Soil Behavior and Characterization of Geomaterials

This study focuses on the physical, mechanical, and durability properties of unstabilized and stabilized compressed earth blocks (CSEBs) with incorporation of natural aggregates (NA) and coir fibres. Several mixes were prepared in two stages with cement contents (0, 4, 7, and 10%), natural aggregates (0, 10, 20, 30, and 40%), and fibres (0, 0.25, 0.5, and 0.75%) by weight of soil to stipulate the optimum mix combination for CSEB production. In first stage, the optimum dosage of natural aggregate was determined, and then the maximum content of fibre was found with optimal dosage of natural aggregate. Results suggest that the addition of natural aggregate up to 30% increases the strength of unstabilized blocks. CSEBs made with cement content ≥4% improves the strength and durability. As the cement content reaches to 10%, the inclusion of 30% aggregate provides the maximum strength beyond that strength drops but the water absorption steadily decreases with increase in NA content. Inclusion of 0.5% coir fibre alone significantly improves the strength of both stabilized and unstabilized earth blocks. The addition of fibres further improves the strength of aggregate incorporated blocks. Overall, considering the strength and durability the mix made of 10% cement, 30% NA and 0.5% fibre was suggested.

The Cauvery River plays an important role and provides significant agricultural productivity in Tamil Nadu. Agricultural activities are carried out in the delta area due to the availability of water resources. In recent years, river water has been polluted in various ways through human activities and the process of industrialization. Consequently, contamination has an impact on the soil health of agricultural land. As a result, our focus has been on soil health analysis by measuring the chemical properties and heavy metals that exist in the soil. A classification model has been developed to determine the contamination level that exists in the soil through interpolation techniques. Soil samples are analysed in terms of soil chemical properties such as macronutrient, micronutrient, pH, and electric conductivity. Samples are collected at different locations at various depths where the sample size is 33. Samples are taken from the different regions that cover the category of farmland, urban areas, industrial areas, and river beds in the Cauvery delta region. A continuous surface had created for the concentration of the chemical constituents that are present in the soil through the space interpolation techniques using GIS technology which was determined from the analytical classification of the amount of the chemicals or the heavy metals that present in the soil has been determined through the fuzzy logic membership function. The soil contamination analysis based on the GIS approach provides an ongoing basis for monitoring contaminated sites. The contamination level along with to which extent it was contaminated is determined. The classification of the overall soil contamination levels of the Cauvery delta region is provided in detail, and its dispersed outcome is represented as a statistical analysis report in the form of the spatial variation maps.

Soil is the basic foundation material which supports all natural and manmade infrastructures. The use of soil either as foundation or fill material is based on its physicochemical and engineering properties. Being a complex system made up of inorganic and organic components, the engineering behaviour of soil largely depends on its chemical composition. The chemical composition of soil depends upon a number of factors viz. grain size, surrounding geology, depth, moisture level, and climatic conditions. Therefore, geotechnical investigations of soil for any river valley project are associated with field and laboratory testing to assess its suitability for construction purposes. The core chemical parameters required for assessing the suitability of soil for construction purpose are pH, total soluble salts, (TSS), calcium carbonate content, organic matter, water soluble sulphate, water soluble chloride, sodium, potassium, calcium, and magnesium. pH of soil extract indicates its acidic and alkaline characteristics. Determination of soluble salt content (total soluble salts) is important to study the impact of ground water on concrete buried in the ground. Estimation of parameters such as organic matter, cation exchange capacity, silica sesquioxide ratio are important for the purpose of stabilization of soil. The dispersive nature of soil is also need to evaluate for stability of hydraulic earth structures. In specific conditions total chemical composition, cation exchange capacity (CEC) and soil mineralogical examination by X-ray diffraction (XRD) method are also need to investigate. The present paper deals with the chemical and mineralogical evaluation of soils collected from various projects to assess their suitability in geotechnical application. Selected soil samples were analysed for different chemical parameters as per standard procedures laid down in BIS and ASTM codes. The interpretation and correlation of results then evaluated for engineering applications for desired purposes. The pH of majority of soil samples was observed to be in the range of 6.5–8.5. However, some soil extracts were also shown pH values beyond this range. Both extreme ranges may pose threat to civil engineering structures. The total soluble salts (TSS) contents of majority of samples observed to be below 1 millimhos per centimetre showing normal presence of soluble salts. Few samples were also exhibit TSS values between 1–2 millimhos/cm showing fairly good amount of soluble salts. The presence of water soluble sulphates and chloride values observed to be in acceptable range for majority of soil samples except samples with high soluble salts. The high values of calcium carbonate content were observed in some calcareous soil samples which shows good cementing property of soils and values of organic matter were observed to be in the range of 0.2–2.5% by weight. The value of soluble sodium content was found to be more than 60% of TDS value (sum of the four metallic cations, i.e. Ca, Mg, Na, and K) in some clay soils and shows dispersive nature which were also supported by XRD analysis these soils. The presence of typical clay minerals is responsible for dispersive nature.

