the calculus of variations, we establish the equivalence between solving the stress–strain relations, equations of motion and boundary conditions that govern the propagation of P–SV waves, and determining the extremum or stationarity of a properly defined functional. The structured rectangular element is utilized to partition the entire computational region. We validate the FDFE method by conducting a comparison with an analytically-based method for models of a horizontal planar contact of two poroelastic half-spaces, and a poroelastic half-space with a free surface. The excellent agreements between the analytically-based solutions and the FDFE solutions indicate the effectiveness of the FDFE method in modelling the poroelastic waves. Modelling results manifest that both propagative and diffusive natures of the Biot slow P wave can be effectively modelled. The proposed FDFE method simulates wavefields in the frequency domain, allowing for easy incorporation of frequency-dependent parameters and enabling parallel computational capabilities at each frequency point (sample). We further employ the developed FDFE method to model two simplified poroelastic reservoirs, one with gas-saturated sandstone and the other with oil-saturated sandstone. The results suggest that changing the fluid phase of the sandstone reservoir from gas to oil can substantially impact the recorded solid and relative fluid–solid displacements. The modelling suggests that the proposed FDFE algorithm is a useful tool for studying the propagation of poroelastic waves. [ABSTRACT FROM AUTHOR]

Reducing the gap between geophysical inversion and geological interpretation can be achieved by integrating geological modelling into geophysical inversion. For this, we use a generalized, iterative level-set gravity inversion scheme in which geological units are deformed automatically. During the inversion process, a regularization term is defined using automated geological modelling to account for geological data and principles. This provides model-dependent geological constraints and encourages geological realism throughout inversion. To alleviate the dependence on the starting model and consider the possibility of features unseen by direct observations, an automated geophysical data-driven method is proposed to insert new rock units in the model. Uncertainty quantification is achieved through the null-space shuttle algorithm, which is used to generate a series of alternative models that are consistent with geophysical data. This methodology is applied to assess the uncertainties of a pre-existing 3-D crustal-scale geological model of the Western Pyrenean orogeny (France, Spain). The area is characterized by a positive gravity anomaly generally attributed to the presence of a shallow mantle body. The impact of variations in shape and density of key crustal and mantle features is investigated. Different scenarios are explored in 3-D space to produce a range of viable, relatively simple crustal-scale models of the area. This application demonstrates the capability and potential of this approach to evaluate alternative interpretations of geophysical data. The results show the plausibility of scenarios with a shorter subducted Iberian lower crust and a denser Axial Zone than in the pre-existing model. [ABSTRACT FROM AUTHOR]

Lattice structures are very interesting since they present good mechanical properties coupled with lightness. Today, the maturity reached by additive manufacturing technologies allows the production of such structures. However, the mechanical properties of the constituting material can be affected by the process itself, because of the particular geometry. In fact, in a previous work, the mechanical characteristics of the bulk‐printed material were used for modelling the bending behavior of lattice‐cored specimens made of Ti6Al4V and produced through electron beam melting (EBM) process, but a certain discrepancy with experimental results was found. Therefore, in this work, a procedure was proposed to determine the mechanical properties of the material the lattice specimen is made of, in order to reduce the gap between the numerical and the experimental results. By considering the redetermined yield strength, such mismatch was reduced. Moreover, the metallographic analysis of the material found that the α laths of the α + β microstructure, typical of the studied alloy, were thinner than those of bulk specimens, and the presence of α′ martensite was discovered too. The fracture surface analysis determined a ductile failure mode for the lattice core while a fragile mode for the skins. Highlights: A procedure to calculate the effective material properties was proposed.The numerical model for bending behavior resulted.A different microstructure for lattice material than bulk one was found.Damaging mechanisms were identified through SEM analysis. [ABSTRACT FROM AUTHOR]

