Surcharge

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 15231 Experts worldwide ranked by ideXlab platform

Buddhima Indraratna - One of the best experts on this subject based on the ideXlab platform.

  • Performance of marine clay stabilised with vacuum pressure: Based on Queensland experience
    Journal of rock mechanics and geotechnical engineering, 2019
    Co-Authors: Buddhima Indraratna, Pankaj Baral, Cholachat Rujikiatkamjorn, Jayantha Ameratunga
    Abstract:

    Abstract Stabilising soft marine clay and estuarine soils via vacuum preloading has become very popular in Australasia over the past decades because it is a cost-effective and time-efficient approach. In recent times, new land on areas outside but adjacent to existing port amenities, the Fisherman Islands at the Port of Brisbane (POB), was reclaimed to cater for an increase in trade activities. A vacuum preloading method combined with Surcharge to stabilise the deep layers of soil was used to enhance the application of prefabricated vertical drains (PVDs). This paper describes the performance of this combined Surcharge fill and vacuum system under the embankment and also compares it with a Surcharge loading system to demonstrate the benefits of vacuum pressure over conventional fill. The performance of this embankment is also presented in terms of field monitoring data, and the relative performance of the vacuum together with non-vacuum systems is evaluated. An analytical solution to radial consolidation with time-dependent Surcharge loading and vacuum pressure is also presented in order to predict the settlement and associated excess pore water pressure (EPWP) of deposits of thick soft clay.

  • finite element analysis of vacuum consolidation with modified compressibility and permeability parameters
    International Journal of Geosynthetics and Ground Engineering, 2017
    Co-Authors: Yuebao Deng, Buddhima Indraratna, Mojtaba E Kan, Rui Zhong
    Abstract:

    Laboratory tests and case history studies indicate that soil subjected to vacuum preloading may not behave the same as ground treated by traditional Surcharge preloading. In detail, soil compression under vacuum pressure is smaller than or equal to that induced by positive pressure with the same magnitude; soil rebound after stopping the vacuum is not as high as after removing the Surcharge; and the consolidation rate is usually faster under vacuum pressure than with Surcharge preloading. Analysis of vacuum consolidation with existing methods cannot gain all these differences. Thus, in this study, three factors for adjusting compressibility and permeability are proposed based on past laboratory and field results which are used in a finite element analysis of soft soil foundation under vacuum-assisted preloading. This proposed method can be incorporated in existing computer programs associated with classical soil models (e.g., the modified Cam-Clay model and the Soft-Soil model); it is then examined via three distinct simulation scenarios including a laboratory model test and two prototype field cases. The improved accuracy in relation to consolidation by the proposed method is demonstrated and practical ranges for the adjustment factors are discussed.

  • Soft soil foundation improved by vacuum and Surcharge loading
    Proceedings of the Institution of Civil Engineers - Ground Improvement, 2012
    Co-Authors: Buddhima Indraratna, Cholachat Rujikiatkamjorn, Richard Kelly, Henk Buys
    Abstract:

    The Pacific Highway has been upgraded to support the high transportation demand between Sydney and Brisbane, along the north-east coast of Australia. To avoid the traffic through the busy town of Ballina, a bypass route was designed to traverse on a floodplain consisting of very soft, highly compressible, saturated marine clays up to 30 m deep in certain locations. A vacuum-assisted Surcharge load scheme in conjunction with prefabricated vertical drains was selected to reduce the required time to consolidate the deep subsoil layers. The design of the combined vacuum and Surcharge fill system and the construction of the embankment are described, and a comparison of the performance between the combined vacuum and Surcharge loading system with the conventional Surcharge only system is highlighted. Field data are presented and interpreted to demonstrate how the embankments performed during construction in both vacuum and non-vacuum areas. Suitable design charts for vertical drains are presented and discussed ...

