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2024 | Book

Proceedings of the Indian Geotechnical Conference 2022 Volume 3

Geotechnics: Learning, Evaluation, Analysis and Practice (GEOLEAP)

Editors: Babu T. Jose, Dipak Kumar Sahoo, Anand J. Puppala, C. N. V. Satyanarayana Reddy, Benny Mathews Abraham, Ravikiran Vaidya

Publisher: Springer Nature Singapore

Book Series : Lecture Notes in Civil Engineering


About this book

This book comprises the select proceedings of the Indian Geotechnical Conference (IGC) 2022. The contents focus on recent developments in geotechnical engineering for a sustainable world. The book covers behavior of soils and soil–structure interaction, soil stabilization, ground improvement, and land reclamation, shallow and deep foundations, geotechnical, geological and geophysical investigation, rock engineering, tunneling and underground structures, slope stability, landslides and liquefaction, earth retaining structures and deep excavations, geosynthetics engineering, geo-environmental engineering, sustainable geotechnics, and landfill design, geo-hydrology, dam and embankment engineering, earthquake geotechnical engineering, transportation geotechnics, forensic geotechnical engineering and retrofitting of geotechnical structures, offshore geotechnics, marine geology and sub-sea site investigation, computational, analytical and numerical modeling, and reliability in geotechnical engineering. The contents of this book are useful to researchers and professionals alike.

Table of Contents


Soil Stabilization, Ground Improvement and Land Reclamation

Geotechnical Benign Characterization of Nano-amended CLS Stabilized Soil

Nanomaterials are gaining acceptance in the geotechnical and geoenvironmental engineering fields due to their non-toxic nature and less energy required for production. This paper deals with the effect of iron oxide nanoparticles (nano-Fe2O3) inclusion along with calcium lignosulfonate (CLS) as a binder in enhancing the strength characteristics of locally available soil. CLS acts as an initiator and enhances the interaction of nanoparticles with soil. The different proportions of nano-Fe2O3 and CLS considered for the tests were 0.1%–0.3% and 1%–3%, respectively. Compaction tests and unconfined compression strength tests were carried out at different proportions of nano-Fe2O3 and CLS dosages, blended individually and in combination. The desired values of maximum dry density and optimum moisture content were obtained for a combination of 0.2% nano-Fe2O3 and 2% CLS. Unconfined compressive strength (UCS) test was conducted for samples cured for 7, 14, and 28 days, which were mixed with different proportions of nano-Fe2O3, and CLS showed a tremendous improvement in soil strength. There was a significant improvement in the 28 days strength from 183.4 kPa to a maximum of 496.5 kPa. The mechanism responsible for the improvement in the strength characteristics was confirmed by the SEM images of the stabilized soil samples obtained from UCS tests.

Harshit Harsh, Arif Ali Baig Moghal, Romana Mariyam Rasheed
Effect of Granite Sand and Calcium Lignosulphonate on the Shrinkage Characteristic of Clay

Clay soils that undergo significant volume change due to seasonal moisture variations cause severe damage to the superstructure. The shrink-swell potential is quantified by relying on either shrinkage characteristics or by measuring the swelling characteristics. This study explains the shrinkage behavior of clay soil stabilized with granite sand (GS) and calcium lignosulphonate (CLS). CLS is used as a binder for clay-GS mix. The dosages of GS and CLS (by weight of soil dry mass) were maintained at 30%–50% and 0.5%–2%, respectively. With the increase in dosage of GS, the shrinkage limit increased by 88.46% at 50% dosage. This is attributed to the replacement of a fine fraction of the soil with GS. In similar lines, the addition of CLS increased the shrinkage limit to the maximum of 123% at 2% CLS dosage. This is attributed to the formation of a flocculated structure. In addition to this, the clay is blended with both GS and CLS in the combination of each of the dosages to know the response of shrinkage characteristics which will enhance its potential applicability for targeted civil engineering applications.

Gudla Amulya, Arif Ali Baig Moghal
Performance of Black Cotton Soil Reinforced with Randomly Distributed Banana Fibers

The most significant part of India and a portion of South India are covered with black cotton soil. These soils have high swelling and shrinkage characteristics and low shear strength. Hence, there is always need of improvement in various engineering properties using suitable reinforcement material. Many researchers used various materials to stabilize or reinforced the black cotton soil. For sustainable construction, it is essential to use natural material or material with low pollution capacity satisfying, all parameters of good soil. The use of different natural fibers as soil reinforcement changed various properties of soil. Here, an attempt had been made to reinforced black cotton soil with randomly distributed banana fires. The unconfined undrained triaxial tests and direct shear tests were conducted on black cotton soil (BC Soil) mixed with banana fibers. The fiber content in reinforced specimens varied from 0.5 to 2.0% with an increment of 0.5% by dry weight of soil. The samples were prepared by adding banana fibers at different percentage and with different aspect ratio of, 10, 20 and 30 mm. The MDD and OMC of reinforced soil were determined and the test samples were prepared for respective MDD and OMC of reinforced soil. The results of the experimental investigation of triaxial test and direct shear show that use of banana fiber as reinforcement to BC soil results in significant increase in shear strength. The increase in length of banana fiber shows increase in cohesion by 110–600% and angle of internal friction of 116–227%.

