COMSOL Multiphysics Platform Research Articles

Unveiling the water sorption kinetics, thermodynamics, and air dehumidification performance of sustainably synthesized metal–organic frameworks

This study focuses on the feasibility of sustainably synthesized MIL-100(Fe) as an alternative to conventional desiccants, such as silica gel and zeolites, which have low adsorption capacity and poor thermal characteristics for air dehumidification. MIL-100(Fe), a metal–organic framework, shows promise due to its excellent adsorption and customizable thermal properties. However, its synthesis typically involves toxic materials and high temperature/pressure conditions, which restrict its bulk production for large-scale applications. This study aims to explore sustainable synthesis methods for MIL-100(Fe) using non-toxic materials and milder reaction conditions and investigate its material characteristics and dehumidification performance. Experimental analyses are carried out to measure adsorption isotherms, kinetics, sorption heat, activation energy, and cyclic stability, and numerical simulations are conducted in COMSOL Multiphysics platform to estimate dehumidification performance. The test results demonstrate that MIL-100(Fe) has a higher water adsorption capacity compared to silica gel, with a unique stepwise adsorption into its two types of mesoporous cages. Increased temperatures cause the adsorption and desorption isotherms to shift towards higher relative humidity levels. The heat of water adsorption and desorption ranges between 2630–2906 kJ/kg and 2763–2848 kJ/kg, respectively. MIL-100(Fe) demonstrates high stability and no significant loss in water uptake capacity. The simulated performance indicate that MIL–100(Fe) has superior reaction rates and is 82 % more effective than the silica gel rotary wheel dehumidifiers.

Evolution of river–aquifer disconnections and the migration and transformation of iron and manganese under non-time-varying/time-varying riverbed permeability

Changes in the composition, structure, and thickness of riverbed sediments caused by riverbed clogging strongly affect the hydraulic connection, migration and transformation of nutrients between river water and groundwater in groundwater source areas. However, previous studies have not extensively investigated the mechanisms of river–aquifer disconnection and the migration and transformation processes of iron and manganese under non-time-varying and time-varying conditions of riverbed permeability. This study developed a model using the COMSOL Multiphysics platform to characterize the riverbed clogging–groundwater exploitation–disconnection process, considering microbial growth and related biogeochemical processes, and investigated feedbacks between the reactive migration of iron and manganese and physical clogging-groundwater exploitation processes or bioclogging processes. The research findings showed that under non-time-varying conditions of riverbed permeability, the evolution of river–aquifer disconnection was strongly affected by the thickness and permeability coefficient of riverbed sediments. The dissolved oxygen attenuation rate in the disconnection zone decreased by up to 88.8 %. Additionally, the Mn2+ and Fe2+ generation rates in sediment pore water decreased by 65.8 % and 62.7 %, respectively. In contrast, during the riverbed bioclogging process, as the biofilms on the surface of the riverbed sediments developed, the sediment pores gradually clogged, leading to a significant reduction in the porosity and permeability coefficient. Consequently, the hydraulic connection between the river and aquifer transitioned from a saturated connection to a disconnection. However, reduced permeability due to riverbed bioclogging primarily controlled the release of Fe and Mn. When the river–aquifer was in complete disconnection, compared to the saturated connection state, the Mn2+ and Fe2+ generation rates increased by up to 5.8 and 3.8 times, respectively. This study deepens our understanding of the biogeochemical cycling mechanisms of Fe and Mn under riverbed clogging conditions in groundwater source areas and contributes to ensuring a secure and stable water supply in these areas.

Optimizing Microfluidic Channel Design with High-Performance Materials for Safe Neonatal Drug Delivery.

Designing the microfluidic channel for neonatal drug delivery requires proper considerations to enhance the efficiency and safety of drug substances when used in neonates. Thus, this research aims to evaluate high-performance materials and optimize the channel design by modeling and simulation using COMSOL multiphysics in order to deliver an optimum flow rate between 0. 3 and 1 mL/hr. Some of the materials used in the study included PDMS, glass, COC, PMMA, PC, TPE, and hydrogels, and the evaluation criterion involved biocompatibility, mechanical properties, chemical resistance, and ease of fabrication. The simulation was carried out in the COMSOL multiphysics platform and demonstrated the fog fluid behavior in different channel geometries, including laminar flow and turbulence. The study then used systematic changes in design parameters with the aim of establishing the best implementation models that can improve the efficiency and reliability of the drug delivery system. The comparison was based mostly on each material and its appropriateness in microfluidic usage, primarily in neonatal drug delivery. The biocompatibility of the developed materials was verified using the literature analysis and adherence to the ISO 10993 standard, thus providing safety for the use of neonatal devices. Tensile strength was included to check the strength of each material to withstand its operation conditions. Chemical resistance was also tested in order to determine the compatibility of the materials with various drugs, and the possibility of fabrication was also taken into consideration to identify appropriate materials that could be used in the rapid manufacturing of the product. The results we obtained show that PDMS, due to its flexibility and simplicity in simulation coupled with more efficient channel designs which have been extracted from COMSOL, present a feasible solution to neonatal drug delivery. The present comparative study serves as a guide on the choice of materials and design of microfluidic devices to help achieve safer and enhanced drug delivery systems suitable for the delicate reception of fragile neonates.