  • consolidation analysis of a stratified soil with vertical and horizontal drainage using the spectral method
    Geotechnique, 2009
    Co-Authors: Rohan T Walker, Buddhima Indraratna
    Abstract:

    A novel use of the spectral method to determine excess pore water pressure during vertical consolidation of multi-layered soil with time constant material properties is presented, considering a unit cell with combined vertical and radial drainage. Equal strain conditions are assumed in the analysis. The novel adoption of material properties that vary in a linear fashion with depth allows arbitrary distributions of properties to be modelled. By incorporating Surcharge and vacuum loading that vary with both depth and time, a wide range of consolidation problems can be analysed. The spectral method is a meshless approach producing a series solution to the consolidation problem based on matrix operations. Accuracy can be improved by increasing the number of terms used in the series solution. The model is verified by the analysis of selected case studies characterised by: analytical free strain consolidation with thin sand layers (Surcharge only); laboratory test and embankment trial with Surcharge and vacuum ...

  • vacuum preloading techniques recent developments and applications
    GeoCongress 2008, 2008
    Co-Authors: Jian Chu, Singapore S Yan, Buddhima Indraratna
    Abstract:

    ABSTRACT: In this paper, an overview on the mechanisms, techniques and applications of the vacuum preloading method are presented. Some recent developments in the vacuum preloading techniques, including the use of new materials, the expansion of the method, and new analysis or numerical modeling methods are briefly summarized. INTRODUCTION It has been 56 years since the idea of vacuum preloading was proposed by Kjellman (1952). Since then, the vacuum preloading method has evolved into a mature and efficient technique for the treatment of soft clay. This method has been successfully used for soil improvement or land reclamation projects in a number of countries (Holtz 1975; Chen and Bao 1983; Bergado et al. 1998; Chu et al. 2000; Indraratna et al. 2005). With the merging of new materials and new technologies, this method has been further improved in recent years. A brief overview of this technique and the recent developments and applications is given in this paper. In adopting this technique, sand drains and recently prefabricated vertical drains (PVDs) have often been used to distribute the vacuum pressure and discharge pore water. A nominal vacuum load of 80 kPa is normally used in design although a higher vacuum pressure of up to 90 kPa may be achieved sometimes. When a Surcharge load higher than 80 kPa is required, a combined vacuum and fill Surcharge can be applied. For the treatment of very soft ground, the vacuum preloading method is faster than the fill Surcharge method, as the 80 kPa vacuum pressure can be applied almost instantly, without causing stability problem. The vacuum preloading method is also cheaper when compared with the fill Surcharge method for an equivalent load (Chu et al. 2000). The vacuum preloading method has also been incorporated in the land reclamation process when clay slurry dredged from seabed is used as fill material for land reclamation. As the clay slurry fill is too soft for fill Surcharge to be applied, the vacuum preloading method is ideally used for the consolidation of the clay slurry. Thousands of hectares of land have been

Jinchun Chai - One of the best experts on this subject based on the ideXlab platform.

  • Surcharge loading rate for minimizing lateral displacement of pvd improved deposit with vacuum pressure
    Geotextiles and Geomembranes, 2015
    Co-Authors: Jinchun Chai, Steeva Gaily Rondonuwu
    Abstract:

    Abstract A series of laboratory radial drainage odometer and triaxial tests were conducted to investigate the deformation behaviour of clayey soils under combined vacuum pressure and Surcharge loads. Based on the test results, a method for determining the optimum Surcharge loading rate (SLR) which will result in minimum lateral displacement of a deposit under combined loads has been proposed. The method using a dimensionless parameter, α, defined as the ratio of SLR and the parameters controlling the rate of consolidation of a deposit improved by prefabricated vertical drains (PVDs). The ratio between Surcharge load (Δσs) to the vacuum pressure (Δσvac) is designated as ( L R = Δ σ s / | Δ σ v a c | ) . Values for the optimum SLR increase with increasing of initial effective stress in the soil and with reducing LR. It is suggested that the method can be used for design the preloading project with combined vacuum and Surcharge loads.

  • lateral displacement of soft ground under vacuum pressure and Surcharge load
    Frontiers of Architecture and Civil Engineering in China, 2011
    Co-Authors: Chinyee Ong, Jinchun Chai
    Abstract:

    Surcharge load (e.g. embankment fill) will induce settlement and outward lateral displacement, while vacuum pressure will induce settlement and inward lateral displacement of a ground. Ideally, combination of Surcharge load and vacuum pressure can reduce or minimize the lateral displacement. Laboratory large scale model (length: 1.50 m, width: ∼0.62 m, height: 0.85 m) tests and finite element analyses (FEA) were conducted to investigate the main influencing factors on lateral displacement of a soft clayey ground under the combination of vacuum pressure and Surcharge load. For the conditions investigated, the results indicate that the outward lateral displacement increases with the increase of the ratio of Surcharge load to vacuum pressure (RL) and the loading rate of the Surcharge load (LR). Also, it is shown that for a given RL and LR condition, lateral displacement reduces with the increase of the initial undrained shear strength (S u) of the ground. To predict the lateral displacement of a ground under the combination of Surcharge load and vacuum pressure, the loading conditions in terms of RL and LR, and S u value of the ground have to be considered.

