Low Surcharge Research Articles

A novel test set up to study three-dimensional electrokinetic dewatering of dredged soil

The dredged soil obtained from maintenance activities of water bodies has emerged as a potential alternate fill material for infrastructure development. However, dredged soil requires stabilization due to high initial water content, low shear strength and high compressibility. Among several methods, stabilization of dredged soil by using electrokinetics is one of the effective ground improvement techniques that uses electric field to dewater and strengthen the soil. In this context, a series of experiments were conducted on dredged soil by using a combination of electrokinetic treatment with and without 6 kPa seating pressure (viz., low surcharge). A customized and patented electrokinetic dewatering (EKD) test set up was used for the three-dimensional electrokinetic treatment of soil. The potential difference (in the range of 6 V–48 V) within the soil was achieved by inserting stainless steel pipes of 21.4 mm outer diameter, 1.2 mm thickness, and 170 mm length. Two control tests (with and without seating pressure of 6 kPa) also were performed to understand the effectiveness of EKD. From the study, up to 1057% and 427% increase in dewatering was noted in EKD tests due to application of 24 V (optimum voltage noted in EKD tests) as compared to control tests, without and with seating pressure, respectively. Further, seating pressure with EKD resulted in effective control of crack formation in the dredged soil and uniform improvement in shear strength along the depth (up to 95 kPa). The combination of low surcharge with EKD, adopted in the study, is also expected to yield lower differential settlement, and hence better performance of geotechnical structures built on improved dredged soil. The novel 3-dimensional patented EKD test setup with Arduino-programmed automatic water pumping enables collecting and accurately measuring dewatered effluent volume, performing cone penetration tests on undisturbed soil, and collecting soil samples for determination of water content/physiochemical properties from different locations. Overall, the developed EKD setup can be utilized for evaluating the effectiveness and adopting real-time progress management for EKD or other ground improvement methods, and remediation of sludge, mine tailings, dredged sediments, and contaminated soils.

ANALISIS PENGARUH WAKTU DAN JARAK PERJALANAN KAPAL TERHADAP BIAYA LOW SULPHUR SURCHARGE

AbstractThe danger of ship emission caused by HFO (Heavy Fuel Oil) fuel type has become a serious matter due to its high containment of sulphur as much as 3.50% m/m. The IMO (International Maritime Organization) took action on this problem by releasing new regulation to limit sulphur in the ship fuel as low as 0.50% m/m. This regulation leads to an additional tariff called the LSS (Low Sulphur Surcharge). As an impact, shipping companies charge this fee to customers and ocean freight forwarders, hence there is an increase of the total shipping charges. Meanwhile, the dominant variable which determines the LSS charge amount is not yet known, so it is still uninformative for the public and the academic field. The purpose of this study is to analyse which variable gives the most influence on the amount of the LSS tariff. By using multiple linear regression method, the study finds that the shipping distance variable is the dominant variable with a contribution value of 86.48% and has positive relationship with the LSS tariff. On the other hand, though the voyage time also has influence on the tariff, the effect is weak and it shows negative relationship with the LSS tariff.

Integrated impacts of vegetation and soil type on slope stability: A case study of Kheyrud Forest, Iran

In this study, an integrated 2D numerical model is applied to investigate the mechanical effects of the vegetation and soil type on slope stability. The developed model can assess the mechanical aspects of vegetation in slope stabilization. For this purpose, a case study of the Kheyrud forest located in northern Iran is considered as a real case site. Different scenarios including; three soil types (fine grain with low-, medium-, and high-strength) and two vegetation types (Maple and Common-ash) are assessed in the stability analysis (based on safety factor). The results confirm that the considered vegetation can prevent shallow landslide occasions, but has a limited impact on deep landslide events. The ratio of root zone depth to the depth of slide is the most important parameter in the contribution of vegetation in the increasing of the slope stability. The simulation results show an improvement in the safety factor up to 25% when the mechanical aspects of vegetation are considered. This improvement leads to stability for slopes with 10% more gradient. The results also demonstrate the reinforcement effect of the roots (stability improvement up to 25%) and negative effect of the surcharge load (Reduction of stability up to 5% at a surcharge of 1.2 kPa) on the slope stability. The extent of these impacts varies by soil properties, tree characteristics, and slope geometry so that the overall result can vary. The sensitivity analysis demonstrated an increase in the soil cohesion grows the negative effect of tree weight. Also, it is observed that the increase of soil unit weight follows a decrease in the stabilization role of vegetation. The role of the soil's friction angle is insignificant. The findings can serve as a foundation for enhancing the scientific understanding of the relationship between the stabilization role of vegetation and soil, vegetation, and slope characteristics. Generally, in the stabilization of a slope by artificial planting forests, the native shrubs or trees with more reinforcing effects and low surcharge are more effective.

