Best Practices in Geotechnical and Pavement Engineering

Every site on earth is unique in its own way. Two work sites usually do not have the same sub-soil profile with identical properties. From an engineering point of view, conducting a geotechnical investigation at any site where a structure is being constructed is essential. Geotechnical investigation methods can be effectively employed based on the nature of construction, anticipated super-structural loads, and scope of the project. Precise and standard procedures shall be adopted to arrive at the optimal type and size of the foundation. In residential projects, where parent ground consists of loose or non-uniform soil stratifications, placing the shallow foundation on top of the engineered fill is routine. This paper presents a case study of a site consisting of 3 m of compacted silty sand-engineered fill. Inconsistent standard penetration resistance (N) values were reported at the founding level across different borehole locations on the site. Due to inconsistent N values, different safe-bearing capacities were reported. A raft foundation was initially planned and the philosophy of a shallow sub-structure system could not be adopted with uneven bearing pressures across the site. A root cause analysis by conducting in situ density tests revealed non-uniform or improper compaction methods adopted at the site leading to improper densities of topsoil across the site. Proper compaction control and engineered fill construction were adopted at the site to arrive at optimal foundation dimensions. Further, the measurement of the energy transfer ratio, proper tools, and quality procedures adopted in the geotechnical investigation program have added value toward sustainability in construction practice.

The utilization of scrap tires as the rubber material for engineering applications has received significant attention in recent years. Tire crumbs have low specific gravity, high damping ratio, high elasticity, high durability, and low compaction energy, making them a cost-effective way to consume stockpiles of scrap tires globally while promoting a cleaner environment. The primary aim of this study is to determine the energy absorption capacity of the gravel tire crumb mixture (GRM) under earthquake loads or vibrations and hence determine the optimum layer of low-cost base isolation in shallow bedrock sites. Soil samples were collected from different sites in East Bengaluru based on borehole data. Direct shear tests were conducted to determine the shear strength characteristics, energy absorption capacity, and brittleness index of GRM mixtures with percentages ranging from 0 to 40%. The results showed a sudden drop in shear until 10% of GRM was observed, followed by a gradual reduction in shear with increasing GRM percentages. Shear values after 30% of GRM began to show the shear value of rubber. The energy absorption capacity increased with an increase in confining pressure, and every 5% increase in GRM resulted in a good amount of improvement in energy absorption capacity with doubling of the confining pressure. The brittleness index increased and decreased with every 5% increase in GRM. Based on the DEEPSOIL analysis, we have found out that there is a significant decrease in the PGA observed in the various sites. In Site-1, there is a decrease in the PGA by 16.8%; in Site-2, there is a decrease in the PGA by 13.77%; in Site-3, there is decrease in the PGA by 4.04%; and in Site-4, there is a decrease in the PGA by 19.4%. (All the percentage shown is at the top of surface layer).Using GRM at foundation depth resulted in a definite decrease in PGA(g) and effective stress (kPa), which is highly desirable. It was observed that there is a decreases in the PGA about 9.05%, 9.54%, 12.96%, 23.8% for Site-1, Site-2, Site-3, Site-4, respectively, at the foundation level. The optimum thickness of GRM layer was found to be 1 m for all the sites as there is a decrease in the PGA in the range of 18.81–25.41% for varying thickness of GRM for the given sites. It is observed that further studies can be made on GRM so that it can be used as an cost-effective vibration isolation system around footing and foundation.

The paper presents the results of field surveys of the settlements of adjacent multi-story buildings on large-sized slab foundations, the soil base of which is composed of weak water-saturated sandy soils on top. The settlements of the building were surveyed during its construction using the high-precision Class 2 leveling method. The analysis of the results and comparison of the theoretical and actual values of the settlements of the building show the possibility of using of the model of the soil base as a linear elastic layer of finite width has been confirmed for forecasting adequate deformations of sectional buildings on large-sized slab foundations which are based on weak water-saturated soils on top. However, it is necessary to additionally consider the processes of filtration consolidation of sandy and clayey soils within the compressible mass of the base, as well as the process of mechanical suffusion of sand particles into crushed stone bed.

Geosynthetic-reinforced solution is a novel type of soil strengthening technique among other ground improvement techniques because of its cost-effectiveness, environmental advantages, and ease of installation to improve load-bearing characteristics of weak subsoil. This study aims to investigate the improvement potential of using geotextile on a sandy soil bed. Different influencing parameters such as the top layer arrangement, spacing among consecutive layers, number of reinforcing layers, and width of reinforcement have been investigated to examine layout arrangement’s effect on load-settlement characteristics. A steel plate of dimension 70 mm × 70 mm has been chosen to replicate model footing with a thickness of 16 mm. A series of model plate load tests has been incorporated to examine the effects of layout arrangements on soil bed. Further numerical validation has been incorporated using PLAXIS 2D with experimental results. The study’s findings demonstrate that reinforcement configuration has a high potential to improve the load-bearing characteristics of the geotextile-reinforced solution, where experimental results depicted a good agreement with numerical simulations. The configured reinforcement arrangements show an increasing trend of the load-bearing capacity of reinforced fill compared to the unreinforced condition, along with a substantial reduction of footing settlement. The incorporation of geotextiles in this research study is a commendable step toward ensuring environmental sustainability by stabilizing soil.

