Dali Naidu Arnepalli

Indian Institute of Technology Madras | IIT Madras · Department of Civil Engineering

The stabilization of problematic fine-grained soils using lime as an admixture is a widely accepted practice, owing to its simplicity and cost-effectiveness. The optimal quantity of lime required for soil stabilization primarily depends upon the reactive nature of soil as well as the degree of improvement desired. The term ‘optimum lime content’ (O...

The time to rupture of a 1.5-mm-thick high-density polyethylene geomembrane aged in a typical landfill composite liner configuration is investigated under a pressure of 250 kPa at 85°C. The geomembrane was underlain with a geosynthetic clay liner and had a 560 g/m2 needle-pinched nonwoven geotextile protection layer separating it from 50 mm of drai...

Estimation of thermal resistivity of soils is very important for various engineering projects. Many researchers have demonstrated that, soil thermal resistivity is a property of the soil that depends on various parameters such as type of soil, particle size distribution, and compaction characteristics and hence its estimation based on existing empi...

The fate and transport of reactive contaminant(s) in geomaterials (i.e., soils and rocks) and efficacy of the immobilizationremediation methodology of the contaminated geomaterials is governed mainly by the sorption and desorption characteristics of these geomaterials and immobilizing agents. As such, establishment of these characteristics becomes...

Characteristics of fine-grained soils primarily depend on their specific-surface area and hence, reliable determination of this parameter is essential. In this context, researchers have employed quite sophisticated instruments (viz., a BET surface area analyzer, the mercury intrusion porosimetry, internal reflectance spectroscopy, X-Ray diffraction...

ime is a popularly adopted binder for improving the mechanical properties and controlling the volume change behavior of problematic clayey soils. However, lime treatment offers certain limitations due to the durability issues arising from varying physico-chemical conditions exacerbated by climatic stresses or clay mineralogy. Lime-treated soils ric...

The performance of the lime-stabilized layers exposed to water is uncertain owing to moisture intrusion and leaching of cementitious binders. The present study aims to assess the effect of water percolation on calcium leachability and microstructure alterations in lime-treated soils. The leachate is analyzed using an atomic absorption spectrophotom...

Carbon capture and storage (CCS) in deep geological aquifers has shown to be the most viable option for mitigating the greenhouse gas effect of carbon dioxide (CO2) at a large scale. However, the underground formations often possess discontinuities in the caprocks, leaking the stored CO2. Potential leakage paths, such as abandoned wells, have been...

This study describes the nondestructive testing and evaluation of different clay–lime composites by real-time impedance spectroscopy (IS) monitoring of lime hydration and cementation mechanisms. The experimental investigations were carried out on two different clays, white clay (with predominantly kaolinite mineralogy) and brown clay (with predomin...

Expandable clay minerals play a pivotal role in the geological sequestration of greenhouse gases due to their contribution to storage capacity and caprock integrity. The charge-balancing cations in the interlayer space are known to influence carbon dioxide adsorption. The present study investigated the general adsorption behaviour and characteristi...

Bacterial attachment is one of the fundamental phenomena that control the efficacy of the microbially induced calcite precipitation (MICP) treatment in soils. Moreover, flow, deformation and transport processes govern the effectiveness of MICP treatment through complex interactions among bio-chemo-hydro-mechanics (BCHM). Thus, for a realistic repre...

The long-term performance of lime-stabilised earthworks is a major concern for the sustainability and durability of infrastructure. The manuscript presents a comprehensive investigation into the impact of carbonation and leaching on lime-stabilised soil by focusing on the mechanical, chemical, and microstructure changes. The study employed accelera...

Cotton micro-dust (CMD) is a low-cost feedstock produced by cotton spinning mills. It consists of cellulose as the chief component, along with other non-cellulosic lignin and extractives. The two-stage pretreatment of CMD using alkali and acid facilitated cellulose enrichment and promoted favorable morphology for producing cellulose-based biomateri...

