Retnamony G. Robinson

Retnamony G. Robinson
Indian Institute of Technology Madras | IIT Madras · Department of Civil Engineering

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107
Publications
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Publications

Publications (107)
Article
Class C fly ash, a byproduct of thermal power plants, is often preferred for the stabilisation of expansive soils. However, improper optimisation of the stabiliser may lead to the premature failure of treated soils during wet–dry cycles. This study demonstrates the volume change behaviour of fly ash-stabilised expansive soils subjected to wet– dry...
Chapter
Expansive soils are mostly found in semi-arid and arid regions, and these soils suffer significant volume change when exposed to seasonal moisture fluctuations. Further, this volume change may cause extensive damages to the engineering structures and also the cost of damages increases every year. Practicing geotechnical engineers used different tre...
Article
Triaxial tests are generally conducted to establish the mechanical behaviour of cement-treated clays. Numerical simulations of these tests involve selection of the correct constitutive model, which can capture the key features of the stress−strain response of the geomaterial. However, as cement-treated clays behave differently to untreated clay in...
Article
Full-text available
Tensile properties of geomaterials often play an important role in many geotechnical engineering problems. Compacted soil layers in dams, clay liners in landfills, reinforced earth-retaining wall systems, cement stabilized crushed rocks in pavements, etc. are constantly checked for tensile cracking. This type of cracking happens when the developed...
Article
Pond ash is a mixture of fly ash and bottom ash obtained from thermal power plants. It has pozzolanic properties and is commonly treated with cement to impart cohesion and improve strength. The increase in strength gain in cemented pond ash is attributed to the hydration of cement and pozzolanic reactions due to silica present in the pond ash. Unco...
Article
Full-text available
Expansive soils exhibit volume-change behaviour on exposure to moisture changes due to the presence of the montmorillonite mineral. The swell–shrink behaviour of these soils could lead to instability of the structures found on them, specifically the light-weight structures and pavements. Chemical stabilisation of expansive soils has always proven t...
Article
Swell potential and pressure of expansive soils are conventionally determined using an oedometer apparatus. The specimens are commonly saturated by submerging in water under a seating pressure. Generally, the test takes a long time, as the saturation process is slow. This article presents an improved saturation method by back pressure application i...
Chapter
Flowable fills, also called as Controlled Low Strength Materials (CLSM), are often used as alternative to compacted granular materials in specific situations like bedding layer to buried pipelines and backfill behind retaining walls. The fills are widely used in places where compaction cannot be done due to inaccessibility for moving compaction equ...
Chapter
Coefficient of secondary compression is one of the important consolidation properties of fine-grained soils exhibiting high secondary compression. Generally, soils containing significant amount of organic matter exhibit high secondary compression. It is generally determined by performing laboratory one-dimensional incremental loading (IL) consolida...
Article
Full-text available
Secondary consolidation of soils has gained much importance as a major contributor in the long term settlements of soft clays. In the scenario where constructions on such problematic soils are increasing, accurate prediction of long term settlements is very challenging. This paper reviews the evolution of the secondary compression characteristics f...
Conference Paper
Tensile properties of geomaterials often play an important role in many geotechnical engineering problems. Compacted soil layers in dams, clay liners in landfills, reinforced earth-retaining wall systems, cement stabilized crushed rocks in pavements, etc. are constantly checked for tensile cracking. This type of cracking happens when the developed...
Conference Paper
Analysis of the pile driving is extremely important when the pile driving is met with premature refusal. The present study is aimed at analyzing the offshore driven pile met with refusal using the continuum method of numerical analysis.
Article
Marine clays are reported to undergo an irreversible change in plasticity on drying. Various reasons such as the presence of halloysite and allophane minerals that change their structure, presence of sesquioxides or organic matter that undergo cementation and presence of salinity that generates strong attractive forces leading to aggregation on dry...
Conference Paper
This paper presents the results from 3-dimensional analysis of offshore driven pipe piles using FLAC3D (Fast Lagrangian Analysis of Continua in 3 Dimensions) program. The numerical model was developed with solid elements for both the pile and the surrounding soil. Interfaces are created both on the inside and outside surfaces of the pipe pile along...