Reinforced cement concrete foundations undergo settlement and damage when there is an error in the design or in situations when the loads transferred to the foundations from the superstructure exceeds the supporting soil’s bearing capacity. Retrofitting of foundations is a challenging job when compared to retrofitting other structural members present in the superstructure. The work presented in this paper is a practical case of retrofit of a slab-type reinforced concrete raft foundation that supports a mercantile building founded on medium sand. The raft foundation has undergone settlement and deformation at few locations due to erroneous design and has previously experienced an earthquake. The settlement and damage that have taken place at various locations in the existing raft are assessed and retrofitting of the raft foundation is carried out by introducing new RC beams and RC jacketing of the raft. The new RC jacket comprises an additional new layer of concrete with reinforcement increasing the overall thickness of the raft slab. Parametric study carried out through analysis adopting finite element methods in ETABS, for different thickness of reinforced concrete jackets and depths of RC beams when the structure along with the retrofitted raft foundation is subjected to gravity and seismic loading. The structural effectiveness of the retrofit applied on the raft is assessed based on the respective optimum RC jacket thickness and depths of newly introduced reinforced concrete beams to check for any possible settlements in post-retrofit scenarios.

Increase in infrastructure development for rapid growth of population demands the construction of earth structures on soft compressible ground. A tendency exists in geotechnical practice for rapid construction of embankments to meet the stringent construction schedules. Embankments constructed on soft ground develop large settlements and deform laterally resulting in instability. The rates of increase of both settlement at the centre and the lateral displacement at the toe increase sharply with such rapid construction practice indicating embankment instability. Matsuo and Kawamura (Soils Found 17:37–52, 1977 [1]) proposed construction control chart based on field measurements of settlement at the centre of the embankment and the lateral deformations near to toe to predict the degree of safety or stability of an embankment during the construction itself. The present study analyses the stability of various embankments constructed using Matsuo stability charts for different embankment loading. Further, these embankments constructed on soft ground are modelled in SLOPE/W based on the limit equilibrium method and the factor of safety (FOS) estimated. Factor of safety obtained from the Matsuo charts accounts for deformations that occur during construction, whereas SLOPE/W software is based purely on limit equilibrium state and not on actual response of the ground. The analyses are carried out considering slope geometry, geotechnical properties of soils and of the ground, e.g. water table. Stability of embankments is evaluated using Bishop simplified and Janbu’s methods and the factors of safety compared. Reported case records of embankments that are stable are considered in this analysis and the field measurements reported are used for assessing the stability with increase in embankment loading. Results of the present study confirm that the Matsuo chart predicts the slope stability across different embankment conditions with a high degree accuracy. Janbu’s method predicts the FOS similar to the value obtained from Matsuo charts.

For strong foundations, especially in residential projects, the building industry needs effective soil quality improvement technologies. This study will evaluate whether metakaolin (MK) stabilizes clay soils. We treated certain soil samples with 0, 5, 10, and 15% metakaolin after examining their physical and chemical properties. They were lab-tested for durability and water transfer. The 15% metakaolin content decreased hydraulic conductivity by nearly 70% relative to unmodified soil. The metakaolin-hydrated calcium silicate gel (C-S-H gel) is more water-resistant due to its pore-filling and pore-shrinking actions. With 15% metakaolin, the treated soil samples had 75% greater unconfined compressive strength (UCS). Pozzolanic interaction between metakaolin and dirt caused this rise. The reaction produced more concentrated products, strengthening the substance. Adding metakaolin to clay soil increases erosion resistance and decreases water permeability. This may be a cost-effective way to improve clay soil’s mechanical and hydraulic qualities for building. This information may be used to plan and build clay soil embankments, dams, and retaining walls. We now have another instrument to preserve earth’s balance.

The process of enhancing soil engineering properties is known as soil stabilization. The problematic soils can be improved by adding bio-enzymes and cement. In the present examination, a bio-enzyme named terrazyme is utilized. Terrazyme is a liquid enzyme that is non-toxic and all-natural plant fermentation in its production; hence, it is adopted to investigate the effect of stabilized performance in road construction. The main objective of the study was to identify the optimum dosage of terrazyme-stabilized soil with cement. The dosage of cement was added in percentages of 3, 3.5, 4, 4.5, and 5% by the dry weight of soils. An analysis of the physical and mechanical properties of the soil was analysed by using the CBR test and UCS tests. For 7, 14 and 28 days, the samples were evaluated and cured, respectively. The results were found to be that the optimum dosage of 4.5% along with cement gave maximum strength for terrazyme 5x chemical, 5% along with cement gave maximum strength for terrazyme 11x chemical, and hence bio-enzymes chemical like terrazyme can be used for soil stabilization in problematic soil.

Today the engineering profession faces twin challenge of developing massive infrastructure as well as global issues of climate change. Projects today require complex engineering in difficult conditions with extremely tight financial, time and technical constraints. These requires multidisciplinary teams interacting closely with each other to develop safe, optimum and sustainable infrastructures. This paper discusses and outlines geotechnical knowledge required for nurturing sustainable engineering practices and their integration with existing education and training of geotechnical engineers. Starting with the main activities of geotechnical engineers including exploration, analysis and design, management and construction, the paper discusses the key sources of geotechnical knowledge such as engineering sciences, models, software, codes of practice, judgement and heuristics and their applications in engineering practice for developing a multidisciplinary talent in engineers. This is then followed by a discussion on trends such as development and incorporation of new technology, climate change and requirements of complex but sustainable projects in difficult conditions which are likely to impact the profession in the coming decades and concludes with requirements on education and training of geotechnical engineers to make them ready for future challenges. The study reflects great divergence existing between academics and practitioners and suggest ways to bridge this gap by inculcating a better understanding of the geotechnical knowledge required in engineering practice and incorporating this knowledge in education and training of geotechnical engineers.