  • comparison of vacuum consolidation with Surcharge load induced consolidation of a two layer system
    Geotechnique, 2009
    Co-Authors: Jinchun Chai, K Matsunaga, A Sakai, S. Hayashi
    Abstract:

    Laboratory consolidation tests for a two-layer soil system under oedometer conditions were conducted under both vacuum pressures and Surcharge loads. The effects of the order of soil layers on the behaviour of vacuum consolidation of the two-layer soil system have been investigated by comparing vacuum pressure and Surcharge load induced consolidations. Under one-way drainage conditions, for both a Surcharge load and a vacuum pressure, the order of soil layers only influences the rate of consolidation but not the final settlement. When a layer with a relative lower value of hydraulic conductivity (k) is located immediately adjacent to the drainage boundary, the consolidation rate is slower. However, for vacuum pressure applied under two-way drainage conditions, the order of the soil layers not only influences the rate of consolidation but also the magnitude of settlement.

  • ground deformation induced by combination of vacuum pressure and Surcharge load
    Jioshinsetikkusu Rombunshu (geosynthetics Engineering Journal), 2009
    Co-Authors: Jinchun Chai, Chinyee Ong
    Abstract:

    Laboratory large-scale model (length: 1.50m, width: ~0.62m, height: 0.85m) tests and finite element analyses (FEA) were conducted to investigate the deformation characteristics of soft clayey ground under the combination of vacuum pressure and Surcharge load. Both the model test and FEA results indicate that the combination of vacuum pressure with Surcharge load can reduce the lateral displacement of the model ground. The outward lateral displacement increases with the increase of the loading rate (LR) of Surcharge load and the ratio of Surcharge load to vacuum pressure (RL). The results also indicate that by adjusting LR and RL, the lateral displacement of the ground can be minimized.

Matthias Sutter - One of the best experts on this subject based on the ideXlab platform.

  • to buy or not to buy price salience in an online shopping field experiment
    Social Science Research Network, 2020
    Co-Authors: Markus Dertwinkelkalt, Mats Koster, Matthias Sutter
    Abstract:

    We examine whether shrouding or partitioning of a Surcharge raises demand in online shopping. In a field experiment with more than 34,000 consumers, we find that consumers in the online shop of a cinema are more likely to select tickets for a 3D movie when the 3D Surcharge is shrouded, but they also drop out more often when the overall price is shown at the checkout. In sum, the demand distribution is independent of the price presentation. This result outlines the limits of the effectiveness of shrouding practices.

  • to buy or not to buy price salience in an online shopping field experiment
    Research Papers in Economics, 2020
    Co-Authors: Markus Dertwinkelkalt, Mats Koster, Matthias Sutter
    Abstract:

    We examine whether shrouding or partitioning of a Surcharge raises demand in online shopping. In a field experiment with more than 34,000 consumers, we find that consumers in the online shop of a cinema initiate a purchase process for a 3D movie more often when the 3D Surcharge is shrouded, but they also drop out more often when the overall price is shown at the check-out. In sum, the demand distribution is independent of the price presentation. This result qualifies previous findings on the effectiveness of shrouding Surcharges and can be rationalized through low cancellation costs.

Cholachat Rujikiatkamjorn - One of the best experts on this subject based on the ideXlab platform.

