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Full-Text Articles in Engineering

Performance And Prediction Of Surcharge And Vacuum Consolidation Via Prefabricated Vertical Drains With Special Reference To Highways, Railways And Ports, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Xueyu Geng Mar 2014

Performance And Prediction Of Surcharge And Vacuum Consolidation Via Prefabricated Vertical Drains With Special Reference To Highways, Railways And Ports, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Xueyu Geng

Cholachat Rujikiatkamjorn

Much of the world’s essential infrastructure is built along congested coastal belts that are composed of highly compressible and weak soils up to significant depths. Soft alluvial and marine clay deposits have very low bearing capacity and excessive settlement characteristics, with obvious design and maintenance implications on tall structures and large commercial buildings, as well as port and transport infrastructure. Stabilising these soft soils before commencing construction is essential for both long term and short term stability. A system of vertical drains combined with vacuum pressure and surcharge preloading has become an attractive ground improvement alternative in terms of both …


Performance And Prediction Of Marine Clay Treated With Vacuum And Surcharge Consolidation At Port Of Brisbane, Buddhima Indraratna, A S. Balasubramaniam, Harry Poulos, Cholachat Rujikiatkamjorn, Jayantha Ameratunga Mar 2014

Performance And Prediction Of Marine Clay Treated With Vacuum And Surcharge Consolidation At Port Of Brisbane, Buddhima Indraratna, A S. Balasubramaniam, Harry Poulos, Cholachat Rujikiatkamjorn, Jayantha Ameratunga

Cholachat Rujikiatkamjorn

During the past decade, the application of vacuum preloading for stabilising soft coastal clay and other low-lying estuarine soils has become popular in Australia. The cost-effectiveness isa major factor in most projects in view of the significantly reduced time for achieving high degree of consolidation. Due to an increase in trade activities at the Port of Brisbane, new facilities on Fisherman Islands at the mouth of the Brisbane River will be constructed on the new outer area (235 ha) adjacent to the existing port facilities via land reclamation. A vacuum assited surcharge load and conventional surcharge scheme in conjunction with …


Radial Consolidation Modelling Incorporating Downdrag Effect For A Multi-Layer Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna Mar 2014

Radial Consolidation Modelling Incorporating Downdrag Effect For A Multi-Layer Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna

Cholachat Rujikiatkamjorn

A system of vertical drains (PVDs) with preloading is a successful method for promoting horizontal drainage and accelerating soil consolidation. A piecewise technique is used to capture the radial consolidation in the multi-layer soil system to incorporate (a) the effect of soil downdrag and (b) smear zone where soil permeability varying linearly. The effect of soil dragged down from the upper soil layer into the lower layer has been analysed in terms of required time for consolidation. It can be seen that the consolidation of the multi layer soil depends on the interaction between 2 adjacent layer, penetration depth, and …


Numerical Prediction Of Unsaturated Ground Behavior Influenced By Vegetation And Vacuum Consolidation, Cholachat Rujikiatkamjorn, Buddhima Indraratna, B Fatahi Mar 2014

Numerical Prediction Of Unsaturated Ground Behavior Influenced By Vegetation And Vacuum Consolidation, Cholachat Rujikiatkamjorn, Buddhima Indraratna, B Fatahi

Cholachat Rujikiatkamjorn

Bioengineering including native vegetation is an ancient method of improving the stability of slopes. In modern railway engineering, this technique is re-captured for increasing the soil stiffness and shear strength of subgrade beneath rail tracks. Currently this practice has become increasingly popular in Australia for stabilising railway corridors built over expansive clays and compressive soft soils. This paper looks at the stabilisation role by suction generated by both the natural vegetation and the artificial vacuum application using the numerical analysis. For demonstrating the role of native vegetation, a mathematical model for the rate of root water uptake was incorporated in …


Application Of Vacuum Consolidation For Sustainable Transport Infrastructure, Cholachat Rujikiatkamjorn, Buddhima Indraratna Mar 2014

Application Of Vacuum Consolidation For Sustainable Transport Infrastructure, Cholachat Rujikiatkamjorn, Buddhima Indraratna