Over time there is a natural accumulation of fine sediments and organic matter in lake beds reducing the depth and water storage capacity of these lakes. Removal of this deposited silt from lake beds is crucial to maintain the health and functionality of these natural resources. Disposing of this dredged silt has been a challenge to local governments and organizations working to restore and rejuvenate lakes in their locality. The use of this silt as a landfill liner material is investigated in this paper. In order to serve its purpose as an efficient liner material, the hydraulic conductivity of silt has to be modified using a suitable additive. This study explores the effectiveness of magnesium-rich olivine or forsterite in reducing the hydraulic conductivity of silt. Olivine is a naturally occurring nesosilicate mineral available abundantly in the earth’s subsurface. It is a sustainable and cost-effective additive that may be effective in stabilizing soil due to high amounts of magnesium oxide. Silt samples collected from two different lake beds were used in this study. Test results indicate that the hydraulic conductivity values for both the forsterite-treated silt samples satisfy the minimum requirement of hydraulic conductivity (≤ 1 × 10–7 cm/s) as per the US Environmental Protection Agency (U.S EPA) guidelines. Hence, forsterite can be employed as an environmentally friendly additive that facilitates the use of dredged silt from the lake beds as a liner material.

Mineralogy is the major parameter to be considered while dealing with expansive soils. Montmorillonite among different minerals in clay soils is the prime reason behind volume change behaviour. These contents may vary with the origin of the soils, and so does the swelling behaviour. Their estimation with respect to different soils offers better accuracy in swell determination. The current study aimed to investigate the influence of Montmorillonite Content (MMC) on swelling behaviour in relation to its plasticity. To do the same, soil samples have been collected from different locations across India, i.e. Bhopal, Guntur, Kendrapara, Warangal, Vijayawada, Kakinada, Mysore, Raipur and Nagpur, and subjected to experimental investigation. The consistency limits, swelling, and MMC of the respective soil samples were determined by employing Atterberg’s limits, free swell index (FSI), and XRD analysis, respectively. From the measured values, relationships were established between MMC and FSI in reference to their plasticity (i.e. CH and CL). It was observed that the swelling increases linearly with MMC in both CH and CL cases, irrespective of the location. However, more scatter can be observed in the case of CL when compared to CH, which is likely due to the variation of MMC and their associated minerals. It is essential to know the mineralogy of soils for better estimation of swelling behaviour to avoid infrastructural failures, especially in arid regions.

Stone columns, which are known as a ground-improvement technique, are frequently employed by geotechnical engineers to strengthen the stability of foundations, reduce differential settlement, and raise the bearing capacity of soft soil. In the current research, numerical simulations utilizing Plaxis 3D, a FEM-based program, and stone column behavior are examined. The behavior of the stone columns has been examined concerning several characteristics, such as column spacing, diameter, length, and material attributes. The load-bearing capacity of the improved ground has been analyzed both qualitative and quantitative on Plaxis 3D and comparing the results with the different level of variable such as different column diameter which includes 65, 75, and 90 mm, change in L/D 4, 5, 6, change in shear strength Cu = 7, 14, 30 kPa, change in the angle of internal friction 40°, 43°, 46°. The load bearing capacity has been found to increase by 151, 234, and 376% when change in diameter. The similar trends were noted in the case of L/D column, bearing capacity increased by 226, 230, and 234%; for shear strength 7 kPa is decreased by 57.41% and undrained shear strength of 30 kPa increased by 234% concerning clay bed respectively; for the angle of internal friction, bearing capacity is increased by 193, 234, and 284%. The detailed analysis reveals that the stone column has a better capacity to reach the load-bearing capacity of columns.

Determination of properties of foundation soil is an essential and indispensable part of any construction activity. However, mining of the geotechnical parameters is a challenging task requiring both a sound judgment and a vast experience. There are numerous uncertainties present in the field of geotechnical engineering due to various kinds of sources. Therefore, the degree of uncertainty arising from sources generally depends on various factors like variability of the soil profile at the site, equipment used, procedure maintained during the testing, and tests carried out by person. Uncertainty that is too large may affect reliability of the decision and make the situation more complex. Hence, it is more important to estimate the uncertainty of measurement. In this study, an attempt has been made to apply the NABL procedure for the estimation of uncertainty measurements for geotechnical parameters of a lateritic soil. The tests were repeated for five times to assess the uncertainty. The soil tests carried out in laboratory were compared with tests performed in NABL-accredited laboratory. The uncertainty for liquid limit, plastic limit, optimum moisture content, maximum dry density, angle of internal friction, and cohesion was determined to be 2.51 ± 0.02, 33.11% ± 0.79%, 23.31% ± 1.98%, 16.39% ± 0.06%, 1.67gm/cc ± 0.09 gm/cc, 20.60 ̊ ± 1.16 ̊, and 0.12 kg/cm2 ± 0.03 kg/cm2, respectively.