Slope instability is a complex geological phenomenon triggered by heavy rainfall, earthquakes, tectonic forces and anthropogenic activities. Unplanned excavation of rock slopes for the development and maintenance of infrastructure such as highways, railways, and buildings in hilly regions plays a significant role in causing slope instability. The present work conducts a comprehensive stability assessment of rock slopes along the national highway (NH-44) section of the Ramban district of Jammu and Kashmir. The kinematic investigation was carried out to determine the different modes of failure of road-cut slopes, and two main modes were found: planar and wedge. Various empirical classifications have been applied for the assessment of slope stability, like geological strength index (GSI), slope mass rating (SMR), Chinese slope mass rating (CSMR), and continuous slope mass rating (CoSMR). Numerical analysis through universal distinct element code (UDEC) has been conducted to evaluate the stability of four critical rock slopes under static and dynamic loading conditions. Modelling results have provided insights into the failure mechanism, and based on these findings, remedial measures have been proposed. Three (L-1, L-3, and L-13) out of four slopes were determined to be unstable under static conditions, with factors of safety (FoS) < 1.2 and under dynamic conditions, two slopes were unstable with FoS < 1.0. However, one (L-8) slope was found to be stable under both static and dynamic conditions, with FoS 1.29 and 1.12, respectively. Installing rock bolts reduced displacement for slopes L-1 and L-13, with reductions of 11.86% and 21.05% under static conditions and 4.09% and 18.75% under dynamic conditions, respectively, while L-3 does not stabilise even after installation of rock bolts. [ABSTRACT FROM AUTHOR]

The asymmetric wave equation encompasses the influence of the actual fine structure inside the medium on the wave field, which can better represent the complex seismic wavefield excited by the complex source and reflect the scale effects of the seismic wave response under equal computational power. However, when the finite-difference (FD) operator is applied to implement the numerical modelling using the asymmetric wave equation, numerical dispersion appears due to the use of difference operator to approximate the differential operator, which negatively affects the analysis of the seismic wavefield. To suppress the numerical dispersion, this paper proposes an improved Dung Beetle optimization (IDBO) algorithm to obtain the optimized FD operators. The IDBO algorithm adopts an improved Tent map and the opposition-based learning strategy to initialize the population, which improves the diversity of the population. The nonlinear function adaptive control strategy is introduced to adjust the population allocation ratio and boundary selection parameter R to achieve an adequate balance between global exploration and local exploitation. In addition, adaptive weights and the Levy flight mechanism are combined to improve the ball-rolling dung beetle position updating strategy to avoid falling into local extremes. Numerical dispersion analysis and numerical modelling results demonstrate that the optimization of FD operators based on the IDBO algorithm can effectively suppress numerical dispersion. It is of great significance to extract the wave field perturbation caused by heterogeneity due to the complex microstructure in the medium and analyse the influence of the microstructural properties in the medium on seismic wave propagation. [ABSTRACT FROM AUTHOR]

The soil arching effect is the key mechanism for load transfer in pile-supported reinforced road (runway) foundations. To investigate the formation and evolution process of soil arching effect in the whole process of embankment filling and soft soil foundation consolidation, a three-dimensional hydro-mechanical coupled numerical model of pre-fabricated high-strength concrete (PHC) pile-reinforced soft soil runway foundation was established based on the foundation treatment project in Pudong Airport. The laws of variation of soil settlement, pore water pressure and pile soil stress were analysed, and the influence of pile spacing was considered. These data from both numerical simulation and field test indicate the soil arching effect in the foundation reinforced by PHC piles and preliminarily reveal the evolution of soil arching in the process of embankment filling and soft soil foundation consolidation. The preliminary results encourage the authors to continue this research to investigate the evolution of soil arching under aircraft dynamic loads through adding a more suitable constitutive model or subroutine in this numerical model. [ABSTRACT FROM AUTHOR]

Intake structures are commonly used in drainage systems to redirect surface rainfall runoff into underground tunnels. The Hong Kong West Drainage Tunnel (HKWDT) system is designed to capture stormwater from steep upland catchments during periods of heavy rainfall, concurrently maintaining a minimal environmental flow downstream during dry weather. However, during heavy rainfall events, excess rainfall water is often directed into the drainage system, presenting a significant challenge to the urban drainage system. Undistorted Froude scale physical models and computational fluid dynamics (CFD) models are developed to investigate the flow performance. In this study, effects of various design parameters on water diversion performance are examined across a wide range of inflow conditions. Steeper channel bottom slopes leading to a larger proportion of water being directed downstream. Extending the length of the bottom rack effectively reduces adhering flow. Introducing a transverse barrier generates a hydraulic jump, which increases flow diversion into the LFC. With higher barrier heights, the hydraulic jump becomes stronger, facilitating greater water diversion into the downstream sewage system. The results indicate potential solutions to these challenges and provide valuable insights into optimizing flow diversion performance in intake structures, particularly in areas characterized by steep terrains and varying flow conditions. [ABSTRACT FROM AUTHOR]