L. B. Patil, S. S. Pusadkar
Preparation of Lightweight Bricks by Using Agro-waste Materials

Bricks are the most important component in the building industry, for which several types are available across the world depending upon the availability of the basic manufacturing materials. In India, burnt clay bricks are the most sought-after type for which enormous quantities of top fertile soil are being harnessed. Efforts are being made to reduce the self-weight of these bricks while retaining the strength requirements. The present study is an effort to utilize the locally available agro-waste materials along with the native black cotton soil. Trial mixes were investigated for their relative effectiveness in order to get the optimum mix combination. In the first trial, the black cotton soil mixed with 10% RH and 10% RHA, the dry density is obtained as 1.32 g/cc. In the second trial, in order to reduce the dry density further, the RH and RHA contents were increased to 20% at which the dry density is obtained as 0.90 g/cc. Despite the encouraging reduction in self-weight, the burnt bricks at 800 °C were observed to be subjected to self-cracking after exposing them to environment within 24 h. In order to overcome the cracking problem, the straw fibers were tried along with the RH and RHA. Even then, the problem of self-cracking could not be overcome. In further trials, locally available red soil is mixed with black cotton soil by 10–20%, and also the burning temperature is increased up to 1000 °C by which the cracking problem could be overcome while maintaining the lower density. The strength of the bricks is obtained as about 73.49 kg/cm2 satisfying the requirement for the II-class bricks as per IS:1077 (1992).

G. Venkata Ramana, V. Ramana Murty, G. Thulasiram
Experimental Study on Performance of Prefabricated Vertical Drain on Kaolinite with Various Drain Material

The improvement of soft clay by primitive method of sand drain is extended to PVD (pre-fabricated vertical geodrain). In this context, the present investigation provides economical materials for fabrication of vertical geo-drain, comfortable operational procedure, and effective results of improving the bearing capacity and relative cost effective solutions. Theme of the research work comprises of consolidation of soft clay by radial drainage through radial seepage using PVD considering the effect of drain materials. Modern modified Rowe type hydraulically pressurized oedometer is employed for measurement of settlement and pore pressure. An empirical co-relation between strength of soil and n-value is developed. It has been found that the success of improvement of soft soil using PVD is dependent on ideal short- and long-term properties of drain, rate of loading, pattern of drain installation, and uniform distribution of pore pressure at any time (isochrones) and rate of pore pressure distribution. Among various drains of different material considered in investigation, Jute wrapped with polyamide polyester geosynthetics seems to be efficient among various other drains viz. Sand, SD, and SDW seems to be efficient showing higher rate of dissipation of pore water pressure, i.e., higher rate of settlement and magnitude of settlement along with best fitting with Barron’s theoretical results. Further, it is efficient and appropriate to use the same drain in prototype model because of having good hydraulic conductivity and discharge capacity which has induced good compressibility and higher gain in strength at all radial distances from the drain.

R. P. Shrivastava, A. V. Shroff, Sweta Dave
Improvement of Clayey Soil Using Fly Ash and Cement

Clayey soils are found in abundance in few regions of India. To improve its properties, local soil stabilization by addition of an admixture is important. Stabilizing the locally available weak soils is important practice in construction industry. The widespread availability of fly ash which is a by-product of coal combustion requiring effective disposal with bulk utilization on a continuous basis to avoid environmental pollution is widely used for such beneficial stabilization purpose. Many research on the performance assessment of soil–fly ash systems have been published in the literature. The primary goal of this research is to determine the optimal proportion of fly ash that may be added to soil with cement as a stabilizing agent, as well as to analyze the index characteristics, influence of compaction, and compressive strength using an unconfined compressive strength (UCS) test. These experimental investigations were carried out for 13 different combinations. The first combination is only virgin clayey soil, followed by 3 combinations of clayey soil + fly ash, and 9 combinations of clayey soil + fly ash + cement. A little addition of cement even at 1% to the soil–fly ash mixes significantly increases the unconfined compressive strength. The unconfined compressive strength increases linearly for 7, 14, and 28 days curing period by about 12–30%. The stabilization of clayey soil with fly ash using and cement is effective in order to enhance the compressive strength by about 6 times. The strength in compression is found to be higher in case of soil stabilized with 30% fly ash and 3% cement, i.e., soaked and unsoaked conditions, indicating the optimum performance of the mix with 30% fly ash at 3% cement content.

Jigisha Vashi, Anand Daftardar, Babu V. Sundararaman
Mitigating the Problematic Behaviour of Expansive Soils Using Zycobond and Stone Dust

Expansive Soils are predominantly constituted of hydrophilic clay minerals with swelling and shrinkage properties. The seasonal moisture changes result in the extensive shrink–swell processes causing severe damage to the structure founded on them. Several ways are in use to improve the problematic Expansive Soils, and the most common method is mechanical stabilization. Research revealed that partially replacing problematic soils with waste materials and modifying them mechanically or chemically. Hence, an attempt has been made to use waste material, Stone Dust (SD) and a Binder, Zycobond (ZB) to mitigate the behaviour of problematic Expansive Soil. This paper presents the results and analysis of the various tests conducted on the Expansive Soil before and after blending it with different percentages of Stone Dust and Zycobond. The Expansive Soil is partially replaced with Stone Dust from 0 to 30% with an increment of 5%, and further Zycobond is added with 0–2% with an increment of 0.5% to the optimum mix of Stone Dust and Expansive Soil. The results yielded that Stone Dust and Zycobond blends had effectively improved the problematic behaviour of the Expansive Soil with an optimum of 25% Stone Dust as replacement and 1.5% Zycobond as additive, respectively.