Cholachat Rujikiatkamjorn

A system of vertical drains combined with vacuum preloading to accelerate soil consolidation by promoting radial flow is an effective method. In this paper, the analytical modelling of vertical drains incorporating vacuum preloading in an axisymmetric condition is proposed. The distribution of vacuum pressure along the drain and variations in volume compressibility, and permeability of soil based on large scale laboratory observations are included in the proposed solutions. These analytical predictions are compared with a case history taken from Thailand where the entire embankment was stabilised with vertical drains and subjected to vacuum preloading. This analysis employing the writer’s model …


Non-Linear Analysis Of Soft Ground Consolidation At The Ballina By-Pass, Xueyu Geng, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Richard Kelly Mar 2014

Non-Linear Analysis Of Soft Ground Consolidation At The Ballina By-Pass, Xueyu Geng, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Richard Kelly

Cholachat Rujikiatkamjorn

This study presents a numerical assessment of consolidation under vacuum preloading with a system of vertical drains and membrane, considering the non-linear properties of the soil This membrane system, already widely used in Australia, is where an airtight membrane is placed over the drainage layer to allow a vacuum to be distributed within the sand platform, along the surface of the soil, and down the vertical drains. To date, there have only been a few fundamental investigations and field studies that have tried to assess the way in which the vacuum can propagate in soft clay, both laterally and vertically. …


Performance And Prediction Of Marine Clay Treated With Vacuum And Surcharge Consolidation At Port Of Brisbane, Buddhima Indraratna, A S. Balasubramaniam, Harry Poulos, Cholachat Rujikiatkamjorn, Jayantha Ameratunga Mar 2014

Performance And Prediction Of Marine Clay Treated With Vacuum And Surcharge Consolidation At Port Of Brisbane, Buddhima Indraratna, A S. Balasubramaniam, Harry Poulos, Cholachat Rujikiatkamjorn, Jayantha Ameratunga

Buddhima Indraratna

During the past decade, the application of vacuum preloading for stabilising soft coastal clay and other low-lying estuarine soils has become popular in Australia. The cost-effectiveness isa major factor in most projects in view of the significantly reduced time for achieving high degree of consolidation. Due to an increase in trade activities at the Port of Brisbane, new facilities on Fisherman Islands at the mouth of the Brisbane River will be constructed on the new outer area (235 ha) adjacent to the existing port facilities via land reclamation. A vacuum assited surcharge load and conventional surcharge scheme in conjunction with …


Performance And Prediction Of Vacuum Combined Surcharge Consolidation At Port Of Brisbane, Buddhima Indraratna, Jayantha Ameratunga, Cholachat Rujikiatkamjorn, Harry G. Poulos, A S. Balasublamaniam Mar 2014

Performance And Prediction Of Vacuum Combined Surcharge Consolidation At Port Of Brisbane, Buddhima Indraratna, Jayantha Ameratunga, Cholachat Rujikiatkamjorn, Harry G. Poulos, A S. Balasublamaniam

Buddhima Indraratna

During the past decade, the application of vacuum pressure for stabilising soft coastal clay and other low-lying estuarine soils has become increasingly popular in Australia, mainly due to the proven costeffectiveness in view of the significantly reduced time for achieving a high degree of consolidation and enhanced shear strength. Due to an increase in trade activities at the Port of Brisbane, new facilities on Fisherman Islands at the mouth of the Brisbane River will be constructed on the new outer area (235ha) adjacent to the existing port facilities via land reclamation. A scheme of vacuum assisted surcharge load in conjunction …


Vertical Drains, Vacuum Consolidation & Preloading, Buddhima Indraratna Mar 2014

Vertical Drains, Vacuum Consolidation & Preloading, Buddhima Indraratna

Buddhima Indraratna

Due to the rapid increase in population, and the subsequent industrial and construction boom, especially in the urban and coastal regions, many countries have intensified the inevitable need for developing infrastructure on problematic soils, including soft compressible clays and deposits with low bearing capacities. Moreover, good quality geological materials for construction are also becoming scarce, a problem exacerbated by the numerous environmental constraints imposed in various countries. Because of these reasons, and environmental restrictions on certain public works, ground improvement has now become an integrated and essential component of infrastructure development. Consequently, civil engineers are forced to utilise even the …