Black cotton (BC) soil consists of montmorillonite minerals. Montmorillonite is one of the reasons to show the swell and shrink behaviour of black cotton soil. The unequal settlement develops under the structures due to this behaviour of black cotton soil. Thousands of researchers and investigators conducted an experimental study to improve soil black cotton soil properties using different materials. These researchers and investigators reported that the geotechnical properties of soil can be enhanced using waste materials. Still, the determination of the geotechnical properties of soil by the experimental procedure is a cumbersome and time-consuming task. A suitable quantity of waste materials is predicted to improve the geotechnical properties of BC soil. The regression analysis, random forest (RF), support vector regression (SVR), decision tree (DT), Gaussian process regression (GPR), and artificial neural networks (ANNs) AI approaches are used to predict the suitability of waste materials in the present research work. The artificial neural network models are developed by one to five hidden layers with ten neurons. The hidden layers are selected in the range of one to five. The performance of MLR, SVR, GPR, RF, DT, LMNN_1H10, LMNN_2H10, LMNN_3H10, LMNN_4H10, LMNN_5H10 is 0.4447, 0.3593, 0.8788, 0.7296, 0.6341, 0.5025, 0.7770, 0.6320, 0.5389, and 0.3856, respectively. The GPR model is identified as an optimum performance AI model and used to predict the suitability of waste materials to improve the geotechnical properties of soil.

The so-called undisturbed samples are widely used in the laboratory to obtain the engineering and index properties of the soils. Rarely does one get a perfect undisturbed sample as the method of sampling itself induces disturbances in the soil sample, such as changes in moisture content, soil structure, and stress conditions, all of which effect the compressibility and consolidation properties of the soft soils especially. In the present study, void ratio versus log effective stress results from both disturbed and undisturbed samples available in the literature are analysed, and compression and swelling indices, maximum past consolidation stress and OCR are estimated. Casagrande and log–log (Sridharan et al. in Geotechnique 41(2):263–268, 1991, [14]) methods were applied to estimate the preconsolidation pressures. Maximum past consolidation stress and OCR get reduced and the effect of past overconsolidation partly erased in the disturbed or not so perfect samples. Settlements for a given surcharge stress and layer thickness are then estimated for both disturbed and undisturbed states. Ratio of settlement based on disturbed state with respect to the undisturbed one is found to be greater than one implying settlements are overestimated in the conventional practice based on imperfect samples.

India is well enriched with abundant resources of magnetite and hematite iron ore. Mining activities are tremendously increasing to cater the demand of market, which in turn is responsible for huge generation of mining waste. Mine tailings impoundments produced during beneficiation and extraction of iron ores create environmental threat and are disposed at high monetary and ecological cost. There is a need to find a sustainable and economical solution to handle large quantity of generated waste. Depleting natural resources like granular soil as backfill material needs a substitution in many application-like pavements, mechanically stabilized wall, embankments, etc. This paper presents a critical review on literatures highlighting on use and reuse potential of iron ore tailings as a backfill material in structural application such as MSE wall, embankments, pavements. Characterization and engineering behaviour of the tailings are the central necessity for estimating its effectiveness as its properties vary from ore structure. Mineralogical characterization, shear strength, permeability, workability, and compressive strength are the properties discussed in this paper. Results show that iron ore tailings have properties which can be considered as an effective substitute in structural applications. Adopting it as backfill material can be considered an environmentally friendly method of stabilization. It protects the surface structures and abate subsidence in abandoned underground mines. It has its potential in handling large volume of tailings and significantly reduces the quantity of waste generated in the state.

Expansive soils undergo significant volume change with respect to the change in water content, which can be either in the form of swelling or in the form of shrinkage. The liquid limit of expansive soils may even vary from 100 to 500%. In general, all expansive soils have low shear strength, high compressibility and low permeability at very high initial water content. The same expansive clay would undergo high swelling, and shrinkage depends on seasonal fluctuation of water content in the wetting and drying process, respectively. Even though the compressibility and expansivity coexists, still there is no correlation between these two parameters. In this paper, an attempt is made to correlate compressibility with expansive characteristics of natural and synthetic soil whose liquid limit ranges from 62 to 389%.

