Landslide Accumulation Research Articles

Mechanism of colluvial landslide induction by rainfall and slope construction: A case study

The landslide hazards occurring in the complex geological genesis accumulation body are usually controlled by the coupling action of many internal and external factors. Therefore, this paper takes the dam-front Danbo accumulation body landslide of Yangfanggou hydropower station on the Yalong River as the geological prototype, and discusses the process and mechanism of slope stability degradation under the combined action of rainfall and slope construction. Based on the detailed understanding of the basic characteristics of the accumulation body, the development characteristics of the landslide and the construction situation of the slope engineering, the study conducted correlation analysis between rainfall and landslide displacement, the physical and mechanical tests of all types of rock-soil masses, and the numerical simulation testing of seepage field variation of the landslide section. It is found that the special slope structure and material composition of the old landslide accumulation layer on the upper part of the Danbo accumulation body are the internal factors for the occurrence of thrust load-induced landslide, and the construction of the slope engineering not only creates free space conditions for sliding, but also provides channels for the infiltration of rainfall into the slope after confluence, which is an external factor that caused the mechanical properties of the sliding zone soil to gradually weaken from the trailing edge to the leading edge. The geomechanical model of such landslide is that the active section of the trailing edge produces the “source of force”, the transition section of the middle section affects the occurrence of sliding, and the anti-sliding section of the leading edge controls the occurrence of landslide hazards. The results of this research provide not only a useful supplement to the theory of landslide formation mechanisms but also a scientific basis for guiding the prevention and control of similar hazards.

Numerical analysis of dynamic characteristics of sludge-type slag landfill landslide

The Artificial landfill landslide in Guangming District, Shenzhen, which occurred on December 20, 2015, showed the same characteristics as mudflow after sliding, which had long sliding movement distance and large coverage area, and caused serious casualties and property losses. Therefore, research on the dynamic characteristics of artificial accumulation landslide is of great significance for landfill slope hazard assessment and prevention in urban construction. On the basis of detailed collection of landslide investigation data and field investigation, the motion of the landslide was simulated with the friction rheological model by the software DAN-W in this paper, in order to obtain the characteristic parameters of landslide movement. The results showed that, the maximum movement distance was 1,112 meters and a running time of 105s simulated by friction model. The maximum front velocity was 22.5m/s and occurred at a horizontal distance of 632 meters. The horizontal length of the accumulation mass was 580 meters and the average thickness was about 8.2m. The numerical simulation results are basically consistent with the field survey results. The simulation model and the motion characteristic parameters of the muck can be used as reference for the prevention and control design of slope of similar muck field.

Analysis of the Decadal Kinematic Characteristics of the Daguangbao Landslide Using Multiplatform Time Series InSAR Observations After the Wenchuan Earthquake

AbstractThe Daguangbao landslide was the largest landslide triggered by the “5.12” Wenchuan Mw 7.9 earthquake. This landslide is among the few superlarge‐scale landslides of 1 billion m3 magnitude worldwide. As the landslide accumulation represents a potential hazard, long‐term monitoring and geological interpretation of the Daguangbao landslide is important to reveal the postsliding deformation characteristics and laws of this landslide type. To study the kinematic characteristics 10 years postearthquake, the landslide accumulation deformation was monitored in two stages using different data sets and processing methods. First, regarding the deformation 2 years postearthquake, we selected PALSAR‐1 data (21 October 2008 to 14 March 2011) and obtained the LOS (line of sight) direction time series deformation of the landslide using the Small BAseline Subset (SBAS) algorithm. Second, for the last 4.5 years of deformation, Sentinel‐1 data sets (26 November 2015 to 8 June 2020) in two ascending and one descending path are experimentally used. The vertical and east‐west deformations during this period are obtained. Thickness, topography, precipitation, and other factors are combined to analyze the landslide accumulation deformation. The landslide accumulation volume decreases under gravitational influence, shrinkage is accelerated under precipitation influence, and periodic fluctuations occur, which lag precipitation changes. The maximum vertical direction deformation rate is below 80 mm/year, and the deformation magnitude in the east‐west direction is approximately ±35 mm/year. Local deformation is still affected by the surface slope and aspect, and the overall landslide accumulation movement trend involves gathering of the eastern and western parts toward the middle. In the observation window, with the stabilization of accumulation, the deformation tends decrease.