Guwahati, the gateway to Northeast India, is surrounded by hilly terrain from three sides, which also constitutes the bulk of the city region. The hill soil consisting of stratified layers formed out of different degrees of weathering of the parent rock. Primarily, two distinct types of soil formations are observed. A cohesive reddish clayey soil layer forming the top layer of the slope formations mostly underlain by a less stable yellowish sandy soil layer building the core and bulk of the slope. The shear behaviour of this yellowish soil primarily governs the overall stability of a slope during any triggering event such as rainfall infiltration. The study analyzes numerically the overall strength and shear behaviour of the hill slopes with varying slope inclination and its effects on slope geometry. Applying the Morgenstern–Price method of stability analysis, the stability comparison between slope geometries of undisturbed and remoulded soil has also been studied. The parametric study of undisturbed soil slopes signifies about 40% loss of stability with respect to 100% increase in slope angle at low moisture content. As the slope becomes more and steeper, the factor of safety decreases and also the variation of factor of safety with respect to slope geometry gradually diminishes. At slope angle more than 70°, the slope becomes unstable owing to its height and shape only; hence, saturation due to infiltration need not play a crucial role in instigating instability. For remoulded soil slopes, the values of factor of safety and shear strength for all slope geometries and moisture content are significantly lower than their counterpart values of undisturbed ones with approximately 15% deficiency. It manifests for the presence of strong cementing properties in the original skeleton of the soil, which, once re-constituted, cannot be fabricated again. It implies the supremacy of models utilizing the application of such properties of undisturbed soil which may be considerably significant for slope-based construction in the region.

Unconfined compressive strength (UCS) of soils is considered as a significant soil parameter. The soil strength provides the benchmark for usage in any subsurface civil infrastructural constructions. The purpose of this research was to investigate the effect of soil type on the rheological parameters of a re-engineered cohesive soil. According to the ASTM standard, the shear strength of the unconsolidated soil under unconfined circumstances is measured using the unconfined compressive strength (UCS) technique. Soil samples of Outer Ring Road, Mysore city, were subjected to tests. The studies illustrate that, for clayey sand (SC), silty, clayey sand with gravel (SC–SM), silty sand (SM), and well-graded sand with silt soil (SW–SM), normal stress ranges from 1.693 to 6.428 kg/cm2, whereas shear stress ranges from is 0.847 to 2.384 kg/cm2 and internal angle of friction (α) ranges from 57° to 64°. The stress–strain diagram and Mohr circle exhibit average values of normal stress, shear stress and internal angle of friction for four major types of soil of the study area. The outcome of the experimental program led to govern the shear strength of the soil is also conferred.

Recycling plastic trash from water bottles has become a significant global concern since plastic garbage is one of the critical components of urban solid waste. The present study has taken the initiative to mitigate the harmful effect of plastic on the environment by performing a laboratory 3D consolidation test to investigate the impact of waste plastic fibres on the consolidation behaviour of the soil. The experimental study used two different aspect ratios of 4 and 2 (length-to-width ratio) of raw plastic bottle fibres. Four plastic fibre percentages, such as 0.00, 0.20, 0.50, and 1.00% by dry weight of the soil, have been chosen for the present study. The result shows that with the increase in plastic strip percentage, the compressibility of the soil decreases, and the coefficient of consolidation increases, thus reducing the soil settlement. Incorporating plastic waste improves the soil consolidation characteristics; at the same time, it reduces the waste plastic material from the environment, reducing environmental pollution.

Landfill liners are crucial in preventing the migration of contaminants by blocking the flow of leachate. Although clay liners are commonly used owing to low permeability, they are susceptible to cracking and shrinking during unsaturated states, which can lead to leachate leakage. To address this, alternative materials with low permeability and shrinkage potential are needed. Treated pond ash, a by-product of coal combustion containing fine sand-sized spherical particles, shows potential as the landfill liner material. This study examines the geotechnical properties of pond ash-Bentonite mixtures as potential liner materials. Mixtures with different Bentonite percentages (0, 2, 4, 6, 8, 10, 12, 14, 16, and 18%) were tested using various experiments like liquid limit, plastic limit, consolidation, and unconfined compression tests. The results display that the Bentonite addition significantly increases the plasticity index and thus the water-holding capacity of pond ash. The unconfined compressive strength of this mixture increased by 64% with the addition of Bentonite up to 8%, and then, it reduced with further Bentonite addition. The consolidation tests displayed that the hydraulic conductivity of raw pond ash decreased below 10−9 m/s by adding Bentonite, indicating that pond ash-Bentonite mixtures have low permeability and can be suitable as landfill liner materials.

Slopes along the highway, especially in hilly areas, are highly susceptible to landslides. Several factors such as heavy traffic and abundant rainfall during monsoon can contribute to slope failure. The slope failure can lead to damage to the mankind and the property. To mitigate risk associated with slope failure, different slope stabilization techniques, such as anchors, anti-slide piles, reinforcement, geotextiles, terracing, vegetation, soil nailing, can be adopted. Therefore, it is essential to conduct slope stability analysis for assessing the safety of slopes or embankments and also for the selection of most suitable stabilization technique before commencing any construction activities. In the present study, deterministic 2D slope stability analysis has been performed for a specific slope in Agumbe ghat, Karnataka and another landslide prone region in Dhobighat, Hyderabad. Both slope stability analysis has been performed using limit equilibrium analysis (LEA) and finite element analysis (FEA). Both slopes are found to be unstable according to LEA and FEA. Further, using anchors the slope has been stabilized and the factor of safety (FOS) increases in both FEA and LEA. In addition to that parametric study has been carried out to determine the effect of the design parameters on 2D slope stability analysis using LEA. It has been found that the slope at Dhobighat, where well graded sand is predominant are more affected due to the changes in the design parameters as compared to Agumeb ghat slope, which mainly consisted of stiff clay. The study also concludes that for a specific slope FEA provide more conservative FOS value compare to LEA.

