Madhavi Latha Gali

• PhD
• Professor at Indian Institute of Science Bangalore

Liquefaction-induced flow failures, excessive settlements, lateral spreading, and loss of shear strength in granular soils can become massive hazards during earthquakes. Among the various mitigation techniques available, soil reinforcement using dense granular columns can be considered as a very effective technique, and its effectiveness gets furth...

The smooth surface texture of the commercially available geogrids limits the shear strength mobilization at the interfaces. This study presents the design, manufacturing, and interface performance evaluation of innovative textured geogrids. Geogrids with square, triangular, and hexagonal apertures with and without inherent surface texture were manu...

The generation of artificial granular media to investigate micro-to-macro correlations in sands is one of the innovations inspired by the recent advancements in 3D printing technology. While several 3D printing techniques exist to print granular particles, the basis for the selection of a specific technique and the relative accuracy in mimicking th...

Geocells are being extensively used in road and rail embankments, pavements and retaining structures. Research on the cyclic load performance of these structures is heavily based on reduced scale model tests coupled with numerical modelling. Most of the available model studies on geocell-reinforced structures use prototype geocells or geocells made...

Additive manufacturing of honeycomb shaped geocells using fused deposition 3D printing is explored in this study. The freedom to customize the strength and surface features of geocells is utilized through 3D printing of low-strength polypropylene sheets and ultrasonically welding them to manufacture interconnected networks of geocells. The processe...

Particle morphology at different length scales is important in understanding the mechanical behaviour of granular materials. In this sense, it is crucial to accurately describe and measure the size and shape of the grains using suitable definitions of morphological descriptors. Most of the research up until this point has analyzed particle shape in...

Liquefaction is a phenomenon in which soil loses its strength and stiffness due to the buildup of pore water pressure during an earthquake, which can significantly damage buildings and other structures. Encased Stone Columns (ESCs), which are columns of compacted gravel or sand encased in geotextile fabric, established themselves as a promising gro...

This paper investigates the influence of particle shape on the multi-scale shear behavior of sand–geomembrane interfaces through advanced imaging techniques. Two sand specimens with similar particle size distribution but varying particle shapes were scanned using X-ray micro-computed tomography (µCT). The data were processed and analyzed using MATL...

The ability and freedom to translate complex conceptual creations into designs and prototypes using simple digital and mechanical tools make additive manufacturing (3D printing) attractive and rewarding to all fields that involve manufacturing. Though 3D printing is rapidly spreading into all fields of engineering and science, its scope in geotechn...

Construction of retaining walls using geocell stacks as facing has many advantages such as inherent flexibility, reduction in construction cost and time, dispensability of concrete facing, and overall improvement in stability. Though soil–geocell interactions at element level are well understood, various aspects of these interactions at a bigger sc...

Geosynthetic clay liner is used in the design of cover and barrier systems in engineered landfills. The shear strength at the interfaces is critical for slope stability. Though the interface shear characteristics of natural sand with GCLs are well established in literature, the recent problems of sand extraction and its harmful impact on coastal er...

Geocells, which are polymeric interconnected cells filled with soil, provide excellent support to loads through all-round confinement and a beam effect; hence, they are extensively used in various geotechnical applications such as embankments, foundations, pavements, slopes, railways, and reinforced earth (RE) walls. Although the applications of ge...

One of the major earthquake risks is sand liquefaction, which has caused numerous global losses. Grouting and densification are two common yet pricey liquefaction mitigation methods. Coir fiber is one of the most important by-products of the coconut business worldwide. The excellent tensile strength of coir fiber can be used to improve the resistan...

The morphology of granular materials, such as sands, is of significant importance due to the effect of grain shape on their physical, mechanical, and hydraulic behavior. As technology has progressed from visual identification to modern computer-based techniques, numerous methods have been developed for quantifying grain shapes, many of which utiliz...

Three-dimensional (3D) printing technology is replacing most of the conventional manufacturing processes of civil engineering materials because of the control that can be offered on the properties of the materials produced. 3D printing is particularly beneficial for printing polymeric geosynthetics, which are used in soils to perform various functi...

Liquefaction in sands is a natural hazard associated with an earthquake and remains a major concern for geotechnical engi- neers, as the shear strength of saturated loose sands reduces drastically with the development of positive pore pressures under dynamic loads resulting in the breakage of grain contacts. Traditional remedial measures to avoid...