Article
Conventional Triaxial Compression (CTC) and Unconfined Compressive Strength (UCS) tests are the most common testing methods used in the laboratory, to determine the shear strength of soil. These tests employ axisymmetric condition for testing. However, several geotechnical problems in the field can be approximated as plane strain (PS) problems. Hen...
Article
Full-text available
In the interest of utilizing high-plasticity excavation soil as a replacement for fine aggregate in cement mortar, a study on the thermal treatment of soils containing 25% and 40% clay fractions was carried out. A range of tests including thermogravimetric analysis (TGA) and X-ray diffraction (XRD) were conducted to examine the transformation of fi...
Article
This article presents the details of a simplified Constant Rate of Strain (CRS) consolidation apparatus for determining consolidation properties of soils. The apparatus has a loading piston with peripheral O-rings that slides through the consolidation ring. The loading piston has provision for back pressure application. The excess pore water pressu...
Article
Full-text available
Preloading, coupled with vertical drains, is one of the popular ground improvement techniques for the stabilization of soft clay deposits due to its efficiency and environmental credentials. Accurate prediction of the magnitude of final settlement and settlement duration is vital for planning preloading projects. Commonly, Asaoka’s method and Recta...
Conference Paper
Deep soil mixing is widely used technique for stabilizing thick deposits of soft clays. A laboratory trial was carried out to extend its application for stabilizing the expansive soils at high water content. Lime was used as a stabilizing agent, and in addition to that pond ash was mixed at proportions of 10%, 20% and 30% based on dry weight basis....
Article
Cement-based controlled low-strength material, also called flowable fill, is often used as both subbase and subgrade material in pavement construction. This article investigates the properties of a pond ash–based flowable fill with special reference to pavement applications. Properties such as flowability, unconfined compressive strength, Californi...
Article
Full-text available
Subgrade soils play a major role in the proper functioning of pavements. They are subjected to repeated loads due to traffic and often subjected to moisture ingress during monsoon seasons. If the subgrade is expansive in nature, lime stabilization is commonly adopted to mitigate swelling and shrinkage. However, the behavior of lime treated expansiv...
Chapter
Several types of apparatus are available for the determination of properties of soils. It was observed that the same property, determined using different equipment, may yield different results. This paper discusses the effect of test method on properties of soils such as liquid limit, swelling pressure, drained angle of internal friction of fine gr...
Conference Paper
In the present study an attempt was made to stabilize the thick deposits of expansive soil using Deep Soil Mixing (DSM) technique. The strength and volume change characteristics were studied through unconfined compressive strength and swell test on 28 days cured samples. From the experimental study it was observed that with the addition of lime (4%...
Article
The Atterberg limits – liquid limit (wL), plastic limit (wP) and shrinkage limit (wS) are of great importance for fine-grained soils. Though the procedure for their determination is empirical in nature, attempts were made in the literature to provide meaningful interpretation. In the present study, it is attempted to find out the consolidation pres...
Article
Full-text available
The aim of this work is to broadly investigate the possibility of utilizing excavated soil as alternative for river sand in cementitious system. Three different types of soils with low, medium and high plasticity (with different proportion and type of clay) were used as fine aggregates to produce cement mortar. The same soil samples were treated by...
Article
Various testing methods, such as the static triaxial test, cyclic resilient modulus test, repeated-load static triaxial test, repeated-load California Bearing Ratio (CBR) test, and repeated-load oedometer test, were explored to characterize pavement granular materials. Using such methods, an experimental data set of the stress–strain response of a...
Article
Full-text available
Subgrade soils play a major role in the proper functioning of pavements. They are subjected to repeated loads due to traffic and often subjected to moisture ingress during monsoon seasons. If the subgrade is expansive in nature, lime stabilization is commonly adopted to mitigate swelling and shrinkage. However, the behavior of lime treated expansiv...
Article
This paper presents a case study of a two-storey building in Oragadam, near Chennai (India), which has undergone distress due to the presence of expansive soil. Undulations in the floors, cracks in partition walls and non-uniform heave in the pavement are some of the failure patterns noticed in and around the structure. Undisturbed soil samples wer...