Calcium carbide residue (CCR) is a waste by-product of the acetylene gas manufacturing industry. Because of its zero-recovery value, the current Indian practice is to dump it in open land or landfills. This adversely impacts the landfill volume and reduces the biodegradation process of many other wastes because of its high alkali content. Due to industrialization and modernization, a huge amount of CCR generated by industries causes a huge effect on environmental and human health due to disposal problems. Hence, it is necessary to reuse this industrial waste to support the environment. In addition, these materials can be utilized in soil stabilization. This comprehensive review examines the sustainable usage of CCR, which exhibits pozzolanic properties for improving the soil, especially clayey soil. CCR is the major calcium hydroxide composition that reacts with pozzolanic material such as fly ash and rice husk ash to form calcium silicate hydrate. This paper reviews traditional soil stabilization techniques using CCR with their respective geotechnical and engineering properties. This study also discussed the outcome of physicochemical effects on soil properties. A focus on chemical processes such as X-ray diffraction analyses and microstructure interaction using scanning electron microscopy has been reviewed in light of the findings of past researchers. The study concluded that using CCR for soil stabilization is suggested as a sustainable approach for developing countries.

The development of any nation depends upon the development of good infrastructure. In India, due rapid infrastructural development needs good roads, generally, road subgrade and subbase layers are constructed using locally available soil (expansive soil), it may not have desired strength, so its need to improvement to use as construction material, mostly through chemical treatment (as cost effective and sustainable method). This paper presents the strength properties of local soil enhanced by mean of alkaline activated (hybrid) saw dust ash (SDA). The experimental investigation through compaction and unconfined compression test was carried out to understand the feasibility of effect of alkaline activated saw dust ash on local soil. The experimental result shows that replacement of local soil with hybrid SDA content up 15% improves the strength properties of the soil mass nearly about 900 kPa and indicates that hybrid SDA is a good sustainable soil stabilizer. This may reduce the natural resource material and increases consume of industrial waste materials.

Slope failures induced by seismic activity are critical issues related to geotechnical earthquake hazards thereby damaging various transportation corridors such as road embankments, highways and dams. This paper discusses slope stability of a 8 m high road embankment resting on soft soil under saturated conditions under the action of seismic activity analogous to 0.38 g acceleration caused in seismic zone IV using equivalent linear dynamic model in Quake/W and Slope/W. Unreinforced road embankment and soft soil resulted in poor factor of safety of 1.138 and subsequently large displacements and accelerations thereby causing the simulations to be unstable. Further, the prevalence of saturated conditions yielded liquefaction zone underneath the road embankment which holds the potential of intensifying the destruction and complete collapse of the structure. Since the simulation yielded low factor of safety, layers of geotextile were applied based on the susceptible liquefaction zone. The reinforcement enhanced the stability in terms of total and vertical displacements, q/p′ ratio, induced accelerations. In addition, effect on total stress and excess pore-water pressures were also analyzed. Geotextiles proved to be effective in stabilizing the concerned simulation yielding factor of 2.813 and 1.793 for pre- and post-earthquake events and declining displacements and acceleration by 33.3% and hence proved to be an effective reinforcement in minimizing seismic-induced dynamic forces and enhancing the overall seismic performance of the simulation model. This research can be useful in rectifying stability-related issues with similar geotechnical and prevailing seismic conditions.

The Vande Bharat Express, which travels at a speed of 180 km/h, is the high-speed train currently in operation in India. India intends to start using its first bullet train by 2026. Given that railway travel will become much faster in the coming years. The strains on India’s railway subgrade component would significantly rise with the addition of high-speed railways and bullet trains. The strains may cause failure in soil that is more brittle. Utilizing geosynthetics in the lengths of currently weak formations is an alternate strategy to reduce the number of stress. The paper investigates the importance of using geosynthetics (geogrids) for existing layers of ballast and blanket. Using the finite element software PLAXIS 3D, the vertical deformations and stresses of a railway embankment (with and without geogrid) are calculated under a moving train load of 90 kN. The speed of the moving train is taken as 180 km/h. Dynamic analysis was used to simulate the real-time movement of the train. It also investigated the different stresses and shear wave velocities of moving trains at various sections. The results showed that including additional numbers of geosynthetics helped in reducing deformations and stresses further to a certain level (up to 40%).

Subgrade’s poor strength is a common challenge in many road projects. Several materials are used as admixtures to reinforce the subgrade. However, geotextiles are one of the best solutions for reinforcement in the soil. In this work, an investigation of the strengths of subgrades reinforced with jute textile and polypropylene (PP) geotextile is the topic of a comparative study. On both reinforced and non-reinforced soil, tests called the direct shear test (DST) and California bearing ratio (CBR) are conducted. This geotextile’s positioning demonstrates how crucial it is to the subgrade’s overall strength. According to the test results, jute textile (natural fibre) increased the soil sample’s shear strength. Contrarily, the soil’s shear strength decreased when it was reinforced with polypropylene geotextile (synthetic fibre). Selecting D/2, D/3, and D/4 as the placement depths from the top surface for the geotextile, a single, double, and triple layer of geotextile is used to reinforce soil samples for the CBR test. The double-layer reinforcement at depths D/3 and D/4 shows optimum strength.

