scholarly journals Deformation Mechanism of Deposit Landslide Induced by Fluctuations of Reservoir Water Level Based on Physical Model Tests

2021 ◽  
Author(s):  
Zihua Jiang ◽  
Huanling Wang ◽  
Weichau Xie
Keyword(s):  
Water Level ◽  
Physical Model ◽  
Failure Process ◽  
Model Tests ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Deformation And Failure ◽  
Landslide Stability ◽  
Level Difference ◽  
Physical Model Tests

Abstract Located in reservoir area of Dahuaqiao Hydropower Station in Lancang River, the Dahua ancient deposit landslide exhibits high possibility of reactivation due to reservoir impoundment. In this study, physical model tests are conducted to investigate the variations of groundwater, deformation, and failure process of the landslide under different fluctuation speeds of reservoir water level. Influence of groundwater on landslide stability when reservoir water level fluctuating is analyzed then. Results indicate that the seepage pressure caused by water level difference can increase landslide displacement. During the dropping process of reservoir water level, the relationship between landslide displacement and water level difference can be described by a power function model. Groundwater has negative effects on stability of landslides, and the damage is characterized by traction landslide. More attentions should be paid on the displacement of the front edge of the landslide during the first rise and drop of reservoir water level. The study provides indispensable information for scheduling reservoir water level in the Dahuaqiao and others similar reservoir areas, thus having vital importance.

scholarly journals Research on the Normal Use of a Plug Discharge Tunnel

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Wen Liu ◽  
Jun Deng ◽  
Zhong Tian ◽  
Faxing Zhang
Keyword(s):  
Physical Model ◽  
Structural Damage ◽  
Surface Profile ◽  
Similarity Criterion ◽  
Model Tests ◽  
Cavitation Number ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Discharge Tunnel ◽  
Physical Model Tests

This study analyzed the normal use of an unusual flood-releasing tunnel with a plug dissipator. Firstly, normal physical model tests based on the Froude criterion (1 : 50) were finished. Secondly, depression physical model tests based on the Froude criterion (1 : 50) and cavitation similarity criterion were finished. Thirdly, 3-dimensional numerical simulation of flow field was finished, and free surface profile was captured, which was based on RNG k-ε two-equation turbulence model and VOF method. The focus of this study is on the relationship between normal use and cavitation characteristics (e.g., pressure, turbulence kinetic energy, and cavitation number). The results show that lowering the reservoir water level, reduced by 20.41 m at most, increases the risk of cavitation of a plug discharge tunnel, which means with the decrease of the flow cavitation number, the possibility of structural damage will increase dramatically, while reducing the outlet height can effectively raise the flow cavitation number, ensuring the safety of normal use. Under the conditions of free outflow, for the H1/e values of 4.45, 4.00, and 3.55, the conditions in which the tunnel meets the requirements of anticavitation are h/D ≤ 0.42, h/D ≤ 0.39, and h/D ≤ 0.35, respectively. In addition, the discharge capacity of the tunnel is not significantly reduced with the lowering of outlet height, implying that operation under a low water head of the plug discharge tunnel, as low as 3.55 of H1/e in the test, is feasible. The results obtained in this study can serve as reference information in engineering design of the plug discharge tunnel.

The Design of Movable Landslide Physical Model Testing Frame

2011 ◽  
Vol 201-203 ◽  
pp. 1433-1438 ◽  
Author(s):  
Dai Peng Zhao ◽  
Shi Mei Wang ◽  
Yun Zhi Tan ◽  
Xiao Ling Liu
Keyword(s):  
Water Supply ◽  
Water Level ◽  
Physical Model ◽  
Model Testing ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Water Level Variation ◽  
Physical Model Tests ◽  
Uniform Sample ◽  
Mechanism Of Landslide

