Physical modelling of local scour at twin piles under combined waves and current

Qi, Wen-Gang; Li, Yixuan; Xu, Kai; Gao, Fu‐Ping

doi:10.1016/j.coastaleng.2018.10.009

Cited by 54 publications

(17 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the case of live-bed scour, the equilibrium scour depth is achieved faster than the clear-water case, generating a smaller time scale. The time scale of scour process can be defined in several ways according to different mathematical functions for approximating the scour development toward the equilibrium stage [57]. For example, Briaud et al [58] proposed a hyperbolic function S t ¼ S e t tþT 0 , where S e is the equilibrium scour depth.…”

Section: Time Scalementioning

confidence: 99%

Local Scour around a Monopile Foundation for Offshore Wind Turbines and Scour Effects on Structural Responses

Qi¹,

Gao²

2020

Geotechnical Engineering - Advances in Soil Mechanics and Foundation Engineering

Self Cite

View full text Add to dashboard Cite

Monopile is the most commonly used foundation type for offshore wind turbines. The local scour at a monopile foundation generated by the incoming shear flow has significant influence on both quasi-static lateral responses and dynamic responses of the monopile. This chapter focuses particularly on characterizing the local scour in both spatial and temporal scales and revealing the scour mechanisms associated with the flow field around a monopile. The predicting methods for the equilibrium scour depth and the time scale of scour are detailed under various representative flow conditions in the marine environment. The scale effect while extrapolating the results of model tests to prototype conditions is highlighted. The local scour imposes significant influence not only on the deformation and stiffness of the monopile foundation, but also on the natural frequency and fatigue life of the structure system. Monopiles with diameters up to 10 m have become a feasible option as the industry is currently advancing into deeper waters. More meticulous considerations for monopile design associated with the scour depth prediction and evaluation of scour effects are still in need to efficiently minimize the cost while remaining safety simultaneously.

show abstract

Section: Time Scalementioning

confidence: 99%

Local Scour around a Monopile Foundation for Offshore Wind Turbines and Scour Effects on Structural Responses

Qi¹,

Gao²

2020

Geotechnical Engineering - Advances in Soil Mechanics and Foundation Engineering

Self Cite

View full text Add to dashboard Cite

show abstract

“…Flow field and local scour around circular bridge piers have been extensively researched computationally and experimentally during the last few decades. Latest and significant research in this category include several previous reports (Khan et al 2017;Qi et al 2019;Nagel et al 2020;Pandey et al 2020a;Bordbar et al 2021;Jain et al 2021;Malik et al 2021). Furthermore, several investigations on a set of piers have been also conducted by researchers, such as the work of Sumner et al (1999) who used flow visualisation, particle image velocimetry (PIV) and hot-film anemometry to explore the flow field for two and three circular cylinders positioned side by side, with the centre-to-centre pitch ratio expanding.…”

Section: Introductionmentioning

confidence: 99%

Estimation of local scour depth around twin piers using gene expression programming (local scour around twin piers)

Devi

Kumar

2022

Water Supply

View full text Add to dashboard Cite

The scour around the bridge piers has been estimated using conventional empirical formulae; however, these formulas are unable to predict the scour depth precisely. The present study is conducted in two parts (a) experimental investigation for evaluating the behaviour of local scour around twin piers positioned in the transverse direction of flow and (b) an empirical equation to estimating scour depth is proposed utilising new evolutionary Artificial Intelligence technique Gene Expression Programming (GEP). Experimental results of the present study demonstrate the influence of the rate of flow and clear spacing between the piers on the scour depth. Additionally the results of the soft computing technique GEP during testing and training of proposed modelling, fitness function Root Mean Square Error is observed as 0.00133 and 0.00113, with the coefficient of determination as 0.950 and 0.955, respectively. Furthermore, in order to find out the role of each variable for scour depth sensitivity analysis has been conducted. The findings of the sensitivity analysis show that the pier spacing and rate of flow play the most significant role in scour depth estimation. Results of this study demonstrate good agreement with the proposed GEP model and conclude that it is a better approach for forecasting scour depth.

show abstract

“…In bridge construction, pile foundations are used to transmit the load of the superstructure and substructure to a lower level, which is a stronger soil layer in the soil mass [7]. However, several issues, including the scour phenomenon, must be addressed to ensure the safety and stability of the offshore pile foundation which will directly affect the bridge structure [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Local Scour around Three Cylindrical Piles in a Tandem Arrangement

Tang

Puspasari

2021

Water

View full text Add to dashboard Cite

Scouring is one of the most common potential causes of bridge pile foundation failure, with loss of life, economic and environmental impacts. Comprehensive studies on the numerical simulation of local scour around pile groups are still limited. This paper presents a numerical simulation using Flow-3D software to calculate the maximum sediment scour depth and investigate the mechanism around the groups of three cylinders in a tandem arrangement. A validation using the experimental study was carried out to confirm the reliability of the present numerical model. By using the Van Rijn transport rate equation and RNG k-ε turbulence model, the results of time evolution of scour depth and bed elevation contour show good agreement with the experimental study. The numerical simulation of three cylinders in a tandem arrangement were conducted with pile spacing ratios, G/D of 2 and 3. The local scour is affected by the horseshoe vortex from the downflow driven by the downward pressure gradient and rotates in front of the pile and the high bed shear stress, triggered by flow acceleration. The deepest maximum local scour depth is always obtained by the front pile as a shield pile, followed by the piles behind. The trend of the maximum local scour depth in a tandem arrangement is in accordance with the experimental studies and has a better agreement than previous numerical studies with the same model setup. This means that the numerical model used to simulate pile groups is accurate and capable of calculating the depth of sediment scour.

show abstract

Physical modelling of local scour at twin piles under combined waves and current

Cited by 54 publications

References 24 publications

Local Scour around a Monopile Foundation for Offshore Wind Turbines and Scour Effects on Structural Responses

Local Scour around a Monopile Foundation for Offshore Wind Turbines and Scour Effects on Structural Responses

Estimation of local scour depth around twin piers using gene expression programming (local scour around twin piers)

Numerical Simulation of Local Scour around Three Cylindrical Piles in a Tandem Arrangement

Contact Info

Product

Resources

About