Influence of rainfall on transient seepage field of deep landslides: A case study of area II of Jinpingzi landslide

Rainfall is one of the primary factors that induce landslides. Rainfall infiltration forms a transient seepage field in slopes, thereby leading to an increase in water content, a decrease in matric suction, and an increase in the volume weight of slopes. The increase in water content in rock and soil leads to the degradation of the mechanical properties of the slope medium and reduces the shear strength, thus causing slope instability. In this study, a large-scale accumulation landslide is taken as the research object. The front edge of the landslide is high and is not eroded by river water. Hence, rainfall is regarded as the main external factor that changes the groundwater and seepage field of the landslide. According to the landslide’s topography, geological data, local rainfall, and hydrological monitoring results, the saturated–unsaturated seepage theory of rock and soil and the finite difference method are used to analyze the impact of rainfall on the landslide’s seepage field and groundwater. The evolution law of the transient seepage field of the landslide under the condition of rainfall duration is studied. The results provide a basis for the analysis of landslide deformation and stability.

Application and Research of GPS Digital Image Measurement Technology in Landslide Disaster Monitoring and Prediction

This article mainly uses GPS high-precision satellite positioning technology, using low-power, long-term maintenance-free power supply system monitoring equipment in the field, to establish a scalable and expandable landslide displacement deformation monitoring system. The system uses a combination of real-time monitoring, real-time processing, and timing processing to detect mountain deformation in time. Taking the monitoring of landslide accumulation area of a nuclear power plant as an example, through the monitoring data and the actual situation on the spot, the disease symptoms of the slope were discovered in time, and the development status of the disease was grasped. At the same time, preventive measures for related disease remediation were provided, especially when the climatic conditions changed the dynamic changes of the slope at the time, forecast the occurrence and development of the main diseases of high-risk slopes, analyze and predict the possibility of sudden diseases, do well in advance control, and reduce unnecessary losses.

Characterization of landslide dams in a sector of the central-northern Apennines (Central Italy)

The paper analyses the landslide dam phenomenon in an area of the central-northern Apennines (Italy). A census of 53 landslides was carried out, identifying the salient parameters of both the landslides and the riverbed–alluvial plain systems. Correlations between these parameters were tested, in order to characterize the phenomenon in the study area. The most interesting relationships are those that compare the volume of landslide material either with the area of the catchment subtended by the dammed section and with the width of the riverbed–alluvial plain system. The results indicate that as the width of the fluvial system increases, and the area of the river basin subtended by the natural dam increases, the volume of the landslide accumulation necessary to produce occlusion also increases. Only one case, among those examined, escapes this general rule: a landslide of small volume made a full occlusion even though a relatively large area of basin was subtended. In this specific case, landslide velocity played an important role. So, while a high ratio between the volume of the landslide and the area of the affected basin represents a predisposing condition for the occurrence of total occlusion, it is not wholly reliable. Indexes, proposed in the literature, suggesting a quantitative assessment of landslide dam hazard, fail to forecast total occlusion unequivocally. This is because of the special characteristics of each territorial area, from lithological, geomorphological and geological-structural point of views. Such indexes, when they do not lose their intrinsic reliability (as in this case), must at least be identified with, and applied to, specific and restricted territories: they cannot be generalized.

Deforming tendency prediction study on typical accumulation landslide with step-like displacements in the Three Gorges Reservoir, China

Lots of accumulation landslides with step-like displacements occurred in the Three Gorges Reservoir due to periodic reservoir operation. This type of landslide has continued to deform for a long time, with large cumulative deformation, which may influence the land use in the reservoir and landslide control risk judgment. The accumulation landslides with four typical step-like displacement-time curves during more than 10 years, namely Baijiabao landslide, Laoshewo landslide, Heishiban landslide, and Shuping landslide, are demonstrated. The cumulative displacement-time curve of Laoshewo landslide obviously shows that its deforming tendency is slowing down, while that of Heishiban landslide clearly indicates the increasingly serious deformation. When the step-like displacement increments get close to each other, it is harder to predict the landslide tendency based on displacement, velocity, inverse velocity, or acceleration in a whole continuous period. A step-like displacement-time curve can be considered as a curve of a piecewise function, varying as time goes. Therefore, the piecewise function is proposed to analyze the tendency by different time periods. As the environment of rapid deforming period is similar, the deforming tendency of a landslide with step-like displacements can be better demonstrated by collecting data in the rapid deforming period to analyze its tendency. For Shuping landslide, the fluctuating decline in velocity and acceleration in the rapid deforming period shows that the landslide tends to become more and more stable. This well matches the status quo of Shuping landslide, as it has been treated during August 2014 to March 2015, which also verifies the effectiveness of this proposed method. For Baijiabao landslide, the inverse velocity-time curve in the rapid deforming period features fluctuating decline, indicating that the landslide tends to be increasingly unstable. Meanwhile, the discussion on failure prediction found that the watch window for critical prediction of Baijiabao landslide may open in the flood season of several years’ future. The method proposed is effective for predicting the deforming tendency of landslides with step-like displacements, provides a time window for critical prediction, and offers technical support for landslide risk control, alarm, and forecasting.