The study presents a comprehensive coupled thermo-bio-chemo-hydraulic (T-BCH) modeling framework for stabilizing soils using microbially induced calcite precipitation (MICP). The numerical model considers relevant multiphysics involved in MICP, such as bacterial ureolytic activities, biochemical reactions, multiphase and multicomponent transport, a...

Geomaterials with inferior hydraulic and strength characteristics often need improvement to enhance their engineering behaviors. Traditional ground improvement techniques require enormous mechanical effort or synthetic chemicals. Sustainable stabilization technique such as microbially induced calcite precipitation (MICP) utilizes bacterial metaboli...

Compacted bentonites are often considered as the buffer material in constructing Deep Geological Repositories (DGR). Bentonite buffer exhibits volume expansion when it comes in contact with water. During saturation, the bentonite swells and generates swell pressure. In a DGR, the swell pressure of bentonite buffer gets generated when the voids form...

Global warming is having a severe impact on the climate of the earth. Minimising global warming is a significant challenge [1]. Geological sequestration is one of the ways to capture the most liberated greenhouse gas, such as carbon dioxide (CO2), in deep saline aquifers. Due to the high heterogeneity in the caprock adjacent to aquifers, they often...

The thermo-hydro-mechanical processes in a deep geological repository (DGR) influence the bentonite buffer’s long-term performance. The buffer’s temperature evolution over a repository’s service life imposes a thermal history in the DGR. The developed thermal history causes shrinkage of the buffer and generates the technological voids (i.e., annula...

There is a need to develop methane mitigation strategies to curb the increasing global warming and restrict the global rise in temperature to below the threshold of 2 °C, per the Paris Agreement's goals. Methanotrophs represent an attractive natural sink, for they can fix even atmospheric methane concentrations by assimilating it into biomass. Desp...

Bio-augmented systems based on methanotrophs are indispensable in curbing anthropogenic methane emissions from engineered landfills or dumpsites to curtail rising levels of greenhouse gases. Using a defined methanotroph culture immobilized on an inert material-based bio-carrier makes it possible to harness these methane emissions for creating value...

Among clay minerals, smectite adsorbs a considerable amount of CO2 at geological sequestration conditions resulting in volumetric expansion or swelling-stress generation in free or constant volume conditions, respectively. The adsorption-induced volumetric strain can cause a reduction in the porosity and permeability of smectite at constant volume...

Many engineering applications use geosynthetic clay liners (GCLs) containing sodium bentonite (NaB) as hydraulic barriers. GCLs possess low permeability and high self-healing capacity. The interaction of NaB-GCL with permeants containing highly concentrated solutes and cation valence may compromise these properties, making them unsuitable for barri...

Carbonation is an inevitable reaction during the construction and curing stages of lime-stabilized earthworks. Both bench-scale and field studies on lime stabilization recognize carbonation as a deleterious reaction due to the consumption of lime, which otherwise participates in pozzolanic reactions. Besides lime paucity, exposure of stabilized cla...

The CO2 adsorption capacity of carbon materials depends on their structural properties and chemical nature of the functionalization of carbon networks. In this work, amorphous carbon materials are derived from coco peat by activation using KOH and melamine. These are studied to determine the relative influence of pore size distribution and N-doping...

The conversion of methane into liquid biofuels using methane-consuming bacteria, known as methanotrophs, contributes to sustainable development, as it mitigates the problem of climate change caused by greenhouse gases and aids in producing cleaner and renewable energy. In the present research, an efficient methanotroph, Methylosarcina sp. LC-4, was...

High-density polyethylene geomembranes (HDPE GMBs) are indispensable in constructing composite barriers of modern engineered landfills. GBMs would be exposed to various weathering conditions apart from the interaction of organic pollutants in landfill gas and leachate. Though many studies have investigated the contaminant's migration, the transport...

The interaction between clay minerals and CO2 at in-situ conditions of geological carbon sequestration leads to adsorption-induced strain, which increases the mineral's interlayer space. The effect of change in interlayer spacing of minerals on the evolution of macro-permeability, gas storage capacity, gas pore pressure, and stress state of compact...

