Riverbank Collapse Research Articles

Analisis Dinding Penahan Tanah Tebing Sei Seruyan Desa Pembuang Hulu Kecamatan Hanau

River buffers are an important part of a road network system because they have a significant effect if the river collapses or if it does not function properly. Because riverbanks are structures that cross roads and other traffic, the collapse of riverbanks will reduce or withstand traffic and also cause buildings that stand alongside eroded rivers and landslides, which in turn will disrupt the comfort of community traffic and live and disturb economic relations. So it is very important to calculate the structure of the cliff building in Pembuang Hulu Village, Hanau District, so that it does not endanger the road users and community comfort activities. This study uses secondary data collection methods, then calculated in three models of variations in the condition of the retaining wall to obtain stability and structural analysis which can then calculate the value of bolster safety and sliding safety in buildings. Based on the calculation results obtained as follows, the capacity value of the soil behind the building of the retaining wall is qa = qu / 3 = 17.933 t/m^2 where the safety factor = 3.00 is normal qae = qu / 2 = 26,900 t/m^2 where the safety factor = 2.00 earthquake conditions. The value of stability and analysis of the structure of the retaining wall against rolling is Fg = 3.027>1.5, the shear is Fs = 1.587> 25.25 and foundation reinforcement 221.5 and the minimum stress value of qmin = 3.8006 tons/m² and the maximum stress value of qmax = 9.6454 tons/m² . The reinforcement design of the walls and the foundation of the soil retaining building to be safe against landslides is to reinforce 1925 the walls using 2225. guide

Viscous flow and collapse of macroscopic cavities in a granular material

The viscous flow in a granular material containing macroscopic cavities (or clear fluid regions) is determined on the basis of the generalized Darcy equation (outside the cavity region) and the Stokes equation (inside the cavity region). A three-dimensional singularity termed a “Darcylet”, which is a fundamental solution in the granular material, is distributed over the surface of a spherical cavity of unit size that surrounds the isolated singularity. The latter is calibrated with the exact solution and applied to describe the interaction between two cavities, which successfully reproduces previous analytic results. The proposed method is applicable to two cavities until they come into contact, thus providing a theoretical explanation of the fundamental collapse-and-merger process of two cavities. Furthermore, we extend this method to the interaction among multiple cavities, which reveals the effect on the flow field of an arbitrary number of cavities in an arbitrary configuration. To demonstrate the potential of the proposed method, we first apply it to a one-dimensional array of cavities of arbitrary orientation and curvature and estimate the convective diffusion of fluid volume, before considering a two-dimensional slightly disordered array of cavities. The results indicate the development and creation of new fluid passages, which may provide clues for predicting the anomalously fast spread of contaminants in inhomogeneous granular material; the formation of waterways, collapse of river banks, and landslides in civil engineering; and fluidization in chemical engineering. Our results may also provide insights into medical engineering techniques for creating new blood veins for micro-circulation (angiogenesis).

Estimating risk to prevent damage: predicting and preventing coypu (Myocastor coypus) damage to transport infrastructure.

A major impact of invasive Myocastor coypus in their introduction range is the collapse of riverbanks and nearby infrastructure, such as railway lines, due to the species' burrowing activities. Because widespread implementation of preventive measures along watercourses is unfeasible, identifying susceptible areas is key to guide targeted management actions. This study used species-habitat models to: (i) identify local environmental features of the railway line/watercourse intersections (RLWIs) that make them particularly susceptible to coypu damage, and (ii) predict species occurrence probability over a wide lowland-hilly area of northern Italy (Lombardy) to identify priority areas for monitoring. Local-scale models identified that the RLWIs most susceptible to burrowing were those surrounded by arable land with interspersed hedgerows locally characterized by high herbaceous vegetation and clay soil. In urbanized areas and areas of intensive agriculture, coypu dens were generally located significantly closer to the railway, increasing the risk of collapse. A landscape-scale species distribution model showed that lowland areas along major rivers and lake shores, and also agricultural areas with a dense minor hydrographic network, particularly in the southeast of the study area, are more likely to be occupied by coypu. Local-scale models showed that specific environmental characteristics increase the risk of burrowing near RLWIs. The landscape-scale model allowed us to predict which areas require thorough monitoring of RLWIs to search for such local characteristics to implement preventive management measures. The proposed model-based framework can be applied to any geographical context to predict and prevent coypu damage. © 2024 Society of Chemical Industry.