Measurement of Particle Size of Loose Accumulation Based on Alpha Shapes (AS) and Hill Climbing-Region Growing (HC-RG) Algorithms.

The loose accumulation CAUSED by landslide, collapse, debris flow, and mine blasting, exerts considerable negative influence to human activities. Besides, it can easily trigger secondary disaster under inner and outer geological conditions. Extraction and measurement of the particle of loose accumulation is of importance for prediction of slope stability and mine blasting. In this paper, the 3D laser scanning is utilized to collect the point clouds of granular materials in physical model (three types of materials) and landslide accumulation in field, respectively. Then, the alpha shapes (AS) and hill climbing-region growing (HC-RG) algorithms are introduced for identifying particles and finding their dimensions (e.g., particle number and radii). Comparison between the recognition results and reality shows that both algorithms can provide a good performance in laboratory physical model, and acceptable results can be obtained when applying two algorithm to field survey. AS algorithm needs less time to process data than HC-GR algorithm; however, the recognition from HC-RG algorithm is more accurate than that by AS algorithm.

ОПРЕДЕЛЕНИЕ УСТОЙЧИВОСТИ ОПОЛЗНЕВОГО СКЛОНА ПРИ ПРОЕКТИРОВАНИИ МОСТА ЧЕРЕЗ Р. ПОШНАРКУ В ЧУВАШИИ

Актуальность изучения оползневых процессов заключается в том, что они приводят к чрезвычайным ситуациям с угрозой разрушения сооружений, использования земель, безопасности людей. Особые трудности при изучении оползней вызывают вопросы прогнозирования активизации оползневого процесса. Целью данного исследования является оценка инженерно-геологических и гидрогеологических условий площадки мостового перехода и прогноз развития оползневого процесса на склонах с помощью моделирования методом конечных элементов. Объектом исследования является геологическая среда района проектируемого мостового перехода в пределах Приволжской возвышенности. Рассмотрены основные факторы, влияющие на развитие оползневого процесса: геоморфологические и тектонические условия; литологический состав; физико-механические свойства пород, гидрологические и гидрогеологические условия района. Методы: краткий обзор литературы; анализ информации, полученной из фондов изыскательской компании, расчет устойчивости склонов, моделирование поведения грунтового массива методом конечных элементов. Результаты. Дана характеристика основных факторов оползневого процесса данной территории, приведены результаты расчета устойчивости склонов по опасным сечениям различными методами. Склон является неустойчивым в целом. При сезонном повышении уровня подземных вод моделирование показало расширение зоны оползневых деформаций по левому борту до 107 м, по правому берегу реки до 10 м от русла. Выводы. Основными причинами деформаций являются: слаболитифицированные юрские глины, слагающие весь склон; подземные воды, формирующиеся в пределах плато и разгружающиеся в оползневые накопления, поддерживая в них высокую влажность. В качестве несущего слоя для опор моста рекомендуется использовать слой пермских глинистых отложений с высокими физико-механическими характеристиками.

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

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.

Modeling of Landslide–Tunnel Interaction: the Varco d’Izzo Case Study

This paper reports a case study of the interaction between a slow-moving landslide in clay soil and a railway tunnel protected by sheet pile walls, that crosses the landslide accumulation. The earthflow, that develops in the Southern Apennines, Italy, has been long studied and monitored by different organizations, such as the national railway company and the University of Basilicata. Since the investigated landslide and construction typologies are quite diffused in mountainous areas, the case study can be considered representative of a large number of other similar cases. Differently from other approaches proposed in the literature, the role of the landslide slip surface depth, changing in the directions longitudinal and transversal to the tunnel, and of structural connections, affecting the pile–tunnel system response, are accounted for in detail. Several numerical models are used to simulate the interaction between the sliding soil and tunnel. Different 2D and 3D geotechnical and structural models are adopted to reproduce stress–strain scenarios compatible with the experimental evidence. The modeling results indicate that the interaction varies considerably along the tunnel length because of the 3D geometry of the landslide, and is conditioned by the residual shear strength available on the slip surface. The expansion joints in the tunnel lining only marginally influence the stress in the structure because of the presence of the adjacent sheet pile walls, which enable considerable collaboration between the tunnel sectors.