Smectite-based geosynthetic clay liners (GCLs) are popularly employed as hydraulic barriers due to their low permeability and high swelling capacity. The exposure of GCLs to aggressive inorganic permeants is inevitable in the majority of field applications. GCLs exhibit inferior hydraulic properties and low swelling in these scenarios due to the co...

The usage of polymer-modified clays to construct hydraulic barriers has gained popularity due to their superior hydraulic properties. Altering the clays using polymer enhanced the chemical resistance of composite material in containing aggressive inorganic solutions to which the untreated virgin clays fail. The present study is focused on evaluatin...

In the last decades, the environmental sustainability problem has been pronounced due to the rapid industrialization and urbanization and ever-increasing quantities of waste materials. The construction industry is a principal consumer of natural reserves, resulting in a fast depletion of non-renewable resources, accumulating more waste, and creatin...

Ground improvement techniques involving chemical additives are often energy-intensive and unsustainable due to the environmental distress caused by them. Sustainable biocementation processes such as microbially induced calcite precipitation (MICP) can overcome the drawbacks of traditional ground improvement techniques. Capturing the underlying coup...

The knowledge of adsorption characteristics of bentonite (B) is mandatory for heavy metals removal from the wastewater and contaminant retention in landfill liner. Adsorption characterization of geomaterials requires the use of a buffer for pH adjustment. Previous studies have not investigated the impact of using a buffer on the adsorption characte...

The carbonation of lime-treated soils that occurs during the short-term and long-term curing is not sufficiently explored in the domain of lime stabilization. The present study investigates the carbonation mechanism in lime-treated silty clay treated with two lime contents (4%, 8%) subjected to different curing periods (7, 90, 180, and 365 days). T...

Soil has been the most widely explored material for construction purpose, since our ancestors stepped out from the cave dwellings and went in search for alternate shelters. As it is the plasticity and consequent mouldability of the soil, that attracted the early humans; it is evident that the clay minerals are the prime contributors for the desired...

Geosequestration deals with the long-term storage of captured carbon dioxide into various geological formations. Previous studies have focused on the different aspects involved in geological sequestration. The need to capture carbon dioxide from the emitting sources is to curb the rise in atmospheric temperature. The colossal energy demand since th...

This paper reports the impact of COVID-19 on the practice and delivery of geotechnical and geoenvironmental engineering (GGE) education modules including lectures, lab sessions, student assessments, and research activities based on the feedback from faculty members in 14 countries/regions around the world. Faculty members have since adopted a serie...

In recent times methanotrophs have gained immense interest due to their ability to sequester and utilize methane, which is an inexpensive carbon source as well as a very potent greenhouse gas. Despite their vast potential for both industrial and environmental applications, only a few methanotrophs have been well studied to date. A novel and an effi...

Soil–lime interactions involve concomitant short-term and long-term alterations of the fine-grained soil resulting in the formation of a workable material bonded by various pozzolanic compounds. These pozzolanic compounds being cementitious in nature are expected to hold the soil particles together and bring long-term strength and stability to the...

The clay mineral-based soils having low permeability and high swell–shrinkage characteristics are preferred as a backfill and buffer material for containing hazardous waste. Though many factors influence the behaviour of these soils, the contribution of various particle sizes present in them is not thoroughly investigated. In order to examine the e...

Application of biopolymer-modified geomaterials in waste disposal practices is gaining wide acceptance due to their superior tensile characteristics and improved crack resistance. Permeability is an important design parameter which determines the suitability of a material as a liner for construction of engineered landfills. Given this, the permea...

Application of biopolymer-modified geomaterials in waste disposal practices is gaining wide acceptance due to their superior tensile characteristics and improved crack resistance. Permeability is an important design parameter which determines the suitability of a material as a liner for construction of engineered landfills. Given this, the permeabi...