This paper presents a fundamental study to explore the independent effects of grain size and shape on the pre-liquefaction, liquefaction, and post-liquefaction shearing behaviour of granular ensembles through a series of multi-stage constant volume simple shear tests. Three different granular materials (glass ballotini, river sand, and manufactured...

This paper investigates the effect of different experimental and sample conditions on the velocity-weakening tendency of model rock joints. A total of 100 triaxial tests were conducted on fabricated jointed samples under displacement rates of 0.05-25 mm/min by varying sample porosity (55%-65%), confining stress (100-800 kPa), and over-consolidation...

The present study aims to explore and bring out morphological insights into the prior-liquefaction, liquefaction, and post-liquefaction response of sands with geotextile inclusions. For this, a series of multi-stage drained constant volume simple shear tests with different cyclic stress ratios (CSR ranging from 0.1125 to 0.225) and different fre...

Translational sliding failures in landfills are often triggered by inadequate shear strength of interfaces in liners and covers. Geosynthetic Clay Liners (GCL) are used in different components of landfills to contain the leachate. GCLs are usually placed above a compacted sand subgrade to develop higher shear resistance. In the context of depleting...

Though it is known that the geometric features of geogrids are crucial for deriving optimal interface shear strength, not much work is done to optimize the size and shape of the apertures relative to the particle size of the soils in contact. Most of the commercial geogrids have rectangular or square apertures, which are many times bigger than the...

Liquefaction in sands is of grave concern for geotechnical engineers to ensure the stability of soil structures subjected to dynamic loadings like earthquakes. Grouting, installing seismic drains, and compaction are the traditional liquefaction remediation methods. These techniques are expensive, energy and resource-intensive. Finding sustainable s...

Using low-cost polymeric geosynthetics has proven to be a sustainable solution for a wide range of geotechnical problems, including liquefaction and associated disasters. The grain shape of sand governs the sand-geosynthetic interactions and its macro-level mechanical behavior and is the key to understanding and obtaining performance-based designs...

Liquefaction, which is an earthquake hazard caused by undrained cyclic loading, is a phenomenon where a significant portion of the soil's shear resistance is lost as a result of a rise in pore water pressure and starts flowing like a dense liquid. Many studies have been carried out in literature to understand the concept of liquefaction in soils an...

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 geo...

Inadequate shear strength mobilization at the interfaces results in translational failures in Geosynthetic Clay Liners (GCL). Periodic addition of solid waste into the landfill causes additional normal and shear stresses in GCLs. The mechanical response of GCLs is highly time dependent and over the time, the quality and strength of fibres of GCL de...

The effectiveness of tensile reinforcement in controlling the deformations of soil slopes under sinusoidal base shaking conditions is studied through model tests carried out on shaking table and the results are analyzed using computational modelling based on Newmark’s rigid block analysis. The acceleration and frequency of shaking are varied in dif...

Though the qualitative effects of grain size and grain shape on the tendency or resistance of a sand to liquefaction are well established, quantitative correlations between them are elusive. Most of the studies in this direction used conventional methods to quantify the size and shape of the grains, which include sieve analysis and visual observati...

Importance of grain shape and size on the cyclic load response of sands and their liquefaction potential is well recognized by researchers. However, the effects of grain size and shape are coupled in most of the available studies and research on individual effects of these parameters in quantifying the liquefaction resistance of sands is still elus...

Interface friction in GCL-sand interfaces is primarily controlled by the shape characteristics of the sand grains and the surface texture of the GCL. Friction at the GCL-sand interface is also affected by the hydration of bentonite present in the GCL, which alters the interaction mechanisms of sand and GCL. The present study involves the use of ima...

Angularity is an important aspect of particle morphology, directly correlated to the mechanical response and strength of granular materials. Many researchers have proposed multiple direct and indirect methods such as visual charts, analytical formulas, and advanced image-based techniques for qualitative and quantitative assessment of particle angul...

Interface shear strength of geosynthetic clay liners (GCL) with the sand particles is predominantly influenced by the surface characteristics of the GCL, size and shape of the sand particles and their interaction mechanisms. This study brings out the quantitative effects of particle shape on the interaction mechanisms and shear strength of GCL-sand...

