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

2020 ◽  
Vol 12 (5) ◽  
pp. 2092 ◽  
Author(s):  
Songlin Li ◽  
Qiang Xu ◽  
Minggao Tang ◽  
Huajin Li ◽  
He Yang ◽  
...  
Keyword(s):  
Water Level ◽  
Pressure Sensors ◽  
Three Gorges Reservoir Area ◽  
Centrifuge Model Test ◽  
Front Part ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Transverse Tensile ◽  
Reservoir Drawdown ◽  
Rear Part

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.

scholarly journals The Coupling Effect of Rainfall and Reservoir Water Level Decline on the Baijiabao Landslide in the Three Gorges Reservoir Area, China

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Nenghao Zhao ◽  
Bin Hu ◽  
Qinglin Yi ◽  
Wenmin Yao ◽  
Chong Ma
Keyword(s):  
Water Level ◽  
Three Gorges Reservoir ◽  
Coupling Effect ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Reservoir Area ◽  
The Three Gorges ◽  
Water Level Decline

Rainfall and reservoir level fluctuation are two of the main factors contributing to reservoir landslides. However, in China’s Three Gorges Reservoir Area, when the reservoir water level fluctuates significantly, it comes at a time of abundant rainfall, which makes it difficult to distinguish which factor dominates the deformation of the landslide. This study focuses on how rainfall and reservoir water level decline affect the seepage and displacement field of Baijiabao landslide spatially and temporally during drawdown of reservoir water level in the Three Gorges Reservoir Area, thus exploring its movement mechanism. The monitoring data of the landslide in the past 10 years were analyzed, and the correlation between rainfall, reservoir water level decline, and landslide displacement was clarified. By the numerical simulation method, the deformation evolution mechanism of this landslide during drawdown of reservoir water level was revealed, respectively, under three conditions, namely, rainfall, reservoir water level decline, and coupling of the above two conditions. The results showed that the deformation of the Baijiabao landslide was the coupling effect of rainfall and reservoir water level decline, while the latter effect is more pronounced.

Analysis of Bazimen Landslide Deformation Based on GPS

2011 ◽  
Vol 347-353 ◽  
pp. 435-439
Author(s):  
Peng Fei Tu ◽  
Sheng Chao Wu ◽  
Hong Tao Li
Keyword(s):  
Water Level ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Analysis Method ◽  
Mathematical Relationship ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
The Three Gorges ◽  
Landslide Deformation ◽  
Major Factors

Rainfall infiltration and reservoir water level fluctuation are major factors inducing slope deformation. Taking nearly three years data of Bazimen landslide in the Three Gorges Reservoir area and basing on the mathematical regression analysis method, a mathematical relationship among landslide deformation, water level and rainfall is established. And then the most adverse condition under the superposi¬tion of rainfall and reservoir water level is obtained.

Bankside Stability Analysis under the Actions of Rainfall and Reservoir Water Level Fluctuation

2012 ◽  
Vol 610-613 ◽  
pp. 2658-2662
Author(s):  
Xu Tao Wang ◽  
Shu Jun Chen ◽  
Qian Feng
Keyword(s):  
Stability Analysis ◽  
Water Level ◽  
Water Level Fluctuation ◽  
Three Gorges Reservoir Area ◽  
Level Fluctuation ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Rainfall Condition ◽  
Landslide Mass ◽  
Reservoir Water Level Fluctuation

It has been accepted that the rainfall and the reservoir water level fluctuation plays an important role in the stability of the reservoir bankside. However, at present, there has not been suitable simplification method for the project application to calculate and appraise. Therefore, based on the Boussinesq’s differential equation of unsteady-seepage and boundary condition, and Laplace’s transform, the curvilinear equation of phreatic line in landslide mass is deduced under the rainfall and the reservoir water level fluctuation conditions, and a simplified formula which can be used in the project is gained by the polynomial fitting. Meanwhile, it holds together the transmission coefficient method to write programs about the bankside stability analysis in the paper. With the Er-Liban landslide of the three Gorges Reservoir area for the computation model, this paper use the program to analyze the change rule and stability of the phreatic line under the reservoir water level fluctuation and rainfall condition.