Application of biopolymer-modified geomaterials in waste disposal practices is gaining wide acceptance due to their superior tensile characteristics and improved crack resistance. Permeability is an important design parameter which determines the suitability of a material as a liner for construction of engineered landfills. Given this, the permeabi...

It is essential to understand the phenomena of adhesion, deadhesion, and transport of microorganisms in porous media to scale up bioengineering processes. In this study, the adhesion and deadhesion of two ureolytic microorganisms were investigated in loose sand using a set of flow-through column experiments by varying the pore fluid chemistry. An i...

Surface charge properties of colloids can be studied from their point of zero charge (PZC) measurements. The point of zero salt effect (PZSE), a category of PZC, indicates the pH value at which the effect of electrolyte concentration on a pH-dependent charge is zero. In the present study, it was mathematically deduced that for clay minerals, the ra...

Geomaterials involved in deep geological repositories, geosequestration of greenhouse gases, oil and gas exploration and so on are subjected to moderate temperatures in response to the natural geothermal gradient, as well as an imposed thermal flux. In such instances, the influence of temperature on the gas permeability characteristics of geomateri...

Surface charge properties of colloids can be studied from their point of zero charge (PZC) measurements. The point of zero salt effect (PZSE), a category of PZC, indicates the pH value at which the effect of electrolyte concentration on a pH-dependent charge is zero. In the present study, it was mathematically deduced that for clay minerals, the ra...

The quantification of the kinetics of short-term clay–lime interactions is a key step for optimizing the parameters during lime stabilization of fine-grained soils, and also for predicting the long-term performance of lime treated soil matrix. The existing scientific literatures often believed that monitoring of consistency limits as well as compac...

Electrochemical treatment of soil, ECT is the technique of deploying an external electric potential for introducing stabilizing chemicals into the intended zone of soil improvement. The current flow modifies the basic soil-electrolyte chemistry, reflected mostly in the form of soil pH. In view of this, the manuscript reviews the alterations in clay...

A deep geological repository, DGR is an underground disposal facility for the safe disposal of high-level radioactive wastes. In DGR, the radioactive waste is vitrified and placed in metallic canister, which is encrusted with a thick layer of engineered geomaterial called buffer material. As the radioactive waste generates moderate amount of heat d...

Microbially induced calcium carbonate precipitation (MICP) at laboratory scale for modifying the geotechnical properties of soils has been extensively investigated. The successful implementation of MICP in the field encounters many biotic and abiotic challenges. The study aimed to comprehend the role of oxygen availability on the efficacy of MICP c...

Rapid industrialization and urbanization cause release of significant quantities of hazardous contaminants, including heavy metals and radionuclides, into the biosphere. Severe accumulation of these contaminants and their exposure deteriorates human health, environment, and biota system. Conventional remediation of heavy metal, radionuclide contami...

The unconfined compressive strength is one of the influencing parameters that are used for determining the in situ strength of soft, fine-grained soil deposits. Since many previous research works have highlighted the influence of pore fluid type, electrolyte concentration, pH and valence of the pore fluid on unconfined compressive shear strength. T...

The benefit from using admixtures in soil to improve properties was discovered in ancient times. Various admixtures such as straw, bitumen, lime, salts and pozzolans are conventional additions to soil, while cement, petrochemicals and bacteria are currently being increasingly used in an effort to improve and stabilize soil from both mechanical and...

Water vapour diffusion is a predominant moisture transport mechanism in an unsaturated soil due to the presence of either thermal gradient or concentration gradient. In such soils, as water content decreases, the continuity of liquid films is lost, and as a result, water movement is mainly in the form of water vapour. The knowledge of water vapour...

Electro-kinetic properties of colloidal substance can be studied in terms of its zeta potential, which indicates the stability of the colloidal system. Numerous investigations have been made in the past several decades in areas of electro-kinetic remediation and stabilization of fine-grained soils. A proper understanding of the underlying mechanism...