Liquefaction is a phenomenon that occurs due to the rearrangement of grain contacts in saturated sands, under the influence of cyclic loads. Literature suggests that finer sands and sands with rounded particles liquefy easily compared to sands with coarser or angular grains. Despite the fact that researchers are familiar with the impacts of grain s...

Low tensile strength of soils makes them unsuitable for constructions where soils are subjected to tensile loads. Earthquake loading on soils impose compression and tension loading cycles during which there is a high possibility of failure in geotechnical structures like embankments, slopes and retaining walls. Geosynthetics come to rescue in many...

Since their inception in early 70s, geocells have found numerous applications in civil engineering. One of the most important applications of geocells, which has created considerable impact in the field of reinforced soil structures, is their usage in various transportation geotechnical applications. Geocells are successfully being used for the rei...

This volume comprises select papers presented during the Indian Geotechnical Conference 2018. It discusses concepts of soil dynamics and studies related to earthquake geotechnical engineering, slope stability, and landslides. The papers presented in this volume analyze failures connected to geotechnical and geological origins to improve professiona...

This book presents the select proceedings of the International Conference on Sustainable Practices and Innovations in Civil Engineering (SPICE 2019). The chapters discuss emerging and current research in sustainability in different areas of civil engineering, which aim to provide solutions to sustainable development. The contents are broadly divide...

This volume comprises select papers presented during the Indian Geotechnical Conference 2018. This volume focuses on discussing the many challenges encountered in geoenvironmental engineering. The book covers sustainability aspects related to geotechnical engineering, problematic soils and ground improvement, use of geosynthetics and concepts of so...

In view of the problems of sand extraction and its harmful impact on coastal erosion, research now focusses on viable alternatives. Manufactured sand (Msand) has become an admissible alternative to be used in concrete instead of river sand. In countries like India, sand mining is illegal, considering the adverse effects it can cause to river basins...

This volume comprises select papers presented during the Indian Geotechnical Conference 2018. This volume discusses construction challenges and issues in geotechnical engineering. The contents cover foundation design and analysis, issues related to geotechnical structures, including dams, retaining walls, embankments and pavements, and rock mechani...

This volume comprises select papers presented during the Indian Geotechnical Conference 2018, discussing issues and challenges relating to the characterization of geomaterials, modelling approaches, and geotechnical engineering education. With a combination of field studies, laboratory experiments and modelling approaches, the chapters in this volu...

In view of the problems of sand extraction and its harmful impact on the coastal erosion, research now focusses on viable alternatives. Manufactured sand (M-sand) has become an admissible alternative to be used in concrete instead of river sand. In countries like India, sand mining is illegal, considering the adverse effects it can cause to river b...

Probabilistic methods are the most efficient methods to account for different types of uncertainties encountered in the estimated rock properties required for the stability analysis of rock slopes and tunnels. These methods require estimation of various parameters of probability distributions like mean, standard deviation (SD) and distributions typ...

This article presents the challenges encountered during the stability analysis and stabilization of two Himalayan rock slopes supporting the Chenab Railway Bridge in India, which will be the highest railway bridge in the world after completion. Owing to the importance of the project, extensive geological investigations, in-situ and laboratory tests...

This volume contains contributions by eminent researchers in the field of geotechnical engineering. The chapters of this book are based on the keynote and theme lectures delivered at the Indian Geotechnical Conference 2018, and discuss the recent issues and challenges, while providing perspective on the possible solutions and future directions. A s...

The shear strength of rock joints is an important property required in order to analyze the stability of rock slopes and tunnels. However, estimation of the shear strength of rock joints for in situ conditions is a complex task due to various influencing factors present in the field. Among these factors, the shear velocity or the shear displacement...

A large gold reserve was recently discovered at Haveri district of Karnataka state of India where open pit mining was planned to extract these deposits. Stability analysis for open pit mine slope at this site is presented in the article. Extensive geological investigations and laboratory testing suggested high variability in geological features of...

Recent advances in digital technology led to great improvement in understanding and solving many geotechnical engineering problems. This paper presents few important image-based techniques for precise characterizations, applicable to geotechnical engineering and demonstrates the same. Some of the important applications discussed in this paper are p...