TC11, with a nominal composition of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si, is the preferred material for engine blisk due to its high-performance dual-phase titanium alloy, effectively enhancing engine aerodynamic efficiency and service reliability. However, in laser powder bed fusion (L-PBF) of TC11, challenges such as inadequate defect control, inconsistent part quality, and limited optimization of key processing parameters hinder the process reliability and scalability. In this study, computational fluid dynamics (CFD) was used to simulate the L-PBF process, while design of experiments (DoE) was applied to analyze the effect of process parameters and determine the optimal process settings. Laser power was found to have the greatest impact on porosity. The optimal process parameters are 170 W laser power, 1100 mm·s−1 scanning speed, and 0.1 mm hatch spacing. Stripe, line, and chessboard scanning strategies were implemented using the optimal process parameters. The stripe scanning strategy has ∼33% (∼400 MPa) greater tensile strength over the line scanning strategy and ∼12% (∼170 MPa) over the chessboard scanning strategy. This research provides technical support for obtaining high-performance TC11 blisks. [ABSTRACT FROM AUTHOR]

Coastal regions are often exposed to marine floods, usually generated by storm surge events. Each year, they are responsible for major losses in terms of lives and economic infrastructures. Numerical models are crucial to understand, assess, and forecast these consequences, especially in the absence of direct observations of these hazardous events. The present study evaluates the impact of the two storms of January 7, 2014, and February 28, 2017, on the coast of El Jadida (Morocco), using Iber software on a high-resolution topo-bathymetric digital elevation model with wind, wave and tide as forcing parameters. It also predicts the effect of the same storms under future sea level rise projections for 2050 and 2100 under the RCP2.6 and RCP 8.5 scenarios. The simulations reveal a total flood area (TFA) of 1.1 and 1.3 km2 for the storms of 2014 and 2017, respectively. The maximum run-up was equal to 6.4 m, as a result of the 2017 storm. The impact of storms similar to the 2017 event will be more dangerous for the coast of El Jadida under future sea level rise. For the RCP 2.6 (optimistic scenario), the TFA will reach 1.7 km2 associated with a run-up of 7.6 m in 2100. For the same period, the TFA and run-up under the RCP 8.5 scenario (pessimistic) are equal to 2 km2 and 7.7 m, respectively. The obtained flood hazard maps show that several economic infrastructures, such as commercial parks, hotels and coffee shops are located in areas at risk of coastal inundation. These results underscore the urgent need for targeted adaptation strategies to mitigate future flooding risks along the coast of El Jadida. [ABSTRACT FROM AUTHOR]

The use of geogrid reinforcement has proven to be an effective measure to improve the anchor uplift capacity. However, previous studies are limited to analyzing the axial pullout capacity of plate anchors. In comparison, the anchor foundations employed in field are compelled to resist both uplift and lateral forces. In most cases, the foundation's safety against lateral forces dictates the design criteria for tall structures. Therefore, improving the foundation's lateral load-bearing capacity is of utmost importance. This paper presents a three-dimensional numerical analysis of anchor foundations in geogrid-reinforced sand under uplift and lateral forces. The results highlight the benefits of geogrid reinforcement on the anchor's response to uplift and lateral loads. The geogrid reinforcement is modelled using cable elements capturing the actual apertures responsible for tensile force mobilization along the geogrid ribs. A significant reduction in the displacements of the anchor foundation is observed in geogrid-reinforced sand, both in horizontal and vertical directions, when combined loads are applied on the anchor. However, the maximum reduction is found in the case of vertical uplift forces for higher values of the applied load. The practical implication of this study is demonstrated using a performance-based design example of transmission tower foundations in geogrid-reinforced sand. [ABSTRACT FROM AUTHOR]

