International Research Journal of Engineering and Technology (IRJET) Volume: 09 Issue: 06 | Jun 2022
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e-ISSN: 2395-0056 p-ISSN: 2395-0072
Comparative Study of Slag and Slag-Lime Columns in Kuttanad Clay S. Gowri 1, A. Shyla Joseph2 PG student, Geomechanics and Structures, Dept. of Civil Engineering, Saintgits college of Engineering, Kerala, India Assistant Professor, Dept. of Civil Engineering, Saintgits college of Engineering, Kerala, India ---------------------------------------------------------------------***--------------------------------------------------------------------in stone column was altered with that of shredded tyre Abstract – Now a days, a major issue for proper
Aggregates , Finite Element Analysis , PLAXIS 3D
chips (Ankitha et.al, 2017) and the load settlement behavior was obtained from the plate load test of both end bearing and floating stone columns with and without encasement. They found that in both end bearing and floating columns, mixture of 70% aggregates and 30% tyre chips showed better performance. Zukri et.al (2018) reviewed the stone column which enhances the weak soils by the partial replacement of compressible soil by more competent materials like sand, silica manganese slag, pulverized fuel ash, coal ash, quarry dust, highway ballast, stone dust shredded waste tyres, and flyash in terms of their consolidation behavior. Unit cell concept was used by Shahraki et.al (2018) on ABAQUS for 3 D modelling of stone columns in saturated soft grounds. 2D and 3D numerical analyses on PLAXIS were compared for a test embankment in Rio De Janerio, Brazil (2012) stabilized with basal geogrids and geosythetic encasement (Hosseinpour et.al, 2019). He concluded that 3D analyses were better since they can stimulate field conditions better. Ghorbani et.al (2020) did a parametric study of the factors affecting stone column properties and also the stability analysis of the embankment.
1. INTRODUCTION
2. MATERIALS AND METHODOLOGY
Provision of granular piles or aggregate piers is one of the ground improvement techniques where weak soils are reinforced with compacted aggregate columns in a grid pattern. The purpose is to enhance load carrying capacity, accelerate consolidation to permit the application of higher imposed loads, and reduce settlement by densification and reinforcement of the subsoil. The load carrying capacity is obtained from the lateral confinement from the surrounding soils (Greenwood, 1970). The granular column behaviour can be further improved by encasing it with geosynthetics. In this numerical study, the aggregates are replaced by slag aggregates which are waste materials from the iron and steel industry.
The soil to be improved is taken from Kunnamkaery, Kuttanad. Both the stone and slag aggregates are of 20 mm size. Encasements using geogrids were provided. The soil and aggregate properties were tested in the laboratory and the input parameters to be used in the software were found.
development is the increasing cost and non-availability of land. An effective solution is to utilize the available land with weak strata which has low shear strength and high compressibility which are otherwise not utilized for construction. This demands the use of a proper ground improvement technique. Among various ground improvement techniques including dewatering, preloading, sand drains, prefabricated vertical drains, granular column etc., use of stone columns is a cost-effective and environment friendly method for improving the low bearing capacity and large-scale settlement of weak soils. In this study the analysis of ground improvement by stone columns will be carried out using finite element software PLAXIS 3D. The stone aggregates will be replaced by slag aggregates. Slag aggregates are the waste materials from the iron industry. Utilizing these aggregates in stabilization techniques helps in reducing its degrading effect on the environment. A comparison when slag aggregates are used with lime along with geotextile layer in between is also studied.
Key Words: Stone Column, Stone Aggregates, Slag
The numerical analysis is done in a finite element software, PLAXIS 3D. The finite element analysis in PLAXIS 3D is utilized to analyse the settlement and total stress characteristics of various stone columns as in ordinary stone columns and encased stone columns both with stone aggregates and slag aggregates. Encasement is provided using geogrid element. Positive and negative interface elements were also provided.
1.1 Literature review Jorge et.al (2017) performed review on the most recent advances and recommendations on modelling stone columns. He concluded that for numerical analyses of a problem, conditions such as an embankment, the simplified geometrical model of a three-dimensional slice of columns is recommended. For a more simplified model, the unit cell approach is recommended. The filler material
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