Article
Standard penetration test (SPT) is one of the widely used in-situ penetration tests for subsurface exploration. It’s suitability to assess and predict the design parameters of granular materials has been well appreciated by the geotechnical engineering community over several decades. However, in the case of soft to very soft clays, the correlation...
Article
Open-ended pipe piles are commonly used for the foundations of offshore jacket platforms, mooring piles, offshore wind turbines and, in general, for pile foundations like micro piles, etc. Driveability of open-ended piles is greatly affected by the formation of soil plug during the driving, particularly in sandy soils. In order to study the behavio...
Article
Full-text available
Full flow penetrometers (FFPs) such as T-bar and ball penetrometer provide reliable estimates of undrained shear strength (su) of soft soil deposits. Several studies are reported in the literature on the field application of these penetrometers for offshore applications typically for the deep-water environment. However, the lack of sampling provisi...
Article
This paper describes a modified conventional fixed ring consolidation cell to perform constant rate of strain (CRS) consolidation test for determining consolidation properties of soils. The modified consolidation cell is similar to the conventional oedometer cell with an additional provision for measuring pore water pressure at the bottom of the so...
Article
Vertical drains are widely used to accelerate the consolidation of soft clay deposits when preloading is used as a ground-improvement technique. Barron's theory is generally used for the design of vertical drains. One of the important input parameters required in Barron's theory is the coefficient of horizontal consolidation, ch. A reliable estimat...
Article
Full-text available
The possibility of reusing excavated soil as an alternative to river sand in the production of mortar was studied. The soil samples before and after wet sieving were used as fine aggregate in mortar preparation. The resulting wash water in wet sieving was analysed for the presence of soluble ions and its effect in cement hydration and mortar proper...
Article
Full-text available
To explore the significance of geopolymer technology on producing environmental friendly waste based mortar which could be a sustainable replacement for conventional mortar; Low, medium and high plastic soil from different locations was used as fine aggregate to produce fly ash based geopolymer mortars. The experiments were designed using central c...
Article
Consolidation parameters are essential for the design of a variety of geotechnical structures. These parameters are commonly determined by performing laboratory one-dimensional consolidation test. The conventional one-dimensional consolidation test takes about 10–14 days to complete one test. This paper describes an accelerated consolidation testin...
Article
Full-text available
It is important for geotechnical engineers to understand the intrinsic and mechanical behaviour of silt as it is presently recognised that there exist gaps in understanding its fundamental behaviour. The behaviour of kaolin samples with varying clay and silt contents was investigated in the present study. This study characterised the samples by the...
Article
Full-text available
This paper presents a simple, cost effective and reliable image processing technique for deformation measurement in geotextiles during wide width tensile strength tests. Localised strains are likely to be generated in the geotextiles due to production defects, seams and punctures. Accurate measurement of localised strains will help in better unders...
Article
This paper presented the details of a double acting piston based volume change apparatus for measuring volume change during the routine soil testing in the laboratory. The apparatus works in the principle of movement of a piston when water flows through a cylinder. The volume change was related to the area of the cylinder and the displacement of th...
Article
Full-text available
The piles in expansive soils would experience uplift force on the shaft of the piles due to the swelling of the soils. For a given soil, the magnitude of interface shear stress (uplift force) on pile depends on the interface friction between the pile material and the soil, normal stress acting on the pile surface and the magnitude of swelling, whic...
Conference Paper
Full-text available
Determination of resilient modulus involves the use of sophisticated cyclic triaxial apparatus. In this investigation, it is attempted to evaluate an identical modulus through repeated load California Bearing Ratio test. A pavement granular material normally used as a granular base course in Indian highways was tested at three moisture contents, fo...
Article
Full-text available
Equivalent approach to analyse reinforced soil has an advantage that the study of complex interaction between the soil and reinforcement is avoided and the stress–strain characteristics are obtained similar to a homogeneous material. Present study aims to investigate the behaviour of reinforced soil structures by considering it as an equivalent med...