Solid waste slurry grouting transformation mechanism of loose sand layer based on slurry-water replacement effect

During coal mining, when loose water-bearing sand layers are exposed and connected, it is extremely easy to cause water and sand inrush accidents, threatening the lives and properties in mines. Because of the intricate and tortuous internal structure of the sand layer, the diffusion pattern of grouting slurry within the loose sand layer has not been accurately characterized. Improving the efficiency of grouting and reducing the cost of grouting are common difficulties faced by industrial and mining enterprises in the grouting renovation of loose water-bearing sand layers. This paper innovatively proposes the mechanism of slurry-water displacement effect based on the diffusion characteristics of grouting slurry within the water-bearing sand layer. It studies the power-law fluid seepage and diffusion mechanism of porous media tortuosity effect and slurry-water displacement effect and derives the spherical diffusion equation of power-law fluid seepage grouting considering the coupling of porous media tortuosity effect and slurry-water displacement effect. At the same time, an indoor experimental device considering the slurry-water displacement effect is designed to verify the rationality of the spherical seepage grouting diffusion equation considering the superimposed effects of the two. Furthermore, relying on the COMSOL Multiphysics platform, a three-dimensional numerical calculation model of the power-law fluid spherical seepage grouting mechanism considering the porous media tortuosity effect and slurry-water displacement effect is constructed. It analyzes the seepage and diffusion characteristics of power-law grouting slurry in water-bearing sand layers, and studies the influence of different porosity of loose water-bearing sand layers, spacing between slurry and water holes, grouting pressure, and slurry viscosity on the volume of loose water-bearing sand layers. The key factors affecting the volume of loose water-bearing sand layers are grouting pressure > spacing between slurry and water holes > porosity of sand layer > slurry viscosity. Compared with previous grouting technologies and processes, the slurry-water displacement grouting technology can solve the problems of small grouting diffusion range and poor grouting effect in high-pressure underwater water-bearing sand layers to a certain extent.

Growth mechanism of intermetallic compound in SnAg/Cu interface of micro-bumps under extremely low-temperature by phase field method

Scientific investigation will increasingly focus on deep space exploration. Spacecraft will be subjected to extremely low-temperature, changing internal microstructure and micro-bumps mechanics, reducing reliability. Thus, micro-bumps must be tested in extremely low temperatures. This research examines the impact of low-temperature storage on IMC (Intermetallic Compound) growth and micro-bumps crystallography at −196 °C. Secondly, a diffusion-weak coupled phase field theory is summarized, and the COMSOL multi-physics simulation platform simulates the growth of IMC layer in micro-bumps developing during extremely low-temperature storage. Finally, microhardness and elastic modulus of various phases were studied. Experimental data indicate that holding Sn at −196 °C for 1000 h produces recrystallization, resulting in tiny grains with diverse orientations. Micro-bumps with Sn/IMC interfaces have highest von Mises equivalent stress. Strain gradient thickens IMC layer at low temperatures with storage time, and edge IMC layer is thinner than axis IMC layer. The diffusion-force weak coupling phase field model's driving force curve indicates that stress gradient, not phase separation, drives IMC growth at extremely low temperatures. Low-temperature storage enhances Sn microhardness and elastic modulus through compressive stress and grain refining. IMC microhardness and elasticity decrease with tensile stress.

