Groyne

About: Groyne is a research topic. Over the lifetime, 397 publications have been published within this topic receiving 4549 citations. The topic is also known as: groin & Breakwater.

Semi-permeable groyne and molding method thereof

Abstract: The invention provides a semi-permeable groyne. The semi-permeable groyne is molded underground, and comprises a groyne body, an inverted filter layer, a protection surface structure and a wave wall, wherein the groyne body is a main body of the groyne; the inverted filter layer is laid on the groyne body; the protection surface structure is laid above the inverted filter layer to form a wave resisting structure; and the wave wall is mounted and laid at the top of the groyne body. Multiple sand bags are filled in the groyne body; gravels are filled in the sand bags; and the sand bags are constructed on water and built on the edge of the groyne body to form an underwater cofferdam so as to prevent the loss of backfill materials and reinforce the side edges of the backfill groyne body. The sand bags are covered with soil engineering pipe belts; the soil engineering pipe belts are built above the sand bags to form a land cofferdam; the tubular sand bags and the soil engineering pipe belts are respectively built on the edges of the groyne body to protect the backfill materials in the groyne center to prevent or reduce the permeable loss, so that the edges of the groyne body are reinforced, the antiskid stability of the groyne body is improved, the effect of reinforcing ribs is achieved, and the whole stability of the groyne is promoted; and the groyne center adopts the backfill materials to reduce such building materials as groyne center stones, so that the engineering cost is saved. The invention further provides a method for molding the semi-permeable groyne.

Inundated Flood Planes and the Flow over Groynes and Oblique Weirs

Abstract: At high water stages the flow in groyne fields is highly affected by the water flowing over the groyne. For those conditions the groyne acts as an (im)perfect weir. In a similar way local elevations in the flood planes can be considered as weirs. The arbitrary orientation of those obstacles with respect to the flow prohibits the use of straightforward weir formulations. By considering the generic case of the flow over oblique weirs, a simple analytical approach already gives good insight and acceptable estimates, whereas a 3D numerical model clearly shows the complexities of flow separation and non-hydrostatic effects.

Sediment characteristics and hydrodynamics of nearshore gudong in the yellow river delta

Abstract: The sediment stirring-up and transporting have been studied based on the data of wind,tidal currents and bottom sediments observed during the period from 2004 to 2006.The results show that sediments at the Gudong coasts are mostly silt and poorly-sorted.Sediment particles become finer and poorer-sorted with water depth.Influenced by wind-residual currents,coastal line and groynes,sediments show different transporting trends in different regions.Analysis of sediment grain-size tendency shows that the study area can be divided into three areas:in the north embankment nearshore area of Gudong,sediments are mainly transported towards northeast;in the east embankment nearshore area,sediments go from north to south except the area between NO 2 Groyne and NO 18 Groyne where sediments show an opposite direction of transportation;in the Xintan area of the Yellow River delta on the south side of Gudong,sediments migrate from west to east.Tidal current velocity is not great enough to stir up bottom silt in the nearshore Gudong,but silt is often suspended by waves around groynes that have made tidal currents change.Waves are often seen to be 1.0 m high,and silt suspension is concentrated in area shallower than 5 m of water depth.Silt stirred up by waves is carried to open sea by tidal currents.Erosion becomes serious due to short of silt recharge.

Model based estimation of sediment erosion in groyne fields along the River Elbe

Abstract: River water quality is still a vital environmental issue, even though ongoing emissions of contaminants are being reduced in several European rivers. The mobility of historically contaminated deposits is key issue in sediment management strategy and remediation planning. Resuspension of contaminated sediments impacts the water quality and thus, it is important for river engineering and ecological rehabilitation. The erodibility of the sediments and associated contaminants is difficult to predict due to complex time depended physical, chemical, and biological processes, as well as due to the lack of information. Therefore, in engineering practice the values for erosion parameters are usually assumed to be constant despite their high spatial and temporal variability, which leads to a large uncertainty of the erosion parameters. The goal of presented study is to compare the deterministic approach assuming constant critical erosion shear stress and an innovative approach which takes the critical erosion shear stress as a random variable. Furthermore, quantification of the effective value of the critical erosion shear stress, its applicability in numerical models, and erosion probability will be estimated. The results presented here are based on field measurements and numerical modelling of the River Elbe groyne fields.

An Experimental Study on a Characteristics of Flow around Groynes for Groyne Spacing

Abstract: In design of groyne series, groyne spacing is a important factor and have an effect on not only the characteristics of backward and recirculation flow in groyne zone but also flow field in main channel. It is necessary study about flow pattern of recirculation zone and main channel that is a cause of bad change, local scour and bank erosion by groyne spacing. In this study, flow variation of groyne zone and main chanel for spacing of groynes were analyzed from the experiment results in order to offer a fundamental data that can be used to decide the proper groyne spacing. Experiments were conducted 12 cases for groyne spacing(L) by groyne length(l) rate and the velocity profile was measured using LSPIV and ADV. From the results, two vortex flows developed in recirculation zone for L/l=3~9 and three vortex flows developed over L/l=10. The velocity of backward flow in recirculation zone was decreased up to 20% over L/l=4. The velocity of main channel flow was increased from 1.3 to 2.0 times by groyne spacing and the rate of velocity increased by increasing groyne spacing. The maximum velocity occurred in 0.7~0.8 times of groyne spacing downstream of upper groyne.