Permeability of gases through geomaterials are critical in areas like landfill cover design, buffer material characterization in deep geological repositories for radioactive waste containment, geosequestration of greenhouse gases, oil and gas recovery. In general, there are two types of laboratory methods for determination of gas permeability of ge...

Population explosion and rapid industrialization have led to generation of large amount of solid and liquid wastes, which require safe disposal and containment. Currently, land disposal or shallow disposal of these wastes is being practiced by industries and the municipal authorities. However, subsequent interaction of the disposed of waste with ra...

The clay mineral based soils having low permeability and high swell-shrinkage characteristics are preferred as a backfill and buffer material for containing hazardous waste. Though many factors influence the behaviour of these soils, the contribution of various particle sizes present in them is not thoroughly investigated. In order to examine the e...

The intrinsic morphology, mineralogy and gradation characteristics of geomaterials and geosynthetics play a pivotal role in determining their vital geotechnical properties. In view of this, this paper attempts to demonstrate the relevance of advanced digital image analysis for micromorphological characterisation of geomaterials and geosynthetics ba...

The recent research infers that the detailed characterization of lime-treated soils using analytical techniques enables better understanding of the complex soil–lime interaction mechanisms as well as the pivotal factors influencing the efficacy of lime treatment. In view of this, the present study focuses on evaluating the effects of lime treatment...

The present study describes the calcium adsorption behavior of clays exhibiting distinct mineralogical composition. The adsorption characteristics were determined using conventional batch-equilibrium sorption method, and different theoretical models were applied to describe the equilibrium sorption isotherms. The variation in calcium adsorption cap...

The complex physico-chemical interactions occurring in a clay-lime system involves number of strongly coupled processes, such as short-term cation exchange reactions and flocculation mechanism as well as long-term poz-zolanic reactions [1,2]. The adsorption of free lime significantly alters the physico-chemical and surface charge properties of clay...

The geotechnical properties of fine-grained soils are predominantly determined by their electrical diffused double layer (DDL) formed around them upon interaction with the pore-fluid. In the past many empirical and numerical approaches have been proposed to correlate the geotechnical properties such as hydraulic conductivity, compressibility, swell...

The fundamental behaviour of fine-grained geomaterials compacted over a range of moisture content is strongly influenced by the resulting porosity and pore size distribution (PSD) characteristics. The majority of pertinent studies have employed mercury intrusion porosimetry (MIP) for determining these properties. Since the PSD analysis using MIP te...

The fundamental behaviour of fine-grained geomaterials compacted over a range of moisture content is strongly influenced by the resulting porosity and pore size distribution (PSD) characteristics. The majority of pertinent studies have employed mercury intrusion porosimetry (MIP) for determining these properties. Since the PSD analysis using MIP te...

Four geosynthetic clay liners (GCLs) serving as single liners were exhumed from below 0.7 m of silty sand on a 3:1 (horizontal:vertical) north-facing slope at the QUELTS site in Godfrey, Ontario, after 5 and 7 years. The 300 mm GCL overlaps with 0.4 kg/m supplemental bentonite were all physically intact. The exchangeable bound sodium was completely...

Coupled heat and water transport has found to be relevant in unsaturated soils because of increasing interest in disposal of radioactive wastes, geothermal energy, hydrology and agricultural problems. In an unsaturated soil, heat can be either latent or sensible or both and water may take the form of either liquid or vapour or both. The impact of t...

Coupled heat and water transport has found to be relevant in unsaturated soils because of increasing interest in disposal of radioactive wastes, geothermal energy, hydrology and agricultural problems. In an unsaturated soil, heat can be either latent or sensible or both and water may take the form of either liquid or vapour or both. The impact of t...

Determination of thermal conductivity of buffer materials is an important aspect in the design and characterization of engineered barrier systems (EBS) in deep geological repositories (DGRs) for safe containment of high-level nuclear waste. Several factors, viz. compaction state, particle size distribution, and mineralogical characteristics of buff...