THz radiation distribution for the identification of infiltrating ductal carcinoma in human breast model: a computational study

With numerous biomedical applications of terahertz (THz) imaging, spectroscopy, and sensing, the THz regime of the spectrum is quickly emerging as an important area of research with the potential to usher in a new era in the healthcare industry. In the medical field, THz radiation has been explored to diagnose and monitor several ailments, including foot diabetes, skin dryness, wounds, and burns. Compared to X-rays, THz waves' phase sensitivity to bodily fluid levels and water results in superior contrast and stronger absorption. This feature makes THz potentially useful for the diagnosis of various malignant tumor forms because cancerous tumors have higher water molecule contents than healthy tissues. The current study presents a computational analysis of a CW-THz point-by-point scanning technique for breast cancer detection. COMSOL multiphysics platform was utilized to create a multilayer three-dimensional breast model containing an irregular-shaped infiltrating ductal carcinoma in the glandular layer. The propagation of the THz radiation in the constructed breast model was simulated based on the radio frequency module and electromagnetic waves in the frequency domain interface. Furthermore, different volumes and locations of the induced tumor were examined. The results demonstrated significant disparities in the acquired electric distribution at different tumor sizes and sites between normal and diseased breasts. The resultant electric field for healthy breast ranged from 1.1 × 10–5 to 0.61 V/m, however, the electric field ranges following tumor addition fluctuate based on its volume and location. Additionally, the position of the THz source and detector array influences the reflected THz signal.

Humidity field for unsaturated subgrade accounting for the hydro-mechanical coupling and the difference of compactness: A simulation method

The safety and stability of road structures heavily rely on the precise assessment of subgrade humidity. However, existing methods often fall short in fully considering the coupling effect between humidity and stress states, as well as variations in compactness across different subgrade areas. In this study, a new model is proposed for simulating water migration in soil subgrade, incorporating hydro-mechanical coupling and the degree of compaction. The model is implemented using a newly added physical field in the COMSOL Multiphysics platform, and a numerical method is developed for calculating subgrade humidity. Moisture migration behavior in subgrades is investigated by selecting two atmospheric environments, namely dry and wet conditions. The results demonstrate that the developed humidity calculation method, accounting for hydro-mechanical coupling and compactness variations, yields reasonable and accurate predictions. Substantial differences in subgrade humidity are observed between wet and dry conditions. Compared to the dry conditions, pronounced fluctuations in subgrade humidity are observed in areas near slopes, with the equilibrium moisture content increasing by approximately 50% compared to the initial content. Additionally, the equilibrium time for moisture migration is significantly shortened under wet conditions. Based on these findings, it is recommended that waterproof should be considered in subgrades exposed to wet atmospheric environments to avoid excessive moisture content in subgrade.

Numerical study of flow after NASA 4412 aerodynamic profile based on the SST turbulence model

This article investigates the application of the SST turbulence model within the Comsol Multiphysics platform to analyze subsonic airflow around a NACA4412 airfoil at an angle of attack of 13.87 degrees. The study employs the finite element method to solve the turbulence equations numerically, with stabilization achieved through the Galerkin least squares technique. Comparisons between the computational results and experimental data are conducted to assess the model's performance. The findings demonstrate favorable agreement between the SST turbulence model predictions and experimental observations, indicating promising convergence. This research contributes to the understanding of turbulence modeling in aerodynamics simulations and underscores the potential of the SST model in accurately capturing flow behavior around complex geometries like the NACA4412 airfoil.

Reactive transport model for bentonites in COMSOL multiphysics: Benchmark and validation exercise

At present, the deep geological repository concept for spent nuclear fuel is considered the most reliable and safe technique for the permanent disposal of this type of waste. One of the many safety elements used is an engineered barrier made of compacted bentonite. This material allows the encapsulated waste to be isolated from the host rock. Therefore, there is great interest in a detailed study of the behavior of bentonites to different changes in the composition of the surrounding groundwater.In this context, this work presents a new reactive transport model for bentonites implemented in the COMSOL Multiphysics platform. The model contemplates a non-simplistic geochemical system composed of 42 species and 4 minerals. Reactive transport involves the diffusive-dispersive-advective processes defined by the Nernst Planck equations for two overlapping modeling levels (macro- and microstructural) to simulate the behavior of double-porosity media. The uniqueness of this model is that the system of equations used to calculate the chemical speciation problem and the advective-diffusive-dispersive transport can be integrally solved in COMSOL. The model has been satisfactorily verified and validated using the benchmark exercise consisting of the simulation of the multicomponent advective-diffusive column experiment conducted on a compacted bentonite core extracted from a field experiment (LOT project) in the Äspö Hardrock laboratory (Sweden).

