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Faculty of Engineering - Papers (Archive)

2011

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Full-Text Articles in Engineering

Vertical Drain Consolidation Analysis In One, Two And Three Dimensions, Rohan T. Walker Jan 2011

Vertical Drain Consolidation Analysis In One, Two And Three Dimensions, Rohan T. Walker

Faculty of Engineering - Papers (Archive)

A new method, the g or 'eta' method, for modeling consolidation by vertical and horizontal drains is presented. The approach is applicable in one, two and three dimensional as well as axisymmetric cases. Material and geometry properties are familiar from unit cell vertical drain analysis and are consistent across dimensions. An uncoupled finite element method (FEM) program is used to test the efficacy of the new approach. Because drains are not explicitly modeled in the finite element mesh, mesh complexity and computational time are greatly reduced. Unlike existing plane strain matching methods there is no special transformation of permeability or …


Use Of Geosynthetics In Railways Including Geocomposites And Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Sanjay Nimbalkar Jan 2011

Use Of Geosynthetics In Railways Including Geocomposites And Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Sanjay Nimbalkar

Faculty of Engineering - Papers (Archive)

Australia relies heavily on rail for the transportation of bulk commodities and passenger services, and has introduced faster and heavier trains in recent years due to a growing demand. Large cyclic loading from heavy haul and passenger trains often leads to progressive deterioration of the track. The excessive deformations and degradations of the ballast layer and unacceptable differential settlement or pumping of underlying soft and compressible subgrade soils necessitate frequent costly track maintenance works. A proper understanding of load transfer mechanisms and their effects on track deformations are essential prerequisites for minimising maintenance costs. The reinforcement of the track by …


Consolidation By Vertical Drain Beneath A Circular Embankment Using Analytical And Numerical Modelling, Cholachat Rujikiatkamjorn, Buddhima Indraratna, A Aljorany Jan 2011

Consolidation By Vertical Drain Beneath A Circular Embankment Using Analytical And Numerical Modelling, Cholachat Rujikiatkamjorn, Buddhima Indraratna, A Aljorany

Faculty of Engineering - Papers (Archive)

When prefabricated vertical drains (PVDs) are installed beneath circular embankment (i.e. circular oil tanks or silos), the system of vertical drains can be replaced by axisymmetric concentric rings with equivalent drain walls. A value for the equivalent coeffi cient of soil permeability must be obtained to provide the same degree of consolidation. A rigorous solution for PVDs installed under circular embankment is proposed and verifi ed by comparing its results with conventional unit cell model. The model is then validated via the consolidation process by vertical drains at the Skå-Edeby circular test embankment (Area II). The calculated values of settlement, …


Cyclic Behaviour Of Soft Soil Subgrade Improved By Prefabricated Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Jing Ni Jan 2011

Cyclic Behaviour Of Soft Soil Subgrade Improved By Prefabricated Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Jing Ni

Faculty of Engineering - Papers (Archive)

The behaviour of saturated soft clays subjected to cyclic loading is of considerable importance in the design of railway subgrades. Soft clays can be extensively found in many coastal regions of Australia up to significant depths, including the coastal belt and the central part of NSW. These soft clay deposits are characterised by very low bearing capacity and excessive settlement. The increase in generated excess pore pressures due to heavy freight trains significantly reduces the bearing capacity and causes serious damage to the rail infrastructure such as clay pumping underneath railway tracks and excessive subsidence. The use of prefabricated vertical …


Experimental Study On The Effectiveness Of Prefabricated Vertical Drains Under Cyclic Loading, Cholachat Rujikiatkamjorn, Buddhima Indraratna, Guanghui Meng Jan 2011

Experimental Study On The Effectiveness Of Prefabricated Vertical Drains Under Cyclic Loading, Cholachat Rujikiatkamjorn, Buddhima Indraratna, Guanghui Meng

Faculty of Engineering - Papers (Archive)

This study is an attempt to investigate the effectiveness of a prefabricated vertical drain (PVD) installed in remoulded soft clay, where a large-scale cyclic triaxial process simulation rig was employed to simulate cyclic loading representing a track environment. The experimental data show that PVD successfully prevents excessive accumulation of pore water pressure during cyclic loading, and their dissipation continues to occur after the load is removed. The findings of this study have direct significance to rail track environments, e.g. in coastal Australia, where PVD installation beneath rail tracks constructed on low-lying estuarine soils has been recently adopted.