Reducing heave of expansive clay beds through granular pile–anchor groups
01 May 2014-Vol. 167, Iss: 2, pp 99-107
TL;DR: The granular pile-anchor (GPA) foundation system, a more recent technique, has also been found to be quite successful in controlling heave of expansive clay beds as discussed by the authors.
Abstract: The granular pile-anchor (GPA) foundation system, a more recent technique, has also been found to be quite successful in controlling heave of expansive clay beds. This paper presents experimental data obtained from laboratory-scale heave tests conducted on an unreinforced expansive clay bed (n = 0) and expansive clay beds reinforced by a single GPA (n = 1), twin GPAs (n = 2) and a group of GPAs laid in equilateral triangular pattern (n = 3). The thickness of all the test clay beds was 200 mm. Heave was monitored at different depths of clay beds as they were inundated. Ground heave (or surface heave) was also monitored at different radial distances (r) from the centre of the test tank. The unreinforced clay bed and the GPA-reinforced clay beds were identical with regard to thickness (H), placement water content (w%) and dry density (γd). Heave decreased at all depths of the clay beds as the number of the GPAs (n) increased. Furthermore, heave decreased with increasing depth (z) from the top of the clay bed...
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TL;DR: Granular pile anchor (GPA) system is a simple and cost-effective foundation technique for resisting the uplift of foundation caused by swelling of expansive clay as discussed by the authors, which is used in the heave resu...
Abstract: Granular pile anchor (GPA) system is a simple and cost-effective foundation technique for resisting the uplift of foundation caused by swelling of expansive clay. This paper presents the heave resu...
11 citations
Cites methods or result from "Reducing heave of expansive clay be..."
...Tests performed on laboratory scale GPAs (Phanikumar et al. 2004; Phanikumar and Muthukumar 2014) and field scale GPAs (Rao et al....
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...Tests performed on laboratory scale GPAs (Phanikumar et al. 2004; Phanikumar and Muthukumar 2014) and field scale GPAs (Rao et al. 2007; Rao et al. 2008; Phanikumar et al. 2008) shows that GPA foundation system is efficacious in controlling heave of the expansive clay beds....
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...This establishes the efficacy of GPA technique in reducing uplift of foundation caused by expansive clay beds upon saturation and agrees with previous research findings (Phanikumar and Muthukumar 2014, 2015)....
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01 Oct 2019
TL;DR: In this article, an attempt has been made to reuse the waste expanded polystyrene (EPS) beads as an environmentally friendly additive to mitigate the swelling potential of expansive soil.
Abstract: Expansive soils exhibit greater volume change with variation in moisture content. In this study, an attempt has been made to reuse the waste expanded polystyrene (EPS) beads as an environmentally friendly additive to mitigate the swelling potential. The swelling behaviour of expansive soil was examined with and without EPS geobeads inclusions. Several swell-compression tests were carried out on one-dimensional large consolidation apparatus (LCA) which can accommodate the California bearing ratio (CBR) mould. The swelling characteristics of remoulded soil specimens were evaluated with the addition of 0%, 0.25%, 0.5%, 0.75% and 1% geobeads content (gc) by the dry weight of the soil. The test result shows that the increase in gc from 0.25 to 1%, there is a gradual decrease in the vertical swelling potential (i.e. percent swell and swelling pressure). A higher recycled gc inclusion up to 1% could be preferable to reduce maximum swelling potential, where compressional deformations are not of primary concern.
10 citations
TL;DR: In this article, a new design of horizontal pivoting pile anchors used as supports for main pipelines on heaving and watered bases is proposed to reduce the deformability of this type of foundation and increase its load-bearing capacity under the influence of the forces of frost heaving of the soil.
6 citations
Additional excerpts
...Однако их устройство подразумевает большой расход металла и высокую трудоемкость производства [16]....
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4 citations
References
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TL;DR: In this paper, a new elasto-plastic framework for unsaturated soils is proposed, involving coupling of hydraulic hysteresis and mechanical behaviour, and a specific constitutive model for isotropic stress states is proposed.