Article
This paper compares the results of laboratory studies carried out to determine the engineering properties, response under cyclic loading and the microstructure of soft clay after subjecting it to preloading by surcharge and vacuum. The samples for these tests were prepared at different initial consolidation pressures of 25, 50 and 100 kPa under K0...
Article
The angle of internal friction of sands from direct shear tests and plane strain tests is reported to be higher by about 2–8° compared to the triaxial compression tests. However, information about the comparison for the case of fine grained soils is scarce in the literature. In the present study a comparison of the results of a series of direct she...
Article
Full-text available
Granular materials are conventionally used as backfills behind retaining walls and many other filling applications. Normally, the backfills are compacted in layers at a relative compaction of not less than 95 % of the Standard Proctor unit weight at desired water content. Depending on the type of backfill material, suitable compaction equipments ar...
Article
Vertical drains are extensively used to accelerate the consolidation of soft clay deposits when preloading is used as a ground improvement technique. Barron's theory is widely adopted for the design of vertical drains. One of the important input parameter required in Barron's theory is the coefficient of horizontal consolidation ch. The reliable es...
Article
Full-text available
Expansive soils have the tendency to undergo volume change behavior and cause large uplift pressures and upheaval of structures built on them. Avoiding expansive soil in most of the cases is not practically possible, hence stabilization practices are undertaken to treat them. Chemical stabilization through lime is the most sought after treating met...
Article
Full-text available
Preloading coupled with vertical drains is a successful ground improvement technique for soft clay deposits. Though surcharge in the form of sand pile is conventionally used, vacuum consolidation is also an option. This paper presents a case study on ground improvement using vacuum consolidation technique carried out near the shoreline in the city...
Article
Clay deposits often exhibit inherent anisotropy due to different microfabrics, resulting from both environmental conditions during deposition and stress conditions subsequently. Many anisotropic elastic-plastic models are developed for modeling the behavior of clays subjected to anisotropic stress conditions. In this study, the drained and undraine...
Article
Full-text available
Determination of critical state parameters are essential, when critical state soil mechanics based soil models are used for the analysis. Isotropic consolidation test and triaxial tests with accurate measurements of volume change and pore pressure are essential for the direct measurement of critical state parameters. However, in the conventional ge...
Article
The flexible wall permeability apparatus was modified for the direct measurement of the hydraulic conductivity of soils in the horizontal direction. Constant head permeability tests were carried out using the radial flow flexible wall permeameter on soil samples with central sand drain to allow the water to flow radially from the central sand drain...
Article
The post-cyclic behaviour of a clayey soil after subjecting to cyclic loading is presented in this paper. Tests were carried out on the samples both by allowing the cyclic pore pressure developed during cyclic loading to dissipate and without dissipation. While the samples subjected to post-cyclic monotonic loading without dissipation of cyclic por...
Article
The use of stone columns is one of the proven ground improvement techniques for improving the load carrying capacity of soft clay deposits. When the stone columns are installed in soft clays, there is a possibility of intrusion of fine clay particles into the column which reduces the shear strength of the stones resulting in reduction in capacity....
Article
The in-situ deep cement mixing method is an established technique for improving the strength and reducing settlement of soft soil deposits. In practice, upon completion of the cement treatment, the improved ground will be left for curing over a specific period of time, before commencement of construction activities. In the case of deep mixing, curi...
Article
Full-text available
Vacuum preloading of clay deposits is becoming an increasingly popular ground improvement technique. Although many studies have been reported in literature, the mechanism of vacuum preloading is still not properly understood. Soil under vacuum preloading is expected to undergo an inward lateral deformation, therefore the influence of lateral deform...
Article
Clays treated with lower cement contents often exhibit behaviour similar to stiff clays with planar failure surface under triaxial compression. In the present work the behaviour of a marine clay treated with 5 % cement, subjected to undrained triaxial compression tests is studied. The pre-consolidation pressure of the cemented clay due to the cemen...
Article
Stone columns are often considered as an excellent ground improvement technique adopted to improve the load carrying capacity and reduces the settlement characteristics. However the load carrying capacity mainly depends on the undrained shear strength of surrounding soils. Reinforcement in the form of encasement is usually provided around the stone...