Assessing riverbank collapse with lateral displacement of shoreline for ecologically friendly erosion-resistant solutions

Assessing riverbank collapse with lateral displacement of shoreline for ecologically friendly erosion-resistant solutions

Deciphering the role of riverbank collapse in the braided reach of the lower Yellow River: Helpful or harmful?

Deciphering the role of riverbank collapse in the braided reach of the lower Yellow River: Helpful or harmful?

Uncovering the lack of awareness of sand mining impacts on riverbank erosion among Mekong Delta residents: insights from a comprehensive survey

Global sand demand due to infrastructure construction has intensified sand mining activities in many rivers, with current rates of sand extraction exceeding natural replenishment. This has created many environmental problems, particularly concerning riverbank stability, which adversely affects the livelihoods of people in the Vietnamese Mekong Delta (VMD). However, sand mining’s social impacts in the region remain inadequately understood. Here we assess locals’ perception of sand mining activities in the VMD and its impacts on riverbank erosion. Residents living along the Bassac River, a hotspot of sand mining, were interviewed. Our results showed that while sand mining is perceived as destructive to the environment, few were aware of its role in worsening riverbank erosion. Only residents directly affected by riverbank collapse were aware of the implications of sand mining and its negative effect on bank stability, as they seem to have actively sought clarification. Our findings highlight the need for greater awareness and understanding among the locals regarding sand mining’s impact on riverbank stability.

Viscous flow around three-dimensional macroscopic cavities in a granular material: asymptotic theory for two sufficiently distant spherical cavities of arbitrary configuration

Viscous flow around two spherical macroscopic cavities (or void spaces) in a granular material, which is exposed to an otherwise uniform flow at infinity, is investigated. The flow field is obtained analytically by solving the Stokes equation inside and the Darcy–Brinkman equation outside of the cavities, where continuity of the velocity and that of the stress are assumed on the boundary. In our previous complementary paper (Sano, Karmakar & Sekhar, J. Fluid Mech., vol. 931, 2022, A20), we obtain that two cavities of equal size in a tandem position are more prone to collapse for a shorter centre-to-centre distance with low permeability. In the present study, the asymptotic analysis of the interaction of two spherical cavities of different sizes with arbitrary configuration is presented. Particular attention is paid to the configuration dependence of two cavities of equal radius. The velocity field and the volume flux into respective cavities are calculated, which reveal that two cavities with orientation less than a certain critical angle are given a larger volume flux and are more prone to collapse. The present results are applicable to predicting the behaviour in a fixed-bed regime of a solid–gas transport system, microscale waterway formation in a granular material, onset of landslides, collapse of cliffs and river banks, etc.

Influence of the freeze-thaw effect on the seasonally frozen riverbank stability: A case study of the typical reach of Songhua River, China

岸滩侧蚀崩塌现象普遍存在于江河湖泊中，是一种危害较大的自然灾害。季节性冰冻河流受水动力、冻融耦合作用，岸滩崩塌机理复杂，开展其岸坡稳定性研究对河势控制和河流综合治理具有重要意义。以松花江干流大顶子山航电枢纽下游近坝段为例，采用BSTEM断面尺度模型，对河岸崩塌过程进行了模拟，定量分析了冻融作用对河岸稳定性的影响。研究结果表明：涨水期河岸稳定性相对较高，洪水期和退水期稳定性相对较低，为崩岸多发时期；冻融作用会使河岸稳定安全系数F_s提前达到不稳定临界值，即与不考虑冻融作用相比，河岸提前崩塌，且考虑冻融作用的崩塌宽度更接近实测值，累计冲刷崩塌总量增幅约为7%~41%。研究结果可为季节性冰冻河流岸滩崩塌及河道演变研究提供一定借鉴和参考。;The phenomenon of lateral erosion and collapse of bank is widely distributed in major rivers in the world, which is a kind of natural disaster with great harm. Seasonal frozen rivers are affected by the coupling of hydrodynamics and freeze-thaw, and the mechanism of bank collapse is complex. The research on the collapse process is of great significance to river bank protection and comprehensive river management. Taking the downstream part of the main stream of the Songhua River near the dam of Dadingzishan Aviation Power Project as an example, the BSTEM model was used to analyze the bank slope stability in different periods by considering the freezing and thawing effect, and the collapse process of the dual structure bank was simulated. The results showed that the stability of the river bank was higher in the dry and high water periods, and the stability was lower in the flood period and the receding water period, which was the stage of frequent bank collapse. Considering the freezing and thawing effect, the simulated river bank slope shape and collapse width were in good agreement with the measured values, and the amount of erosion and collapse was increased by 7%-41%. The research results can provide some reference for the study of river bank collapse in seasonally frozen areas.