G. Surya Teja, R. Dayakar Babu, K. Ramu
Effect of Nano Silica on Dispersion and Strength Characteristics of Silty Soil

Dispersive soils, one of the most problematic soils due to their unstable structure when unidentified, cause numerous geotechnical problems. In this study, an attempt was made to monitor the effect of nano silica on reducing the dispersive nature as well as improvement in strength characteristics of silty soil. The soil was identified as medium dispersive soil by doing the identification tests. Crumb test, double hydrometer test and pinhole test were done to identify the dispersion percentage of the soil. Nano silica (NS) was laboratory synthesized using combustion method and was added to the soil in increments of 0.50% within the range of 0.50–3% of dry weight of the soil. With 1.50% of nano silica addition, the soil was brought to a lower dispersion state. By adding different nano-SiO2 percentages, the increased values of UCS were 1.03, 1.18, 1.45, and 2.45 times than that of original soil for 0.50%, 1%, 1.50% and 3% NS, respectively. Micro-structure of the raw soil sample and treated specimens were analysed using FESEM and XRD which shows that the lower dispersion rate is due to the agglomeration of the particles which occurs due to the addition of nano silica.

Shilpa Mary Sam, P. K. Jayasree, Elsa Jacob Joseph
Performance of Lime-Cement as Column and Raft in Soft Clay Bed

Owing to high compressibility and low shear strength of soft clay deposits, they are generally unfit for geotechnical engineering applications. However, such soft clays can be readily used after they have been subjected to ground treatment methods such as stone column, lime column and compaction granular piles. An attempt is made in this paper to study the influence of lime pile, lime-cement pile and composite raft (lime + geogrid) in the remolded soft clay bed. From the model load test, load-settlement characteristics were evaluated for the above combinations. From the test results, it is found that the load carrying capacity of lime, cement, lime-cement pile and lime-cement pile with composite raft is 100–400% higher than that of untreated soft clay. However, the order of increase in load carrying capacity is lime-cement pile with composite raft > lime-cement pile > cement pile > lime pile.

V. K. Stalin, A. Annie Varshini Raj, B. Mathangi
MICP-Based Indian Desert Sand Stabilization

This study investigates MICP's efficacy in reducing wind-induced sand erosion in Indian desert sand. The sand was treated with S. pasteurii bacterial solution and cementation solution via spray application at 45 °C for 7 and 14 days. Wind tunnel tests at speeds of 5 m/s, 15 m/s, and 25 m/s assessed erosion, while the pocket penetrometer measured crust strength. Calcite formation was gauged with a calcimeter, and microcharacterization was done with SEM and EDX analysis. Results indicate significant erosion in untreated sand with increasing wind speed, contrasting with minimal erosion in biotreated sand. Compressive strength and calcite content rose with treatment duration, supported by calcium peaks in EDX analysis and observed bond formation in SEM images.

Monika Dagliya, Neelima Satyam
Effect of Polypropylene Planar Reinforcement on the Unconsolidated Undrained Behavior of Black Cotton Soil

Black cotton soil is very compressible and cohesive with extremely low bearing capacity. This study’s objective is to enhance the shear parameters such as the internal friction angle and cohesion of black cotton soil, thereby enhancing the bearing capacity of the soil. For the present study, soil sampling has been carried out near Kollegal, Karnataka. The coordinates of the site are 12° 08′ 21.0″ N and 77° 04′ 59.0″ E. The undisturbed and representative soil samples have been extracted from three different geographical locations at different depths. A detailed experimental study has been carried out to determine the physical, index, and engineering properties. Cohesion and the internal friction angle determined for the soil under consideration were 0.05 N/mm2 and 0°, respectively. To increase the internal friction angle of soil, polypropylene planar reinforcements were introduced. Reinforcements were introduced. Unconsolidated undrained (UU) triaxial tests were conducted on planar reinforced soil. Reinforcements were introduced in the soil specimen with one, two, and three individual layers, and results demonstrate that cohesion was increased marginally to 0.057 N/mm2, 0.059 N/mm2, and 0.061 N/mm2, and the internal friction angle was increased to 2.7°, 4.2°, and 6.6°, respectively.

Anand M. Hulagabali, C. H. Solanki, Manya Harish, K. Shama, K. L. Namratha, K. Bharath Kumar
Influence of Addition of Admixtures and Lime on the Properties of Pond Ash-Based High Strength Flowable Fills

Flowable fills or controlled low strength materials (CLSM) are currently considered as better alternative to the conventional fills for various civil engineering applications such as backfill behind retaining walls, bedding layer of pipelines and as subgrade and subbase for pavements, etc. Cement is the primary binding material added along with fine aggregates and water in producing flowable fill mixes. In this paper, the influence of adding lime and admixture along with the regular constituent materials in the production of CLSM mixes is investigated.. Lime contents of 1 and 2% and superplasticizer of 0.2, 0.6 and 1% were added along with regular CLSM mix. The properties of flowable fills, such as flowability and unconfined compressive strength of different mixes of flowable fills, are considered to identify the effect of both lime and admixture addition on the plastic and in-service properties. Based on the experimental analysis, it was concluded that the addition of lime was found to be more effective than that of superplasticizer addition for high strength flowable fills as the unconfined compressive strength values obtained for lime added mixes were significantly higher.