The small landslide physical model testing frame was designed and made in order to analyze the induction mechanism of landslide by rainfall and reservoir water level variation by adopting the physical model tests. It is consisted by exterior frame, internal body box, water supply and discharge pipelines, hoisting jacks and steel rollers. Some functions such as uniform sample preparation, confined effect reduction, lifting flexibility as well as water level change simulation and so on are realized through some design technologies like removable model frame, adjustable width, rotatable frame body ,mobile model frame and water supply and discharge pipeline and so on.

scholarly journals Stability Analysis of Hydrodynamic Pressure Landslides with Different Permeability Coefficients Affected by Reservoir Water Level Fluctuations and Rainstorms

Water ◽  
2017 ◽  
Vol 9 (7) ◽  
pp. 450 ◽  
Author(s):  
Faming Huang ◽  
Xiaoyan Luo ◽  
Weiping Liu
Keyword(s):  
Water Level ◽  
Permeability Coefficient ◽  
Hydrodynamic Pressure ◽  
Water Level Fluctuations ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Stability Coefficient ◽  
Permeability Coefficients ◽  
Landslide Stability ◽  
The Stability

It is significant to study the variations in the stability coefficients of hydrodynamic pressure landslides with different permeability coefficients affected by reservoir water level fluctuations and rainstorms. The Sifangbei landslide in Three Gorges Reservoir area is used as case study. Its stability coefficients are simulated based on saturated-unsaturated seepage theory and finite element analysis. The operating conditions of stability coefficients calculation are reservoir water level variations between 175 m and 145 m, different rates of reservoir water level fluctuations, and a three-day continuous rainstorm. Results show that the stability coefficient of the hydrodynamic pressure landslide decreases with the drawdown of the reservoir water level, and a rapid drawdown rate leads to a small stability coefficient when the permeability coefficient ranges from 1.16 × 10−6 m/s to 4.64 × 10−5 m/s. Additionally, the landslide stability coefficient increases as the reservoir water level increases, and a rapid increase in the water level leads to a high stability coefficient when the permeability coefficient ranges from 1.16 × 10−6 m/s to 4.64 × 10−5 m/s. The landslide stability coefficient initially decreases and then increases as the reservoir water level declines when the permeability coefficient is greater than 4.64 × 10−5 m/s. Moreover, for structures with the same landslide, the landslide stability coefficient is most sensitive to the change in the rate of reservoir water level drawdown when the permeability coefficient increases from 1.16 × 10−6 m/s to 1.16 × 10−4 m/s. Additionally, the rate of decrease in the stability coefficient increases as the permeability coefficient increases. Finally, the three-day rainstorm leads to a significant reduction in landslide stability, and the rate of decrease in the stability coefficient initially increases and then decreases as the permeability coefficient increases.

Stability Analysis of Accumulation Landslides in the Three Gorges Reservoir Area Under Reservoir Water Level Fluctuation Based on Multi-Circular Model

2021 ◽  
Author(s):  
Zhiqiang Fan ◽  
Yanhao Zheng
Keyword(s):  
Stability Analysis ◽  
Water Level ◽  
Three Gorges Reservoir ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Landslide Stability ◽  
Slip Surfaces ◽  
The Three Gorges ◽  
The Stability

Abstract In the Three Gorges Reservoir (TGR) area, the accumulation landslide characterized by stepped slip surfaces is widely developed, and its stability is significantly affected by the fluctuation of reservoir water level. In this paper, the Shuping landslide, a typical accumulation landslide in the TGR area, was selected to study the effect of water level fluctuations on landslide stability. Based on Multi-Circular (M-C) model, it is found that the decline of reservoir water level was the dominant factor causing the decrease of landslide stability. At the end of the decline of reservoir water level, the landslide stability was minimum and the corresponding moment was the most dangerous. The effect of the drawdown speed of reservoir water level on the minimum value of landslide stability had a threshold effect, although the minimum stability coefficient of landslide decreased with the increase of drawdown speed. Under the most dangerous water level conditions, the stability of the piled landslide increased linearly with the increase of the net thrust of piles. Also, by comparing with other classical models, the effectiveness of the M-C model in evaluating landslide stability under the dynamic changes of reservoir water level was verified. The results could provide a reliable scientific basis for improving the stability analysis and reinforcement measures of the accumulation landslide with the multi-circular slip surfaces in the TGR area, as well as can be applied to similar landslides in reservoir areas.