Experimental Study on Swelling Behavior and Its Anisotropic Evaluation of Unsaturated Expansive Soil

Evaluation of swelling behavior is important for designing structures in expansive soils areas, especially for highway that the swelling pressure generated upon pavement and retaining structures in both vertical and horizontal directions due to infiltration. In this study, modification was made on unsaturated consolidation oedometer to provide synchronized measurement of vertical swelling strain (VSS) and lateral pressure (LP) of expansive soil under constant net normal stress and controlled matric suction. Vertical swelling (VS) test and lateral swelling (LS) test were conducted to investigate the anisotropic swelling behavior. The influence of mean net stress and net stress ratio on VSS was investigated, and the anisotropic swelling behavior of unsaturated expansive soil was characterized using anisotropic swelling ratio. The results show that the VSS nonlinearly decreased as the mean net stress increased and increased as the net stress ratio increased. The expansive soil would rapidly enter the passive state due to lateral swelling pressure under relatively low surcharge, with major principal axis rotating from vertical direction to lateral direction, which advances the possibility of passive failure for light retaining structures. The anisotropic swelling behavior objectively exists and varies with matric suction and net normal stress, which should not be ignored for engineering application.

Effect of Acceleration on Wrap Faced Reinforced Soil Retaining Wall on Soft Clay by Performing Shaking Table Test

This research incorporates shaking table testing of scale wrap faced soil wall models to evaluate the seismic response of embankment. Currently the seismic designs of highway or railway embankment rely on little or no empirical data for calibrating numerical simulations. This research is working towards filling that empirical data gap. The specific purpose of the study was to evaluate the seismic response of constructed embankment model regarding the different input base accelerations with fixed frequency. A series of one-dimensional (1D) shaking table tests (0.05g, 0.1g, 0.15g and 0.2g), were performed on a 0.4 meters high wrap faced reinforced-soil wall model. Additionally, it was placed over 0.3 meters high soft clayey foundation. Predominantly, the influence of the base acceleration on the seismic response was studied in this paper. The physical models were subjected to harmonic sinusoidal input motions at a fixed frequency of 1 Hz, in order to assess the seismic behavior. The effects of parameters such as acceleration amplitudes and surcharge pressures on the seismic response of the model walls were considered. The relative density of the backfill material was kept fixed at 60%. The results of this study reveal that input accelerations and surcharge load had significant influence on the model wall, pore water pressure, and changes along the elevation. Acceleration response advances with the increase in base acceleration, so the difference being more perceptible at higher elevations. The pore water pressures were found to be high for high base shaking and low surcharge pressures at higher elevations. The results obtained from this study are helpful in understanding the relative performance of reinforced soil retaining wall under different test conditions resting on soft clay.