Characteristics and Formation Mechanism of Giant Long‐Runout Landslide: A Case Study of the Gamisi Ancient Landslide in the Upper Minjiang River, China

The upper reaches of the Minjiang River are in the eastern margin of the Tibetan Plateau, where active faults are well developed and earthquakes frequently occur. Anomalous climate change and the extremely complex geomechanical properties of rock and soil have resulted in a number of geohazards. Based on the analysis of remote sensing interpretations, geological field surveys, geophysical prospecting and geological dating results, this paper discusses the developmental characteristics of the Gamisi ancient landslide in Songpan County, Sichuan Province, and investigates its geological age and formation mechanism. This study finds that the Gamisi ancient landslide is in the periglacial region of the Minshan Mountain and formed approximately 25 ka BP. The landslide initiation zone has a collapse and slide zone of approximately 22.65×106–31.7×106 m3 and shows a maximum sliding distance of approximately 1.42 km, with an elevation difference of approximately 310 m between the back wall of the landslide and the leading edge of the accumulation area. The landslide movement was characterized by a high speed and long runout. During the sliding process, the landslide body eroded and dammed the ancient Minjiang River valley. The ancient river channel was buried 30‐60 m below the surface of the landslide accumulation area. Geophysical prospecting and drilling observations revealed that the ancient riverbed was approximately 80‐100 m thick. After the dam broke, the Minjiang River was migrated to the current channel at the leading edge of the landslide. The Gamisi ancient landslide was greatly affected by the regional crustal uplift, topography, geomorphology and paleoclimatic change. The combined action of periglacial karstification and climate change caused the limestone at the rear edge of the landslide fractured, thus providing a lithological foundation for landslide occurrence. Intense tectonic activity along the Minjiang Fault, which runs through the middle and trailing parts of the Gamisi ancient landslide, may have been the main factor inducing landsliding. Studying the Gamisi ancient landslide is of great significance for investigating the regional response to paleoclimatic change and geomorphologic evolution of the Minjiang Fault since the late Pleistocene and for disaster prevention and mitigation.

Study on the Spatially Variable Saturated Hydraulic Conductivity and Deformation Behavior of Accumulation Reservoir Landslide Based on Surface Nuclear Magnetic Resonance Survey

Saturated hydraulic conductivity (Ks) is spatially variable in accumulation landslide sites that exert significant effort onto landslide seepage and deformation behavior. To better understand spatial variability and the effect of Ks on the slide mass of an accumulation landslide, this study introduced the surface nuclear magnetic resonance (SNMR) technology to study a representative reservoir accumulation landslide field in the Three Gorges Reservoir area (TGRA), the Baishuihe landslide, to obtain a series of relative reliable spatial measurements of Ks effectively on the basis of calibration in terms of the field tests measurements. The estimated Ks values were distributed log-normally for the overall landslide mass site with a wide range of 3.00 × 10−6∼7.80 × 10−3 cm/s, which reaches about 3 orders of magnitude. Variogram analysis indicated that the Ks values have the range (A) of 295.89 m and 65.56 m for the overall site and major cross-sectional analysis, respectively. A finite-element seepage-stress analysis associated with a Kriging-interpolated spatial Ks variable calculation model based on the best-fitted theoretical variogram was subsequently performed to study the seepage and deformation behavior of the landslide. The available monitored data and simulated results of the finite-element seepage-stress analysis indicated that the Baishuihe landslide is a progressive landslide, and the main factor influencing the deformation is rainfall and reservoir water fluctuation. This study provides an unconventional framework for studying the heterogeneous geomaterial and contributes to a better understanding of the spatial variation of the hydraulic property of accumulation reservoir landslides at a field scale.

