Author ORCID Identifier
0000-0001-9211-482X
Document Type
Dissertation
Date of Award
5-31-2026
Degree Name
Doctor of Philosophy in Civil Engineering - (Ph.D.)
Department
Civil and Environmental Engineering
First Advisor
Oladoyin Kolawole
Second Advisor
Matthew P. Adams
Third Advisor
Arjunkrishna Venkatesan
Fourth Advisor
Rayan Hassane Assaad
Fifth Advisor
Olufemi Olorode
Abstract
Ground improvement is critical to geotechnical and geo-engineering systems, where modification of the properties of geomaterials (rocks and soils) is required to maintain stability and prevent failure of infrastructure installed within and around them. This need has become increasingly important with rapid urbanization and population growth, which intensify demands on surface and subsurface systems and further challenge the performance of supporting geomaterials. As a result, there is growing interest in nature-based solutions, particularly biologically mediated processes such as biocementation, which can enhance the physical, hydraulic, and mechanical properties of geomaterials while offering environmentally sustainable alternatives to conventional ground improvement techniques.
Although biocementation approaches, such as microbial-induced carbonate precipitation (MICP), enzyme-induced carbonate precipitation (EICP), biopolymer-modified EICP (BP-EICP), and fungal-induced geomaterial improvement (FGI), have been explored in soils, their influence on rock systems across scales is unknown. In particular, the multiscale physico-hydro-mechanical impacts of biocementation on rock structure, permeability, and mechanical response remain poorly understood.
This dissertation integrates experimental and numerical approaches to evaluate how nature-based biocementation treatments modify the behavior of rocks across multiple scales. Specifically, the study investigates: (i) the influence of rock porosity, lithology, and bedding on treatment-induced mechanical enhancement; (ii) the role of distinct curing regimes on treated rock performance; (iii) the depth of treatment penetration and its impact on rock microstructure and physical attributes; (iv) modifications to hydraulic behavior, including permeability and pore network evolution; and (v) the feasibility of fungal-mediated reinforcement in consolidated geomaterials. To translate these findings into engineering applications, this work further evaluates the potential of biocementation for reinforcing karst rock masses, including improvements in tensile strength and fracture behavior within karst-like void systems. This dissertation also introduces a mechanics-informed physics-informed neural network framework that integrates fundamental rock mechanics principles with machine learning to predict multiscale mechanical responses and lithology-dependent strength evolution under varying biocementation treatments.
In addition to rock reinforcement, this work considers the evolving urban environmental conditions that could cause subsurface hazards necessitating the ground improvement. Urbanization and anthropogenic heat generation have contributed to the development of subsurface urban heat islands (SUHI), where elevated ground temperatures may transfer to subsurface and influence the behavior of soils, rocks, and underground infrastructure. This work, therefore, further evaluates the spatio-temporal evolution of SUHI and its potential implications for underground in urban environments. Therefore, this dissertation advances the understanding of nature-based geomaterial modification by linking biotechnology, multiscale rock mechanics, geotechnics, and urban processes, demonstrating how biocementation can enhance ground improvement across depths and support resilient infrastructure.
Recommended Citation
Ngoma, Mary Chikondi, "Mechanics and physical attributes of nature-based alterations: rock reinforcement and urban heat island assessment" (2026). Dissertations. 1886.
https://digitalcommons.njit.edu/dissertations/1886
