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Book ChapterDOI

A Short Review of Geosynthetic Granular Column Treatment of Soft Clay Soils

01 Jan 2019-Vol. 14, pp 373-380
TL;DR: In this paper, the authors discuss the recent advancement of encasing granular columns with geosynthetic products to enhance their performance in load bearing capacity and reducing the foundation settlements.
Abstract: In urban areas scarcity of land to build infrastructure has driven the geotechnical engineers to improve poor subsoil conditions through different techniques Granular column treatment is one of the most promising ground improvement techniques widely practiced all over the world This paper discusses briefly the status of research on this topic Focus is on the recent advancement of encasing these columns with geosynthetic products to enhance their performance in load bearing capacity and reducing the foundation settlements This paper is divided into analytical, experimental, numerical and field studies on the aspect of encased granular columns (EGCs) which have been published in the past three decades The primary objective of this study is to compile the above said aspects of EGCs into one single source of information to interested researchers in this field Lot of studies have been conducted mainly on the laboratory aspects of EGCs Very few attempts have been made by researchers to study the mechanism of granular columns at full-scale levels through field tests Finally a brief summary with necessary discussions is provided on the efforts made so far in studying the behavior of EGCs
Citations
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Journal ArticleDOI
TL;DR: In this article, the effect of lime-zeolite stabilization on the behavior of a silt-sized natural soil of low plasticity, by performing standard compaction tests as well as unconfined compressive experiments evaluating the strength of the composite samples.
Abstract: Soil stabilization, through either physical or chemical techniques of coating-cementation development, is a commonly adopted practice in geotechnical and transportation engineering projects used to strengthen soils and mitigate negative geo-environmental impacts. This can be particularly important in enhancing the mechanical properties of soils which are prone to degradation of their response because of freezing and thawing actions. It was attempted in this research study to examine the effect of lime–zeolite stabilization on the behavior of a silt-sized natural soil of low plasticity, by performing standard compaction tests as well as unconfined compressive experiments evaluating the strength of the composite samples. The natural soil mixed with various contents of lime and zeolite partial replacement was subjected to consecutive freezing and thawing cycles. The results from the study showed significant improvement of the mechanical performance of the treated soil when mixed with lime partially replaced with zeolite in terms of strength and durability and, based on scanning electron microscopic images, additional insights were attempted to be obtained on the microstructure of the specimens subjected to temperature changes.

17 citations

References
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Journal ArticleDOI
TL;DR: In this article, the authors investigated the qualitative and quantitative improvement in load capacity of the stone column by encasement through a comprehensive parametric study using the finite element analysis and found that the encased stone columns have much higher load carrying capacities and undergo lesser compressions and lesser lateral bulging as compared to conventional stone columns.

264 citations


"A Short Review of Geosynthetic Gran..." refers background or result in this paper

  • ...Similar investigations were conducted by Murugesan and Rajagopal (2006) who on the other hand had investigated the geosynthetic stiffness up to 10000 kN/m and observed similar findings....

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  • ...Murugesan and Rajagopal (2006, 2007, 2010) conducted laboratory model tests on ordinary and encased granular columns extensively for both single as well as group and found that the encased granular column exhibited a stiffer response whereas the ordinary columns showed significant strain softening…...

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  • ...Murugesan and Rajagopal (2006) have numerically investigated the advantages of encased granular column over ordinary granular columns using the program GEOFEM and concluded that the elastic modulus of the geosynthetic encasement plays an important role in enhancing the load carrying capacity and…...

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Journal ArticleDOI
TL;DR: In this article, the authors investigated the qualitative and quantitative improvement of individual load capacity of stone column by encasement through laboratory model tests conducted on stone columns installed in clay bed prepared in controlled condition in a large scale testing tank.
Abstract: The stone columns (or granular piles) are increasingly being used as ground reinforcement elements for supporting a wide variety of structures including buildings and flexible structures. The stone columns derive their load capacity from the confinement offered by the surrounding soil. In very soft soils this lateral confinement may not be adequate and the formation of the stone column itself may be doubtful. Wrapping the individual stone columns with suitable geosynthetic is one of the ideal forms of improving the performance of stone columns. This type of encasement by geosynthetic makes the stone columns stiffer and stronger. In addition, encasement prevents the lateral squeezing of stones in to the surrounding clay soil and vice versa, preserves drainage function of the stone column and frictional properties of the aggregates. In spite of many advantages, the behavior and the mechanism of the geosynthetic encased stone columns is not thoroughly understood. This paper investigates the qualitative and quantitative improvement of individual load capacity of stone column by encasement through laboratory model tests conducted on stone columns installed in clay bed prepared in controlled condition in a large scale testing tank. The load tests were performed on single as well as group of stone columns with and without encasement. Tests were performed with different geosynthetics for the encasement of stone column. The results from the load tests indicated a clear improvement in the load capacity of the stone column due to encasement. The increase in the axial load capacity depends very much upon the modulus of the encasement and the diameter of the stone column. The increase in the stress concentration on the stone columns due to encasement was also measured in the tests. The results from the tests were used to develop the design guidelines for the design of geosynthetic encasement for the given load and settlement.

246 citations


"A Short Review of Geosynthetic Gran..." refers background in this paper

  • ...Murugesan and Rajagopal (2006, 2007, 2010) conducted laboratory model tests on ordinary and encased granular columns extensively for both single as well as group and found that the encased granular column exhibited a stiffer response whereas the ordinary columns showed significant strain softening…...

    [...]

Journal ArticleDOI
TL;DR: In this article, the results of a series of small-scale model column tests that were undertaken to investigate the behaviour of geogrid encased columns were discussed. And the results indicated a steady reduction in vertical strain with increasing encased length for both isolated columns and group columns and a significant increase in column stiffness and further reduction in column strain was observed for fully-encased columns.

241 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the qualitative and quantitative improvement of load capacity of individual encased stone columns through laboratory model tests and found that the load-carrying capacity of the encasement improves load transfer to deeper depths of soil.
Abstract: Stone columns (or granular piles) have proven to be ideal ground reinforcement for supporting flexible structures such as embankments and storage tanks. Stone columns installed in very soft soils will have very low lateral confinement: hence they undergo excessive bulging, leading to undue settlement and limited load-carrying capacity. In these situations, the strength and stiffness of the stone column can be enhanced by encasing the individual stone columns with a suitable geosynthetic. The encasement improves load transfer to deeper depths of soil. This paper investigates the qualitative and quantitative improvement of load capacity of individual encased stone columns through laboratory model tests. These tests were performed in a rigid unit cell that represents the stone column and the soil within the contributary area around the stone column. The load tests indicated a clear improvement in the load capacity of the stone column due to encasement. Encasement with geosynthetics having higher modulus resu...

178 citations


"A Short Review of Geosynthetic Gran..." refers background in this paper

  • ...Murugesan and Rajagopal (2006, 2007, 2010) conducted laboratory model tests on ordinary and encased granular columns extensively for both single as well as group and found that the encased granular column exhibited a stiffer response whereas the ordinary columns showed significant strain softening…...

    [...]