Breakage of particle is one of the significant factors which modifies the behaviour of rockfill material, and it is also influencing dilatancy, angle of internal friction (φ), stiffness, and permeability. However, the breakage laws of the rockfill material during the shearing remain uncertain. In this paper, the study of the particle breakage analysis of the poorly graded metamorphic rock, viz. schist, phyllite, and quartzite, has been considered. This investigation is based on the one of the consultancy job project of northern part in India for using rockfill material in the concrete face rockfill dam (CFRD). Sliding and roll over are more constrained under a high confining pressure (0.6, 1.2, and 1.8 MPa) rather than crushing of individual particle. Consequently, the contact force between particle to particle significantly increases and considerable amount of particle breakage occurs. During the application of stresses, breakage initiated from lagger size of particles and smaller sizes of particles initiates to rupture under application of confining pressure increases. The fraction of particles lesser than 0.2 mm diameters always added with increasing shearing strain. The amount of breakage showed more with the increasing of cell pressure. The breakage of particles under different confining pressures (stress level) is quantitatively presented as breakage factor, Bf. Breakage factor of rockfill material is to be calculated as per the pre- and post-test particle size distribution curves for all the maximum sizes (dmax) of particle. The effect of confining pressure (σ3) and dmax on the breakage factor, Bf, is studied by highlighting the plotting between dmax versus Bf for different σ3 for tested material. From the analysis, it is observed that the breakage factor increases from 3.5 to 11.5% with variation of confining pressure ranging from 0.6 to 1.8 MPa. It is found that the breakage factor increases with increase in dmax and σ3 for tested rockfill material.

Utilizing pond ash (PA) deposited in ash lagoons generated from thermal power plants (TPPs) as subbase material for hardstand foundation not only helps the cause of residual waste disposal problem but also solves associated shortcomings like, lower utility and degrading environmental impact for prolonged deposition. However, the property of the PA varies not only among various TPP but also within a single ash lagoon, depending on the point of deposition and subsequent settlement. This study presents detailed analysis of chemical, physical, morphological, and mineralogical properties of inflow and outflow PA within the same ash lagoon. Local sand (LS) has been used as conventional granular subbase material. A comparative analysis of the respective material properties has been drawn to access the feasibility of PA as subbase material, substituting sand. The results showed CBR ranging from 16.63 to 17.19% for standard compacted unsoaked samples, 23.55–24.17% for modified compacted-soaked samples of PA, compared to 25.08 and 32.96% of LS. Consolidated drained triaxial tests showed cohesiveness and φ value 32° for PA samples compared to 40° for LS. FESEM explained distinguished morphological forms of the mineral and showed the presence of microspheres in PA. XRD detected alumina-silicates, cristobalite, anorthite and showed PA particle size is directly proportional to its pozzolanic reactivity. FTIR detected presence of hydroxyl (–OH) stretches and (H–O–H) vibrations along with bond water molecule bending, revealing its pozzolanic nature. Finally, LFWD test provides 1.7% less peak surface deflection than LS predicting PA’s favorably as supplementary granular material for hardstand subbase layer.

The variation of moisture content in the field may occur due to fluctuation in groundwater level due to climatic variation, drainage condition, porosity, density of particle, etc. These variations of moisture content in the soil directly affect the shear strength of soil. Laboratory study to evaluate the shear strength of the compacted soil remoulded with proctor density under varying moisture content and further allowing compacted soil to undergo saturation may help to understand the similar condition of compacted field with fluctuating water levels. To stimulate the field condition, triaxial shear tests were conducted with consolidated undrained (CU) method on MI (Inorganic silt of medium plasticity) type of soil. Two field conditions were modelled in laboratory study. In the first case, specimens were remoulded at 98% maximum dry density (MDD) at varying moisture content (w), considering it in a partially saturated state, as B-factor measurement is less than 0.9. In the second case, specimens were remoulded from same sample, as done in first case and further saturated with the help of back pressure system in a controlled manner exhibiting B-factor > 0.9, representing saturated state of soil. The deviator stress–axial strain graphs are plotted at incremental confining pressures (σ3) and analysed at different remoulded moisture contents. It was observed that deviator stress increases with increase in σ3 and decreases with increase in moisture content. However, deviator stress obtained in the partially saturated samples is much higher than saturated samples. The maximum stresses obtained are also employed to understand modified failure envelopes and shear strength parameters with respect to total stress measurement. Based on the results, it was found that the moisture content is the dominant factor affecting shear strength. Angle of internal friction ‘ϕ’ plays an active role in controlling the shear strength of MI type of soil. The cohesion has little effect on shear strength of soil. This paper discusses the effect of moisture content on shear strength parameters of MI type of soil tested in triaxial loading under incremental confining pressures.

Expansive soils are the most problematic soils, which cover almost one-fifth of area of the Indian subcontinent. These soils exhibit swelling and shrinkage, causing distress in building foundations and pavements. Owing to lack of good construction sites having higher bearing capacity and less subjective settlements, it is imperative that the construction industry has to go in for construction sites in marginal and wastelands. For the coarse-grained soils, physical phenomenon of engineering behaviour is observed and physicochemical behaviour is observed for fine-grained soils. The recent research studies have shown that reinforcement itself gives effective control over swell-shrink behaviour and improves the compaction characteristics of expansive soils. For the present study, natural fine-grained expansive soils having different liquid limit ranges (55, 65, and 85%) were identified. The index properties and IS standard and modified compaction tests were conducted on natural fine-grained expansive soils blended with variation in fibre percentage from 0.5 to 3%. The correlations were developed between liquid limit, plastic limit, shrinkage limit, plasticity index, and shrinkage index, activity of soil with percentage variation in fibre. The maximum magnitude of maximum dry density was achieved at 0.5% blending of fibre for the soils having liquid limit 58%, whereas for soils having liquid limit 74% and 85%, it is 1.5% and 2%, respectively. For the maximum unconfined compressive strength (UCS), the optimum percentage of fibre content for soils 1, 2, and 3 is 0.5%, 1%, and 2%, respectively, and it is increasing with increase in liquid limit of the soil.