Scouring effect of the middle and lower reaches of the Yangtze River and its impact after the impoundment of the Three Gorges Project

三峡及其上游干支流梯级水库建成运用后,大坝下游“清水下泄”引起了长江中下游河道发生长时间、长距离的冲刷。2001-2021年期间宜昌至长江口已累计冲刷了50.3亿m³,需厘清河道冲刷对河势、防洪、航运等方面产生影响。分析表明:三峡工程运用后,长江中下游河势总体稳定,弯道段出现切滩撇弯、汊道段出现塞支强干等现象;河道槽蓄量的持续增加,进一步增大了河道调蓄和行洪能力,但水流顶冲点的变化和近岸河床的冲刷下切,使得河道崩岸频发,并影响河势稳定和防洪安全;在河道冲刷、河势控制与航道工程综合作用下,长江中下游航道条件总体得到改善,但河道不均衡冲刷使得坝下游砂卵石河段出现“坡陡流急”,沙质河段出现洲滩散乱、航槽移位等现象,影响航道条件;同流量下枯水位呈下降态势,逢极枯年份影响长江中下游用水安全;江湖关系发生新变化,“三口”分流道由原淤积转为冲刷,两湖湖区水位不同程度的降低,枯水位出现时间有所提前,不利于湖区水资源和生态环境的安全与可持续发展;三峡工程实施枯水期补水调度和“压咸潮”调度以及长江口北支淤积减缓,对于遏制长江口咸潮入侵有利,入海泥沙显著减少引起长江口近岸河床冲刷,影响沿岸码头的安全运行。;After the construction of cascade reservoirs in the Three Gorges and its upper reaches, the downstream clear water of the dam was discharged, and a long-term and long-distance erosion occurred in the middle and lower reaches of the Yangtze River. From Yichang to the Yangtze Estuary, a total of 5030 million m³ was scoured. Under the background of large-scale erosion in the middle and lower reaches of the Yangtze River, it has a profound impact on river regime, flood control and shipping. The analysis shows that the river regime in the middle and lower reaches of the Yangtze River is generally stable, and the river regime in some parts of the river changes greatly, resulting in the phenomenon of beach cutting and bending, and the phenomenon of strong trunk. The increase of channel storage capacity increases the capacity of river discharge and flood storage, but the change of flow top scour point and the erosion of nearshore riverbed also make the river bank collapse frequently, affecting the stability of river regime and flood control safety. Under the combined action of channel scour, river regime control and channel engineering, channel conditions in the middle and lower reaches of the Yangtze River improved overall. However, due to the unbalanced scouring of the river channel, the sandy pebble river section in the downstream of the dam has a 'steep slope and rapid flow’, and the sandy river section has phenomena such as scattered beaches and channel displacement, affecting the channel conditions; the continuous erosion of river bed results in the decrease of low water level, which affects the water supply safety of life, production and ecology along the middle and lower reaches of the Yangtze River in extremely dry years. The relationship between rivers and lakes has undergone new changes. The three diversion channels have changed from original siltation to erosion. The water levels in the two lakes have decreased to varying degrees, and the low water level has appeared earlier, which has adversely affected the water resources and ecological environment in the lake area. The regulation of water replenishment and saltwater intrusion in dry season of the Three Gorges Project and the slowing down of siltation in the north branch are beneficial to the control of saltwater intrusion in the Yangtze Estuary. The sediment discharged into the sea from the Yangtze Estuary is significantly reduced and the riverbed near the Yangtze Estuary is scoured strongly. It seriously threatens the safety of the main structure of coastal enterprise wharf.

