Scholarlink

<p>Anthropogenic interventions, notably upstream damming and sand mining, have induced severe sediment starvation in major mega-deltas worldwide, triggering the “hungry water” phenomenon. While the general impacts of sediment deficit on lateral erosion are well-documented, the failure mechanisms of heavily engineered riverbanks in morphologically constricted reaches remain poorly understood. This study addresses this critical gap by investigating the compound hydro-morpho-geotechnical failure of hardened revetments under the synergistic stress of profound bed incision, intense hydrodynamic forcing, and extreme hydrological fluctuations. Using a highly constricted reach of the Mekong River (Thuong Thoi Tien) as a natural laboratory, we integrate two-decade bathymetric observations (2006–2025), two-dimensional morphodynamic modelling (MIKE 21 FM), and transient slope stability analysis (GeoStudio). Our findings reveal that the rigid confinement of narrow reaches forces sediment-starved water vertically, causing aggressive local scour (up to 12&#xa0;m deep). This deep-seated incision, combined with a drastic decline in dry-season water levels, eliminates the stabilising hydrostatic pressure, abruptly shifting the failure mode from localised hydraulic wash-out to systemic deep rotational slumping (Factor of Safety &lt; 1.0). To counter this, we propose an adaptive, material-optimised mitigation framework prioritising geosynthetic sand containers (GSCs) over traditional rockfill to restore basal backpressure. Beyond the case study, the proposed diagnostic framework is transferable to other constricted, sediment-starved deltaic reaches, subject to site-specific recalibration. Its principal limitation is the one-way coupling and calibration to a single reach; independent multi-site validation is therefore required before broader generalisation.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Compound Failure of Hardened Riverbanks in a Sediment-Starved Mega-delta

  • 期刊论文

  • 发表日期：

    2026年6月28日

查看全文
  • Thinh Ngoc Pham

摘要

Anthropogenic interventions, notably upstream damming and sand mining, have induced severe sediment starvation in major mega-deltas worldwide, triggering the “hungry water” phenomenon. While the general impacts of sediment deficit on lateral erosion are well-documented, the failure mechanisms of heavily engineered riverbanks in morphologically constricted reaches remain poorly understood. This study addresses this critical gap by investigating the compound hydro-morpho-geotechnical failure of hardened revetments under the synergistic stress of profound bed incision, intense hydrodynamic forcing, and extreme hydrological fluctuations. Using a highly constricted reach of the Mekong River (Thuong Thoi Tien) as a natural laboratory, we integrate two-decade bathymetric observations (2006–2025), two-dimensional morphodynamic modelling (MIKE 21 FM), and transient slope stability analysis (GeoStudio). Our findings reveal that the rigid confinement of narrow reaches forces sediment-starved water vertically, causing aggressive local scour (up to 12 m deep). This deep-seated incision, combined with a drastic decline in dry-season water levels, eliminates the stabilising hydrostatic pressure, abruptly shifting the failure mode from localised hydraulic wash-out to systemic deep rotational slumping (Factor of Safety < 1.0). To counter this, we propose an adaptive, material-optimised mitigation framework prioritising geosynthetic sand containers (GSCs) over traditional rockfill to restore basal backpressure. Beyond the case study, the proposed diagnostic framework is transferable to other constricted, sediment-starved deltaic reaches, subject to site-specific recalibration. Its principal limitation is the one-way coupling and calibration to a single reach; independent multi-site validation is therefore required before broader generalisation.