The behaviour of fine-grained soils can be attributed to their mineral composition and the amount of fines present in them. The present study aims to determine the effect of mineral composition and quantity of fines on the Atterberg limits and compaction characteristics and to determine the correlation between them. Two types of fine-grained artificial soil mixtures were prepared in the laboratory representing kaolinitic and montmorillonitic mineral compositions.The amount of fines was varied at 10% intervals, from 50 to 100%. The Atterberg limits like liquid limit, plastic limit, shrinkage limit, and compaction characteristics like maximum dry density (MDD) and optimum moisture content (OMC) for two compaction energy levels, i.e. standard proctor (SP) and modified proctor (MP) tests, were determined. The correlations were developed between percentage fines and Atterberg limits and similarly between percentage fines, Atterberg limits, and compaction characteristics for artificial mix proportions. The developed correlations were used to predict the properties of natural soil samples, and the predicted and actual values are compared.

Electrical resistivity technique is gaining a lot of significance in the geotechnical engineering field due to the advantages it offers such as non-destructiveness, cost-effectiveness, and rapid investigation of subsurface soil properties. The electrical resistivity is an intrinsic soil property and is considered to be representative of various geotechnical properties such as mineralogical composition, pore fluid conductivity, surface conductivity, particle size, fine content. The present study includes the measurements of electrical resistivity of the mine tailing using the laboratory-based four-electrode method. This paper explores the effect of various geotechnical characteristics of partially saturated and saturated tailing samples and aims at developing the correlations between resistivity and geotechnical properties. Controlled laboratory experiments were conducted to study the variation of resistivity with moisture content, compaction density, porosity, degree of saturation, temperature, and type of pore fluid. The electrical resistivity was found to be influenced by changes in the water content, degree of saturation, dry density, and other listed properties for sample prepared under partially saturated condition. Also, the rigid wall variable head permeameter was equipped with electrodes to enable measurements of electrical resistivity while simultaneously measuring the permeability of saturated tailing samples. The resistivity of tailing samples was found to be related to saturated permeability. The electrical resistivity values of tailing sample under the loosest and densest conditions lie within range of 70 Ω m–5 Ω m. The resistivity of mine tailings was also compared with the fine sand and found to be lower than sand due to traces of particles of metallic origin. The present work may be useful for robust estimation of in situ characteristics of tailing and soils, in general, by means of electrical resistivity surveys and may thus help in preventing the failure conditions by monitoring the changes in geotechnical properties under prevailing conditions.

The polymers are non-toxic and inexpensive soil stabilizers which are being used for improving the soil characteristics. Addition of polymer to soil improves bonding between adjacent soils particles which results in flocculation and stabilization of soil. To study the effect of urea-formaldehyde resin on index properties and density of soil, urea-formaldehyde resin was mixed with soil samples in various proportions, cured, and its index properties were determined. Mixing of urea-formaldehyde resin with soil improves the index properties of the soil. When urea-formaldehyde resin was mixed with soil, the soil changed from non-plastic to plastic and the Atterberg limits of the soil got decreased on increasing concentration of urea-formaldehyde resins in the soil. The grain size analysis showed that proportion of large particles got increased when urea-formaldehyde resin was mixed with the soil. Addition of lime in polymer-mixed soil did not improve compaction characteristics which imply that it is not always having beneficial effect on index properties of soil to mix combination of polymer and lime in soil.

The microstructure of compacted expansive soils differs depending on the remoulding water content and compaction dry density. In particular, along the standard Proctor compaction curve, the expansive soil compacted at water content less than the optimum water content has relatively larger macropores in comparison to the expansive soil compacted at water contents greater than the optimum water content. These changes in microstructure not only influence the hydraulic conductivity but also the infiltration rates during the swelling process of compacted expansive soils. Therefore, this paper brings out the effect of remoulding water content on the infiltration rates during swelling process and hydraulic conductivity at the end of swelling process of a compacted expansive soil. The oedometric-infiltrometer test arrangement was used to determine the hydraulic response, in terms of infiltration rates and hydraulic conductivity, upon inundation of the compacted expansive soil specimens remoulded with water contents corresponding to dry and wet side of optimum water contents at the same standard Proctor compaction dry density. As expected at the end of swelling process, the swell magnitude and hydraulic conductivity were relatively higher for the clay specimen compacted at dry of optimum water content. In addition, the infiltration test results showed that the time needed for the outflow (i.e. permeation flow) to occur and attain a steady state condition was comparatively less for the compacted clay specimen compacted at dry of optimum water content than at wet side of optimum water content. The changes in dry density and water content during the swelling process of compacted clay specimens were also traced.