This paper presents the effect of slope angle of facing on the seismic response of retaining walls with geocell facing. Keeping the dimensions and configuration of geocell layer same, shaking table model tests were carried out with vertical and battered walls retaining sand backfill. In case of battered walls, geocell layers were laid with an offse...

Quantification of particle shape features to characterize granular materials remains an open problem till date, owing to the complexity involved in obtaining the geometrical parameters necessary to adequately compute the shape components (sphericity, roundness and roughness). A new computational method based on image analysis and filter techniques...

The support design for rock tunnels involves a complex problem because of the various types of uncertainties present in rock mass properties; therefore, probabilistic approaches are used to consider these uncertainties systematically in the presented analysis. In earlier studies, uncertainties in peak strength parameters and deformation modulus wer...

Stability analysis of rock tunnels is a complex problem because of various types of uncertainties present in the rock mass properties and hence probabilistic approaches are used to systematically consider these uncertainties in the analysis. While the uncertainty in deformation modulus and peak strength parameters has been considered previously it...

Stability analysis of rock slopes is a complex problem because of uncertainties involved in the rock mass properties. The probabilistic approach is a rational way to deal with these uncertainties. This article investigates the stability of a rock slope by deterministic and probabilistic approaches by considering uncertainty in peak and residual str...

Probabilistic analysis of a Himalayan rock slope supporting the piers of a railway bridge is carried out by considering strength drop from peak to residual strength. Importance of considering the uncertainty in post peak strength parameters for rock slopes in average quality rock mass is discussed. Ignoring the strength drop in post-peak strength p...

This paper studies the effect of slope angle on the seismic response of unreinforced and reinforced soil slopes through a series of laboratory shaking table tests. Slopes were constructed using clayey sand and geogrids were used for reinforcing the slopes. The slope angle varies from 45°, 60° and 75° in different tests and the quantity and location...

The commonly adopted rock mass classifications, namely RMR, Q and GSI, are used to estimate compressive strength and modulus of rock masses. These values have been examined as per modulus ratio concept, Mrj, for their reliability. The design parameters adopted in some of the recent case studies based on these classifications indicate that the Mrj v...

Recent advancement in digital technology enabled the development of sophisticated methods for understanding the fundamental aspects of particle morphology and facilitated the precise quantification of sphericity, roundness, angularity and roughness of particles. This paper presents new computational methods to quantify the particle morphology using...

Till date, most researchers are using visual charts or image based methods for characterizing the shape of the granular materials that are having conceptual and practical deficiencies. In this study, a novel image based method is developed for characterizing the particle shape more accurately as compared to other existing methods. This method imple...

To study the effect of reinforcement type and quantity on the response of model slopes in this study, a series of shaking table tests were carried out on model slopes reinforced with different quantities of geotextile and geogrid. Model slopes were constructed to an angle of 45° using poorly graded sand. Acceleration of base shaking and shaking fre...

Understanding the stress-displacement response of granular materials and their interfaces with geosynthetics through surface topographical analysis is evolving as a new area of potential interest. Recent developments in optical techniques coupled with digital image recording have enabled the measurement of the surface topographical features of sand...

The mechanisms governing the shear behaviour of sand and sand-geomembrane interfaces is studied by carrying out large scale symmetric loading direct shear tests on three sands of different sizes with similar morphological characteristics and a smooth high density polyethylene geomembrane. To focus on the effect of particle size on the shear behavio...

Stability analysis of the two abutment slopes of a railway bridge proposed at about 359 m above the ground level, crossing a river and connecting two huge hillocks in the Himalayas, India, is presented in this paper. The rock slopes are composed of highly jointed rock mass and the joint spacing and orientation are varying along the elevation of the...

Quantitative measurement of induced surface changes in the geomembranes by sliding and plowing of sand particles during shear is highly beneficial for understanding the macro stress–strain response of non-dilative interface systems. This paper presents large scale direct shear and interface shear tests with a smooth geomembrane performed on sands o...

The stability analysis of the two abutment slopes of a railway bridge proposed at about 359 m above the ground level, crossing a river and connecting two hill faces in the Himalayas, India, is presented. The bridge is located in a zone of high seismic activity. The rock slopes are composed of a heavily jointed rock mass and the spacing, dip and dip...