K. Lini Dev, R. G. Robinson
Mitigation of Liquefaction-Induced Settlements Under Shallow Strip Footings Using Ground Densification

The objective of the present study is to establish the optimum influence zone of ground densification to be achieved under shallow strip footings resting on soil deposits susceptible to liquefaction. Finite element-based analysis has been conducted in PLAXIS 2D interface to model the seismic behaviour of liquefiable granular soil by adopting the UBCSAND constitutive law. The developed model has been validated by comparing the numerical results with published centrifuge test results. The effectiveness of ground densification in decreasing the seismic liquefaction-induced settlement of footings has been subsequently investigated over a range of depth and width of densified zone expressed as a function of the footing geometry, varying magnitude of loading on the footing. The numerically obtained results have been utilized for developing a power regression model to quantify the improved settlement response of strip footings resting on ground remediated by densification. The study indicates that the dimension of the improved zone and magnitude of surcharge are the most significant factors influencing liquefaction-induced settlements. The utility of this study is to aid in decision-making in the field regarding the implementation of ground densification as a liquefaction mitigation technique.

Aamir Gulzar, Saptarshi Kundu, Ambarish Ghosh
Numerical Investigation of Behaviour of Geosynthetic Encased Stone Column in Soft Clay Bed

Due to the absence of suitable lateral support, soft soil treated by ordinary stone column (OSC) settles excessively under the vertical pressures as compared to the native soil in the area. To address this problem, encasement of the stone columns is done by a geosynthetic material with higher axial stiffness, which impart the supplementary confinement required. The influence of geosynthetic encasement on the load–settlement behavior of geosynthetic encased stone columns (GESC) under the vertical pressures is investigated using a numerical model. PLAXIS3D was used to create three-dimensional (3D) models to model the characteristics of loose soils treated with stone columns. Various parameters were changed to see how they affected load–settling behaviour while only one column was loaded. Also, the results were validated with experimental results of few literatures.

Srijan, A. K. Gupta
Experimental Studies on the Influence of Chemicals on Geotechnical Properties of Black Cotton Soil in Puducherry Region

Generally, black cotton soils are shrinking and swelling due to changes in water content. In India, this soil is named expansive soil. The swell–shrink behavior of expansive soils causes extensive problems to the substructure and distress in the infrastructures such as buildings, pavements of breast walls. Understanding the performance of black cotton soil and adopting suitable control measures have been significant work for geotechnical engineers. The present study examines the effectiveness of chemicals used to improve the engineering characteristics of black cotton soil (LL = 103%, SL = 1.82%) collected from a location in Puducherry, India. An experimental program has evaluated the effects of alccofine-1203 (3, 6, 9, and 12%) and magnesium chloride (MgCl2) (0.25, 0.5, 0.75, and 1%) contents on the Index, strength properties, pH, EC, and cation-exchange capacity (CEC) characteristics of black cotton soil. Both admixtures were added individually and mixed with the combination of these two admixtures to the untreated soil. The results showed that the combined action of 9% alccofine-1203 + 0.75% MgCl2 increased the dry density and unconfined compressive strength of soil while decreasing the liquid limit, Plasticity Index, and swelling properties. However, further increasing the addition of alccofine and MgCl2 results in a decrease in the unconfined compressive strength. Thus, it proves that by adding the admixture, the problematic soil has turned into the best one, with the addition of 9% alccofine and 0.75% magnesium chloride, which exhibited a significant stabilizer on a high swell, high shrink, and low bearing capacity soil.

V. Jaladevi, V. Murugaiyan
A Numerical Study on Displacement and Bending Moment Behaviour of Laterally Loaded Single CFG Pile Embedded in Layered Soil

Soil having low bearing capacity is one of the greatest problems for the construction of civil engineering structures. Many techniques have been adopted to get rid of the troubles faced from such soil; among them, Cement-Fly Ash-Gravel (CFG) pile technique is an emerging one. It has been used in highways, railways, bridges, embankments, high-rise buildings, and many other places due to its congruous engineering properties. CFG piles were mainly analyzed for transmitting vertical loads in single-layered soil. But practically, piles are always installed in layered soil and the pile may also experience several lateral loads. This paper aims to address the behaviour of a laterally loaded single CFG pile embedded in layered soil. In order to achieve the objective, a numerical analysis is conducted using finite element method-based software PLAXIS 3D and it is validated with the laboratory experimental results. In this study, the load–displacement behaviour and bending moment characteristics are determined by varying the length-to-diameter (L/D) ratios as 8, 10, and 12 where the length is kept constant. It is noticed that due to an increase in diameter by 1.2 and 1.5 times, the lateral load-carrying capacity is increased by 1.4 and 1.9 times, respectively. In consideration of strength and economy, CFG pile can be a suitable one for carrying vertical as well as lateral load that comes on the foundation.