A Hollow Cylinder Radial-Seepage Apparatus for Evaluating Permeability of Sheared Compacted Clay

Compacted clay is widely used to control seepage in earth and rock-fill dams in favor of its low permeability. The clay at certain locations of dams often experience large shear strain due to differential settlement, which may lead to changes in seepage resistance. A new apparatus was developed to examine the permeability evolution of compacted clay during shearing. The apparatus tests a hollow cylindrical specimen holding by a set of inner and outer laminar rings. The specimen can thus be compressed in the height direction and sheared in the circumferential direction. The permeability is measured by radial seepage from the inner side to the outer side of the hollow cylinder. A series of tests on heavily compacted specimens of a core-wall clay were conducted to demonstrate the performance of the new apparatus. The permeability of unsheared specimens under different surcharge pressures and hydraulic gradients was investigated firstly, and the observed phenomenon agreed well with those in conventional permeameters. Then the permeability evolution during shearing was investigated under constant surcharge pressures. It was found that the compacted specimens deformed non-uniformly with a well-developed shear band, and the permeability of the shear band determines the overall seepage resistance. The permeability of the shear band increases during shearing under low surcharge pressure, whereas under high surcharge pressure, it varies insignificantly. Such behavior is related to different structural changes of shear bands under low and high surcharge pressures. The preliminary test results highlighted an important fact, that the heavy-compacted clay under low surcharge pressure could generate low seepage resistance shear bands when subjected to a large shear, leading to a high risk of concentrated leakage and erosion. The new apparatus could prove useful for clarifying stress conditions triggering low seepage resistance shear bands in compacted clays.

Effect of surcharge on gully-manhole flow

In an urban drainage system, surface system and buried system are connected through several linking elements like gullies and manholes. To model an urban flood through a 1D or 2D routing model, proper representation of these linking elements is mandatory. This paper focuses on the effects on inline manhole head loss coefficient and gully flow due to change in manhole surcharges to get knowledge of their characteristics, flow patterns and influence in the overall flow. The solver interFoam with VOF capability under open source CFD toolbox OpenFOAM® is used for the numerical simulations. The CFD model created is a real scale model following the experimental setup installed at the University of Coimbra. The CFD model results were compared with discharge and water depth data at the manhole and velocity data at the gully, measured from the physical model. The manhole head loss coefficient was found very high at low surcharge level and reaching a constant value of 0.3 for higher surcharge levels. The gully flow was found to follow typical orifice flow equation with different discharge coefficients for different water depth conditions of the manhole. Three different surcharged zones were identified at the manhole on which discharge coefficients are dependent. The shear stress pattern at the manhole floor is also found varying due to surcharge depth as well as the gully flow. The variation showed distinctive configuration at different surcharge zones.

Basement wall under earth pressure loading with low surcharge

AbstractThe structural verification of basement walls under earth pressure loading with low surcharge is often a difficult part of the everyday work of engineers. This situation is often encountered for basement walls under terrace doors, stair flights, masonry light wells etc., where the theoretically necessary surcharge loading is lacking. In this case, it is possible to transfer the acting forces from earth pressure with an arch model. One constructively possible measure to resist the resulting arch thrust is the provision of a sufficiently stiff reinforced concrete beam at the head of the basement wall. The article explains the verification of this method according to current standards.

The Consolidated Medium-Term Income and Expenditure Framework

The medium-term income projections have been updated from the April 2015 outlook and the February review of the adequacy of precautionary balances. The main changes to the outlook stem from a more gradual rise in the SDR interest rates and lower surcharge income following the lowering of the surcharges threshold. The revised projections still show a positive forecast for net operational income (and surcharges) over the medium term, albeit lower than projected a year ago. Lending income (excluding surcharges) is marginally higher compared with earlier estimates. Surcharge income is estimated to be lower, reflecting the adjustment of the surcharges thresholds following the implementation of quota increases under the 14th General Review. Projected income from the Fixed-Income Subaccount of the Investment Account and interest-free resources are expected to increase more gradually over the medium-term as market indicators now point to a slower rise in interest rates from their current low levels. The expenditure path includes an increase in real terms of about ½ percent in the net administrative budget for FY 2017 to accommodate rising costs for physical and IT security. Moreover, reflecting further upward pressure over the medium term and uncertainty about the scope for offsetting savings, the traditional baseline assumption of a constant real spending envelope in the outer years is complemented by an alternative scenario with a further moderate spending increase of 1½ percent, phased in over FY 2018–19. In addition, a lower projected U.S. dollar/SDR exchange rate increases the expenses in SDR terms.