An earthquake of magnitude 6.6 shook Uttarkashi district , in the state of Uttar Pradesh, India on October 20, 1991 at 2:52 hours. Around 768 persons died and about 5,066 people were injured. Maximum peak ground acceleration of about 0.31g was recorded at Uttarkashi.

Performance of geocell retaining walls under seismic shaking conditions is studied in this paper. Shaking table tests on geocell retaining walls subjected to ground shaking conditions of different accelerations and frequencies are discussed. Retaining wall models of 600 mm height were constructed using a sand backfill with layers of geocells stacke...

While ground motion parameters influence the initiation of liquefaction in sands to a large extent, the susceptibility to liquefaction itself depends on the physical properties of sand. The concepts and mechanisms of liquefaction were studied extensively by many researchers. Though the factors affecting the liquefaction response of soils during ear...

This paper presents the response of unreinforced and geosynthetic reinforced dry sand under static and dynamic loading conditions. A large scale triaxial apparatus, capable of testing specimens having a maximum size of 300 mm in diameter and 600 mm in height was used for the study. Large specimen size used in this study allowed to overcome the boun...

This paper investigates the effect of particle size of sand and the surface asperities of reinforcing material on their interlocking mechanism and its influence on the interfacial shear strength under direct sliding condition. Three sands of different sizes with similar morphological characteristics and four different types of reinforcing materials...

This paper presents the stability analyses carried out on abutment slopes of the world’s highest railway bridge being built in Jammu and Kashmir, India. This bridge is 1315 m long and 359 m above the river bed and connects two hills on either side of the river. The rock slopes are composed of highly jointed rock mass and the joint spacing and orien...

Review of seismic analysis procedures for earthdams

Shaking tables are used for physical modeling in earthquake geotechnical engineering. Shaking table research provides valuable insight into liquefaction, post earthquake settlement, foundation response and soil-structure interaction and lateral earth pressure problems. This paper describes various components of the uniaxial shaking table at the Ind...

Resilient modulus is an important parameter in flexible pavement engineering design. The stress–strain behavior of unbound granular base materials under static and cyclic loading and the effects of the state of stress, moisture content and loading conditions have been analyzed in the present study. In this paper, the resilient behavior of unbound g...

This paper presents the experimental results from laboratory repeated plate load tests on unreinforced and reinforced model sections of unpaved road constructed in a steel test tank. Different types of geosynthetics, namely, geotextile, two types of biaxial geogrids and geocells were used to reinforce the road sections in different tests. The effec...

This paper focuses on understanding the seismic response of geosynthetic reinforced retaining walls through shaking table tests on models of modular block and rigid faced reinforced retaining walls. Reduced-scale models of retaining walls reinforced with geogrid layers were constructed in a laminar box mounted on a uniaxial shaking table and subjec...

Laboratory tests on geosynthetic-reinforced soil-aggregate systems were carried out by many researchers to understand the improvement in bearing resistance of soil-aggregate systems because of geosynthetic reinforcement. California bearing ratio (CBR) test is one among the common laboratory tests adopted for this purpose. This paper presents the in...

Size and morphological characteristics of particles play vital role on the shear and interfacial shear strength of sands. Often, effects of these parameters are merged and cannot be easily separated. Effect of size of the particles on the shear and interfacial shear strength of sands is presented in this paper through direct shear and interface dir...

Size and morphological characteristics of particles play vital role on the shear and interfacial shear strength of sands. Often, effects of these parameters are merged and cannot be easily separated. Effect of size of the particles on the shear and interfacial shear strength of sands is presented in this paper through direct shear and interface dir...

This paper investigates the effectiveness of planar and geocell layer in reinforcing aggregate bases constructed over weak subgrade. Experiments were carried out in three different test set-ups such as in the conventional CBR mould of 150 mm diameter, a test tank of 750 × 750 mm square and a field stretch of 2 m × 1 m. The unreinforced and reinforc...

The study area comprises right abutment of a railway bridge proposed at about 350 m above the ground level, crossing a river and connecting two huge hillocks in the Himalayas, India. The rock slopes are composed of various discontinuities with highly varying spacing, aperture and infilling. The properties of rock mass and infillings calculated from...

For ages, sieve analysis test remained as a convenient method to determine particle size distribution of granular materials. In sieve analysis, the particle size is characterized by a single linear dimension representing the minimum square sieve aperture through which the particle will just pass. This one dimension size description of sand grains i...