Pritam Debnath, Abhijit Debnath, Sujit Kumar Pal
Stabilization of Expansive Soils Using Industrial Wastes

India is a vast country with several types of soil among which expansive soils constitute over an area of 546,000 km2. Expansive soils consist of various clay minerals which enhance swelling and shrinkage characteristics that need to be treated with stabilizers to prepare it for constructional activities without causing any distress to structures founded on them in reality. Generation of industrial wastes produced by industries nowadays is increasing enormously and causing potential threat to the environment. In the present experimental study, natural expansive soils were procured from different locations in Karnataka having liquid limit range from 45 to 75%. A detailed study of index properties and compaction characteristics for IS light and heavy compaction of plain soils and soils replaced by design mix proportion of steel dust and sugarcane bagasse ash has been carried out. Correlations were established between the compaction, swelling, and shear strength characteristics with index properties using MLRA (multiple linear regression analysis). The MDD and UCS of blended soils were found to be higher than the plain soils, thereby achieving the design economics.

H. S. Prasanna, M. S. Nandankumar, Sahana J. Kashyap, Syed Shakeeb
Matric Suction, Volume Change, and Microstructural Characteristics of a Highly Expansive Soil Treated with Lime

This study examines the impact of lime treatment on matric suction, swelling, and shrinkage response of a highly expansive soil, both at the macro- and micro-scales. The macro-scale investigations include the determination of compaction, compressibility, swelling pressure, DFSI, volumetric shrinkage, and matric suction response of lime-treated expansive soil (0–6% of lime content). The alterations in the pore size and fabric of the soil at micro-scale were assessed using scanning electron microscopy and Brunauer–Emmett–Teller gas adsorption technique. An increase in intra-aggregate pores followed by the reduction in inter-aggregate pores was evident from the microscopic observations. These micro-fabric changes led to an increase in matric suction within the compacted lime-treated specimens. In macro-level investigations, an amount of lime higher than the lime fixation point was found to be efficient to control the volumetric changes in the expansive soil. Addition of 6% lime reduced the compressibility and volumetric shrinkage of expansive soil by 86% and 84%, respectively. The rate of primary shrinkage of expansive soil was also observed to be reduced with lime addition owing to an increase in the water retention capacity. The swelling response of this highly expansive soil was completely nullified with only 4% lime, whereas shrinkage could not be fully controlled even for higher lime content of 6%.

Brijesh Kumar Agarwal, Ajanta Sachan
FEM Modelling of Stabilization of Flexible Pavements with RBI Grade-81

Due to the non-availability of coarse-grained soils in large quantities, it is imperative nowadays to use fine-grained soils for embankment-related work. The presence of clay minerals in fine-grained soils makes its behaviour more complex. Five expansive soils having different clay mineralogy were selected based on physical and index properties. RBI Grade-81 admixture is blended in different percentages of weight with the soils. The blended soils were kept for a maturation period for equilibration. Compaction tests were conducted (SP, RSP, MP and RMP) on the blended soils. The compaction characteristics of these soils that are maximum dry density (MDD) and optimum moisture content (OMC) were determined for various compaction energies, including standard Proctor (SP), modified Proctor (MP), reduced standard Proctor (RSP), and reduced modified Proctor (RMP). The soil compacted to different energy levels with reference to MDD and OMC was kept for the soaked condition. The CBR tests were conducted on the soaked soils. In the current experimental study, the compaction characteristics and CBR were linked with the index properties of soils. Regardless of the soils’ clay mineralogy, the plastic limit can be better connected with compaction characteristics than the liquid limit. Reduction in thickness of pavement ranging from onefold to fourfolds was observed, for the compacted subgrade soils having different clay mineralogy blended with admixture, which saves associated time and cost. FEM modelling was carried out for different dynamic loading conditions with particular reference to material composition to compare the results of the experimental study.

H. S. Prasanna, Unnam Anil, P. K. Pooja
Effect of Guar Gum Biopolymer on Shear Strength and Liquefaction Response of Coal Ash

Improvement in geotechnical properties of coal ash is required for its better utilization in large infrastructure projects. Lime and cement are the most commonly used material to stabilize coal ash for railway and highway embankment construction. However, these admixtures have negative impact on the environment. This experimental study explores the viability of commercially available guar gum biopolymer, as an eco-friendly and cost-effective additive for coal ash stabilization. Guar gum biopolymer is chosen because of its pH stability, cold water dissolving characteristics and formation of hydrogen bonds along with being inexpensive. Different concentrations (1–5%) of guar gum biopolymer were used to treat the coal ash collected from Gandhinagar thermal power plant. A series of shear strength tests were conducted on coal ash before and after its treatment with guar gum biopolymer at different concentrations and curing time/conditions. Scanning electron microscopy (SEM) images of guar gum-treated coal ash specimens were also obtained to evaluate the morphological characteristics of stabilized coal ash. Stress–strain and pore pressure response of guar gum treated coal ash were studied by conducting Consolidated Undrained (CU) triaxial tests. Effect of gaur gum on liquefaction response of coal ash was also evaluated by conducting cyclic triaxial tests with pore pressure evolution.