Simulation of SN transport equation for hexagonal-z reactor using the COMSOL Multiphysics software

Detailed neutron transport simulation has undergone much investigation in advanced reactor engineering, where the adaptability of complex geometrics and the simplicity of computational implementation are of great significance. In this paper, a detailed neutron transport module (DNTM) based on the COMSOL Multiphysics platform is developed for hexagonal-z reactor conditions. The multi-group, multidimensional neutron transport SN equation is discretized using the least-squares finite element method and is embedded in COMSOL using the weak form partial differential equation interface without the necessity for additional coding. The proposed DNTM’s feasibility and accuracy are demonstrated through the analysis of three neutron transport benchmarks, encompassing various energy groups, dimensions, and scales. All the numerical results show good agreement with the reference values, indicating that the proposed DNTM in COMSOL can be used to solve the neutron transport process in the hexagonal-z reactor accurately and reliably. This approach may contribute a simple and practical high-fidelity neutronics solving tool and an effective direction to realize multi-physics tight coupling simulations.

Refractometric Sensing of Protein in Urine by the Photonic Crystal Fiber Biosensor in THz Regime

The presence of albumin in human urine is one of the confirmed early symptoms of kidney dysfunction. A precise urine protein identification process is very important to monitor the kidney’s proper functioning. To identify the presence of albumin in urine, a refractometric protein sensing approach in the photonic crystal fiber (PCF) environment has been introduced here. A PCF geometry with suspended cladding and a circular hollow core has been proposed and investigated in the terahertz (THz) spectrum for protein identification in the liquid samples. Three levels of albumin concentrations in urine (7–125 mg/dl, 250–500 mg/dl, and 1000 mg/dl) are considered to evaluate the sensing performances of the proposed PCF. The numerical investigations are performed on the COMSOL Multiphysics platform where the finite element method (FEM) figures out the numerical outcomes. The performances of the proposed PCF exhibit highly sensitive characteristics for albumin identification in the different albumin concentration levels of urine. The sensitivity shows more than 98.5% for all the tested concentration levels due to the strategic selection of geometrical parameters and proper optimization. Alongside, negligible confinement loss of 10−16 cm−1 is attained at the same operating point of 4.3 THz. Furthermore, dispersion profiles and practical implementation strategies are also investigated and discussed in detail.

Modeling of Bacterial Communication in the Extended Range of Population Dynamics

”Quorum sensing” as a special kind of communication in bacterial populations can be analyzed by means of methods and techniques of mathematical modeling and computer simulation. In the present study, a modification of a deterministic mathematical model of bacterial quorum sensing is proposed, taking into account the law of multiphase population dynamics. The mathematical model is formalized by an initial-boundary value problem for a system of semilinear reaction-diffusion partial differential equations. The equations include generation terms in view of changes in the biomass density. The model describes space-time dynamics of concentrations of special substances (signaling agents and Lactonase enzymes) that characterize the quorum sensing in Gram-negative bacteria. The problem is solved by means of the finite element method using the COMSOL Multiphysics platform. Computational experiments are performed to estimate concentrations of key substances characterizing quorum sensing for Pseudomonas putida bacterial strains in an expanded range of population dynamics.

Simulation and optimization of polysilicon thin film deposition in a 3000 mm tubular LPCVD reactor

The high photoelectric conversion efficiency of tunnel oxide passivating contacts (TOPCon) photovoltaic (PV) cells and their process compatibility are increasingly recognized by the industry, making it of growing importance to develop deposition process technologies for high-capacity polysilicon thin films. Currently, the size of LPCVD reactors for preparing polysilicon thin films in the industry is getting enlarged, which directly leads to the degradation of axial uniformity of polysilicon thin films. In this paper, a coupled multi-physics field model is established to simulate the polysilicon thin-film Low Pressure Chemical Vapor Deposition (LPCVD) process based on COMSOL Multiphysics platform, and the validity of the model is verified by comparing experimental data with simulation results. By investigating the flow field, thermal field, chemical reaction field and surface reaction field, the effects of the process parameters such as chamber temperature and pressure are investigated, as well as characteristics of the polysilicon thin films deposition. The results show that the uniformity of thin films decreases with increasing temperature and pressure, and the deposition rate of thin films increases as temperature and pressure increase. With the help of optimized the process parameters, the deposition rate of polysilicon thin films was increased by 13.0% and the uniformity of thin films was controlled above 96%. The uniformity of the films can be further improved to 96.7% by optimizing the temperature zone parameters and adopting the wafers placement strategy.