Evaporative cooling is an environmentally friendly and low-cost method to deliver cooling load in hot climates. It has been proposed as an alternative to traditional vapour compression systems, mainly due to its lower power consumption and the ability to provide cooling without the need for refrigerants. The present study investigates a novel regenerative indirect evaporative cooling system to address the high cooling demands in hot climates. The proposed unit consists of commercially available aluminium plate cross-flow heat exchangers. Within the study, system performance is simulated in MATLAB software and numerical results are validated with experimental testing results. In the analysis, the effects of exhaust-to-inlet air ratio, inlet air temperature and inlet air relative humidity on the system energetic and exergetic performance were investigated. Individual effects of the inlet parameters on the thermal, mechanical and chemical exergies of the inlet, product and exhaust air streams were also investigated. Maximum wet bulb effectiveness values were achieved as 0.99 and 1.06 for the single and double effect configurations, respectively. In all inlet air conditions, an optimal exhaust-to-inlet air ratio of 0.4 was found to maximize the cooling capacity. Maximum exergy destruction rate was 35W. On the other hand, yearly potential energy savings of 695 kWh was calculated by replacing a vapour compression system with the proposed regenerative evaporative cooler. [ABSTRACT FROM AUTHOR]

This paper presented a procedure for airbag folding for the application in occupant safety studies and analysed the influence of different airbag folding patterns on the occupant severity in frontal impact. Airbags were folded in two patterns: zig-zag and top-roll, using two folding techniques: Initial Metric Method and Explicit Folding. The explicit folding was found to be more expensive in terms of preparation time. However, this approach provided more control over the whole folding process. The Initial Metric Method was more robust, however, it's hard to apply for complex folding patterns. Deployments of airbags were validated against experimental data of pendulum tests. Those airbag models were applied to 2006 Ford F250 pickup truck. This vehicle was used for simulations of frontal vehicle impact where the 50th male Hybrid III crash test dummy was an occupant. Results of this simulation were compared with an actual test with a similar vehicle, under the same impact conditions. Results showed the head and chest accelerations were lower for top-roll folded airbag cases, however neck normal forces were higher compared to zig-zag folded airbag. The internal pressure in the early stage of deployment was 33% higher for the top-roll folded airbags. [ABSTRACT FROM AUTHOR]

This study explores the impact of corrosion on Ground Penetrating Radar (GPR) responses through practical experiments and numerical modelling, focusing on rebar diameter reduction, corrosion product layer thickness, crack formation and corrosion product filling in vertical and transverse crack. Practical experiments involved GPR testing of reinforced concrete slab. By analyzing B-scans we identify areas with moderate and severe corrosion. Numerical modelling using the Finite Difference Time Domain (FDTD) Method to model GPR signal propagation in a concrete bridge deck with corrosion is applied. Key finding includes a significant 26.70% increase in reflected wave amplitude when corrosion product filling in vertical crack increased by 400%, highlighting its extensive effect on signal GPR propagation. Reduced rebar diameter led to a 9.79% amplitude decrease and a 0.06 ns arrival time delay. Increased corrosion product layer thickness primarily affected arrival time with a 0.06 ns extension but significantly amplified GPR signal amplitude. These findings offer insights for improving GPR based corrosion detection and assessment methods, leading to more robust systems for concrete bridge deck inspection and maintenance. This paper contributes to understanding how corrosion affects the signal that is detected by GPR. This information can be used to improve the way that we manage and assess corrosion in concrete bridge deck. [ABSTRACT FROM AUTHOR]

In the electrical resistivity method, electrodes are usually modelled as point current sources and point voltage measurements. If the burial depth of the electrode is significant compared with the spacing between electrodes, this point approximation may not be accurate. Common situations employing long electrodes include the use of metal‐cased boreholes as electrodes and small‐scale, high‐resolution environmental, engineering and archaeological surveys where electrode spacings may be very small. In this contribution, I present analytical expressions for the mutual resistance between long electrodes modelled as line current sources. Mutual resistances are then used to calculate geometrical factors. Additionally, I present an expression for the current density and use it to derive an analytical expression for the sensitivity of electrode arrays with long electrodes. The sensitivity is, in turn, used to calculate the mean depth and position which can be used as estimates of depth and position of investigation and as pseudosection plot points. Example calculations using the geometrical factor, sensitivity and mean depth are shown, and comparisons are made with simulations and lab‐scale experiments. [ABSTRACT FROM AUTHOR]

