Streambed instabilities around a bridge pier in a dredged channel

Lade, Abhijit D.; Kumar, Bimlesh

doi:10.1002/rra.3629

Cited by 7 publications

(5 citation statements)

References 17 publications

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“…Such cases have been reported in rivers of central Spain, Poland, England, France, and India (Chen and Liu 2009, Brestolani et al 2015, Barman et al 2017. Experimental studies have confirmed the streambed instabilities around piers as well as transverse exposure of piers, because of dredging (Yanmaz and Cicekdag 2000, Lade et al 2019a, 2019b, 2019c, Lade and Kumar 2020. Recent studies have manifested the escalation of turbulent stresses and intensities in the region of sand removal and its downstream side , Barman et al 2018.…”

Section: Introductionmentioning

confidence: 75%

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Effect of sand mining on the flow hydrodynamics around an oblong bridge pier

2021

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Extraction of sand from riverbed has catastrophic repercussions on aquatic animalia habitat, water quality, and the environment. Alongside, physical alterations in the fluvial hydraulics arising on account of sand mining are also worthy of attention. Flows passing over the pits excavated in a channel have enhanced erosive propensity, which can be a cause of concern for the downstream hydraulic structures. The complex nature of flow interacting with the bridge piers after passing over a mining pit is not fully understood. Experiments were conducted to apprehend the effects of a dredged pit on the turbulence flow-field around an oblong pier. Flow was passed in an erodible sand bed rectangular channel having an oblong pier for the first case. In the second case, a pit was dredged in the mobile bed to replicate a mined channel, and the pier was subjected to the same discharge. The streambed at the approach of the pier experiences greater mean bed shear because of dredging. The amplification of the instantaneous bed shear beneath the turbulent horseshoe vortex (THSV) zone at the pier front is almost twice due to channel dredging. The findings can be useful in understanding the streambed instabilities around bridge piers in mining-infested channels.

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Section: Introductionmentioning

confidence: 75%

“…Consequently, excess erosion inside the scour hole might occur due to channel mining. Previous studies have already conformed excess scour and undermining around the hydraulic structures caused due to sand mining (Kondolf 1994, Lade and Kumar 2020.…”

Section: Time-averaged Flow Characteristics At the Pier Approachmentioning

confidence: 89%

Effect of sand mining on the flow hydrodynamics around an oblong bridge pier

2021

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“…The most significant event posing risks to the bridge observed in the MS image stack was the removal by dredging of the gravel pads built during bridge construction. Dredging activity around bridge piers can pose risks of settlement due to excess sediment removal [39,40] or damage from dredging vessels or dredging equipment striking the bridge. We did not observe any evidence of unexpected bridge deformations in the InSAR data throughout the period of dredging operations and gravel pad removal, nor did we observe any evidence of unexpected bridge deformations in the year following pad removal, where the remaining fill material below the waterline was left to be eroded by normal river processes.…”

Section: Dredging Activitymentioning

confidence: 99%

Satellite Synthetic Aperture Radar, Multispectral, and Infrared Imagery for Assessing Bridge Deformation and Structural Health—A Case Study at the Samuel de Champlain Bridge

Cusson,

Stewart

2024

Remote Sensing

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A space-borne remote sensing method was applied, validated, and demonstrated in a case study on the Samuel de Champlain Bridge in Montreal, Canada. High-resolution C-band radar satellite imagery was analyzed using the Persistent Scatterer Interferometric Synthetic Aperture Radar technique to derive bridge displacements and compare them against theoretical estimates. Multispectral and long-wave thermal infrared satellite imagery acquired during the InSAR observation period and historical environmental data were analyzed to provide context for the interpretation and understanding of InSAR results. Thermal deformation measurements compared well with their theoretical estimates based on known bridge geometry and ambient temperature data. Non-thermal deformation measurements gave no evidence of settlement during the 2-year monitoring period, as would normally be expected for a newly constructed bridge with its foundation on bedrock. The availability of environmental data obtained from multispectral and thermal infrared satellite imagery was found to be useful in providing context for the bridge stability assessment. Ambient temperature measurements from thermal infrared satellite imagery were found to be a suitable alternative in cases where data from in situ temperature sensors or nearby weather stations are not available or not fit for purpose. No strong correlation was found between the river conditions and bridge deformation results from the InSAR analysis; this is partly due to the fact that most of these effects act along the river flow in the north–south direction, to which the satellite sensor is not sensitive.

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“…The EIA study magnifies turbulence characteristics in the downstream flow (Barman, Kumar, & Sarma, 2018; Barman, Kumar, & Sarma, 2019a; Barman, Kumar, & Sarma, 2019b; Daneshfaraz et al, 2021; Lade, Deshpande, & Kumar, 2020; Neyshabouri, Farhadzadeh, & Amini, 2002, Padmalal & Maya, 2014). It aggravates the erosion/scouring of the river structures of interest (Lade & Kumar, 2020; Li, Wang, Ma, & Nie, 2020). It calls for auxiliary arrangements for the protection of these river structures.…”

Section: Introductionmentioning

confidence: 99%

Turbulence structure and bank erosion process in a dredged channel

Arora

Patel

Lade

et al. 2023

River Research & Apps

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Riverbank erosion has significant geomorphological as well as anthropogenic consequences. The geomorphological impacts include form changes such as lateral channel migration, meanders, channel expansion, etc. The anthropogenic effects include the threat to floodplain human habitation, agricultural land, and stability of instream hydraulic structures and buried pipelines. Channel dredging for the extraction of sand and gravel has seen a multi‐fold rise in the last few decades. Therefore, riverbank erosion response to channel mining gains importance in river basin management. Sandpits dredged in the riverbeds can significantly impact the downstream riverbank stability. In order to assess these impacts, we conducted a series of experiments at a laboratory scale in a recirculating water flume. Three riverbank slopes, 25° (gentle), 31° (equal to the angle of repose of the bank sediments), and 40° (steeper than the angle of repose), were tested along with a sandpit. Remarkable changes in the turbulence structure of riverbank flow were found due to the channel pit. Pit excavation directly impacts the fluvial erosion characteristics of the riverbank. Pit action increases the Reynolds shear stress fields in the near‐bank flow, which causes progressive fluvial erosion of the berm at the bank toe. The erosivity of the main channel flow in the riverbank also leads to channel degradation, which increases the exposed height of the bank slope. Pit dredging leads to the generation of stronger ejection bursts which provide a mechanism for berm sediment mobility and erosion. The hydro morphological response of the riverbank due to sand mining was analysed, and process understandings are presented in the paper.

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Streambed instabilities around a bridge pier in a dredged channel

Cited by 7 publications

References 17 publications

Effect of sand mining on the flow hydrodynamics around an oblong bridge pier

Effect of sand mining on the flow hydrodynamics around an oblong bridge pier

Satellite Synthetic Aperture Radar, Multispectral, and Infrared Imagery for Assessing Bridge Deformation and Structural Health—A Case Study at the Samuel de Champlain Bridge

Turbulence structure and bank erosion process in a dredged channel

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