Arching effect in case of exterior walls with low surcharge under wind action / Ausbildung der Bogentragwirkung bei Außenwänden mit geringer Auflast unter Windbeanspruchung

AbstractIt is very important to have a minimum surcharge on external masonry walls to help the wall resisting wind actions. The present contribution describes the behaviour of masonry wall under wind action with low surcharge. The behaviour has been investigated using a finite element non‐linear model that considers the large displacement non‐linearity. An increasingly wind load has been applied and the deformation state and the thrust line within the wall have been investigated. The results of the analysis show that the behaviour of the wall under low surcharge was greatly characterized by the arching effect. Due to the low surcharge the influence of the second order effect was very small and can be neglected.

Experimental investigation of wall pressure and arching behavior under surcharge pressure in mass-flow hoppers

Based on Jenike's method, only the self-weight of each arch element is involved in the calculation of the arch thickness parameter which leads to the surcharge pressure not being taken into account in determining the critical outlet dimension of a bulk material storage bin. The aim of this study is to investigate the influence of surcharge pressure on wall pressure distribution and arching behavior in mass-flow structures. A method is introduced to measure the hopper wall pressure distribution. The measurements of the wall pressure and critical outlet dimension were conducted under different surcharge pressures and at various filling levels. The experimental results are compared with existing prevailing theories, where the theoretical outlet dimensions demonstrated significant overdesign in terms of low surcharge pressure and reasonable estimates corresponding to high surcharge. The peak wall pressures around the transition area of the bin are smaller than the calculated values, whereas the stresses close to the outlet are larger than the relative theoretical values.

Framing online promotions: shipping price inflation and deal value perceptions

PurposeThis research seeks to examine differences in perceived shipping charge inflation associated with online promotions presented as reducing base product price, reducing shipping surcharge, or reducing all‐inclusive price and its impact on deal values for shipping charge skeptics and non‐skeptics.Design/methodology/approachDrawing from research on multi‐component pricing and mental accounting, a laboratory experiment investigates if shipping charge skeptics differ in their perceptions of shipping charge inflation for different presentations of online promotions from non‐skeptics, and if they differ in perceived deal value of economically equivalent promotions presented as reduced product price, reduced shipping charge promotion, or reduced all‐inclusive price for high and low priced items with small or large shipping fees at retail websites.FindingsAnalyses show that shipping charge skeptics differ from non‐skeptics in their perceptions of shipping charge inflation and deal values for different online promotions only when the surcharge is large relative to the base price. Reduced price promotions are most attractive for high‐priced items with low surcharge but least attractive for large surcharge sizes. For large surcharge sizes, shipping charge skeptics prefer reduced all‐inclusive price promotions to reduced shipping promotions, while non‐skeptics prefer reduced shipping promotions to reduced all‐inclusive price promotions.Research limitations/implicationsThe results suggest that the effectiveness of various promotion frames at online stores differ based on base price, surcharge size, and consumer skepticism of shipping charge. Robustness of the results obtained at different levels of discount sizes need investigation.Practical implicationsOnline retailers that have to charge high shipping fees can use promotions to shift the referent price component used by consumers to calculate savings and mitigate perceptions of shipping or base price inflation. For equivalent dollar savings, retailers can use reduced shipping charge promotions to communicate higher deal values to shipping charge non‐skeptic consumers than reduced base price or reduced all‐inclusive promotions.Originality/valueThis research examines how consumer perceptions of deal values differ, even though objective savings and financial outlay is the same, when promotions are presented as reducing product price versus surcharge.

Consumer response to promotions in the presence of surcharge: implications for online retailing

This research examines the impact of surcharges on deal value perceptions of online promotions and purchase intentions. Based on research on mental accounting and price partitioning laboratory experiments investigate if consumers differ in perceptions of economically equivalent promotions presented as reduced product price, reduced shipping surcharge, a partitioned price (dollars-off promotion) or a bundled price (free shipping) for high and low priced items with relatively low or high shipping fees at retail websites. Experimental analyses show that sales price promotions are more effective than others for low-base price and low surcharge items. For relatively high surcharge or high base price, purchase intent is highest for free shipping followed by reduced shipping, dollars-off and sale price for all items. Results suggest that effectiveness of various promotion frames at online stores differs based on base price and relative surcharge level.