Radial Consolidation Modelling Incorporating Downdrag Effect For A Multi-Layer Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna Mar 2014

Radial Consolidation Modelling Incorporating Downdrag Effect For A Multi-Layer Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna

Buddhima Indraratna

A system of vertical drains (PVDs) with preloading is a successful method for promoting horizontal drainage and accelerating soil consolidation. A piecewise technique is used to capture the radial consolidation in the multi-layer soil system to incorporate (a) the effect of soil downdrag and (b) smear zone where soil permeability varying linearly. The effect of soil dragged down from the upper soil layer into the lower layer has been analysed in terms of required time for consolidation. It can be seen that the consolidation of the multi layer soil depends on the interaction between 2 adjacent layer, penetration depth, and …


Numerical Prediction Of Unsaturated Ground Behavior Influenced By Vegetation And Vacuum Consolidation, Cholachat Rujikiatkamjorn, Buddhima Indraratna, B Fatahi Mar 2014

Numerical Prediction Of Unsaturated Ground Behavior Influenced By Vegetation And Vacuum Consolidation, Cholachat Rujikiatkamjorn, Buddhima Indraratna, B Fatahi

Buddhima Indraratna

Bioengineering including native vegetation is an ancient method of improving the stability of slopes. In modern railway engineering, this technique is re-captured for increasing the soil stiffness and shear strength of subgrade beneath rail tracks. Currently this practice has become increasingly popular in Australia for stabilising railway corridors built over expansive clays and compressive soft soils. This paper looks at the stabilisation role by suction generated by both the natural vegetation and the artificial vacuum application using the numerical analysis. For demonstrating the role of native vegetation, a mathematical model for the rate of root water uptake was incorporated in …


Radial Consolidation Model Incorporating The Effects Of Vacuum Preloading And Non-Darcian Flow, Kourosh Kianfar, Buddhima Indraratna, Cholachat Rujikiatkamjorn Mar 2014

Radial Consolidation Model Incorporating The Effects Of Vacuum Preloading And Non-Darcian Flow, Kourosh Kianfar, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Buddhima Indraratna

A modified 150 mm Rowe cell equipped with pore water pressure measurement was used to capture the flow relationship during vacuum-assisted radial consolidation. Based on the measured data, a radial consolidation model incorporating the effects of vacuum preloading is proposed, based on a non-linear relationship between the flow velocity and hydraulic gradient. The predictions of the proposed consolidation model are then compared with the predictions based on Hansbo’s Darcian and non- Darcian models. The agreement between the proposed model and the measured data is shown, and the advantages of the proposed model compared with the existing models are discussed. An …


Application Of Vacuum Consolidation For Sustainable Transport Infrastructure, Cholachat Rujikiatkamjorn, Buddhima Indraratna Mar 2014

Application Of Vacuum Consolidation For Sustainable Transport Infrastructure, Cholachat Rujikiatkamjorn, Buddhima Indraratna

Buddhima Indraratna

A system of vertical drains combined with vacuum preloading to accelerate soil consolidation by promoting radial flow is an effective method. In this paper, the analytical modelling of vertical drains incorporating vacuum preloading in an axisymmetric condition is proposed. The distribution of vacuum pressure along the drain and variations in volume compressibility, and permeability of soil based on large scale laboratory observations are included in the proposed solutions. These analytical predictions are compared with a case history taken from Thailand where the entire embankment was stabilised with vertical drains and subjected to vacuum preloading. This analysis employing the writer’s model …


Non-Linear Analysis Of Soft Ground Consolidation At The Ballina By-Pass, Xueyu Geng, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Richard Kelly Mar 2014

Non-Linear Analysis Of Soft Ground Consolidation At The Ballina By-Pass, Xueyu Geng, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Richard Kelly

Buddhima Indraratna

This study presents a numerical assessment of consolidation under vacuum preloading with a system of vertical drains and membrane, considering the non-linear properties of the soil This membrane system, already widely used in Australia, is where an airtight membrane is placed over the drainage layer to allow a vacuum to be distributed within the sand platform, along the surface of the soil, and down the vertical drains. To date, there have only been a few fundamental investigations and field studies that have tried to assess the way in which the vacuum can propagate in soft clay, both laterally and vertically. …