During the process of lime stabilization of fine-grained cohesive soils, the sorption and diffusion properties of soil play chief role in determining the immediate and long-term soil-lime interactions, which in turn decides the degree of improvement that can be achieved. In view of this, the present manuscript aims to investigate the sorption and d...

The benefit from using admixtures in soil to improve properties was discovered in ancient times. Various admixtures such as straw, bitumen, lime, salts, and pozzolans are conventional additions to soil, while cement, petrochemicals and bacteria are currently being increasingly used in an effort to improve and stabilize soil from both mechanical and...

The unconfined compressive strength is one of the influencing parameter that is used for determining the in-situ strength of soft, fine-grained soil deposits. Since many previous research works have highlighted the influence of pore fluid type, electrolyte concentration, pH and valence of the pore fluid on unconfined compressive shear strength. The...

The quantification of the kinetics of short-term clay-lime interactions is a key step for optimizing the parameters during lime stabilization of fine-grained soils, and also for predicting the long-term performance of lime treated soil matrix. The existing scientific literatures often believed that monitoring of consistency limits as well as compac...

Water vapour diffusion is found to be a predominant moisture transport mechanism in an unsaturated soil due to the presence of thermal gradient or concentration gradient. In such soils as water content decreases, the continuity of liquid films is lost and, as a result water movement is mainly in the form of vapour. The knowledge of water vapour mig...

Rajasthan Sun Technique Energy Pvt. Ltd. has implemented a 125 MW large-scale grid connected concentrated solar thermal power project in Jaisalmer district, Rajasthan, India. This manuscript is a critical evaluation of the design and construction of raw water reservoir liner system at the concentrated solar thermal power plant. The initial liner co...

Geomembranes are popularly employed as part of composite liners in engineered landfills to control contaminant migration from the landfill. Volatile organic compounds (VOCs) present in the leachate can migrate through geomembranes by advection through defects or by diffusion. Among these processes, diffusion is an important contaminant transport ph...

In this era of steadfast industrial developments and expansion of urban areas, lime stabilization is an attractive proposition for upgrading the engineering performance of problematic fi ne-grained soils. The optimum lime content which allows for maximum performance of lime-treated soil is determined using various conventional methods; however, non...

Construction of embankments on soft soil or sludge is a challenging task due to the inferior strength of the foundation soil and excessively large total as well as differential settlements. If the embankment is constructed as part of an engineered landfi ll project, it becomes even more challenging because of the requirement of leak-proof lining sy...

The intrinsic morphology, mineralogy and gradation characteristics of geomaterials and geosynthetics play a pivotal role in determining their vital geotechnical properties. In view of this, this paper attempts to demonstrate the relevance of advanced digital image analysis for micromorphological characterisation of geomaterials and geosynthetics ba...

This study investigates effect of liquid to solid ratio, initial concentration of heavy metals, pH and composite heavy metal solution and nature of sorbent on sorption capacity of two different geomaterials such as clayey soil and moorum. The batch sorption experiments were carried out with the selected geomaterials using different heavy metal solu...

Infrastructure development and industrialisation have led to an ever increasing demand for energy and tremendous generation of industrial and municipal solid wastes in India. With indiscriminate human encroachments, the impact of disasters such as rainfall-induced landslides, river/coastal erosion, flash floods and cloud bursts is quite high. In or...

Mankind has generated and disposed of waste from the earliest times till the present day. With increase in population and industrialization, there has been a tremendous increase in generation of solid wastes, which contain high concentrations of toxic heavy metals. Historically, a landfill site was a dumping area meant for waste disposal. In small...

A black 1.5 mm geomembrane (GMB) and geosynthetic clay liner (GCL) liner were placed on both a 3H: 1V (18.4°) slope and a gently sloping (3%) base (latitude 44°34 ¢15²N) and left exposed for 4.7 years. The observed solar radiation, ambient air temperature, temperature at the interface between the GMB and GCL, and temperature at various depths (to 6...