scholarly journals Phreatic line calculation and stability analysis of slopes under the combined effect of reservoir water level fluctuations and rainfall

2017 ◽  
Vol 54 (5) ◽  
pp. 631-645 ◽  
Author(s):  
Guanhua Sun ◽  
Yongtao Yang ◽  
Shengguo Cheng ◽  
Hong Zheng
Keyword(s):  
Water Level ◽  
Three Gorges Reservoir ◽  
Combined Effect ◽  
Water Level Fluctuations ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Reservoir Area ◽  
The Three Gorges

Rainfall and reservoir water level fluctuations are the main external factors of landslides in the Three Gorges Reservoir area. To improve the analysis of slope stability under the combined effect of reservoir water level fluctuations and rainfall, a simplified method for phreatic line calculation of slopes is proposed in this study. Based on the obtained phreatic line, the expression of normal stress on the sliding surface of the slope under the hydrodynamic forces is deduced, and a global analysis method to solve the slope safety factor under hydrodynamic force is proposed. Finally, the safety evolution of a slope in the Three Gorges Reservoir area is studied under the combined effect of reservoir water level fluctuations and rainfall.

Analysis of Dynamic Response of Landslide Stability to Reservoir Water Level Fluctuation Using Numerical Simulation

2012 ◽  
Vol 594-597 ◽  
pp. 407-414
Author(s):  
Wu Yi ◽  
Zhao Ping Meng ◽  
Guo Qing Li ◽  
Zhi Wei Jin
Keyword(s):  
Dynamic Response ◽  
Water Level ◽  
Water Level Fluctuation ◽  
Level Fluctuation ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Landslide Stability ◽  
Reservoir Drawdown ◽  
The Stability ◽  
Reservoir Water Level Fluctuation

Reservoir water level is one important factor influencing the stability of landslides. The dynamic response of landslide stability under reservoir water level function and its features are analyzed using theoretical and numerical methods. The results show that, in terms of reservoir water level fluctuation and landslide permeability, the seepage filed of landslide can be divided into four types: lag behind impoundment(X-Ⅰ), lag behind drawdown(T-Ⅰ), synchronization with impoundment(X-Ⅱ) and synchronization with drawdown (T-Ⅱ). Under lag behind drawdown, at a certain rate of reservoir drawdown, the stability drops with the permeability of landslide. Under lag behind impoundment, with the rise of water level, the lower the permeability of landslide is, the more stable the landslide is. Under synchronization with impoundment or drawdown, the stability of landslide drops with reservoir impoundment and rises with reservoir drawdown.

Simulation of Landslide Seepage Field with the Action of Reservoir Water Fluctuations

2011 ◽  
Vol 71-78 ◽  
pp. 4802-4807 ◽  
Author(s):  
Wei Mao ◽  
E Chuan Yan ◽  
Yang Bing Cao ◽  
Sheng Lai Jiang
Keyword(s):  
Water Level ◽  
Saturation Line ◽  
Water Level Fluctuations ◽  
Three Gorges Reservoir Area ◽  
Seepage Field ◽  
Convex Shape ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Cyclical Fluctuations ◽  
Rate Of Increase

Taking a landslide in the three gorges reservoir area as an example and considering the seepage field in different time periods with rise and fall of reservoir water level of the eight conditions, we use GEO-STUDIO / SEEP module to establish a seepage model and to calculate the distribution of seepage. The results showed that: the groundwater saturation line appears in the back-phenomenon during a certain range of slope in the rising water level, saturation line was concave shape, and with the rate of increase in water level increased and that concavity gradually increase; the groundwater saturation line appears in the downstream phenomenon during a certain range of slope in the drawdown water level, saturation line was convex shape, and with the rate of decline in water level increased and that convexity increases. The effective simulation studies of the greatly and cyclical fluctuations of water level under the slope seepage field has a certain reference meaning to the landslide control in the reservoir water level fluctuations about reservoir bank landslide.