Mangalam Dam is one of the significant sources of irrigation water in Kerala. Sediment deposition due to devastating floods and massive rainfall reduced the capacity of the reservoir significantly. Dredging is essential for maintaining the storage capacity of reservoirs, which yield a bulk quantity of soil. Understanding variation in the physical and engineering properties of sediments in the water body concerning depth and locations is helpful to assess the scope of reservoir dredged sediments in earthwork structures. This paper focuses on the use of Arc GIS for recording, analysing, and presenting the geotechnical data of dredged sediments to make a record of sediment properties. Arc GIS is used to prepare a zone map of properties of dredged sediments in different locations. For that collected 15 soil samples from the reservoir bed at a depth of 2 m for GIS mapping and statistical analysis. The initial characterization is done by conducting particle size distribution, Atterberg limits and specific gravity tests on various samples. The samples collected can be classified as low, intermediate, and high compressible silt and silty sand soil. Based on the laboratory test results, the percentage of clay and soil liquid limit varied among places. Using the IDW technique, soil properties of nearby areas are interpolated. The IDW method generates continuous fields of characteristics at all locations by employing the same set of parameters at all times. The map is helpful to get information regarding the type of sediment deposit at different areas of the reservoir. Compaction tests on soil samples from two reservoir locations showed that reservoir sediment could be used for embankment construction with or without stabilization depending upon the nature of sediment assessed using the GIS map.

Field compaction of soil usually involves different types of equipment with the compaction energy varying significantly. If can relative density be correlated with index properties of cohesionless soil, the developed correlations of relative density at different compaction energy are very useful in fieldworks. As per literature, for granular soil, relative density (Dr) depends on the particle shape, size, particle size distribution, and variance in gradation curve. Present study involves development of correlation model, where multiple linear regression analysis is used to relate relative density at specific compaction energy of soil by its index properties. Thirty samples of cohesionless soil from Ahmedabad region collected and tested for soil properties, i.e. grain size distribution (Fc%, D10, D30, D50, D60, Cu, Cc), specific gravity (Gs), density index test for maximum and minimum void ratio (emax and emin), laboratory compaction test (standard and modified) for void ratio (es and em). Based on tested index properties of cohesionless soil, multiple linear regression analysis carries out in SPSS software and individual regression model developed for all assign output variables emax, emin, es and em, which are predicted by Fc%, D10, D30, D50, D60, Cu, Cc, Gs input variables. By relating above regression model, predictive model of relative density was concluded. Accuracy of model checked by relating predicted value to experimental value of relative density, where 85% sample size lies within range of ±5% (95% confidence interval) with reference to 1:1 line and all with in ±10. The relative density correlations described above will be useful for field design specification.

Geotechnical investigation at site for a multistoreyed residential complex in south Delhi indicated the presence of steeply dipping and folded rock. The variation in the depth to rock within each tower highlighted the possibility of differential settlement of the raft foundation planned at basement level. To characterize the formation, seismic refraction tests were performed along four lines. The tests assisted in confirming the trend of the rock profile in the area of the towers. The geophysical evaluation was used to evaluate whether the dip of the rock clearly defines the variation in the rock profile across the site.

India being a tropical country, the temperature during summer reaches as high as 40–45 °C as a result of which the ring-wells introduced for the purpose of irrigation and domestic utilization goes dry. This has an adverse effect on the crops as well as the livelihood of the villagers, which necessitates to increase the yield of ring-wells by low-cost/user-friendly methods. A ring-well was chosen as the prototype in cultivated land, and the physical parameters of the soil along the well's periphery were evaluated to determine the well's soil profile. Furthermore, at the bottom of the well, perforated laterals of two different lengths were placed in eight radial directions alternately, and the yield was measured at regular interval of time. The double-ring infiltrometer test was conducted in the field at different locations representing the area in the field to assess the magnitude of permeability. Undisturbed soil sample were obtained from the field to estimate the magnitude of coefficient of permeability in the laboratory by falling head method. Accordingly, a model was created, and the yield of the model was determined by recuperation testing. Furthermore, at the bottom of the well, perforated laterals of two different lengths were alternately inserted in eight radial directions, and yield was recorded for various combinations of the laterals. To determine the model's efficiency, the yield of the model without laterals and the yield of the model with laterals were compared. The coefficient of correlation for the yield obtained from both perforated and slotted laterals was determined using regression analysis. The yield obtained from the model studies was compared with that of prototype.