Abstract: Consideration of the different roles of pore air pressure, pore water pressure within bulk water and pore water pressure within meniscus water suggests that the degree of saturation will have a significant influence on the stress–strain behaviour of an unsaturated soil, in addition to any influence of suction. This suggestion is supported by experimental evidence. In the light of this, a new elasto-plastic framework for unsaturated soils is proposed, involving coupling of hydraulic hysteresis and mechanical behaviour. Within the proposed framework, plastic changes of degree of saturation influence the stress–strain behaviour, and plastic volumetric strains influence the water retention behaviour. A specific constitutive model for isotropic stress states is proposed, and model predictions are compared with experimental results, in order to demonstrate some of the capabilities of the new framework. Forms of behaviour that can be represented include proper transitions between saturated and unsaturated types ...
719 citations
TL;DR: In this paper, the effect of fly ash content on the free swell index, swell potential, swelling pressure, plasticity, compaction, strength, and hydraulic conductivity characteristics of expansive soil was evaluated.
Abstract: This note presents a study of the efficacy of fly ash as an additive in improving the engineering characteristics of expansive soils. An experimental program has evaluated the effect of the fly ash content on the free swell index, swell potential, swelling pressure, plasticity, compaction, strength, and hydraulic conductivity characteristics of expansive soil. The plasticity, hydraulic conductivity and swelling properties of the blends decreased and the dry unit weight and strength increased with an increase in fly ash content. The resistance to penetration of the blends increased significantly with an increase in fly ash content for a given water content. Excellent correlation was obtained between the measured and predicted undrained shear strengths.
348 citations
TL;DR: A 3.5 km (2.2 mi) section of a road in Georgia developed unexpected transverse bumps within 6 months after construction and the source of the bumps appeared to be expansion within the cement-stabilized base course as discussed by the authors.
Abstract: A 3.5-km (2.2 mi) section of a road in Georgia developed unexpected transverse bumps within 6 months after construction. The source of the bumps appeared to be expansion within the cement-stabilized base course. Laboratory examination of samples from areas showing distress revealed the presence of ettringite, a calcium sulfoaluminate the formation of which can be accompanied by severe expansion. This expansive materials was the probable cause of the volume changes causing the transverse bumps. The calcium and alumina needed to form ettringite ware available from the portland cement and the stabilized soil`s clay minerals. The source of the sulfur was identified as the well water that was mixed with the cement-stabilized base. Sulfate attack of cement-stabilized soils is a relatively infrequent problem, but it is highly destructive when it occurs. Currently, there are no firm criteria for identifying when sulfate attack of a cement-stabilized soil is a potential problem nor are there established methods of preventing the attack.
165 citations
TL;DR: In this paper, the authors developed a rational and practical methodology to determine both clay mineralogy distribution and dominant clay mineral in a soil by using three measured chemical soil properties and their analyses.
Abstract: Stabilization design guidelines based on soil plasticity properties have certain limitations. Soils of similar plasticity properties can contain different dominant clay minerals, and hence, their engineering behavior can be different when stabilized with the same chemical additive and dosage. It is essential to modify stabilizer design guidelines by including clay mineralogy of the soil and its interactions with chemical additives used. Chemical properties of a soil including cation exchange capacity (CEC), specific surface area (SSA) and total potassium (TP) are dependent on clay mineral constituents, and an attempt is made in this study to develop a rational and practical methodology to determine both clay mineralogy distribution and dominant clay mineral in a soil by using three measured chemical soil properties and their analyses. This approach has been evaluated by determining and evaluating clay minerals present in artificial and natural clayey soils of known and unknown clay mineralogy. A total of twenty natural and six artificial soils were considered and used in the chemical analyses. Test results and subsequent analyses including the development of artificial neural network (ANN) based models are evaluated and described in this paper.
83 citations
TL;DR: In this article, a field-scale test program conducted to study the pullout response of granular pile anchors embedded in expansive clay beds was conducted on GPAs of varying lengths and diameters.
Abstract: Granular pile anchors (GPA) are one of the recent innovative foundation techniques devised for mitigating the problems posed by swelling clay beds. In a granular pile anchor, the footing is anchored to an anchor plate at the bottom of the granular pile. This makes the granular pile tension resistant and enables it to absorb the tensile force caused on the foundation by the swelling clay. An understanding of the amount of uplift resistance offered by the GPA is important in the design of granular pile-anchor foundations in field situations causing tensile forces on foundations, such as in expansive clay beds. This paper presents the results of a field-scale test program conducted to study the pullout response of GPAs embedded in expansive clay beds. Pullout load tests were conducted on GPAs of varying lengths and diameters. It was found from the field pullout load tests that granular pile anchors of larger surface area resulted in higher pullout capacity. Of the various single granular pile anchors with l∕...
71 citations