Considered as one of the notorious soil category as of swelling, shrinkage and cracking behaviour eventually damaging civil engineering structures instigating wide-ranging difficulties for construction purpose. Over the years, lime treatment has been broadly used to reinforce the soil but then again it comes with the unscrupulous effects on the soil such as carbonation or sulphate attack. This paper intends to evaluate the effect of fibre reinforcement (coir and jute fibre) obtained from Jodhpur, Rajasthan, in improvement of geotechnical behaviour of the natural clayey soil mixed with sand along with comparison of two natural fibres in improving soil strength. The author performed direct (UCS) strength test on reinforced and unreinforced soil. Initial test was conducted on coir by varying fibre content/percentage (2, 2.5 and 3%) and eventually on jute fibre in varying fibre content/percentage (2, 2.5 and 3%). The present paper indicates that in both the fibre employed for reinforcement exhibited an increment in soil strength. Amongst coir and jute fibre content/percentage, jute seems to have shown improvement accompanied by enhanced resistance to the cracking. An attempt has been made to validate the experimental results by Finite Element Analysis using ABAQUS software. Thus, natural fibre (coir and jute) can be used as an alternative to reinforce the soil which in turn is not damaging for Rajasthan’s environmental circumstances.

Soil liquefaction is a phenomenon that occurs in saturated cohesionless soils and has been of great concern for many years. Natural geosynthetics have been used in numerous studies to enhance soil characteristics and lower the possibility of liquefaction. Natural geosynthetics are helpful since they are economical and easily accessible in geotechnical engineering practice. But, according to the research published so far, coir products have yet to be used to their full potential as reinforcing materials. This paper studies the effects of coir geocell reinforcement on the strength improvement of geocell-reinforced coastal sand through laminar box shake table tests. In these tests, the initial relative density of the saturated sand bed was kept as 30% and the model's total height, including coir geocell, was 600 mm. Four tests were conducted placing geocell (GC) of various heights (full height (FH), half height (HH), and intermediate height (IH). According to the findings, using coir geocell has decreased coastal sand's susceptibility to liquefaction regardless of its height. This might be due to the additional confinement qualities the geocell displayed, given that each cell was concurrently filling and confining and strengthening the sand bed. The 200 mm full height geocell (FHGC) reinforcement caused the most significant reduction or a 44.5% gain in liquefaction resistance.

The existing soil at a particular site may not be suitable for construction activity due to poor bearing capacity and excessive compressibility. Natural jute geotextile fibers have recently been widely used for ground improvement because the material is environmentally friendly and abundant in Asian countries. A laboratory experimental program through a triaxial test and a numerical analysis using PLAXIS 2D finite element model has been implemented to study the influence of jute geotextile on sub-grade soil modification. The experimental and numerical result shows that including jute geotextile on sub-grade soil significantly improves the soil strength by lowering the stress, strain, and displacement at the top of the sub-grade soil, increasing the shear strength and bearing capacity of the soil and by reducing the quantity of instant settlement. Therefore, by ensuring adequate long-term durability through suitable treatments already developed, jute geotextile may be considered an environmentally friendly, sustainable material for sub-grade soil strengthening applications.

Ground penetrating radar (GPR) has become a fundamental tool in the realm of infrastructure projects. It is a non-destructive and non-invasive investigational technique that enables data collection in a non-destructive manner, thereby reducing the probability of errors and minimizing the cost of the projects. GPR is suitable for a wide range of infrastructure projects, including those related to geotechnical engineering and civil engineering. This paper presents an overview of the role of GPR in infrastructure projects, including its benefits, applications, and limitations. The paper also discussed simulation approach using forward modelling tools to visualize the response of GPR for various subsurface conditions. The paper summarizes the role of GPR in geotechnical engineering, such as soil analysis and investigation, subsurface characterization, and site planning. Additionally, it investigates the applications of GPR in the domain of civil engineering, such as pavement thickness measurement, bridge evaluation, and tunnel inspection. The challenges and limitations of GPR and possible approaches for overcoming them are also discussed. Finally, this paper concludes by emphasizing the key role of GPR in infrastructure projects, enhancing data accuracy, reducing errors, and minimizing project costs. In summary, GPR is a valuable asset for infrastructure project professionals, providing accurate and reliable data for geotechnical engineers and civil engineers to evaluate structural performances of the building and avoid any dangers or risks.

Geophysics is a scientific field that studies the Earth’s physical properties and processes using non-invasive techniques. With the advent of advanced geophysical investigation methods, the role of geophysics in structural and geotechnical engineering has become increasingly important. In this paper, we will discuss the key applications of geophysics in these fields, focusing on how it has revolutionized site characterization, foundation design, and hazard assessment. The accurate characterization of subsurface geology, groundwater conditions, and soil properties is crucial for any construction project. Geophysics provides a non-intrusive method to investigate the subsurface without the need for drilling or excavation. Foundation design is also one of the most critical aspects of any construction project. By applying geophysical techniques to map subsurface features, the variability and the lateral extent of soil properties can be quantified. Hazard Assessment: Natural hazards, such as earthquakes, landslides, and subsidence, can pose significant threats to infrastructure and human life. Geophysics can play a vital role in hazard assessment by helping to identify potential hazards and allowing for more effective mitigation strategies. It is important to recognize that geophysics is only one part of the overall site characterization process, and it should be complemented by other geotechnical investigation methods.

