Scour depth under pipelines placed on weakly cohesive soils

Postacchini, Matteo; Brocchini, Maurizio

doi:10.1016/j.apor.2015.04.010

Cited by 22 publications

(8 citation statements)

References 24 publications

(55 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This response also aligned with the international survey by Lohnes et al (2001), which concluded that floodway constructions on loess (sedimentary soils) should be avoided due to its increased erosive potential. Furthermore, it aligns with various sources of literature such as Postacchini and Brocchini (2015) who explain that the action of scour and particle movement within cohesive and non‐cohesive soils is vastly different. The movement threshold for non‐cohesive granular sediments is a product of particle size, density, shape, packing, and orientation, while erosion within non‐cohesive sediments is reliant on shear stress, shear strength, and also the chemical and physical bonding of soil particles (Najafzadeh et al, 2013).…”

Section: Industry Surveysupporting

confidence: 85%

Qualitative investigations into floodways under extreme flood loading

Greene,

Gunasekara,

Lokuge

et al. 2024

J Flood Risk Management

View full text Add to dashboard Cite

The Australian use of the term floodway refers to a trafficable transverse structure designed to facilitate the safe crossing of watercourses. Floodways are also commonly referred to as fords and causeways. This research explores areas of focus through experimental, numerical and survey methods to improve floodway resilience with regard to flood risk management. The industry‐based survey provides a dataset relating to user experiences, deduces the likeliness of floodways to sustain damage, defines several key focus areas, and reveals that the current risk levels are primarily managed without significant investigation into design. A floodway experimental and numerical simulation program was developed to investigate the lateral forces induced through debris impact using scaled models in a soil box and finite element analysis. Qualitatively, crack propagation and displacement correlated closely with the strain concentrations and displacements in the numerical simulation, with failure attributed to tensile strength being exceeded, followed by plastic strain development within the soil elements. It was concluded through this research that floodway failure during flood is complex and can be attributed to several different failure modes including concrete failure, yielding of adjoining soil material, and hydraulically via scour.

show abstract

Section: Industry Surveysupporting

confidence: 85%

Qualitative investigations into floodways under extreme flood loading

Greene,

Gunasekara,

Lokuge

et al. 2024

J Flood Risk Management

View full text Add to dashboard Cite

show abstract

“…Laboratory experiment studies have focused on the onset of scour [2,3], tunnel and lee-wake erosion [4], the mechanism of three-dimensional scour hole development [5,6], the spanwise scour propagation rate [7][8][9], and the equilibrium scour depth [10]. Numerical simulation has also been widely used in the investigations on the aspects above [11][12][13][14]. Other literature has addressed scour protection measures [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

“…Sci. 2020, 10, x FOR PEER REVIEW 2 of 11 been widely used in the investigations on the aspects above [11][12][13][14]. Other literature has addressed scour protection measures [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Visualization of the Onset of Scour under a Pipeline in Waves

et al. 2020

View full text Add to dashboard Cite

This paper visualizes the onset of scour under a pipeline in regular waves and studies the mechanism in this process. After the test started, the sand particles near the downstream mudline began to oscillate periodically, probably due to the distribution pattern of the seepage hydraulic gradient under the pipeline as well as asymmetric waves. As the wave height gradually increased, the sand under the pipeline began to oscillate at increasing amplitude and the coverage of oscillation extended upstream. Some sand rushed out from the bottom of the pipeline, and the sand oscillated almost symmetrically around the bottom line of the pipeline thereafter. The oscillation amplitude of the sand particles continued to rise, probably due to a decrease in the seepage path under the pipeline and loosened sediment in the oscillation. The scour onset occurred after more sand rushed out from under the pipeline. The visualization results reproduced the delay in the scour onset reported previously, and related the delay to the aforementioned increase in sediment oscillation amplitude. This visualization can improve the understanding of the scour onset mechanism, and can serve as a guide to further investigate the critical conditions of scour onset and scour control countermeasures for offshore structures.

show abstract

“…Many investigations have focused on the two-dimensional scour under a pipeline, wherein the currents or waves are assumed to propagate towards the pipeline perpendicularly and the properties of the pipeline and the sediment are supposed to be identical along the pipeline [2]. These investigations have focused on the mechanism of the onset of scour [3,4], the equilibrium scour depth [5][6][7], the time scale of tunnel erosion [8][9][10], and field observations and tests [11,12]. Numerical simulation is also widely adopted in researches on the two-dimensional scour hole development process [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Visualization Tests on Variation of Scour Front under a Pipeline in Steady Currents

Xie

Zhu

2019

JMSE

View full text Add to dashboard Cite

The intersection of the span shoulder and the scour hole under a pipeline, also called the scour front, can affect the scour hole extension rate and the bearing capacity of the span shoulder, which is associated with pipeline spanning and failure. Studies on scour front evolution are limited due to technical restrictions. In this study, visualization experiments on three-dimensional scour under a pipeline in steady currents were performed to reveal the evolution of the scour front at the beginning of scour process, and the parametric effects on the scour front pattern. The angle of scour front witnessed a steady drop at the start of the scour development process and fluctuated gently thereafter. This can be attributed to the decrease in the blockage effect over time. A gravitational movement was observed on the downstream end of the scour front, which is associated with the variation of fluid pressure along the scour front. The scour front pattern was described by the angle between the scour front and the streamwise direction. Parametric analysis showed that the averaged scour front angle climbs as the Froude number increases and the pipeline embedment drops. This phenomenon can be expounded by the intensified flow deflection near the span shoulder due to the enhancement of the pipeline blockage effect, caused by the ascending Froude number and descending pipeline embedment. The results of this study can be adopted in future mechanism investigations on the scour hole propagation rate and the failure analysis on the span shoulder.

show abstract

Scour depth under pipelines placed on weakly cohesive soils

Cited by 22 publications

References 24 publications

Qualitative investigations into floodways under extreme flood loading

Qualitative investigations into floodways under extreme flood loading

Visualization of the Onset of Scour under a Pipeline in Waves

Visualization Tests on Variation of Scour Front under a Pipeline in Steady Currents

Contact Info

Product

Resources

About