Finite element analysis of skirted foundation adjacent to sand slope under earthquake loading

In this research work, Rock Mass Rating (RMR) was used for the characterisation of rock mass along the tunnel alignment based on physical, geological and geotechnical data of the project area. The deformation modulus was determined using established empirical models for each geotechnical unit of considerations (GTU-4, GTU-5 and GTU-6). The support systems were recommended for all geotechnical units using RMR support chart. Hoek and Brown constants were estimated for numerical modelling using Roclab software. Phase2 software was used for the investigation of redistributed stress conditions and changes in the rock behaviour due to sequential enlargement of the small size rail tunnel. Various design input parameters such as physical and geotechnical properties, in situ stresses, modulus of deformation of rock mass, support systems recommended by RMR were used as input parameters in Phase2 software. The simulated models were analysed for each of the selected geotechnical unit. From the analysis of the...

Numerical modeling for the engineering analysis of rock mass behaviour due to sequential enlargement of Lowari tunnel Chitral Khyber Pakhtunkhwa, Pakistan

A numerical simulation of plate loading test, in order to underlines the size effect on settlements and derived values of geotechnical parameters, is shown. The study is based on the comparison between the results obtained by Finite Element Method (FEM) using the Mohr-Coulomb soil model and by some observations from literature. The obtained numerical results revealed that the subgrade reaction coefficient is strictly dependent on parameters like size of the loaded area and loading magnitude, and thus completely general and generic, and not a fundamental material property of soil that can somehow be determined rationally, as often one claims to be.

Numerical Analyses of Plate Loading Test

One of the key aims of modern football shoe manufacturers is to find the balance between developing a shoe that improves performance but also minimises the risk of injury. Traction properties of the outsole play an important part in reaching this balance; high levels of traction are necessary to enable players to accelerate and change direction without slipping, but excessive traction can lead to stud fixation, a potential cause of injuries. The ability to accurately measure and assess the traction properties is essential in the design of outsoles, but appropriate test parameters need to be used in order for the assessment to relate back to the intended use. The purpose of the study was to develop a method to identify how the shoe interacts with the surface during realistic football movements and then to use observations from data collected to recommend appropriate test parameters.
A high-speed camera system was developed to capture the motion of the shoe in both a laboratory and natural turf environment. The cameras were calibrated using the checkerboard approach and filmed at 1000 Hz. Five markers positioned on the side of the shoe were tracked using a semi-automated algorithm developed using image processing techniques. Transposition matrices were used to identify the location of individual studs on the outsole of the shoe enabling the orientation, velocity and acceleration of the shoe to be calculated. Two data collection studies took place; firstly a single-participant study in the laboratory using a force-plate to relate kinematic results to kinetic information and secondly, a larger scale data collection outside on natural turf. Three movements representing scenarios requiring high levels of traction in football were assessed; acceleration, change in direction and braking. A representative trial for each movement was selected and full post-processing analysis was carried out. Information such as the orientation of the shoe on foot-strike, translation directions and centre of rotations during the transition phase and the number of studs in contact with the surface during push-off was obtained for each movement.
The period at which the player was at greatest risk of slipping was identified for each movement. The motion of the shoe during this period was used to suggest appropriate test conditions for mechanical and computational traction testing methods. The influence of the shoe-surface interaction on outsole design was also considered; with the observed translation directions and centre of rotations being used to suggest a design aiming to enhance translational traction, but minimise rotational resistance.

Understanding shoe-surface interactions in football.

Potentially unstable slopes can be treated by several measurements such as geometry changes, reinforcement, or avoidance of the problem. If avoidance and/or geometry changes are not viable options, the slope may be strengthened. Strengthening of slopes can incorporate many different technologies: drilled shafts, soil nails, tieback anchors, and micropiles as reinforcing elements. Among these technologies, the use of piles have been found effective and economical. The current methods of analysis for pile-reinforced slopes are based on either limit equilibrium (LE) or geomechanical numerical modeling (finite element method, FEM, and finite difference method, FDM). Although in recent years there has been an increase in the use of geomechanical numerical modeling, designers still question the relative advantages, limitations, and accuracy of these methods compared to traditional methods. In this study, a comparative analysis have been performed, and the results of a Deep Foundation Institute, Deep Foundations for Landslides/Slope Stabilization Committee study on Design Comparisons of Slope Stabilization Methods are reported. The evaluation was focused on comparing the current methods of advanced numerical modeling for pile reinforced slopes (LE, FEM, FDM) by analyzing three cases using different analysis approaches performing coupled and uncoupled analysis. From the results, recommendations regarding the selection of the most beneficial method for stability analysis are given. Conclusions regarding pile optimum location, pile optimum length, key factors for each type of analysis, and lesson learned are presented.

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=6638&context=etd

Soon Hue Chew

Papers

Finite Element Analysis in Geotechnical Engineering