Physical modelling and numerical analysis of slope instability subjected to reservoir impoundment of the Three Gorges

Li, Shaojun; Sun, Qiancheng; Zhen-hua, Zhang; Luo, Xianqi

doi:10.1007/s12665-018-7321-x

Cited by 22 publications

(7 citation statements)

References 19 publications

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“…Moreover, two clay layers (0.5-1.5 m thickness) were observed in the shale rock layer, one of which was the sliding surface. According to the other reports, the shear strength properties of the clay have a significant decrease when the moisture content increases (Dafalla, 2013;Li et al, 2018b;He et al, 2018), and are more sensitive than the rock. Therefore, after intense rainfall, the landslide slipped along the clay layer, and the shale rock was fragmented in the sliding mass.…”

Section: Failure Mechanism Of the Zhongbao Landslidementioning

confidence: 84%

“…After the landslide failed, the barrier lake formed in front of the landslide increased the groundwater level of the accumulation area (Figure 14). The reservoir impoundment could accelerate the landslide deformation and failure (Macfarlane, 2009;Huang et al, 2016;Li et al, 2018b;Wang et al, 2019). When the lake flooded the downhill portion of the deposit, the shear resistance was reduced (He et al, 2018), especially for the destroyed deposits, so that the deposit still had a strong response to the rainfall.…”

Section: Failure Mechanism Of the Zhongbao Landslidementioning

confidence: 99%

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Emergency Survey and Stability Analysis of a Rainfall-Induced Soil-Rock Mixture Landslide at Chongqing City, China

Zhou

Ai²,

Huang³

et al. 2021

Front. Earth Sci.

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The stability analysis of damaged landslides and unstable debris is important for rescue work and emergency operations. This paper investigates a predisposed geological emergence, inducing the factors and deformation processes of the Zhongbao landslide, which happened on July 25, 2020. The stability of the landslide debris was evaluated by an integrated monitoring system consisting of ground-based radar, unmanned aerial vehicles, airborne Lidar, thermal infrared temperature monitoring, GNSS displacement monitoring, deep displacement monitoring, and rainfall monitoring. The strata and weak layer controlled the landslide failure, and topography defined the boundary of the failed rock mass. A continually intensive rainfall caused the deformation and accelerated failure of the landslide. The shallow and steep deposit (Part I) firstly slid at a high velocity, and then pushed the rear part of the landslide (Part II) to deform, forming numerous cracks, which accelerated the rainfall infiltrating into the rock mass. The moisture content increase could decrease the strength of the shale rock within the bedding planes. Finally, with the rock and soil mass sliding along the weak layer, a barrier dam and a barrier lake were formed. The monitoring and numerical simulation results showed that after the landslide failure, there was still local collapse and deformation occurrences which threatened rescue work and barrier lake excavation, and the stability of the accumulation area gradually decreased as the rainfall increased. Therefore, the barrier dam was not excavated until the accumulation rate gradually stabilized on July 28. Moreover, most of the reactivated deposits still accumulated in the transportation and source areas. Thus, in August, the displacement of the landslide debris gradually accelerated in a stepwise manner, and responded strongly to rainfall, especially in the accumulation area, so that it was inferred that the damaged landslide could slide again and cause a more threatening and severe failure. The analysis results of the study area can provide references for the failure mechanism of a rainfall-induced landslide and the stability evaluation of a damaged landslide.

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Section: Failure Mechanism Of the Zhongbao Landslidementioning

confidence: 84%

Section: Failure Mechanism Of the Zhongbao Landslidementioning

confidence: 99%

Emergency Survey and Stability Analysis of a Rainfall-Induced Soil-Rock Mixture Landslide at Chongqing City, China

Zhou

Ai²,

Huang³

et al. 2021

Front. Earth Sci.