  • Performance of marine clay stabilised with vacuum pressure: Based on Queensland experience
    Journal of rock mechanics and geotechnical engineering, 2019
    Co-Authors: Buddhima Indraratna, Pankaj Baral, Cholachat Rujikiatkamjorn, Jayantha Ameratunga
    Abstract:

    Abstract Stabilising soft marine clay and estuarine soils via vacuum preloading has become very popular in Australasia over the past decades because it is a cost-effective and time-efficient approach. In recent times, new land on areas outside but adjacent to existing port amenities, the Fisherman Islands at the Port of Brisbane (POB), was reclaimed to cater for an increase in trade activities. A vacuum preloading method combined with Surcharge to stabilise the deep layers of soil was used to enhance the application of prefabricated vertical drains (PVDs). This paper describes the performance of this combined Surcharge fill and vacuum system under the embankment and also compares it with a Surcharge loading system to demonstrate the benefits of vacuum pressure over conventional fill. The performance of this embankment is also presented in terms of field monitoring data, and the relative performance of the vacuum together with non-vacuum systems is evaluated. An analytical solution to radial consolidation with time-dependent Surcharge loading and vacuum pressure is also presented in order to predict the settlement and associated excess pore water pressure (EPWP) of deposits of thick soft clay.

  • Soft soil foundation improved by vacuum and Surcharge loading
    Proceedings of the Institution of Civil Engineers - Ground Improvement, 2012
    Co-Authors: Buddhima Indraratna, Cholachat Rujikiatkamjorn, Richard Kelly, Henk Buys
    Abstract:

    The Pacific Highway has been upgraded to support the high transportation demand between Sydney and Brisbane, along the north-east coast of Australia. To avoid the traffic through the busy town of Ballina, a bypass route was designed to traverse on a floodplain consisting of very soft, highly compressible, saturated marine clays up to 30 m deep in certain locations. A vacuum-assisted Surcharge load scheme in conjunction with prefabricated vertical drains was selected to reduce the required time to consolidate the deep subsoil layers. The design of the combined vacuum and Surcharge fill system and the construction of the embankment are described, and a comparison of the performance between the combined vacuum and Surcharge loading system with the conventional Surcharge only system is highlighted. Field data are presented and interpreted to demonstrate how the embankments performed during construction in both vacuum and non-vacuum areas. Suitable design charts for vertical drains are presented and discussed ...

  • numerical modelling of soft soil stabilized by vertical drains combining Surcharge and vacuum preloading for a storage yard
    Canadian Geotechnical Journal, 2007
    Co-Authors: Cholachat Rujikiatkamjorn, Buddhima Indraratna
    Abstract:

    This paper presents a finite element analysis of a case study of a combined vacuum and Surcharge load through prefabricated vertical drains (PVD) at a storage yard at Port of Tianjin, China. The top 15 m of soil at this site was very soft to soft and needed to be improved using preloading Surcharges of more than 140 kPa. To avoid any stability problems associated with a high Surcharge embankment, 80 kPa vacuum pressure combined with fill Surcharge was applied (40 and 58 kPa for sections I and II, respectively). A plane strain analysis was performed using equivalent permeability and transformed unit-cell geometry. The converted (equivalent) parameters were incorporated in the finite element code ABAQUS, using the modified Cam-Clay theory. The performance of a trial embankment at the site of the storage yard is predicted on the basis of a constant vacuum pressure applied on the soil surface and distributed along the length of the drain. The predictions of settlement, pore-water pressure, and lateral displac...

Henk Buys - One of the best experts on this subject based on the ideXlab platform.

  • Soft soil foundation improved by vacuum and Surcharge loading
    Proceedings of the Institution of Civil Engineers - Ground Improvement, 2012
    Co-Authors: Buddhima Indraratna, Cholachat Rujikiatkamjorn, Richard Kelly, Henk Buys
    Abstract:

    The Pacific Highway has been upgraded to support the high transportation demand between Sydney and Brisbane, along the north-east coast of Australia. To avoid the traffic through the busy town of Ballina, a bypass route was designed to traverse on a floodplain consisting of very soft, highly compressible, saturated marine clays up to 30 m deep in certain locations. A vacuum-assisted Surcharge load scheme in conjunction with prefabricated vertical drains was selected to reduce the required time to consolidate the deep subsoil layers. The design of the combined vacuum and Surcharge fill system and the construction of the embankment are described, and a comparison of the performance between the combined vacuum and Surcharge loading system with the conventional Surcharge only system is highlighted. Field data are presented and interpreted to demonstrate how the embankments performed during construction in both vacuum and non-vacuum areas. Suitable design charts for vertical drains are presented and discussed ...