A long-lasting reinforced concrete diaphragm wall is constructed in the ground to support large-scale construction projects including dams, tunnel designs, deep basements, and enclosures. They function as a foundation, retaining wall, support for the underground construction, a way to prevent access to enable deep excavation. Diaphragm walls are frequently employed to support very deep excavations because since they can resist high stresses. They are suitable in urban areas with vast and older infrastructure, where they help to reduce disturbance to existing nearby structures. They also find vast application in marine structures and also when other earth retention system cannot be used due to geology of the area and presence of groundwater. Diaphragm walls also find its use in deep foundation pits in tunneling work in soft ground. It is advantageous compared to other retaining systems because of its large depth, lower ground settlements, ease in combining top-down and traditional construction techniques and for controlling movement of adjoining structures. In the present study, a detailed review of case studies of application of diaphragm walls in marine conditions as well as for underground structures like metros is done. Also, in the present study, comparison of construction of diaphragm walls including behavior during berthing and seismic conditions is analyzed.

Tunnels are risky and complex geotechnical structures. Long tunnels have been built with proper design ensuring proper stability, safety and have proved to be a boon to humans. Tunnels have been constructed successfully to pass the inter-state traffic and various other reasons. Use of underground space for tunnels leaves the land resource for other human activities. With the fast advancing world, globalization and urbanization has uplifted the life standard of people which has in turn led rapid consumption as well as deterioration of conventional resources. In the present paper, analysis of twin tunnels in granitic rock for Karwar-Kundapura highway is taken up. Rock found at the site is of variable strength which is classified based on rock mass rating (RMR) value. Midas GTS NX software is used to develop 3D model with parameters like terrain, rock properties, and support system like umbrella reinforcement and rock bolts with shotcrete. The analysis is carried out for the tunnel at the time of construction and also post-construction to know various deformation on tunnel.

The rigid pavements have been the most adopted all weather pavements in India in recent years as all the ingredients are available locally, and the concrete pavements can withstand high temperatures and the effects of rain more effectively than the bituminous pavements. The detrimental effect of plastic on the environment is well-established and a known fact. The non-biodegradable plastic is causing havoc with their disposal. Though some of the PET bottles are being recycled, studies show that more than 60% of them end up as waste. Even in the recycling process, many harmful gases are being emitted and a lot of energy is being consumed. The use of fibers such as steel, polypropylene, synthetic, etc., is common practice in concrete these days. The aim of the present project was to find out the effect of waste PET bottles when used as fiber reinforcement in pavement concrete. Here, an attempt was made to use waste PET bottles cut into long fibers as fiber reinforcement in the pavement concrete instead of imported, costly fibers. A regular pavement concrete design of M-30 grade was carried out, and cubes and beam specimens were cast to determine the compressive and flexural strengths, respectively. The same mix design was used, and the commercial fibers were added at 1.2% by weight of cement. In the other two mixes, 1.2 and 2.5% of PET fibers were used, and specimens were cast. The test results of each trial were compared with the conventional mix. There was no considerable increase in compression strength of concrete with PET fibers when compared with the control mix; however, about a 5% increase in flexural strength was observed.

In India, the majority of the road network comprises flexible pavements constructed using the traditional Hot Mix technology. However, this technology has various drawbacks, including environmental concerns related to the emission of greenhouse gases and health hazards for construction labourers. To address these issues, the warm mix asphalt (WMA) production method has been developed, with a lower production temperature than the traditional Hot Mix method. To evaluate the properties of materials used in WMA, laboratory experiments were conducted on aggregates and binders using standard marshal mix design methods. Based on these experiments, WMA was developed in the laboratory, and its stability characteristics were analyzed. To further improve the sustainability of WMA, this study focused on the evaluation of the performance of waste materials as fillers. The waste materials used here are conventional stone dust which was replaced with rice husk ash, waste glass powder, and waste brick powder in different percentages (0, 25, 50, 75, and 100%). Marshal stability tests were conducted to analyze their strength properties and it was found that the WMA with 25% of all the fillers (SD: RHA: WGP: WBP) showed a Marshal Stability 26.93% higher than that of conventional WMA. Therefore, this study recommends the use of 25% of stone dust along with RHA, WGP, and WBP with 25% each for patching potholes with sustainable Warm Mix technology. Future research could focus on using different types of fillers to improve the sustainability of WMA to further levels.

In this work, cohesionless pavement geomaterial reinforced with multi-layers of georeinforcement as jute fibres has been studied. The present work is carried out on unreinforced soil and jute fibre-reinforced soil to investigate the strength and stiffness capacity of pavement geomaterials using the California bearing ratio (CBR) test. The number of layers, optimum depth, and placement of the georeinforcement in geomaterial are investigated. The embedment depth of jute fibre, i.e. D/2, D/3, and D/4 in single, double, and triple layers has been optimized using CBR values. A novel concept of stiffness capacity along with penetration factor is introduced to evaluate the strength of the unreinforced and jute-reinforced geomaterial. The test results demonstrate that including jute fibre in single, double, and triple layers increases the stiffness capacity of the soil at the optimum depth of D/4. The stiffness capacity at varied input parameters varies from 0.378 to 0.682 at the maximum penetration factor which shows an 80.42% enhancement of strength in pavement geomaterial. The outcome of the present study provides a cost-effective solution to the strength improvement in cohesionless soils for embankment, subgrade, and pavement construction technologies.