Aparna Shrivastava, Ashray Saxena, Ajanta Sachan
Microstructural Characterization of Expansive Soil Stabilized with Agricultural Waste Materials

Expansive soil is predominantly impervious and exhibits swelling and shrinkage behavior when exposed to moisture fluctuation, making it unsuitable for geomechanical applications. Recently, waste materials and fibers have been used to develop sustainable solutions in designing new soil reinforcing and stabilizing materials. In many rice-producing countries, rice husk (RH) is one of the most widely available agricultural wastes. This study presents a detailed microstructural analysis of black cotton soil (BCS) stabilized with 3–15% rice husk ash (RHA) containing a high amount of amorphous silica needed for implementing pozzolanic action in weak soils. The reconstituted soil structure due to the treatment is studied through a series of microstructural tests, including scanning electron microscopy (SEM), X-ray diffraction (XRD), stereomicroscope, Fourier transform infrared (FTIR) spectroscopy, and X-ray Fluorescence (XRF). The microstructural studies revealed that with the increase in RHA content, new compounds containing functional groups such as silanol and siloxanes (Si–OH and Si–O–Si–OH) got introduced into the BCS + RHA mixture, leading to an enhanced hydrophobic nature of the clay mixture. The XRD tests revealed the amorphous nature of RHA. The XRF tests indicated an increment of 76% in the elemental composition of Silica (SiO2). The FTIR and SEM analyses reveal RHA's specific functional groups and surface characteristics.

Ankur Abhishek, Esha Kurwa, Jeethendra S. Uppala, Anasua GuhaRay
Performance Enhancement of Stone Columns with Geocell Overlay: Numerical Insights

Granular blankets are usually provided above the stone columns to ensure proper drainage and also to enhance the performance of the stone columns. The present study investigates the overall performance of the stone columns with geocell reinforced granular blanket. The effect of geocell overlay has been studied using the finite element analysis software package ABAQUS. Geocell with three different infill materials, namely aggregate, sand, and silty clay, were considered in the study. The equivalent composite approach was adopted to simulate the geocell in a two-dimensional framework. It was observed that the use of geocell in the granular blanket resulted in a 60% increase in the peak stress concentration ratio value as compared to the ordinary stone column. Similarly, a 13% reduction in ground settlement and a 42% increase in the load-carrying capacity of the stone column was observed in the presence of geocells. Maximum improvement in the load-carrying capacity was observed when the geocell was infilled with aggregates. Further, geocells were found to reduce the stress intensity on the stone columns by distributing the load to wider areas. As a result, the lateral bulging of the stone column was found to be reduced by 16% in the presence of geocell.

Razib Hussain, Amarnath Hegde
Effects of Bio-enzyme in Soil Stabilization

The bioaugmentation approach of soil strength enhancement is one of the most efficient and sustainable methods for enhancing soil engineering properties. One of the methods is by using bio-enzymes. Bio-enzymes are organic soil improvement additives which are non-toxic, environmentally friendly, and biodegradable. With this view, the major objective of the current study is to study the effectiveness of bio-enzyme on UCS and swelling properties of soil. For the experimentation, the fractional factorial planning method has been adopted with the target to maximize the UCS of soil with the factors and levels considered. Scanning electron microscope (SEM) analyses were conducted at the end of each UCS test. The results obtained indicate an increase in UCS soil and a reduction in swelling of soil. It was observed from the results of SEM that with the increase in curing period soil specimens are denser. Also, the optimum value of dosage of TerraZyme was found for defined outcomes.

Charu Chauhan, Kala Venkata Uday
Micro-crumbled Rubber Powder as an Additive to Improve Geotechnical Properties and Slope Stability

Disposal of waste tires is an environmental burden, difficult as it is manufactured from synthetic rubber which is hard to get decomposed and may cause an environmental burden, especially in a developing country like India. So, suitability of this waste tire in powder as an additive to improve geotechnical properties was investigated. Rubber powder of size less than 425 micron is added in varying proportions, 8, 10, 12, 14, 16, and 18%. Optimum content of rubber giving maximum shear values and density was found to be at 12%. The application of this mix in slope stability improvement was evaluated using GeoStudio SLOPE/W software by constructing an embankment for different slope angles 27°, 30°, 33° and slope heights 6, 8, and 10 m. Factor of safety was found to be increased which proved the applicability of rubber powder.

V. Vindhuja, P. Swathy
Influence of Terrazyme on Moderately Expansive Black Cotton Soil

Black cotton soil has always posed serious problem to the infrastructures because of its swelling and shrinkage characteristics in the presence and absence of water. Light structures in rural areas of tropical India, especially in the states of Maharashtra, Karnataka, and Andhra Pradesh, suffer considerable swell–shrink characteristics. It is always challenging for engineers to build structures that can resist the problems created by black cotton soil and to make the structures functionally stable and durable. In this paper, an attempt is made to establish that Terrazyme treated black cotton soil performs better than untreated soil. For this purpose, locally available moderately expansive black cotton soil obtained from within the city of Mysore was studied for its performance with and without the inclusion of Terrazyme. The soil was tested for its index properties, compaction characteristics, unconfined confined compression strength, and permeability characteristics. Terrazyme, a non-toxic, non-corrosive, non-flammable, brown colored liquid made from fermentation of plants and extracts of vegetables and fruits was used with different dosages of 3 m3 per 200 ml, 2 m3 per 200 ml, and 1 m3 per 200 ml. The properties of soil were established at different ages of 0th, 7th, 14th, and 21st days. It has been observed that the addition of Terrazyme improved the shear strength and compaction characteristics and increased in the permeability of soil. The dosage of Terrazyme and the age of Terrazyme treated soil had considerable influence on properties of black cotton soil. The test results are represented in the form of tables and graphs.

