Nandhagopal Arasan Raja
Pronouns: He/him
About
My research project
Micro-scale investigation of shear-induced fabric evolution and crushing in carbonate sandsThis project focuses on how the particle‑scale shape features of shelly carbonate sands govern their mechanical behaviour under various loading conditions, using advanced imaging techniques and discrete element modelling.
Firstly, the irregular particle geometry inclusive of the intra‑particle porosity will be quantified from XRCT data and systematically modelled in DEM to assess its influence under shearing conditions while also considering the particle crushing which is innate to the nature of carbonate sands. Various techniques have been presented in literatures for the XRCT‑to‑particle reconstruction. These methods shall be compared to identify the most accurate and computationally efficient approach for generating DEM‑ready geometries of highly irregular, porous carbonate grains.
Using these image‑derived particles, DEM shall be performed for different shearing conditions simulating typical in-situ conditions. This comprehensive study shall help in understanding how grain shape characteristics, inherent fabric anisotropy and particle crushing jointly affect stress–strain behaviour, dilatancy, grading and shape evolution, energy dissipation and critical‑state characteristics.
The micro‑mechanical insights will be interpreted in the context of offshore environments, and macro-analysis for critical conditions shall be simulated to understand the variation in behaviour of this crushable carbonate sands.
Supervisors
This project focuses on how the particle‑scale shape features of shelly carbonate sands govern their mechanical behaviour under various loading conditions, using advanced imaging techniques and discrete element modelling.
Firstly, the irregular particle geometry inclusive of the intra‑particle porosity will be quantified from XRCT data and systematically modelled in DEM to assess its influence under shearing conditions while also considering the particle crushing which is innate to the nature of carbonate sands. Various techniques have been presented in literatures for the XRCT‑to‑particle reconstruction. These methods shall be compared to identify the most accurate and computationally efficient approach for generating DEM‑ready geometries of highly irregular, porous carbonate grains.
Using these image‑derived particles, DEM shall be performed for different shearing conditions simulating typical in-situ conditions. This comprehensive study shall help in understanding how grain shape characteristics, inherent fabric anisotropy and particle crushing jointly affect stress–strain behaviour, dilatancy, grading and shape evolution, energy dissipation and critical‑state characteristics.
The micro‑mechanical insights will be interpreted in the context of offshore environments, and macro-analysis for critical conditions shall be simulated to understand the variation in behaviour of this crushable carbonate sands.
ResearchResearch interests
Micro-analysis of soil, Soil-structure interaction, Experimental and numerical studies
Research interests
Micro-analysis of soil, Soil-structure interaction, Experimental and numerical studies
Publications
Research performed on pile foundations installed over sloping ground has consistently reported a reduction in the lateral load capacity. Therefore, identifying ideal solutions for the related circumstances is imperative. This paper explores the possibility of socketing piles into rock as a viable solution for piles being installed in the vicinity of sloping ground. A parametric study has been conducted on freestanding and rock-socketed piles on sloping ground by varying the position of the pile and the direction of loading. Tests have been performed on loose sand of 35% relative density by maintaining a slope of 1V:1.5H. The positions of the pile from the crest were planned at increments of five times the pile diameter on both sides. The behavior of the pile installed at the crest of the slope, that is, 0D, was also of interest as part of this study. The direction of loading was varied with either forward (toward the slope) or reverse (away from the slope) loading for all positions of the pile. The depth of socketing was established to a height of three times the diameter from the bottom of the pile. The socketed pile behavior was compared with that of freestanding piles that were installed and tested with identical parameters. Based on the experimental results obtained, it was observed that the rock-socketed pile at even +5D distance from the crest achieved the lateral load capacity of an unsocketed pile installed on uninfluenced horizontal ground. It was also observed that the socketed piles exhibited a significant increase in the lateral load capacity relative to the unsocketed piles in all positions considered.