Experimental Study on the Strength Difference of Two Types of Sandstones With Different Composition of Minerals Under the Conditions of Dry and Wet Cycles

2011 ◽  
Vol 374-377 ◽  
pp. 2217-2220
Author(s):  
Zhen Hua Zhang ◽  
Jing Jing Xue ◽  
Hua Yan Yao
Keyword(s):  
Compressive Strength ◽  
Three Gorges Reservoir ◽  
Three Gorges Reservoir Area ◽  
Type I ◽  
Type Ii ◽  
Three Gorges ◽  
Reservoir Water ◽  
Strength Difference ◽  
Composition Of Minerals ◽  
Wet And Dry Cycles

Some rock slides have taken place in Three Gorges Reservoir Area, China. Many Researches on the causes of the slides shows that the more sensitive of rock strength to the reservoir water level fluctuation, the easier to fail of the rock slopes. In order to study the strength difference of different sandstones in reservoir water fluctuation zone of Three Gorges Reservoir, the authors taken two types of sandstones with different composition of minerals as a typical case to study in detail. One type of the two sandstones (called Type I) is composed of quartz, feldspar, muscovite and calcite, argillaceous cement. The other (called Type II) is composed of quartz, feldspar, sericite, argillaceous cement. Uniaxial compression tests indicate that the compressive strength of type I sandstone decreased significantly as they underwent first wet and dry cycle, and then nearly kept constant when they underwent the following wet and dry cycles, and that the compressive strength of Type II sandstones nearly kept constant when they underwent many times of wet and dry cycles.

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 Mechanical Response of Listric Faults in the Three Gorges Reservoir Area Based on Three-Dimensional Morphological Characteristics

2021 ◽  
Vol 9 ◽  
Author(s):  
Guoyong Duan ◽  
Lehua Wang ◽  
Huafeng Deng ◽  
Jingyu Zhang ◽  
Zuosen Luo ◽  
...  
Keyword(s):  
Three Gorges Reservoir ◽  
Water Pressure ◽  
Joint Surface ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Area ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
Before And After

Faults or joints widely exist in rock masses, which deeply affect the mechanical properties of rock. The seismic frequency of the Gaoqiao fault and its surrounding areas in the Three Gorges Reservoir area before and after water storage is significantly higher than that in other areas. In this study, a curved joint is used to simulate the occurrence characteristics of the Gaoqiao fault, and the influence of reservoir water is simulated by adjusting the fracture water pressure. Compared with the changes of joint surface morphology parameters before and after the test, it is found that the macro failure characteristics of rock samples are in good agreement with the micromorphology changes of the joint surface. Among them, the parameters such as root-mean-square height (Sq), arithmetic mean height (Sa), reverse load area ratio (Smc), and minimum autocorrelation length (Sal) can better characterize the joint surface deterioration of rock samples under the action of fracture water pressure. The test results have a certain reference value for studying the fault response under the action of reservoir water.

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.

scholarly journals Failure Mechanism of the Qianjiangping Slope in Three Gorges Reservoir Area, China

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Zhenhua Zhang ◽  
Mingming Qian ◽  
Song Wei ◽  
Juxiang Chen
Keyword(s):  
Failure Mechanism ◽  
Three Gorges Reservoir ◽  
Slope Failure ◽  
Combined Effect ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Impoundment ◽  
Study Results ◽  
Influence Degree

The Qianjiangping landslide is the first large-scale rock slide in Three Gorges Reservoir (TGR) Area, China, after the impoundment of the TGR. Previous studies on the slope showed that most researchers agreed that reservoir impoundment and rainfall were the two main triggering factors of the slope failure. However, there were different views about the influence degrees of the two factors on the slope failure. In order to clarify the influence degrees of each of three conditions (reservoir impoundment, rainfall, and combined effect of reservoir impoundment and rainfall) on the failure of the Qianjiangping slope and reveal the failure mechanism of the slope, underground water tables and stresses in the slope were calculated under the three conditions, respectively, based on fluid-solid coupling theory using the Abaqus software in this paper; then, the failure approach index (FAI) was adopted to analyze the failure characteristics of the slope under each of the three conditions. Research results show that the influence degree of rainfall is greater than that of reservoir impoundment on the slope failure, and the influence degree of the combined effect of reservoir impoundment and rainfall is greater than that of rainfall; the sliding surface runs through only in the condition of the combined effect of reservoir impoundment and rainfall. Study results suggest that with the reservoir water level rising, the toe of the slope was gradually submerged in reservoir water and the strength of rock mass submerged by reservoir water decreased due to water-rock interaction; furthermore, the heavy rainfall was rapidly injected into the slope through the interlayer staggered zone and slope surface, the groundwater table in the middle part of the slope rose rapidly, the sliding force of the slope increased, and the stress concentration appeared at the lower part of the slope; finally, the rock bridges submerged by reservoir water in the front of the slope fractured, and the failure of the slope occurred.

Study on the Landslide Stability Influenced by the Reservoir Water Lifting and Atmospheric Rainfall

2011 ◽  
Vol 243-249 ◽  
pp. 3289-3295
Author(s):  
Gao She Hu ◽  
Yan Ding ◽  
Jun Liu
Keyword(s):  
Working Conditions ◽  
Three Gorges Reservoir ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Reservoir Water ◽  
Reservoir Area ◽  
The Three Gorges Reservoir ◽  
Landslide Stability ◽  
The Three Gorges ◽  
Object Of Study

This article is based on the Bazimen Landslide in the three gorges reservoir area to be the object of study, and uses the Boussinesq unsteady aeolian-equation to calculate the change of the infiltration line in the landslide by the reservoir water decreased and rainfall. The limited equilibrium method is taken to study the variation law of the landslide stability, which is effected by the every factor under different working conditions.

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.

scholarly journals Evaluation of ESV Change under Urban Expansion Based on Ecological Sensitivity: A Case Study of Three Gorges Reservoir Area in China

2021 ◽  
Vol 13 (15) ◽  
pp. 8490
Author(s):  
Hongjie Peng ◽  
Lei Hua ◽  
Xuesong Zhang ◽  
Xuying Yuan ◽  
Jianhao Li
Keyword(s):  
Three Gorges Reservoir ◽  
Urban Expansion ◽  
Urban Land ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Ecological Sensitivity ◽  
Reservoir Area ◽  
Green Development ◽  
Source Data

In recent years, ecosystem service values (ESV) have attracted much attention. However, studies that use ecological sensitivity methods as a basis for predicting future urban expansion and thus analyzing spatial-temporal change of ESV are scarce in the region. In this study, we used the CA-Markov model to predict the 2030 urban expansion under ecological sensitivity in the Three Gorges reservoir area based on multi-source data, estimations of ESV from 2000 to 2018 and predictions of ESV losses from 2018 to 2030. Research results: (i) In the concept of green development, the ecological sensitive zone has been identified in Three Gorges reservoir area; it accounts for about 35.86% of the study area. (ii) It is predicted that the 2030 urban land will reach 211,412.51 ha by overlaying the ecological sensitive zone. (iii) The total ESV of Three Gorges Reservoir area showed an increasing trend from 2000 to 2018 with growth values of about USD 3644.26 million, but the ESVs of 16 districts were decreasing, with Dadukou and Jiangbei having the highest reductions. (iv) New urban land increases by 80,026.02 ha from 2018 to 2030. The overall ESV losses are about USD 268.75 million. Jiulongpo, Banan and Shapingba had the highest ESV losses.

Sign in / Sign up

Export Citation Format

Share Document