scholarly journals Effect of the Water-Rock Interaction on the Creep Mechanical Properties of the Sandstone Rock

2018 ◽  
Author(s):  
Zuosen Luo ◽  
Jianlin Li ◽  
Qiao Jiang ◽  
Yinchai Zhang ◽  
Yisheng Huang ◽  
...  
Keyword(s):  
Water Level ◽  
Term Strength ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Rock Interaction ◽  
The Three Gorges ◽  
Sandstone Rock ◽  
Water Rock Interaction

After the commencement of the Three Gorges hydropower project, the reservoir water level has been fluctuating by 30 m (145–175 m) annually. The stability of the bank slope has been highlighted since the reservoir water level has been repeated. Apart from that, the long-term effect of the water-rock interaction on the rheological and mechanical properties of the rock was not studied sufficiently. Therefore, a typical sandstone rock was brought from the Three Gorges reservoir area, to meet the purpose of this study. Then, a series of water-rock interaction tests were conducted to simulate the fluctuations in the reservoir water level. Based upon the experimental results, the following points were pointed out: 1) for the first three successive water-rock interaction cycles, the long-term strength of the rock was dramatically reduced. In contrast, the rate of reduction on the long-term strength of the rock was getting a steady state after six successive water rock interactions.2) At the failure stress level, the rock specimens exhibited similar characteristics under different water-rock interaction cycles. 3) The densely compacted micro structures of the sandstone rock were transformed into loose and porous state.

scholarly journals Characterizing the Development Pattern of a Colluvial Landslide Based on Long-Term Monitoring in the Three Gorges Reservoir

2021 ◽  
Vol 13 (2) ◽  
pp. 224
Author(s):  
Xin Liang ◽  
Lei Gui ◽  
Wei Wang ◽  
Juan Du ◽  
Fei Ma ◽  
...  
Keyword(s):  
Time Variable ◽  
Development Pattern ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
The Three Gorges ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Colluvial Landslide

Since the impoundment of the Three Gorges Reservoir (TGR) in June 2003, the fluctuation of the reservoir water level coupled with rainfall has resulted in more than 2500 landslides in this region. Among these instability problems, most colluvial landslides exhibit slow-moving patterns and pose a significant threat to local people and channel navigation. Advanced monitoring techniques are therefore implemented to investigate landslide deformation and provide insights for the subsequent countermeasures. In this study, the development pattern of a large colluvial landslide, locally named the Ganjingzi landslide, is analyzed on the basis of long-term monitoring. To understand the kinematic characteristics of the landslide, an integrated analysis based on real-time and multi-source monitoring, including the global navigation satellite system (GNSS), crackmeters, inclinometers, and piezometers, was conducted. The results indicate that the Ganjingzi landslide exhibits a time-variable response to the reservoir water fluctuation and rainfall. According to the supplement of community-based monitoring, the evolution of the landslide consists of three stages, namely the stable stage before reservoir impoundment, the initial movement stage of retrogressive failure, and the shallow movement stage with stepwise acceleration. The latter two stages are sensitive to the drawdown of reservoir water level and rainfall infiltration, respectively. All of the monitoring approaches used in this study are significant for understanding the time-variable pattern of colluvial landslides and are essential for landslide mechanism analysis and early warning for risk mitigation.

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.

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.

scholarly journals The study on the time lag of water level in the Three Gorges Reservoir under the regulation processes

2021 ◽  
Author(s):  
Kunlong He ◽  
Hongwei Shi ◽  
Chenchen Chen ◽  
Yao Cheng ◽  
Jiao Liu
Keyword(s):  
Water Level ◽  
Three Gorges Reservoir ◽  
Flood Control ◽  
Time Lag ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
Operation Period

Abstract The identification of the water level time lag (WLTL) under the regulation processes is of great significance for environmental impact, flood control, and sediment transport of huge reservoirs. The traditional hydrodynamic method can calculate the flood inflow process and the water level change process along the river channel, but it is difficult to estimate the time difference of the reservoir water level fluctuation to the dispatching process. To quantitatively evaluate the reservoir regulation effect on the WLTL in the Three Gorges Reservoir (TGR), the daily water level data from 2011 to 2017 of five stations in the TGR are analyzed in this paper. The results revealed that there is a significant water level difference along the reservoir from April 1 to October 31. The gap between the end of the reservoir and the Three Gorges Dam (TGD) is the largest, reaching 23.67 m on July 2. The longer the distance from the TGD, the longer the time lag. Furthermore, the WLTL is also different at the four different operating periods of the reservoir in a year. During the low water level operation period and high water level operation period, the time lag is 3 days which is the greatest, while in the water level decline period and water level rise period, the time lag is within 2 days.

scholarly journals The Dynamic Response Law of Bank Slope under Water-Rock Interaction

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yinchai Zhang ◽  
Huafeng Deng ◽  
Wei Wang ◽  
Lingling Duan ◽  
Yongyan Zhi ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Damping Ratio ◽  
Seismic Action ◽  
Loading Test ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Rock Interaction ◽  
Bank Slope ◽  
Water Rock Interaction

During the reservoir operation process, the long-term security and stability of the bank slope is affected by dynamic response characteristics of its seismic action directly. Aimed at the typical bank slope existing in the actual reservoir environment, an experiment considering reservoir water level fluctuation and soaking-air-drying cyclic water-rock interaction has been designed and conducted while the cyclic loading test was performed in different water-rock cycles. Research results indicate the following: Firstly, in the process of water-rock interaction, the dynamic characteristics of sandstone show evident degradation trend, with the increase of the damping ratio and Poisson’s ratio and decrease of dynamic elastic modulus, and the former six water-rock cycle degradation effects are particularly obvious. Secondly, the numerical analog computation analysis of dynamic response in typical bank slope shows that as the water-rock interaction period is increased, the dynamic response of the slope hydro-fluctuation belt zone increases gradually, while the other parts weaken. Thirdly, under the long-term water-rock interaction process, the hydro-fluctuation belt zone gradually becomes a “soft layer” which is sensitive to the earthquake effect and dynamic response, resulting in a direct influence on long-term seismic performance of the bank slope. Therefore, it is necessary to make better protection for the bank slope hydro-fluctuation belt zone.

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.

Groundwater Dynamics Analysis of Sanmashan Side Slope in the Three Gorges Reservoir Region, China

2011 ◽  
Vol 250-253 ◽  
pp. 1744-1751
Author(s):  
Jin Guo Wang ◽  
Zhi Fang Zhou
Keyword(s):  
Water Level ◽  
Three Gorges Reservoir ◽  
Hydrodynamic Pressure ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
The Three Gorges Reservoir ◽  
Side Slope ◽  
The Three Gorges ◽  
Three Gorges Reservoir Region

Sanmashan side slope in the Three Gorges reservoir region is located in the center area of the Xincheng district, Fengjie county, China. Based on the analysis of hydrogeological structure of the studied area, one can conclude that a groundwater reservoir form near the side slope area after the impoundment of the Three Gorges Reservoir, which induces large groundwater pressure on the side slope. In particular, large hydrodynamic pressure will occur in the landslide mass under the condition of the reservoir water level descending significantly, which has bad effects on slope stability. Numerical simulation results show that the seepage force on landslide is 43 times of that under normal situation, as the reservoir water level declining dramatically from 175m to 145m. Thus, the influence of hydrodynamic pressure should be considered in the stability calculation.

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.

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