Residual mechanisms and kinematics of the relict Lemeglio coastal landslide (Liguria, northwestern Italy)

The Lemeglio landslide is a deep-seated coastal landslide of the Liguria region (northeastern Italy) involving heterogeneous rock-masses formed by Miocene turbidide series, whose prevalent lithology varies from sandstones to mudrocks. It has been recognized since the end of the nineteenth century and characterized by a relict state of activity. Besides the general state of slope stability given by the current morpho-climatic conditions, different from those that determined its original paroxysmal evolution, a residual slow kinematics of the accumulation zone still exists, posing a threat to buildings and infrastructures located across the landslide foot. Consequently, the Lemeglio landslide represents a relevant case of study for advancing knowledge on residual kinematics, mechanisms and hazard inherited by a relict slope mass-movement phenomenon.The study is based on results of several drilling campaigns and geotechnical investigations carried out mainly by the Regione Liguria in the unstable landslide accumulation zone. Moreover, in this area ground deformations were assessed by inclinometer measurements and ADInSAR data covering two partially overlapping time spans, from June 2009 to July 2011 and from January 2004 to June 2014, respectively. By these data, joined with field geological and geomorphological surveys, an integrated and consistent landslide model was reconstructed, which was used for Limit Equilibrium (LEM) and Finite Elements Modelling (FEM) analyses.Among principal outcomes is the recognition, by field observations, stratigraphic and inclinometer data as well as slope stability modelling, of a basal sheared and softened band, made chiefly of remoulded mudrocks, which constrains the current landslide failure surface. Such basal band can be considered an inherited landslide structure, formed during the original paroxysmal stage of the Lemeglio landslide, which controls the current residual kinematics of the landslide deposits throughout the foot, depending also on the coastal marine erosion acting along the landslide toe.

Analysis of development process of landslide accumulation body based on discrete element method

Large scale landslide accumulations are often seen in the construction of hydropower stations in Southwest of China. It is of great engineering significance to study the development process of these landslide accumulations and their development stages. In this paper, a landslide accumulation of a hydropower station is taken as the object of study. Through the three-dimensional discrete element analysis software 3DEC, the development process of the accumulation body is divided into five stages, and the deformation and failure characteristics of each stage are analyzed in detail. The research of this paper is of great help to guide the safety operation of the project.

Collapse of Granular Columns With Fractal Particle Size Distribution: Implications for Understanding the Role of Small Particles in Granular Flows

AbstractAccording to field measurements, the basic character of the particle size distributions obtained from the landslide accumulations is fractal. The collapse of the granular columns with fractal particle size distribution (FPSD) is performed numerically and experimentally to form dry granular flows and the mechanism of how FPSD affects the particle movements is then investigated. Numerical and experimental analyses show that particle flow mobility increases as the fractal dimension increases. Several linear relationships exist between the fractal dimension and flow mobility parameters. By analyzing the kinetics of granular flows, it is found that a large number of small‐sized particles will form a boundary layer where the particle shearing and velocities are remarkably increased and will thus have a lubricant effect on the flow mobility. Moreover, the number of particle collisions increases, and small‐sized particles are more likely to obtain higher spreading velocities via the greater contribution of particle interactions.

Internal Characteristics of Loose Solid Source of Debris Flow in Zhouqu

In this paper, with debris flow in Zhouqu as the research object, combined with experiments such as cation exchange capacity (CEC), mineral chemical composition and water quality analysis, relation between water and salt in solid source forming debris flow was studied via soil column leaching test and soluble salt analysis, and internal characteristics of debris flow was accordingly showed. It was found that, the soil was loose, and the content of gravel and sand was high, and the content of fine particle was low. The soluble contents at the slope of the accumulation body were described as, collapsed accumulation body > landslide accumulation body, slope toe > slope top, gentle slope > steep slope, also related to length of the slope. The results indicated that accumulations released a large number of base ion after intense weathering, which migrated with water, concentrated and enriched at the slope toe. Saline soil with high salt content collapsed when encountering water and then formed mudflow, thus becoming the internal power to trigger and initiate debris flow to some extent.