Electrical resistivity testing is a well-known geophysical method for the quick assessment of subsurface conditions. It can be performed at a reasonable cost and is known to correlate well with major geotechnical properties of soil. This study was performed to study the variations in electrical resistivity of some local soils and correlate them with some of their geotechnical properties. For this purpose, soil samples were collected from around the Mahura region of Bhubaneswar which included some red lateritic soil, greyish-brown clayey soil, and poorly graded sandy soil. An inexpensive four-electrode soil resistivity box was fabricated and was used for measuring the resistivity of these soils. The Wenner electrode configuration was used for the measurements. Electrical resistivity was measured by applying a 25 V DC through the outer electrodes of the soil box and measuring the ensuing potential difference the two inner electrodes. Variations in resistivity were studied with respect to changes in soil types, moisture content, dry density, and clay content. Resistivity showed a decreasing trend with increase in moisture, dry density, and clay content. Multivariable linear regression analysis was performed to model resistivity as a function of moisture, density, and clay content using the data analysis tool of MS Excel. The multivariable regression models displayed a fairly good correlation between resistivity and the soil variables with R-squared values in the range of 0.75–0.87. The results from this study could be used as a basis for estimating the basic soil properties from field testing methods.

A comprehensive geotechnical investigation is very important to ascertain the suitability of construction materials to be used for different zones in an earthen dam. Core material provides imperviousness in an earthen dam while shell materials provide stability to the dam. Two different borrow areas were selected, and collection of samples for soil investigations was carried out to ascertain the suitability of core material of the proposed earthen dam in the central part of India. The proposed dam would cater the need of drinking water and irrigation in water scarcity area. However, the results of index and engineering properties obtained from the geotechnical investigations indicated that the soil samples collected from the two different borrow areas neither fulfill the requirement of quantity of borrow area materials nor they were found suitable to be used for the construction of core of the dam. Moreover, the availability of alternate borrow areas to cater to the need of the construction of the embankment dam was not available. Therefore, the only option left with the project is to blend the available suitable and the unsuitable materials from the two different borrow areas in different proportions. The paper presents the results of geotechnical investigations of two different borrow area materials as collected and the results of different trials in various proportions of available soil samples as blended from these borrow areas for improving the index and engineering properties of soil such as grain size distribution, soil type, consistency limits, maximum dry density, optimum moisture content, shear strength parameters, compressibility characteristics, and the permeability characteristics. A comparative study between the original and blended borrows area materials exhibits that blended soil samples fulfill the quantity of core material.

Plate anchors are foundation structures used in transmission towers, retaining walls, and submerged pipelines to resist the pullout forces. This article outlines the influence of soil consistency on the pullout behavior of plate anchors buried in reinforced clay. The experimental tests are carried out in unreinforced and reinforced soil conditions at different consistency index of soil (Ic = 0.15 to 0.6). The square plate anchors are placed at embedment ratios (H/B) 1 to 6 and loaded vertically. In reinforced soil conditions, a single-layer reinforcement in the form of a geotextile sheet is positioned at a depth of 0.25 H above the anchor, where H is the embedment depth of the plate anchor measured from the ground surface. The size of geotextile sheet is taken as four times the width of the anchor plate. The embedded plate anchor is subjected to monotonic pull, at a rate of loading 3.5 mm/min. The applied displacement and the corresponding pullout loads are recorded. The variation of pullout capacity and breakout factors with embedment ratios and consistency index are presented. It is found that the inclusion of geotextile reinforcement increases the resistance against pullout load with less ultimate displacement of anchor. The ultimate pullout capacity of the plate anchor was considerably enhanced with an increase in the consistency index of the soil.

Subsurface geology and geotechnical properties play a significant role for the amplification of ground motion at the time of seismic events. Shear wave velocity model is a necessary input for the site characterization of any region. In this study, geophysical investigations in reference to multichannel analysis of surface wave (MASW) and seismic refraction tests have been carried out at 64 places in Vadodara city. The investigations were performed in the study region by dividing the whole region into 2 × 2 km grid size. SeisImager software is used to determine the shear wave velocities (Vs) and compressional wave velocities (Vp) at various depths. Around 430 borehole data have been synthesized to prepare soil profiles which include the information such as soil type, SPT-N value with depth, and water table. The soil profile of the Vadodara region is alluvium soil with loose sediments. The soil layers observed at different depths mainly consist of silty sand, silty clay, silt of low to high plasticity, clay of low to medium plasticity. Shear wave velocity and compressional wave velocity models have been generated at 5, 10, 15, 20, 25, and 30 m depth through ArcGIS software. The classification of the substrata based on the shear wave velocity profile at 30 m depth (Vs30) has been made by using soil characterization. The obtained output from the study will be used for further studies such as liquefaction assessment, seismic hazard, and risk model of the study region.