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“…Landslides in the reservoir area, as a common natural hazard, are prone to being triggered by water level fluctuations. After the impoundment of the Three Gorges Reservoir, water level changes during reservoir operation have brought an adverse impact on the stabilities of numerous bank slopes [1][2][3]. To be specific, the periodic rise and fall of reservoir water level changes the seepage field inside the bank slope, and the long-term immersion can lead to variations of the physical and mechanical properties of slope soils during reservoir operation, which would then affect the stability of the bank slope and result in the reactivation of ancient landslides and the occurrence of new landslides [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Study on the Hydraulic Parameters of Woshaxi Landslide Soils during Water Level Drawdown of Three Gorges Reservoir

et al. 2020

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Variation of hydraulic parameters for unsaturated soil in bank slopes during reservoir water rising or falling process is crucial to scientific analysis and evaluation of bank slope stability. In this paper, soil samples from the Woshaxi landslide in the Three Gorges Reservoir were taken for a permeability test under reservoir drawdown conditions using an independently developed apparatus, which can simulate the variation process of internal seepage in bank slope soils. Changes of particle gradations, soil-water characteristic curves, and unsaturated permeability functions of the soil samples during reservoir falling process were studied by combining with the physical empirical model and numerical simulation. Permeability test results show that fine particles in soil samples migrated and were lost under seepage force action during the tests, leading to a continuous decrease of fine particle content indicated in the grain size distribution curves, in which particles with a size less than 0.02 mm lose the most. As permeation time increases, the soil saturated permeability enhances constantly with the change rate increasing first and then decreasing. The soil-water characteristic curves change obviously in the high matrix suction section (10~104 kPa), and the volumetric water content decreases constantly and shows a positive correlation with the fine particle content. During the permeability test, the unsaturated permeability coefficient corresponding to a fixed matric suction increases with the drawdowns of the reservoir water level. Slope stability results show that neglecting the variational characteristics of hydraulic parameters in slope stability evaluation can result in a bigger safety factor, which is dangerous for slope safety evaluation. The research results can provide a scientific basis for the stability analysis and evaluation of the bank slopes in the Three Gorges Reservoir Area.

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“…According to the field investigation, the main causes and factors of the soil slope's freeze-thaw instability are discussed [25][26][27]. Moreover, although many landslide model tests of combined effect of rainstorm and reservoir water have been carried out [28][29][30][31][32][33][34], large-scale three-dimensional physical model tests of the reservoir bank slope under the combined action of snow melting and reservoir water are in urgent need.…”

Section: Introductionmentioning

confidence: 99%

Reservoir Landslide Physical Modelling under Ice‐Snow Melting and Reservoir Water Combined Action

Xiong

Wang

et al. 2020

Advances in Civil Engineering

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Extreme ice-snow melting in winter affects the infiltration process of snow water on the slope surface significantly and plays an important role in the deformation stability of landslide. Variation in pore water pressure is regarded as an essential factor of landslide instability induced by snow water. In order to figure out the internal relationship between the infiltration process of snow water and the failure mode of deformation and instability of the accumulation landslide, the response law and deformation and failure mode of pore water pressure and soil pressure of landslide accumulation under different ice-snow melting conditions are deeply studied based on the indoor large-scale landslide model test. We have studied the physical model test under the combined action of reservoir water and ice-snow melting. It reveals the seepage erosion deformation and failure mechanism. It undoubtedly provides references of great importance for the geological hazard governance of bank slope in the Three Gorges Reservoir Area.

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Physical modelling and numerical analysis of slope instability subjected to reservoir impoundment of the Three Gorges

Cited by 22 publications

References 19 publications

Emergency Survey and Stability Analysis of a Rainfall-Induced Soil-Rock Mixture Landslide at Chongqing City, China

Emergency Survey and Stability Analysis of a Rainfall-Induced Soil-Rock Mixture Landslide at Chongqing City, China

Study on the Hydraulic Parameters of Woshaxi Landslide Soils during Water Level Drawdown of Three Gorges Reservoir

Reservoir Landslide Physical Modelling under Ice‐Snow Melting and Reservoir Water Combined Action

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