P. C. Vishwanth Gowda, K. Lubna, M. Shivakumar, M. B. Ganesh, S. K. Prasad
Deformation Mode of Geocell–Soil Composite Structure

This paper discusses to develop a three dimensional (3D) numerical model which can effectively simulate the behavior of geocell reinforced soils using a commercial finite element program. In the usual instance, numerical modeling of geocell is difficult due to their curved geometry and complex material surfaces. It is therefore not surprising that much of the previous studies on geocell have eluded this approach and have otherwise used an equivalent composite method. It treats the geocell–soil composites as a new soil layer with improved strength and stiffness properties. Unfortunately, despite its simplicity, this method can often be incorrect as it does not properly account for the state of in situ stress in the soils. Plane stress conditions are also violated especially when the geocell are placed close to the ground surface. Likewise, the shape of the geocells also affect the working of geocell. In the present study, the reinforced soil layer considers the interaction between the geocell and its nodes at connections. Geocell are modelled using poly-curves available in the software. Three types of simulations are then made, they are: reinforced soil with geocell and unreinforced soil, rectangular geocell with curvilinear geocell, and geocell with different axial stiffness. It was seen that the secant modulus of the reinforced soils increases with the increase in the curvature of the geocell. And as the axial stiffness of the geocell material increases, the secant modulus of the reinforced soil also improves.

Kuldeep T. Sankhat, Jitesh T. Chavda, Ashish Juneja
Use of Zycobond in Enhancing the Strength of Expansive Soil Modified with Rice Husk Ash (Rha)

Expansive soil is one such difficult soil that geotechnical engineers find annoying. They absorb water and expand during the monsoon, but they diminish throughout the summer when the water evaporates. Soil stabilization is a technique for improving the geotechnical assets of soil. It allows efficient usage of industrial leftovers as a stabilizer. An attempt is made in this paper, to investigate the impact of industrial waste, rice husk ash (RHA), and an acrylic polymer, Zycobond on the properties of expansive soil. The proportion of rice husk ash (RHA) as a replacement was varied from 0 to 20% with an increment of 5% and further Zycobond was added with varying percentages from 0 to 2.0% with an increment of 0.5%. Tests were conducted to assess the properties of expansive soil blended with RHA and Zycobond. The results were analyzed and found that the optimum percentages of RHA were 15% and Zycobond was 1.5%, respectively. Further, static model plate load tests were conducted on only expansive soil and expansive soil blended with RHA and Zycobond. Hence, the study yielded a better alternative for improving the expansive soil and effective usage of industrial waste RHA giving us a two-fold advantage.

M. Prabodh Kumar, R. Dayakar Babu, K. Ramu
Improvement of Low Compressible Clays Using Crumb Rubber

In India, around 50% of land is prone to earthquakes with huge economic loss annually. In order to reduce impact of earthquake on structures, “rubber–soil mixture” method has been developed. Incorporating rubber into soil in various proportions acts as an effective seismic shock absorber and provides strength, firmness to foundation soil. It also reduces settlement of footing. Recycled tyres are shredded into fragments and are added to soil. This method is economical and eco-friendly. Addition of rubber to soil can reduce linear and lateral shaking of structure significantly. In this paper, various strength parameters of rubber–soil mixture like UCS, CBR-soaked and unsoaked, compaction, Atterberg limits, etc. have been studied by conducting laboratory experiments. 1–2 mm sized rubber crumbs in varying proportions 0–5% are used. The main aim of this paper is to study how the addition of rubber crumbs in various proportions to the soil can affect bearing resistance and strength of foundation soil.

Vinjamuri Sri Vaishnavi, B. N. D. Narasinga Rao, Venkateswarlu Dumpa, Chandra Shekar Rayi
Influence of Polyethylene Terephthalate Waste on Mechanical Properties of Clayey Soil

This paper presents the study on the clayey soil reinforced with polyethylene terephthalate (PET) waste. Post-consumer plastic water bottle was used as a PET waste. Plastic bottles were cleaned and strips were cut manually maintaining aspect ratio 2 and 4. The recycled PET strips were mixed in clayey soil in various combinations. This combination ranges from 0 to 1% of the weight of soil. Especially, the study was carried out on the properties of soil such as compaction characteristics and CBR value of soil. Main parameter was to investigate the optimum dosage and effective aspect ratio influencing the behavior of clayey soil. The investigation shows that there is significant improvement in the properties of soil like OMC, MDD, and CBR value. This experimentation shows the potential use of waste plastic in improving the problematic or weak soil. The entire world is facing the nuisance of plastic pollution, so this may prove the effective way of recycling of waste plastic in the application of pavement.

Alka Shah, Tejaskumar Thaker
Influence of Bio-enzyme on Compaction and Strength Characteristics of Black Cotton Soil in Nagpur (Maharashtra)

Soil stabilization is an effective method for increasing the strength and durability of expansive soils like the black cotton soil. The process involved in the soil stabilization should be such that the end product becomes easily workable and environment-friendly. A bio-enzyme named TerraZyme proves to be a good option for this issue as it is naturally made, safe, bio-degradable liquid which significantly enhances the strength of soil by diminishing the size of voids. It improves the compaction of soil with minimal compactive efforts and its effect is long lasting. This paper presents an experimental investigation on the stabilization of black cotton soil using TerraZyme. The dosages of TerraZyme were taken from 200 to 600 ml/m3 of soil and the tests were conducted after 28 days of curing. It is observed that the OMC decreases and the MDD increases with the increase of TerraZyme content. The UCS value increases initially and then starts decreasing after reaching a peak value as the dosage of TerraZyme has been increased. From these observations, an optimum amount of TerraZyme content is worked out for black cotton soils. This optimum enzyme dosage is supported or validated by the FESEM images of treated and untreated soils.