Incremental sheet forming has emerged as an excellent alternative to other material forming procedures, incrementally deforming flat metal sheets into complex three-dimensional profiles. The main characteristics of this process are its versatility and cost-effectiveness; additionally, it allows for greater formability compared to conventional sheet forming processes. Recently, its application has been extended to polymers and composites. The following review aims to present the current state of the art in the incremental sheet forming of polycarbonate, an outstanding engineering plastic, beginning with initial studies on the feasibility of this process for polymers. Attention is given to the advantages, drawbacks, and main applications of incrementally formed polycarbonate sheets, as well as the influence of process parameters and toolpath strategies on features such as formability, forming forces, deformation and failure mechanisms, geometric accuracy, surface quality, etc. Additionally, new hybrid forming methods for process optimisation are presented. Finally, a discussion is provided on the technical challenges and future research directions for incremental sheet forming of polycarbonate and, more generally, thermoplastics. Thus, this review aims to offer an extensive overview of the incremental forming of polycarbonate sheets, useful to both academic and industrial researchers working on this topic. [ABSTRACT FROM AUTHOR]

ABSTRACT The influence of the India–Asia collision is far‐reaching on the Cenozoic continental deformation in East Asia. Several cratonic lithospheres surrounding Tibet exhibit distinct lithospheric morphologies. However, the mechanisms driving these diverse responses of strong terranes remain incompletely understood. Here, we conduct thermo‐mechanical models to explore the effects of the width of the mobile belts, lithospheric properties and convergence rate on the deformation of the strong terranes. The model results reveal three different deformation modes. Far‐field strong terranes are vulnerable to delamination or underthrusting when the mobile belt is narrow and detached, whereas they remain largely undeformed when it is wide and strong. These deformation patterns align with the observed lithospheric structures around the Tibetan Plateau and are primarily influenced by the convergence rate and proximity to the collision front. Our findings provide new insights into the lithospheric deformation mechanisms of cratonic terranes in response to continental collision. [ABSTRACT FROM AUTHOR]

We present a method to jointly invert surface wave dispersion data and gravity measurements for 3-D shear wave velocity and density models. We implemented a petrophysical approach to combine the kernels of both methodologies in a single process. The synthetic experiments show that jointly inverted models recover shear wave velocity and density better than separate inversions. In particular, density models benefit from the good vertical resolution of surface wave dispersion data, while shear velocity models benefit from the good lateral resolution of gravity data. We also proposed two methods to stabilize the solution when using high-grade polynomials. We applied the methodology to the Los Humeros Geothermal area to demonstrate its applicability in a complex geological scenario. Compared with separate inversion, the joint inversion contributes to enhancing key aspects of the geothermal system by (i) delimitating better the geometry of the caldera deposits in the first 0–2.8 km deep by increasing the vertical resolution in density, (ii) delimitating better the lateral borders of low- Vs bodies at different depths interpreted as a part of a complex magmatic chamber system and (iii) estimating the local shear wave velocity–density relationship that conforms to other known relationships for sedimentary and igneous rocks but with some differences that bring us additional information. [ABSTRACT FROM AUTHOR]

The impact of non-linear soil behaviour on seismic hazard in low-to-moderate seismicity areas is often neglected; however, it may become relevant for long return periods. In this study, we used fully non-linear 1-D simulations to estimate the site-specific non-linear soil response in the low seismicity area, using the city of Lucerne in Switzerland as an example. The constitutive model considers the development of pore pressure excess and requires calibration of complex soil models, including the soil dilatancy parameters. In the absence of laboratory measurements, we mainly used the cone penetration test data to estimate the model variables and perform inversion for the dilatancy parameters. Our findings, using Swiss building code-compatible input ground motions, suggest a high probability of strong non-linear behaviour and the possibility of liquefaction at high ground motion levels in the case study area. While the non-linearity observations from strong-motion recordings are not available in Lucerne, the comparison with empirical data from other sites and other methods shows similarity with our predictions. Moreover, we show that the site response modelled is largely influenced by the strong pore pressure effects produced in thin sandy water-saturated layers. In addition, we demonstrate that the variability of the results due to the input motion and the soil parameters is significant, but within reasonable bounds. [ABSTRACT FROM AUTHOR]