Geohazards in the three Gorges Reservoir Area, China – Lessons learned from decades of research

Tang, Huiming; Wąsowski, J.; Juang, C. Hsein

doi:10.1016/j.enggeo.2019.105267

Cited by 516 publications

(149 citation statements)

References 65 publications

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“…However, as the landslides periodically underwent the disturbances of water level fluctuations, the frequency of reactivated landslides exhibited a decreasing trend, and it decreased dramatically after 2009, i.e., one year after experiencing the highest water level. Many scholars also believed that the reactive landslides are concentrated in the initial stage of water storage, and the frequency of activation as well as the degree of deformation decrease gradually after the last phase of water storage [51,52]. The experimental results in this study also show that the front of the slope slid along the original rupture zone during the second drawdown, but the mid-rear parts had no obvious deformation, which is different from the creep deformation induced by the traction of the front part during the first drawdown; further, its stability was improved after the first deformation.…”

Section: Self-adjustment Of Deformationmentioning

confidence: 99%

Centrifuge Modeling and the Analysis of Ancient Landslides Subjected to Reservoir Water Level Fluctuation

Tang

et al. 2020

Sustainability

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Landslides are among the most severe natural hazards with significant impacts in human life and infrastructure. The Three Gorges Reservoir Area (TGRA) is vulnerable to landslides because of the geological environment and human activities. A centrifuge model test of a landslide with a planar sliding surface in the TGRA was conducted. Based on the multiple monitoring systems composed of a 3D laser scanner, pore water pressure transducers, particle image velocimetry and earth pressure sensors, multiphysical data were obtained. The work described here had the objective of researching the long-term deformation pattern of this kind of landslide that was subjected to periodic fluctuations in the reservoir water level. The results indicated that the failure processes were characterized by progressive retrogression and cracks caused by the reservoir drawdown. Transverse tensile cracks first appeared in the submerged zone of the slope. The front part of the slope was dominated by horizontal displacement, while the consolidation and compaction deformation in the vertical direction dominated at the mid-rear part of the slope. When the water level dropped again, the front part slid down and fell into the river, but the mid-rear part had no obvious deformation and exhibited a phenomenon of self-stabilization. Moreover, the phreatic line is a concave shape directed into the slope during reservoir filling and converts to a convex shape pointing out of the slope during reservoir drawdown. The earth pressures in the slope vary with the failure process of the landslide. Good agreement is obtained for the deformation characteristics between the experimental results and those of prototype landslides.

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Section: Self-adjustment Of Deformationmentioning

confidence: 99%

Centrifuge Modeling and the Analysis of Ancient Landslides Subjected to Reservoir Water Level Fluctuation

Tang

et al. 2020

Sustainability

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“…The section from Fengjie to the west of Zigui is topographically the highest, creating the famous Three Gorges (Qutang Gorge, Wu Gorge and Xiling Gorge). The elevation declines westwards and eastwards from the highest part, forming a hilly landscape and moderate altitude mountains, respectively [18]. The elevation of the meteorological stations ranges from 171 m at Badong station to 604 m at Fengjie station.…”

Section: Study Areamentioning

confidence: 99%

Exploring Empirical Linkage of Water Level–Climate–Vegetation across the Three Georges Dam Areas

Huang

Zhou

Zhang

2020

Water

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The Three Georges Dam (TGD) has brought many benefits to the society by periodically changing the water level of its reservoir (TGR). Water discharging regularly takes places in the falling season when the downstream of the Yangtze River is drying. The TGD, the world’s largest hydroelectric project, can greatly mitigate the risk of flood caused by extreme precipitation with the prior discharging policy applied in the preflood season. At the end of flood season, water impounding in the storage season can help resist a drought the next year. However, owing to the difficulty in mining causality, the considerable debate about its environmental and climatic impacts have emerged in much of the empirical and modeling studies. We used causal generative neural networks (CGNN) to construct the linkage of water level–climate–vegetation across the TGD areas with a ten-year daily remotely sensed normalized difference vegetation index (NDVI), gauge-based precipitation, temperature observations, water level and streamflow. By quantifying the causality linkages with a non-linear Granger-causality framework, we find that the 30-days accumulated change of water level of the TGR significantly affects the vegetation growth with a median factor of 31.5% in the 100 km buffer region. The result showed that the vegetation dynamics linked to the water level regulation policy were at the regional scale rather than the local scale. Further, the water level regulation in the flood stage can greatly improve the vegetation growth in the buffer regions of the TGR area. Specifically, the explainable Granger causalities of the 25 km, 50 km, 75 km and 100 km buffer regions were 21.72%, 19.24%, 17.31% and 16.03%, respectively. In the falling and impounding stages, the functionality of the TGR that boosts the vegetation growth were not obvious (ranging from 6.1% to 8.3%). Overall, the results demonstrated that the regional vegetation dynamics were driven not only by the factor of climate variations but also by the TGR operation.

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“…Loose accumulation, caused by landslide, collapse, debris flow, and mine blasting, poses a huge threat to human life and property. It tends to trigger more concatenated hazards and risks under the conditions of rainfalls, water level fluctuation of reservoirs, and earthquakes, which in turn trigger further hazards to form an interconnected hazard network [1][2][3][4][5]. Loose accumulation can be defined as an assembly of granular materials without too much compaction; measuring the particle shape and distribution is a fundamental task in various fields.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Particle Size of Loose Accumulation Based on Alpha Shapes (AS) and Hill Climbing-Region Growing (HC-RG) Algorithms

Lin

Tang

et al. 2020

Sensors

Self Cite

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The loose accumulation CAUSED by landslide, collapse, debris flow, and mine blasting, exerts considerable negative influence to human activities. Besides, it can easily trigger secondary disaster under inner and outer geological conditions. Extraction and measurement of the particle of loose accumulation is of importance for prediction of slope stability and mine blasting. In this paper, the 3D laser scanning is utilized to collect the point clouds of granular materials in physical model (three types of materials) and landslide accumulation in field, respectively. Then, the alpha shapes (AS) and hill climbing-region growing (HC-RG) algorithms are introduced for identifying particles and finding their dimensions (e.g., particle number and radii). Comparison between the recognition results and reality shows that both algorithms can provide a good performance in laboratory physical model, and acceptable results can be obtained when applying two algorithm to field survey. AS algorithm needs less time to process data than HC-GR algorithm; however, the recognition from HC-RG algorithm is more accurate than that by AS algorithm.

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Geohazards in the three Gorges Reservoir Area, China – Lessons learned from decades of research

Cited by 516 publications

References 65 publications

Centrifuge Modeling and the Analysis of Ancient Landslides Subjected to Reservoir Water Level Fluctuation

Centrifuge Modeling and the Analysis of Ancient Landslides Subjected to Reservoir Water Level Fluctuation

Exploring Empirical Linkage of Water Level–Climate–Vegetation across the Three Georges Dam Areas

Measurement of Particle Size of Loose Accumulation Based on Alpha Shapes (AS) and Hill Climbing-Region Growing (HC-RG) Algorithms

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