Effectiveness of Rolling Dynamic Compaction using a Finite Element Methodology

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dc.contributor.advisorJaksa, Mark
dc.contributor.advisorKuo, Yien-Lik
dc.contributor.authorBradley, Andrew Charles
dc.contributor.schoolSchool of Architecture and Civil Engineering
dc.date.issued2024
dc.description.abstractRolling dynamic compaction (RDC) is a ground improvement technology which has become increasingly adopted in the applications of the densification of subgrade soils in situ, economic compaction of thick layers of in-filling deep excavations, proof rolling and construction of mine haul roads. Additionally, RDC finds application in the agricultural industry to compact soils in irrigated areas, to reduce permeability and water loss. Despite the advancements made by field case studies in showcasing the potential of RDC to improve soils at depth, their scope is limited. Unless the site conditions closely match those of a published case study, project engineers often rely on engineering judgment, necessitating expensive field trials to confirm the technology's efficacy. This uncertainty, stemming from a lack of comprehensive understanding, hinders the widespread consideration of RDC. To address this, additional investigations across a diverse range of initial conditions and approaches are needed. Representing RDC within a numerical framework offers a cost-effective alternative, facilitating in-depth investigations tailored to specific site conditions. This research aims to articulate and represent RDC using the Broons BH-1300 8 tonne 4-sided impact roller on coarse-grained soils within a Finite Element (FE) model framework. The objective is to numerically investigate and quantify the effectiveness of RDC on coarse-grained soils, contributing to a broader understanding and confidence in subgrade soil improvement. A comprehensive FE model formulation of RDC was developed, simulating the BH-1300 8 tonne 4-sided impact roller on coarse-grained soil subjected to a maximum of 30 passes. Validation against a controlled field test yielded good agreement of estimates for soil settlement and improvement profiles. The formulation integrated observed typical motion kinematic profiles of the impact roller through high-speed photography during field testing. Examination of module kinematics concluded that the average peak kinematic energy of the roller to be 62 ± 3 kJ, and energy delivered to the ground per impact to be 23 ± 4 kJ, with a 95% degree of confidence under typical operating conditions. Results from the FE model formulation reasonably reproduced field observations available in the literature. An enhanced understanding of RDC’s impact in relation to ground response emerged through FE simulations, providing distributions and trends for stresses in situ, along with estimates for peak particle acceleration and velocity with depth and along the soil surface. Although resource and time-intensive, the FE model and subsequent post-analysis offer a viable alternative to investigating the potential of RDC, which is traditionally assessed through field trials. The presented FE model herein may offer valuable insights into relationships between initial conditions (soil parameters, roller design, and kinematics) and resulting settlement and improvement profiles. The FE model is however, not without limitation. The limitations of the FE model are highlighted, along with suggestions for overcoming these limitations in future research. Nevertheless, the formulation presented herein provides a significant enhancement in understanding the effectiveness of RDC for practicing engineers and provides a tool to investigate the effectiveness of RDC using a FE methodology.
dc.description.dissertationThesis (Ph.D.) -- University of Adelaide, School of Architecture and Civil Engineering, 2024en
dc.identifier.urihttps://hdl.handle.net/2440/146656
dc.language.isoen
dc.provenanceThis thesis is currently under embargo and not available.en
dc.subjectEnergy
dc.subjectfield testing and monitoring
dc.subjectgranular materials
dc.subjectrolling dynamic compaction
dc.subjectimpact roller
dc.subjectground improvement
dc.subjectvibration
dc.subjectfinite element
dc.titleEffectiveness of Rolling Dynamic Compaction using a Finite Element Methodology
dc.typeThesisen

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