Divya Shanu, Parbin Sultana
An Approach Toward Sustainable Design with Waste Materials for Developing Mining Pit into Tailing Storage Facility

Sustainability has become a key theme in engineering design and construction practice. Use of alternate materials that have lower carbon footprint and reduce environmental hazards is tenets of this modern approach. Approach toward alternative source of material for tailing storage facility which will be developed inside an abandoned mining pit is described in this study. The work considers the study of various engineering properties for secondary product from process plant, waste overburden from mining, and tailing from ore processing plant. Thereafter, detailed site investigations were done for developing an abandoned mining pit to a tailing storage facility. The outcomes from the studies were used for design and construction of tailing dam over a reclaimed land in an abandoned mining pit. The previous designs for tailing dam construction involved use of selected borrow earth having desirable index and strength properties. Objective of the study is the alternative use of waste material for dam construction where sustainability of plant operation was the key. This serves the purpose of reuse of the by-product of both process and mining industries instead of managing it as waste which highlights the tenets of sustainable design.

Manos De, Shuvranshu Rout, Biswajit Das, Anup Mandal
Behaviour of Foundation Resting on Soft Clay Subgrade Shredded Tyre Mixture Using Physical Model Tests

This study presents the improvement of soft clay subgrade utilizing shred tyre-sand layer of varying thickness. A series of physical model tests was conducted on different foundation layers consisting of shred tyre-sand layers of varying thickness. The foundation layers were made up of the shredded tyre-sand mattress overlying soft clay bed. The tests were performed at 80% relative density of sand soil with different percentage mixtures of tyre shreds. The thickness of the sand-tyre mixes layer was varied from 0.5D to 1.5D. The bearing capacity of soil was found to be increased by 2.8 times and 1.5 times for the height of shredded tyre-sand layer h = 1.5D and h = 0.5D, respectively. Moreover, it was also observed that the settlement of footing decrease with the addition of reinforcement.

Bikash Kumar Sah, Shiv Shankar Kumar, A. Murali Krishna
Biopolymer Stabilization of Highly Plastic Silty Soil for Rammed Earth Construction Materials

Earthen construction materials (ECM) have been used in India since ancient times in the form of rammed earth blocks and mud house walls. The subsoil is often stabilized with lime/cement to improve its performance and durability. The use of lime/cement promotes the carbon footprint due to their high embodied energy. On the other hand, soil stabilization with biopolymers such as Xanthan Gum (XG) has demonstrated promising results in strength enhancement and negligible ecological risks. The ECM is expected to have a high unconfined compressive strength (UCS) along with low erodibility and thermal conductivity. The current study investigates the influence of biopolymer amendment varying from 0.5% to 1.5% by weight of soil on the UCS, erodibility, and thermal characteristics of an abundantly available highly plastic silty soil in the Brahmaputra valley of the Assam region of India. The study reveals that the increment in biopolymer content results in a fourfold increment in the UCS of bare soil with no practical variation in the thermal conductivity, implying their potential to provide thermal comfort as a building unit. However, the pocket erosion test revealed that although the biopolymer treatment drastically enhances the erosion resistance of untreated soil, the proposed ECM remains in medium erodibility class, limiting its applicability in infrastructures designed for the long term. Nonetheless, the proposed ECM can be utilized effectively as a building unit for the rapid construction of temporary infrastructure, specifically for armed forces and highway engineers that are required to stay at a workstation transiently.

Deepak Patwa, Anant Aishwarya Dubey, K. Ravi, S. Sreedeep
Effect of Plastic Strips and Bottom Ash on Engineering Properties of Sandy Soil

Scarcity of land with favorable conditions has raised due to the rapid development of urban areas and the increase in construction activities. This has necessitated the use of locally available weak soils for construction activities through stabilization techniques. In the present study, bottom ash (BA) is used as a stabilizing agent, and the suitability of plastic strips as reinforcement is demonstrated through detailed experimental investigations. Soils poor in engineering properties in terms of bearing capacity, shear strength, compressibility and permeability need some proper treatment so that they can be useful in construction purposes. Such soils need to be either replaced or treated well with some materials. This paper deals with the valorization of sandy soil with the use of bottom ash in various percentages of 10, 20, 30 and 50% along with plastic strips of 0.5, 0.75, 1 and 1.25%. The laboratory research indicated that the mechanical properties of the soil are improved with the addition of bottom ash and plastic strips. Test method includes finding unit weight, specific gravity, unconfined compressive strength, peak strength, cohesion and angle of internal friction.

Khushboo Vishwakarma, Shruti Shukla
Proceedings of the Indian Geotechnical Conference 2022 Volume 3
Babu T. Jose
Dipak Kumar Sahoo
Anand J. Puppala
C. N. V. Satyanarayana Reddy
Benny Mathews Abraham
Ravikiran Vaidya
Copyright Year
Springer Nature Singapore
Electronic ISBN
Print ISBN