In this work, the authors have used 63 high strain dynamic pile load tests conducted by the authors in different offshore environments to develop neural network models, accurately predicting the total ultimate pile capacity and shaft resistance and end bearing. This model is developed explicitly considering the offshore pile driving scenario, where open-ended steel pipe piles are driven using different hammers. The pile’s capacity is found using Pile Driving Analyzer [PDA], and post-analysis is done using Case Pile Wave Analyses Program [CAPWAP], which is the standard practice for offshore pile testing. The input parameters used in this prediction involve pile geometry and soil properties available from CPT tests as well as the dynamic measurements obtained from strain gauges and accelerometers during the pile. Also, the pile driveability characteristics like measured blow counts and dynamic stress wave data during the field test are used as inputs to predict pile capacity. The Bayesian regularization function (as the optimization algorithm) with two hidden layers was the best from the different architectures of neural network models used here. The model developed performs the best during the training and testing, where an entirely new set of data is used. This approach is easy to apply in the field and is found to be accurate when the results of CAPWAP from dynamic pile load tests are to be verified because CAPWAP requires high expertise and lacks a unique solution.

Sinkholes are surface depressions which can often be catastrophic because of collapse of large underground openings or voids created due to natural or anthropogenic activities. Previously, the term “sinkhole” was used to indicate any surface collapse which occurs due to the presence of karstic strata, containing cavities due to the dissolution of carbonate rocks, but now it has become a generalized term to represent ground subsidence regardless of the origin. Sinkholes can occur due to either underground mining or tunnelling activities or pipeline failures. This paper provides an insight to the mechanism which occurs in the ground due to sinkholes in karstic but also in non-karstic grounds. It reviews the available research evidence in detail. The classification of sinkholes based on the factors which trigger the cavity formation and the mechanism which leads to the collapse is first discussed. This study shows that damaged pipes are the major source behind sinkholes, many incidences of which are observed in urban areas of this country. The rate of cavity development and geometry of sinkhole are found to be governed by the origin, thickness, and properties of the overburden soil, and the rate of suffosion. The paper further reviews the physical and analogical models which have been developed to predict the size of this problem, and the stains in the soil, which lead to the collapse. This is followed by the review of the advanced investigation techniques using field surveys.

Skirted foundations are steels or concrete-plated foundations with a skirt underneath the periphery. Skirted foundations are mainly used in offshore structures. This foundation reduces the material cost and installation time. As compared to shallow foundations, skirted foundations transfer the load into the deeper level, thus improving the bearing capacity of the foundation and as well as reducing the settlement. The bearing capacity of the skirted foundation is the combination of the end bearing (at skirt tip) and skin friction between the skirt and the soil. This paper investigated the behaviour of axially loaded square skirted foundation resting on the sand with the help of finite element software, ABAQUS 3D. Parametric studies on skirted foundations were performed numerically. The effect of skirt length, skirt angles, and the additional internal skirt on the bearing capacity and settlement of the foundation was assessed. The skirt length to width of foundation (L/B) of 0.0 (surface), 0.5, 1.0, and 1.5 are taken for the analysis. And one number of internal skirted is provided for each skirted foundation. The skirts inclination of 0, 15, 20, and 25 degrees has been considered in the analysis. Results revealed that as the skirt length increases, the foundation bearing capacity increases and settlement reduces; this increase is due to the load being transferred to a deeper level and increasing volume of the soil between the skirts. Also, the introduction of internal skirted results in increases in bearing capacity and reduction in a settlement. It has been also observed that as the skirt inclination increases, bearing capacity increases and foundation settlement is reduced. This increase is due to the increasing skirt area that is in contact with the soil and increasing foundation area projection.

Subsoil investigation plays a major role in the effective planning and execution of construction, land use planning, and so on. The subsoil data available from various borehole records are abundant which can be utilized effectively to generate a database of subsurface information that can be both time and cost-effective in the civil engineering sector. Geographical information system (GIS) has emerged as one of the major spatial database tools in playing a key role in the studies of land suitability, hydrology studies, various hazard risks, and so on. The present investigation deals with the development of geotechnical parameter maps for South Chennai, Tamil Nadu, India, between Perungudi and Kelambakkam using GIS. Geotechnical attributes of borehole samples collected from various locations in the study area are spatially interpolated to obtain attribute maps using different interpolation techniques in ArcMap 10.8 software. Groundwater table, SPT N values, soil classification, safe bearing capacity, and total settlement maps under different loading and footing dimensions are generated which can be used to find the respective parameters within the study area using the spatial coordinates of the location. The resulting models showed that good bearing stratum experiencing less total settlement of soil was observed towards the southern areas in the study area, whereas the soil present in the northern parts had lower bearing capacity undergoing more settlement due to the presence of waterlogged areas and shallow groundwater table. Inverse Distance Weighted (IDW) and Topo to Raster interpolations were identified as the most suitable technique for developing spatial attribute maps in the study area.