Article
Vertical drains are extensively used to accelerate the consolidation of soft clay deposits when preloading is used as a ground improvement technique. Barron's theory is widely adopted for the design of vertical drains. The important input parameter required in Barron's solution is the coefficient of radial consolidation (cr) and a rational assessme...
Article
Microfabric plays an important role in the engineering behavior of soils. Although many studies are available in the literature on the effect of microfabric on the static behavior of soils, the effect on the cyclic behavior is less understood. In the present study, samples with different microfabric were prepared in the laboratory by reconstituting...
Conference Paper
Preloading techniques along with the vertical drains is an effective ground improvement technique for the soft clays having low bearing capacity and high compressibility characteristics. The purpose of preloading is to reduce the water content of the soil so as to increase the shear strength and reduce the post construction settlement. In the prese...
Article
Full-text available
This paper describes the microfabric and mineralogical changes in an expansive soil from Siruseri (South-East Chennai, Tamilnadu, India), when treated with inorganic additives such as Calcium Hydroxide and Calcium Chloride. The engineering and index properties and mineralogical composition of the untreated and treated soil were determined. The soil...
Article
Yield stress is one of the most important properties of soils. This paper addresses the yield stress of a desiccated expansive soil that was subjected to repeated cycles of wetting and drying under controlled laboratory conditions. Identical samples were subjected to different surcharge pressures such as 6.25, 12.5, 25, 50, 100 and 200 kPa so as to...
Article
Expansive soils cover about 20% of the land area of India. These soils undergo volume change due to moisture fluctuations. Therefore, lightly loaded structures and pavements are often severely affected. While several chemical stabilization techniques are available to treat these soil deposits, under-reamed piles are often used as a foundation alter...
Article
Full-text available
Swelling pressure of clays is an important parameter required for the design of a variety of structures founded on expansive soils. Out of many methods available to determine the swell pressure in the laboratory, odometer method is popular because of its simplicity. Three odometer methods are commonly used to determine swelling pressure, such as sw...
Article
Vertical drains are extensively used to accelerate the consolidation of soft clay deposits. Barron's theory is usually used to analyze this problem, in which the drainage occurs in the radial direction. The important input parameter in Barron's theory is the coefficient of radial consolidation (c r ) and a rational assessment of c r is necessary fo...
Conference Paper
Vacuum preloading technique is a viable ground improvement technique for the stabilization of soft grounds. The basic difference between surcharge preloading and vacuum preloading is that surcharge preloading imparts anisotropic stress conditions to the soil whereas the stress induced by vacuum pressure is more close to isotropic as it is applied t...
Article
Full-text available
The values of coefficient of consolidation calculated based on time-settlement data from a laboratory consolidation test are influenced by both initial and secondary compression effects. The effect of secondary compression is predominant when the load increment ratio is less than 1.0. In this Note a method of estimation of coefficient of consolidat...
Article
During desiccation soils are subjected to very high shrinkage stresses, often of the order of 1000 kPa. However, studies on re-saturated desiccated soils do not always show evidence of these soils being subjected to very high stresses. This paper address this important issue and the reason can be attributed to the type of saturation, either by rais...
Article
Land reclamation is a major civil engineering activity in Singapore. Due to depletion of suitable local fills and the cost of imported land, dredged and excavated clay fills, in spite of their poor engineering properties, are being evaluated as a fill material. To reduce double handling, it is desirable for the clay to be used directly in a lump fo...
Article
The disposal of large volumes of clay lumps obtained from underground construction activities and seabed dredging is a problem in a highly built-up environment such as Singapore. The use of such clay lumps for reclamation of land is an environment-friendly proposition. The clay lumps, when placed under water, will undergo three-dimensional swelling...
Conference Paper
Full-text available
An extensive site investigation is performed at a test site off Pulau Tekong Island, Singapore. This test site is one of the three planned test sites where the dredged clay lumps have been dumped on the seabed to form a 3m - 4m thick lumpy fill layer with inevitable inter-lump voids. A 7m sand layer was placed on top of the dredged clay lumps to ac...