The impact of slope height and slope angle on the deformation and stability of the cut slopes is critical for defining road safety projects. Proposed study investigates the stability of vertical slope/cut which is existing at Moira village, Goa, India. The analyses were carried out using FEM-based software PLAXIS 2D V 2023 1.0. Safety factor was found out considering three different cases (1) Existing slope; (2) Different geometric profiles with zero surcharge; (3) Different geometric profile with surcharge value. Bishop’s theoretical method was used to calculate the factor of safety of the existing slope. For each case considered above the slope is found to be unstable. The soil shear strength properties indicate cohesion in the soil. A suitable soil with improved friction angle was used in the analysis along with a reduced height of the vertical cut to 8 m. The stability of slope was found to be > 1. A higher friction angle allows the soil to bear greater loads without experiencing excessive deformation or failure. This is particularly important for vertical cuts in road construction, as the soil needs to support the weight of the road and any vehicles or structures on top of it.

Flexible pavements are subjected to vehicular loads that can affect their performance and decrease the service life due to rutting and fatigue criteria. For the past few decades, flexible pavements in India are constructed using base layers with unbound aggregates. In comparison to unbound granular layers, cement-treated base (CTB) is a superior layer of flexible pavement assembly that significantly reduces the stresses transferred to the soil subgrade. Cement-stabilized pavement bases provide a flexible response to rising traffic loads and frequency because they require little in the way of raw resources. This paper is mainly focussed on a methodical approach to design and evaluate CTB material in the laboratory. The fatigue performance of CTB beam specimens was assessed in the laboratory by repetitive loading under different stress ratios for different curing periods, and the findings were validated by comparing them with the fatigue model provided in the IRC-37:2018 guidelines for the design of flexible pavements. The research findings were utilized to assess how well the CTB performed in terms of fatigue under repeated wheel loads.

In the present era of road construction industry, lot of scope is there with respect to alternate materials used for cement concrete roads. In the case of rural road construction, under Pradhan Mantri Gram Sadak Yojana (PMGSY) scheme, lot of scope is there for new initiatives for the replacement of natural aggregates. In this context, the present research work aims to replace the natural coarse aggregates using construction and demolition (C&D) waste. Also the project aims to replace the fine aggregates using Laterite. As the current population trend is increasing to a greater extent, a lot of construction and demolition waste is being generated. Construction and demolition waste causes adverse effects on the environment that can be effectively used for concrete works. Laterite is a product that is widely available in Western parts of Karnataka. Here the associated problem is that Laterite alone cannot directly be used for agricultural purposes contains iron and aluminum oxides. Hence, an attempt has been made to consider C&D waste and Laterite for the concrete work. Various test proportions were done to determine optimum percentage of replacement. Physical properties were obtained from the laboratory tests and correlated with the natural aggregate test results values. From the literature study, it is an evident that 30–40% of replacement can be done as coarse aggregate using C&D waste (Murali in Int J Eng Res Technol 09:128, 2021). Even in the case of major structural work, C&D waste can be used with significant results (Novakova in Properties of concrete with partial replacement of natural aggregate by recycled concrete aggregates from precast production, 2016). In case of Laterite, literature study suggests 20–30% of replacement can be done effectively for fine aggregate (Srivastava in J Environ Nanotechnol 02:17–20, 2013). At an outset, the significant reduction in natural coarse/fine aggregates, results in both economical and financial benefit for the society. In this regard, combination of C&D waste and Laterite waste can be used effectively thereby producing eco-friendly or sustainable concrete roads for rural areas. In this research work, the compression test and flexural test were conducted to analyze the strength parameters. Low volume roads/rural roads were usually of flexible or rigid pavements.

For many years, hot mix technique has been the main paving mix utilized in road construction. However, there are also drawbacks to the hot mix method, including the release of greenhouse gases, high energy consumption, and compromised bitumen durability as a result of ageing during heating. To overcome these disadvantages of hot mix technology, a cold mix technology is proposed by various researchers to protect the environment as well as for the conservation of energy. In this paper, a cold mix technology is adopted for the preparation of road construction materials using granite aggregate and rubber waste. The experimental results are obtained for pure granite aggregates, basalt aggregates, and a combination of both granite and basalt aggregates. The emulsion content determination test and Marshall Stability test were carried out to fix the optimum bitumen content. The usage of granite aggregates produces better outcomes than basalt aggregates, according to the testing findings.

Due to urbanization the generation and extraction of materials like soil, aggregate, cement will have an ecological impact. Therefore to minimize the environmental impact, waste disposal and global warming, concrete made with demolition and construction waste functions well as a solution. Hence, in the present research work, the feasibility study of using the construction and demolition wastes in the low volume road construction in rural areas is presented. The recycled coarse aggregate produced from building and demolition waste is used to replace the coarse aggregates in concrete as (0%, 50%, and 100%) % replacement. The main objective of present work is to determine the compressive strength of concrete produced using recycled aggregate. The experimental results of 7 and 28 days compressive strength of concrete using recycled coarse aggregate are presented in the paper. Based on the results, the feasibility and suitability study of the concrete with recycled coarse aggregate is discussed.