Analysis on Deformation Failure Mechanism of Woshaxi Landslide in the Three Gorges Reservoir Area

2012 ◽  
Vol 594-597 ◽  
pp. 498-501
Author(s):  
Shu Qiang Lu ◽  
Qing Lin Yi ◽  
Wu Yi
Keyword(s):  
Water Level ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
The Three Gorges ◽  
Landslide Deformation ◽  
Main Factors ◽  
The Right ◽  
Water Level Decline

The Woshaxi landslide is located on the right bank of Qinggan river which is a tributary of the Yangtze River, which continuously and seriously developed after the impoundment of Three Gorges. Surface investigation showed that there were shearing, tensing and crush-pressing fissures. The monitoring data showed that displacement of lower part was bigger than that of upper, and the sliding because of the reservoir water level decline. The landslide mechanism was towing forward and pushing backward, and towing happened mainly in the prophase, while pushing happened mainly in the anaphase. Heavy rainfall and water level drawdown are the main factors of landslide deformation.

The Experimental Research on the Effect of Seepage Pressures on Seepage Time through Red Sandstone

2014 ◽  
Vol 501-504 ◽  
pp. 354-358 ◽  
Author(s):  
Qian Cheng Sun ◽  
Zhen Hua Zhang ◽  
De Zhong Li ◽  
Meng Ping Du
Keyword(s):  
Water Level ◽  
Soft Rock ◽  
Water Infiltration ◽  
Three Gorges Reservoir Area ◽  
Seepage Velocity ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Seepage Pressure ◽  
Red Sandstone ◽  
Cyclic Fluctuation

The cyclic fluctuation of reservoir water level makes soft rock in bank slope under cyclic seepage pressure and will bring certain effects on permeability characteristics of the soft rock. In order to obtain the relationship between the seepage pressure and seepage time, permeability tests were conducted on red sandstone specimens (from Three Gorges Reservoir Area, China) under cyclic seepage pressures by the self-developed equipment with the function to simulate cyclic fluctuation of reservoir water level. Experimental results show that the water infiltration of the sample was not stable in first three cycles, and it changed from 0.444 mL to 0.086mL. After three cycles, the water infiltration fluctuated between 0.060mL and 0.069mL. It can be drawn that the seepage velocity increase with the raise of pressure and it fit a four times polynomial in each cycle. The study indicates that increasing the seepage pressure appropriately can improve the seepage velocity, and greatly shorten the seepage time.

scholarly journals Failure Mechanism of Colluvial Landslide Influenced by the Water Level Change in the Three Gorges Reservoir Area

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhaodan Cao ◽  
Jun Tang ◽  
Xiaoer Zhao ◽  
Yonggang Zhang ◽  
Bin Wang ◽  
...  
Keyword(s):  
Water Level ◽  
Failure Mechanism ◽  
Three Gorges Reservoir ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Landslide Stability ◽  
The Three Gorges ◽  
Colluvial Landslide

The stability of the reservoir bank landslide is affected by a variety of external factors, and the fluctuation of reservoir water level is one of the important influencing factors. The Erdaohe landslide is a typically colluvial landslide in the Three Gorges Reservoir area with periodic reservoir water level fluctuations. According to landslide displacement data, the displacement of the Erdaohe landslide exhibits the significantly stepwise feature. Its failure mechanism was analyzed using strength reduction method by the FLAC3D package in the case of reservoir water level changes. The results indicate that the hydrodynamic pressure has an important impact on the initialization of the landslide failure. When reservoir water level rises rapidly or maintains constant at the lower level, the landslide stability would be higher. When the reservoir water level decreases rapidly or maintains constant at the higher level, the landslide stability will be smaller. When the reservoir water level was in the lowest elevation, the factor of safety (FS) reached the minimum value of 1.11. Findings in this paper can provide guidelines for the risk assessment of colluvial landslides.

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