Multiphysics simulation of VVER-1200 fuel performance during normal operating conditions

Nuclear fuel performance modeling and simulation are critical tasks for nuclear fuel design optimization and safety analysis under normal and transient conditions. Fuel performance is a complicated phenomenon that involves thermal, mechanical, and irradiation mechanisms and requires special multiphysics modules. In this study, a fuel performance model was developed using the COMSOL Multiphysics platform. The modeling was performed for a 2D axis-symmetric geometry of a UO2 fuel pellet in the E110 clad for VVER-1200 fuel. The modeling considers all relevant phenomena, including heat generation and conduction, gap heat transfer, elastic strain, mechanical contact, thermal expansion, grain growth, densification, fission gas generation and release, fission product swelling, gap/plenum pressure, and cladding thermal and irradiation creep. The model was validated using a code-to-code evaluation of the fuel pellet centerline and surface temperatures in the case of constant power, in addition to validation of fission gas release (FGR) predictions. This prediction proved that the model could perform according to previously published VVER nuclear fuel performance parameters. A sensitivity study was also conducted to assess the effects of uncertainty on some of the model parameters. The model was then used to predict the VVER-1200 fuel performance parameters as a function of burnup, including the temperature profiles, gap width, fission gas release, and plenum pressure. A compilation of related material and thermomechanical models was conducted and included in the modeling to allow the user to investigate different material/performance models. Although the model was developed for normal operating conditions, it can be modified to include off-normal operating conditions.

Design of MEMS capacitive comb accelerometer with perforated proof mass for seismic applications

Micro Electro Mechanical System (MEMS) sensors are characterized by their small size, but their performances exceed that of their macro-scale counterparts. The small size of MEMS devices and their integration with microelectronics proves a major advantage. In this paper, a design of MEMS capacitive comb accelerometer for seismology application using COMSOL Multiphysics platform is presented. A seismometer (also known as a seismograph) is a device that is used to measure and record the behavior of seismic waves. With this data, the location and measure of earthquakes can be detected. This seismic device has a large frequency band, compared to traditional geophones and seismographs. In this paper, a study to measure amplitudes and frequencies of vibrations is presented, and the results are analyzed and compared for perforated mass and solid proof mass. The effect of the size of etch hole for perforation is also studied.The displacement sensitivity and capacitive sensitivity of accelerometer are found to be 1.188 × 10-9m/g and 1.093 × 10-21F, respectively.

Size-Dependent Switching in Thin Ferroelectric Films: Mathematical Aspects and Finite Element Simulation

The paper is devoted to the theoretical analysis and numerical implementation of a mathematical model of a nonlinear reaction–diffusion system on the COMSOL Multiphysics platform. The applied problem of the computer simulation of polarization switching in thin ferroelectric films is considered. The model is based on the Landau–Ginzburg–Devonshire–Khalatnikov thermodynamic approach and formalized as an initial-boundary value problem for a semilinear parabolic partial differential equation. The theoretical foundations of the model were explained. The user interface design application was developed with COMSOL Multiphysics. A series of computational experiments was performed to study the ferroelectric hysteresis and temperature dependences of polarization on the example of a ferroelectric barium titanate film.

Surfactant Assisted In Situ Synthesis of Nanofibrillated Cellulose/Polymethylsilsesquioxane Aerogel for Tuning Its Thermal Performance.

Nanofibrillated cellulose (NFC) and polymethylsilsesquioxane (PMSQ) based aerogel are prepared by the sol-gel method. The objective of this work is to study the impact of surfactant and base catalyst on the thermal and mechanical performance of the corresponding aerogel. The rheological premonitory assists in predicting the bulk properties of the aerogel. The chemical structure of the aerogel is studied by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and solid-state nuclear magnetic resonance (NMR). X-ray microtomographic (XMT) analysis confirms the homogeneous and monolithic structure of the aerogel. The lowest thermal conductivity is achieved as 23.21mW m-1 K-1 with V-0 and HBF rating through UL-94 test. Thermal performance of aerogels is cross-verified through modeling and simulation in COMSOL multiphysics platform. The mechanical properties of aerogel are evaluated by monolithic compression test in axial and radial compression test up to 90% strain, cyclic compression loading-unloading, and reloading test, flexural test, and dynamic mechanical analysis. The time-temperature analysis has shown around 5°C temperature difference in the middle of the room after using the aerogel panel at the exposed surface, which assists in the practical application of the synthesized aerogel panel.