Quantitative analysis of riverbank collapse mechanisms based on BSTEM

ABSTRACT Riverbank collapse is a very common phenomenon in natural rivers that plays an important role in their evolution. In this study, we used the Bank Stability and Toe Erosion Model (BSTEM) to study quantitatively the effects of soil properties and bank inclination on its stability. For this, we investigated the stability of homogeneous banks under different bank inclination angles and binary structure banks composed of different materials. Our findings show differences between the cohesive and non-cohesive bank collapse modes, under the condition of ignoring the water table. We find the internal friction angle to be the dominant factor affecting non-cohesive banks, whereas cohesive banks are affected by the effective cohesion. The safety factor and water depth variations follow a quadratic polynomial law, more pronounced in non-cohesive banks. A higher inclination reduces the riverbank stability and safety factor. The latter is sensitive to bank slope changes for larger effective internal friction angles in non-cohesive banks. The material composition and thickness of the upper and lower layers of the riverbank with a binary structure affect the bank stability. The thickness and mechanical properties of the lower material play a key role in riparian stability.

Impact of upstream reservoirs on geomorphic evolution in the middle and lower reaches of the Yangtze River

AbstractIntensive human activities in river basins have substantial effects on fluvial hydrological and morphological processes and developmental trends. In this study, we assessed the evolutionary characteristics and developmental trends of the fluvial morphological system of the Three Gorges Dam (TGD) downstream to understand the impacts of human activities on the fluvial hydrological–morphological system of the region. The results indicated that the Three Gorges Project (TGP) and other upstream cascade reservoirs promoted sediment retention, which in turn aggravated the trend of declining sediment load and cumulative scouring over a long distance in the channels downstream of the TGD. Approximately 84% of scouring occurred in the low‐water channels, along with thalweg scouring and riverbank collapse. Notably, extended operation of the TGP and other upstream cascade reservoirs has resulted in gradual changes in the downstream riverbeds. Specifically, we found that the most intensive scouring zone shifted downstream from the near‐dam Yichang–Chenglingji reach (0–408 km) to the Chenglingji–Hankou reach. The scouring–silting distribution in swales has also changed: the scouring of deep swales and silting on floodplains prior to the TGP have been replaced by the scouring of both deep swales and floodplains. The scouring intensity of riverbeds in the Yichang–Hukou reach (954 km) was slightly higher than that forecasted prior to the TGP; the scouring intensities increased significantly during 2013–2021, which could be attributed to the TGP and other upstream cascade reservoirs; river sand mining and waterway dredging are secondary factors. We conclude that, owing to the effects of sediment retention by cascade reservoirs in the upper reaches of the Yangtze River (or Changjiang River), the cumulative scouring intensities of riverbeds in the middle and lower reaches of the Yangtze River will continue to increase in future decades.

Effects of Sea‐Level Rise on Dredging and Dredged Estuary Morphology

AbstractEstuaries and deltas worldwide are facing land loss and drowning due to sea‐level rise (SLR). Commonly home to ports, their channels are dredged and deepened for navigation. However, little is known about how such sediment management will interact with changing sediment transport patterns due to SLR. Using scale experiments, empirical relations and real world examples from global estuaries and deltas, we identify that dredging and SLR combined enhance bend migration whereas SLR alone leads to decentralizing of channels and drowning of intertidal area. In estuaries where channels are fixed, excess energy due to increasing tidal prism will manifest as bed and bank erosion, placing flood safety measures like dikes at risk. SLR increases dredging volumes in upstream reaches due to the rapid collapse of shoals and river banks along the whole estuary. Channel deepenings are ineffective under SLR conditions due to sediment import induced by increasingly flood‐dominant tides. Non‐dredged systems which have more regular and level elevations will lose intertidal area more quickly than dredged systems that have disconnected higher intertidal flats and a single deep channel. Mid‐size dredged European systems are more likely to drown due to dredging in the present century than from SLR. Effects can be avoided by pursuing sediment management strategies that help restore the morphology disrupted by dredging.