Liquefaction in the soil is one of the most cataclysmic effects of an earthquake. The conventional techniques with field investigation make it possible to forecast the damages with respect to liquefaction triggered by an earthquake event. However, there are many inevitable hurdles to conduct field investigation such as inaccessibility, economic drawback, and instrument-related disadvantages. With the advent of advanced remote sensing techniques, researchers are seeking answers to solve this problem with the help of geospatial technology where pre- and postearthquake satellite images are used. Literature on the use of thermal images and tasselled cap wetness images to hypothesize that soil moisture content increase due to liquefaction exists. Such understanding can be estimated through characteristic spectral features, which are sensitive to soil moisture. However, this has limitations related to the knowledge of terrain sensitivity and soil moisture retention capacity. With the advent of new techniques, the information on soil moisture derived from visible, near-infrared, and shortwave-infrared wavelengths are used to identify the hotspots of liquefaction. Further microwave remote sensing techniques are used to detect liquefaction-induced damages. Similarly, there are works published whereby using the property of bare soil’s inverse reflectance of visible and near-infrared and short-wave infrared relation with soil moisture to establish a correspondence between satellite data and field data with respect to liquefaction is established. In spite of all the efforts, none of the remote sensing techniques are efficient enough to accurately capture the liquefaction. However, combining geospatial techniques with geotechnical investigations improves the efficacy to capture the hazards related to liquefaction in the spatial domain. This work presents an exhaustive literature review on the application of remote sensing and GIS in liquefaction potential mapping.

Brick earth has to satisfy the basic compositional requirements as per the engineering standards. However, at many places suitable brick earth may not be available. The indiscriminate use of top soil for brick making causes an enormous loss of fertile top soil which otherwise could be highly suitable for cultivation. Despite several advancements made for making alternative bricks, still clay bricks are the most sought-after material for walling. In view of this tendency for use of traditional bricks, an attempt is made to reuse the old demolished brick powder for making fresh bricks with an idea of sustainable use of top soil. For this purpose, different proportions of soil and brick powder in the ratio of 60:40, 50:50, 40:60 respectively were tried to make bricks, and subsequently, their physical and mechanical properties are compared with those of the normal bricks. The present study indicated that the old brick powder can be suitably mixed with higher plasticity soils even up to 50% without any difficulty in molding of bricks and the shrinkage of these soils could be overcome. The brick powder as a bulk non-plastic material is serving as a balancing material in these soils. Further, it is observed that these bricks made using old brick powder could be burnt over a lesser time period compared to traditional bricks without any compromise in strength, and also the edges are observed to be intact. Therefore, the waste demolished old brick powder can be a very useful bulk material in brick making even by using higher plasticity soils for sustainable building industry.

Time and cost are the two crucial factors on which project progress is calculated. The time–cost analysis is a crucial parameter in quick and high-budget building projects, which actually demonstrates the alternative paths and optimum one for faster completion of any project. In the case of bridges, marine piling accounts for most of the time. Further marine piling drilling accounts for almost 70% of the time. In the case of drilling, a significant delay occurs because of equipment breakdown, non-availability of consumables, and operator unavailability. The present work aims to reduce the idle time of the equipment, thus improving the productivity of the equipment. Besides, the optimization of the resources, time, and cost in the marine piling construction was undergone. The analysis is carried out by taking the data of two live projects. Optimization will be carried on the activities in the critical path. Drilling is the main critical activity in marine piling. The critical path shall be found using P6 software. The maximum time that can be reduced and optimized in both projects shall be achieved. Maximum cost savings shall also be achieved. A graph will be drawn with time on the horizontal axis and cost on the vertical axis. This strategy inculcates the contractor to accelerate the piling schedule if required by tracking the cost incurred.

The determination of soil water characteristics or retention curves (SWCC) from laboratory procedures is tedious and time-consuming. In this study, the prediction of Fredlund and Xing fitting parameters applicable to finding the suction potential of plastic soils is determined using an artificial neural network modelling. A three-layer ANN model consisting of input, hidden, and output layers. The input layer consists of the highly influencing soil variables such as percentage of soil passing 4.75 mm and 0.075 mm IS sieve, liquid limit, plasticity index, and saturated volumetric water content. The hidden layer consists of 20 neurons to train the input data with the existing output data using the Levenberg–Marquardt backpropagation method. The Fredlund–Xing (FX) model fit parameters, namely af, bf, and cf, were selected as the output variables, and the ANN model with 70% dataset for training, 15% to validate, and 15% to test the network gives a higher correlation of 0.65–0.82. Thus, the use of the ANN model confirms the ability of selected input variables to predict the fitting parameters of the FX model. The study confirms the ability of ANN as an aiding tool to determine the suction potential of plastic soils such that expensive and cumbersome laboratory testing procedures can be replaced.

Shear strength is a very important soil parameter in offshore soil investigations for large-scale projects where time and huge costs are involved for the foundation assessment of jackup rigs, fixed platforms, offshore pipe lay, and other structures. The engineering behaviour of offshore cohesive soils is complex, while the primary parameter for engineering assessment is the undrained shear strength. The estimation of undrained shear strength can be obtained from various methods, such as unconsolidated undrained triaxial test (UU), torvane (TV), pocket penetrometer (PP), and miniature vane shear tests (MV). In this paper, an effort is been made to present from the large database, the differences in the undrained shear strength from various methods, and a recommendation in order to obtain the appropriate ground models for further analysis of foundation assessment for offshore constructions.