Electrical Resistive Tomography to Analyse the Flow Behaviour in Redox Flow Batteries

Redox flow batteries (RFBs) are re-emerging as a safe, scalable, efficient and versatile means of large-scale energy storage. Growing adoption of renewable energy generation has ushered a new optimism regarding future reduction in fossil fuel dependency; limiting further harm dealt to the climate and wider environment. However, this momentum demands more efficient energy storage solutions to reconcile power demand and the intermittent nature of wind, solar and tidal energy generation [1]. Without proper storage, reliable back-up generation – largely provided by fossil fuels – will continue to be an unavoidable reality [2]. RFBs utilise the electrochemical properties of dissolved metal ions to store and release energy. Independent sizing of electrolyte storage tanks and flexible power delivery contributes to the flexibility of RFBs compared to alternative battery technologies [3].RFB reactions occur at the electrode-electrolyte interface, and thus the mass transport at this interface is a critical factor in determining the overall RFB performance. Most RFBs use porous electrodes, with a popular choice of material being carbon felt (CF) due to its low cost, chemical stability and high conductivity [4], although the hydrophobic nature of some CF can cause poor electrode ‘wettability’- decreasing the contact area between the electrode and the electrolyte. Further, electrolyte depletion and asymmetric flow can lead to the presence of ‘dead spots’ where the interface is inactive. Many studies have been conducted on CF to improve the electrochemical performance, using surface treatments, compression and channel flow to improve active area, wettability, and species transport [5-7]. These each have direct impact on current density, pressure drop, overpotentials, and energy efficiency. While the flow of electrolyte in the RFB porous electrodes can be modelled using computational fluid dynamics (CFD) [8], and experimentally assessed using x-ray tomography [9,10] and some optical visualisation methods [11], there are limited experimental methods which can be used on entire RFB stacks.In this study, we explore the use of electrical resistive tomography (ERT) to probe the flow of electrolyte through RFB electrodes. ERT has the advantage that it can provide a non-intrusive means of investigating the hydrodynamics of the otherwise opaque cell stack. Measurements were performed using an array of electrodes place around the perimeter of an RFB electrode chamber which contained conventional carbon felt electrodes. Sensitivity maps were generated using the COMSOL Multiphysics platform and compared with experimental measurements. The flow distribution was evaluated by using injections of concentrated KCl solutions into the background electrolyte. Overall, ERT demonstrated promise as a technique for characterising real-time flow dynamics in RFB stacks and for future research into porous electrode and flow field modifications.

Column Penetration and Diffusion Mechanism of Bingham Fluid Considering Displacement Effect

The diffusion progress of grout is hindered by groundwater, which means the diffusion distance cannot reach the designed values required in engineering for water plugging or reinforcement. In this study, based on the generalized Darcy’s law and the continuity equation of steady column penetration, a column diffusion mechanism for Bingham fluid, considering the displacement effect of grout on groundwater, is proposed. This diffusion mechanism is then validated by the penetration grouting experiments that have been previously performed. The influences of the grouting pressure, groundwater pressure, water–cement ratio and penetration coefficient of porous media on the diffusion radius are analyzed. Based on the Comsol Multiphysics platform, a three-dimensional numerical simulation program for this mechanism is developed using computer programming technology. Numerical simulations of the penetration and diffusion morphology of Bingham cement grout in porous media are then carried out. The results show that the theoretical calculation values of diffusion radius obtained from this mechanism are closer to the experimental values than those obtained from the column penetration grouting theory of Bingham fluid, without considering the displacement effect. The results of this study can provide theoretical support for practical grouting engineering.

Sustainability of Heavily Loaded Raft Foundations on Granular Soils of Arabian Peninsula with Soft Clay Layer

Sandy soil formations are widespread around the globe, particularly in the Arabian Peninsula. The Sandy formations were created as a result of long-term geological activities including but not limited to alluvial and wind deposition. Since the alluvial deposits contain fine soils, the clay layers are often intercepted in the foundation supporting strata. The geotechnical foundation design based on field and lab investigations usually relies on the average response of the layered strata and can satisfy both shear and settlement criteria. However, the enduring sustainability of the heavily loaded foundations is required to be investigated in detail. In this study FEM based numerical investigations have been carried out on a thin raft foundation resting on granular soil, with a soft clay layer in the influence zone. The COMSOL Multi-physics platform has been used for the analysis. The study cases are planned based on the thickness of the clay layer and building load. The analysis results predict the risk involved in the sustainability of rafts in terms of the settlement. The field engineers and designers are recommended to consider the risk and plan accordingly