A continuous-discontinuous deformation analysis method for simulating the progressive failure process of riverbanks

River scouring is the primary cause of impulsive riverbank failure. Its direct effect is to cause catastrophic changes in the structure of the riverbank slope, which then leads to riverbank collapse. However, its internal evolution mechanism is unclear. To solve this problem, a continuous-discontinuous deformation analysis method that can reveal the evolution mechanism has been developed based on the Discontinuous Deformation Analysis (DDA) method. It discretizes the soil into Voronoi-shaped sub-blocks, forces the displacement coordination of the continuous medium through the defined bar element between the sub-blocks, and simulates the evolution from continuum to discontinuum through the bar element failure. At the same time, the open-close iteration algorithm is still used to deal with the contact between the real block boundaries and there is no need to judge the contact between sub-blocks. Then, for the first time, a generalized model of riverbank collapse caused by flow erosion is built, the entire failure process is simulated, and the effects of different soil strengths and slope ratios on the failure mode are discussed. The results indicate that it is insufficient to explain the mechanism of riverbank collapse only by using the concept of circular slip failure of a traditional soil slope.

Изучение русловых процессов и плановых деформаций русел

This paper presents the results of studies of the processes of intense planned deformation of the channels, which are formed as a result of erosion and collapse of the banks by the flow. The substantiation of forecasting the channel-forming activity of the flow and its management is given. A generalization is given of the methods of combating the intensive collapse of river banks, the organization and technology of construction with obtaining reliability, economic efficiency and environmental cleanliness. To carry out channel straightening work on rivers flowing in arid areas, it is possible to use the design of a cut, which should have the smallest approach angle of the dynamic axis of the main flow, the greatest drop in the marks of the beginning and end of the cut, its short and straight route and the minimum amount of excavation. When assessing the effect of planned deformation on the stability of the channel, a formula is presented for calculating the depth of erosion, dimensionless criteria that determine the possibility of formation of erosion for various situations, which made it possible to select the types and designs of bank protection structures.

Viscous flow around three-dimensional macroscopic cavities in a granular material

Viscous flow around spherical macroscopic cavities in a granular material is investigated. The Stokes equation inside and the Darcy–Brinkman equation outside the cavities are considered. In particular, the interaction of two equally sized cavities positioned in tandem is examined in detail, where the asymptotic effect of the other cavity is taken into account. The present analysis gives a reasonable estimate on the volume flow into the cavity and the local enhancement of stresses. This is applicable to predict the microscale waterway formation in that material, onset of landslides, collapse of cliffs and river banks, etc.

Handling of Krueng Jantho Riverbed Degradation with Groundsill Planning

Krueng Jantho river has an important role in the utilization of water resources, watershed conservation, and control of water damage. Dredging of river material has resulted in damage to the ecological factors of the Krueng Jantho river, specifically the degradation of the riverbed which can trigger the collapse of river banks and bridge pillars. The location under review is located in Alue Gintung Village, Seulimuem District, Aceh Besar Regency. Data and maps collected are watershed maps, river discharge data from the Krueng Aceh water level measurement post (AWLR), and topographical and river cross-section data. The method of calculating the generation of discharge data is used the Markov Chain method, the analysis of flood discharge plans using the Pearson Log type III distribution method, and the groundsill building planning for river bottom management and security. The groundsill building for the 25 yearly discharge is planned to be 80.00 m wide, groundsill 1,00 m high and 4.00 m thick groundsill lighthouse.

Study of the effects of check dam construction on the Limau Manih river using GIS

The problem of flooding or flash floods in watersheds often occurs, both in large rivers and small rivers. The frequency of occurrence varies greatly depending on the local climate. As a result of flooding, it causes more erosion and collapse of riverbanks and washes away all kinds of materials, such as wood, sand, and stone. Sometimes it also submerges rice fields, villages, and houses downstream of the river. Likewise, in the study location of the Limau Manih river, there has been a flood with a large discharge. It was recorded twice a year, namely in July and September 2012. One of the ways to reduce energy, scour, and avalanches on riverbanks is by building a check dam or weir. A check dam is expected to reduce the energy that arises due to differences in elevation or slope of the river channel. But on the other hand, the weir will raise the water level, so that the puddle becomes wider. Therefore, it is necessary to study the impact of weir construction on the extent of inundation. The study was conducted using ArcGIS to map inundation and HEC-RAS to simulate water levels along the river. Simulations were carried out for several return periods of rainfall events. The results of the study show that the planned flood discharge in the river of Limau Manih watershed is quite large. Meanwhile, from the simulation results, the inundation area is not too significant with the increase in the return period and the planned flood discharge. Although the simulation of the weir without widening the upstream part of the weir shows a significant increase in inundation area. This is most likely due to the weir in the upstream area of the river which is rather steep, so that water flows quickly through the overflow of the weir. However, the water level in the weir is higher than without the weir, as a result, water jumps and erosion occur downstream of the weir. For this reason, it is very necessary to monitor the scour behavior in the weir and the sedimentation rate, because this area has the potential to be eroded.