ROCK SLOPES WITH OPEN FILTERS UNDER WAVE LOADING: EFFECTS OF STORM DURATION AND WATER LEVEL VARIATIONS

2017 ◽  
pp. 6
Author(s):  
Marcel R.A. Van Gent ◽  
Guido Wolters ◽  
Ivo M. Van der Werf
Keyword(s):  
Water Level ◽  
Physical Model ◽  
Cost Savings ◽  
Design Guidelines ◽  
Model Tests ◽  
Physical Model Tests ◽  
Storm Duration ◽  
Hydraulic Load ◽  
Loading Effects ◽  
Water Level Variations

Rubble mound breakwaters and revetments typically contain granular filters in one or more layers. The transition from the armour layer to the filter layer, and transitions between other layers within the structure, are normally geometrically tight to prevent material washout. This requires a limited ratio of the material size of the upper layer and neighbouring layer. An alternative is a geometrically open filter where in principle underlayer material can be transported into the upper layer, but if the hydraulic load at this transition between two layers remains low, the transition can be designed such that no or limited transport occurs, see for instance Van Gent and Wolters (2015), Van Gent et al (2015) and Jacobsen et al, (2017). This allows for larger ratios of material sizes, which can reduce the number of filter layers, and relax the material requirements with respect to the width of gradings. This can lead to considerable cost savings. In Van Gent and Wolters (2015) physical model tests for the transition between a layer of rock and an underlayer that consists of sand have been performed and design guidelines have been derived. Here, additional physical model tests are presented to study the influence of the storm duration and water level variations on the response of sand underneath a layer of rock.

scholarly journals EFFECTS OF WATER LEVEL VARIATIONS ON THE STABILITY OF ROCK ARMOURED SLOPES

2018 ◽  
pp. 44 ◽  
Author(s):  
Marcel R.A. Van Gent ◽  
Suzanna A.A. Zwanenburg ◽  
Jan Kramer
Keyword(s):  
Water Level ◽  
Physical Model ◽  
Model Tests ◽  
Water Levels ◽  
Level Variation ◽  
Water Level Variation ◽  
Stepwise Approach ◽  
Physical Model Tests ◽  
Water Level Variations ◽  
The Stability

Physical model tests on the stability of rock armoured slopes have been performed to demonstrate the importance of water level variations during a storm, due to a tide or a storm surge. For the stability of rock armoured slopes also the importance of the sequence of storms at various water levels has been studied. The test results indicate that a smooth sinusoidal water level variation leads to an increase in damage compared to the same wave conditions at a constant water level. Furthermore, a stepwise approach of the sinusoidal water level elevation leads to other results than the approach with a continuous water level variation, whereas the continuous water level variation resembles the peak of a storm or the tidal water level variation better than a stepwise approach. If storms with different water levels attack the armour layer, the damage is generally smaller than if all storms attack the armour layer at the same water level. Furthermore, the results have been discussed based on earlier analyses where the statistics of rock armoured slopes have been addressed and the importance of the length effect has been illustrated using a method to apply results from physical model tests to real structures.

Deformation and failure mechanism of deep cement mixing walls: experimental study using physical model tests

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Siriwan Waichita ◽  
Pornkasem Jongpradist ◽  
Pongpeera Patawanit ◽  
Pitthaya Jamsawang ◽  
Goran Arangelovski ◽  
...  
Keyword(s):  
Experimental Study ◽  
Physical Model ◽  
Failure Mechanism ◽  
Model Tests ◽  
Deformation And Failure ◽  
Physical Model Tests

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.

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