Numerical simulation of a high-speed landslide in Chenjiaba, Beichuan, China

High-speed landslide is a catastrophic geological disaster in the mountainous area of southwest China. To predict the movement process of landslide reactivation in Chenjiaba town, Beichuan county, Sichuan province, China, we simulated the movement process of two landslide failures in Chenjiaba via rapid mass movement simulation and unmanned aerial vehicle images (UAV), and obtained the movement characteristic parameters of the landslides. According to a back analysis, the most remarkable fitting rheological parameters were friction coefficient (μ = 0. 18) and turbulence (ξ = 400 m · s-2). The parameter of landslide pressure was applied as the zoning index of landslide hazard to obtain the influence zone and hazard zoning map of the Chenjiaba landslide. Results show that the Duba River was blocked quickly with a landslide accumulation at the maximum height of 44.14 m when the Chenjiaba deposits lost stability. The hazard zoning map indicated that the landslide hazard degree is positively correlated with the slope. This landslide assessment is a quantitative hazard assessment method based on a landslide movement process and is suitable for high-speed landslide. Such method can provide a scientific basis for urban construction and planning in the landslide hazard area to avoid hazards effectively.

A simplified approach for stability analysis of slopes reinforced with one row of embedded stabilizing piles

Embedded stabilizing piles are new anti-slide structures that are unlike traditional stabilizing piles. The pile heads are embedded at a certain depth below the surface of a slope. The piles do not need to support the thrust of the entire upslope sliding mass, and it is, therefore, possible to reduce the sliding thrust on the piles. The embedded depth of the pile heads is an important parameter to maximize the anti-sliding function. Based on an analysis of the stability mechanism of a reinforced landslide with one row of embedded stabilizing piles, a calculation method for the embedded depth of a pile head using limit equilibrium theory is proposed. The related calculation formula is derived in detail using the transfer coefficient method. The proposed method features a close correlation between the embedded depth of a pile head and the design factor of safety of a slope to be reinforced. Additionally, the method can quantitatively demonstrate the relationship that the factor of safety of the slope for the failure mode of the surpassing pile head decreases as the embedded depth of the pile head increases. For a given factor of safety, the range of the maximum bending moment, the maximum shear force on a pile and the lateral displacement at the pile head also can be approximately predicted. Several calculation examples that are closely related to practical engineering applications are examined to show the convenience and rationality of the proposed method. In addition, the theoretical analysis is compared with the results of the numerical simulation of an actual accumulation landslide control engineering project. The results further demonstrate that the proposed theoretical analysis method is reasonable and applicable.

Reservoir-induced landslides and risk control in Three Gorges Project on Yangtze River, China

The Three Gorges region in China was basically a geohazard-prone area prior to construction of the Three Gorges Reservoir (TGR). After construction of the TGR, the water level was raised from 70 m to 175 m above sea level (ASL), and annual reservoir regulation has caused a 30-m water level difference after impoundment of the TGR since September 2008. This paper first presents the spatiotemporal distribution of landslides in six periods of 175 m ASL trial impoundments from 2008 to 2014. The results show that the number of landslides sharply decreased from 273 at the initial stage to less than ten at the second stage of impoundment. Based on this, the reservoir-induced landslides in the TGR region can be roughly classified into five failure patterns, i.e. accumulation landslide, dip-slope landslide, reversed bedding landslide, rockfall, and karst breccia landslide. The accumulation landslides and dip-slope landslides account for more than 90%. Taking the Shuping accumulation landslide (a sliding mass volume of 20.7 × 106 m3) in Zigui County and the Outang dip-slope landslide (a sliding mass volume of about 90 × 106 m3) in Fengjie County as two typical cases, the mechanisms of reactivation of the two landslides are analyzed. The monitoring data and factor of safety (FOS) calculation show that the accumulation landslide is dominated by water level variation in the reservoir as most part of the mass body is under 175 m ASL, and the dip-slope landslide is controlled by the coupling effect of reservoir water level variation and precipitation as an extensive recharge area of rainfall from the rear and the front mass is below 175 m ASL. The characteristics of landslide-induced impulsive wave hazards after and before reservoir impoundment are studied, and the probability of occurrence of a landslide-induced impulsive wave hazard has increased in the reservoir region. Simulation results of the Ganjingzi landslide in Wushan County indicate the strong relationship between landslide-induced surge and water variation with high potential risk to shipping and residential areas. Regarding reservoir regulation in TGR when using a single index, i.e. 1-d water level variation, water resources are not well utilized, and there is also potential risk of disasters since 2008. In addition, various indices such as 1-d, 5-d, and 10-d water level variations are proposed for reservoir regulation. Finally, taking reservoir-induced landslides in June 2015 for example, the feasibility of the optimizing indices of water level variations is verified.