PENGARUH JUMLAH KRIB TIPE ZIGZAG TERHADAP KECEPATAN ALIRAN PADA SUNGAI KRUENG ACEH

The velocity at the inner turns of the Krueng Aceh river which is ± 100 meters from the Pango Bridge results in the collapse of river banks and endangers public facilities. For this reason, it is necessary to design a construction to protect the river bank. One of the alternatives is to use groyne construction. This study simulated the gropozag type groyne as an alternative form of groyne to be installed in the field. The aim of the study is to see the effect of gropozag type groyne on the river speed using the Surfacewater Modeling System (SMS) program to predict the direction of flow after the installation of the crib. Calibration is performed by determining the relative error value using velocity measurement data. This study uses gropozag groyne type with a length of 2,47 m (6 % B), 3 perpendicular groyne formation placements with an inclination of 10o,20o and 30o towards the upstream and the downstream area in 2 variations, namely 5-unit groynes and 3-unit groynes. The results shows that the RMA2 model obtained results that are close to the measurement value, where the value of the relative error obtained is 7.74% in cross 1 and 6.27% in cross 2. The lengthwise analysis of maximum velocity of 5-unit groynes shows that the maximum velocity occurs at V3 of 4,029 m/sec in the KRA5 formation (10o inclined to downstream of 5 units). Maximum speed of 3-unit groynes at V3 with KTA3 formation (3 perpendicular units) is 3,612 m/s. The number of groynes installed also affects the velocity of the simulation results. The velocity of the 5-unit groynes series is greater than that of the 3-unit groynes series.

Monitoring of the collapse of the shores of reservoirs and the technology of their surface and deep fixing

Due to the unique water regime of the Astrakhan region, characterized by an uneven distribution of runoff that is directly dependent on the discharge from the Volgograd hydroelectric power station, coastal zones of water bodies are subject to intense negative effects. It is established that, despite the existing variety of ways to protect coasts from erosion, the search for new technical solutions at the moment continues to be an urgent task in hydraulic construction. The purpose of this work was to evaluate the application of a new methodology for studying the destruction of coastal zones and the method of shore protection. The article discusses the features of work on shore protection of territories subject to slope processes. The role of studies of the leading processes of destruction of coastal zones in the course of engineering and geological surveys, to predict and prevent risk, as well as to ensure the information content of further work on the construction of reliable shore protection, is emphasized. The result of the study was a new method for identifying the destroyed coastal zones, technologies for surface and deep fixing of the Bank slopes, and a method for preventing the collapse of steep river banks. In this paper, a positive assessment of the investigated method of Bank protection was given. Research has shown that prevention of emergency situations, especially in urbanized areas subject to intense anthropogenic impact, is possible only with the construction of engineering protection structures that have a positive effect in both protective and environmental aspects.

Using radar polarimetry to monitor changes in backscattering mechanisms in landslide zones for the case study of the Bureya river bank collapse

The possibilities of radar polarimetry methods for identification of landslide zones are analyzed here. The fact of transformation of the dominant scattering type by the reflecting surface was used as a key feature of the landslide zone. ALOS-2 PALSAR-2 polarimetric data were processed using the Freeman–Durden and Cloude–Pottier decompositions for the four test sites selected in the area of a landslide caused by the Bureya river bank collapse. The decomposition results are consistent with each other in general, however, some areas show significant differences due to the specifics of the basic model provisions. It is shown that before the landslide event on the landslide area there were three main mechanisms of radar signal scattering: surface, volume, and double scattering. After the collapse, this area is characterized by a single scattering from the surface with large-scale irregularities and without vegetation. So, the landslide area can be confidently recognized. The considerable potential of using the radar polarimetry method for remote diagnostics of the effects of landslide phenomena has been demonstrated.