Effect of Surcharge on the Stability of Anchored Rock Slope with Water Filled Tension Crack under Seismic Loading Condition

In this paper, an analytical expression is derived for the factor of safety of the rock slope incorporating most of the practically occurring destabilizing forces as well as the external stabilizing force through an anchoring system. The slope stability is analyzed as a two-dimensional problem, considering a slice of unit thickness through the slope and assuming negligible resistance to sliding at the lateral boundaries of the sliding block. A detailed parametric study is presented to investigate the effect of surcharge on the stability of the rock slope for practical ranges of governing parameters such as inclination of the slope face, inclination of the failure plane, depth of tension crack, depth of water in tension crack, shear strength parameters of the material at the failure plane, unit weight of rock, stabilizing force and its inclination, and seismic load. For the range of parameters considered in the present study, it is found that the factor of safety of the rock slope decreases with increase in surcharge; the rate of decrease being relatively higher for lower values of surcharge. It is also observed that for a specific surcharge, the factor of safety depends significantly on all other parameters, except for unit weight of rock and higher values of inclination of stabilizing force to the normal at the failure plane. For any combination of these variables, the surcharge plays a vital role in the stability. A perfectly stable slope at relatively low surcharge can become unsafe with the increase in surcharge. The deterioration in the stability can be quite rapid, depending on the combination of the factors under consideration. The analysis and the general expression proposed herein can be used to carry out a quantitative assessment of the stability of the rock slopes.

06/02184 The prerequisites for effective competition in restructured wholesale electricity markets: Haas, R. and Auer, H. Energy, 2006, 31, (6–7), 857–864.

A new form of market development for photovoltaics is growing in Germany. “Rate-based incentives” allow the public to install PV systems and recover their investment over time through a per kilowatt hour payment for clean energy generation. The payback is funded through a low surcharge on electric utility bills. The important aspect: there is no need for subsidies from the state, local authority or public utility with this system. The advanced electrical measurement and control techniques are the prerequesites for this development. Some years ago grid-connected PV-systems were very unusual.This paper will provide the specifics behind the rate-based concept and its advantages for PV market development.

Model Study on the Failure Mechanism of Soil-Nailed Structure Under Surcharge Loading

Abstract To investigate the effects of surcharge loading on the failure mechanism of soil-nailed structures, reduced scale-model tests were performed. The main variables for this study were the bending stiffness and tension resistance of nails and applied surcharge loading levels. In addition, two different testing sequences were used to simulate, respectively, the application of soil nailing in both new construction and rehabilitation or widening of earth-retaining systems under surcharge loading. To effectively assess the loading effects on the failure mechanism, failure tests without surcharge loading were performed, and the results were used as reference data. When applying surcharge loading, the failure of the system occurred through a progressive breakage of the nails initiated at the top nails. Under low surcharge loading, the state of stress in the upper nails is close to the stress state for the unloaded wall. As the surcharge loading increases, the equivalent earth pressure coefficient in the upper nails tends to increase toward the atrest value. The locus of nail breakage points under surcharge loading is fairly close to that obtained with flexible nails without surcharge loading regardless of bending stiffness and construction sequence.

A New Path to Self-Sustaining Markets for Photovoltaic

A new form of market development for photovoltaics is growing in Germany. “Rate-based incentives” allow the public to install PV systems and recover their investment over time through a per kilowatt hour payment for clean energy generation. The payback is funded through a low surcharge on electric utility bills. The important aspect: there is no need for subsidies from the state, local authority or public utility with this system. The advanced electrical measurement and control techniques are the prerequesites for this development. Some years ago grid-connected PV-systems were very unusual.This paper will provide the specifics behind the rate-based concept and its advantages for PV market development.