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The deformation evolution of reservoir landslides of ten lags behind the variation in the reservoir water level during the operation of the Three Gorges Project, showing a deformation hysteresis effect, and the hysteresis effect is different with the difference in the permeability coefficient and fluctuation rate of reservoir water. Taking the Baijiabao landslide in the Three Gorges Reservoir area as an example, the variation law of the deformation lag time under different permeability coefficients k and reservoir water level decline rates v is studied by field investigation, monitoring data analysis and numerical simulation. The results show that when the permeability coefficient of the landslide is constant, the higher the decreasing rate of reservoir water level is, the more obvious the groundwater lag. When the reservoir water level drops at a certain rate, the greater the permeability coefficient of the sliding body is, the faster the groundwater drop.When the permeability coefficient of the sliding body is 0.85 m/d, the higher the rate of reservoir water level decline is, the shorter the deformation lag time of the landslide.The corresponding lag time is 3.74-9 d under different decline rates of the reservoir water level.When 0.47 < v/k < 1.18, 0.24 < relative deformation lag time < 1; when 1.18 < v/k < 2.38, 0 < relative deformation lag time < 0.24. When the reservoir water level decline rate is constant, the larger the landslide permeability coefficient is, the shorter the landslide deformation lag time is. Under different reservoir water level decline rates, the change rule of the relative deformation lag time with increasing v/k value is roughly the same, v=1.8 m/d, and the corresponding lag time of different permeability coefficients is 1.7-8 d. When 0.52 < v/k < 0.84, 0 < relative deformation lag time < 0.16; when 0.84 < v/k < 2.12, 0.16 < relative deformation lag time < 0.43; when 2.12 < v/k < 9, 0.43 < relative deformation lag time < 1. The research results have strong application value for the prediction and warning of reservoir landslides.

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.

The new gas-liquid-solid fluidized bed flotation technology can realize the efficiency recovery of coarse particles based on the principle of refloating coupling. Taking 1.0-0.5 mm coarse coal slime as the research object, the effects of water velocity, inflating gas flow, concentration of collector and frother on the fluidization characteristics and separation effect of two-dimensional fluidized-bed in the laboratory were systematically investigated. The results show that the fluctuation of pressure signal can be effectively reduced and the stability of fluidized-bed can be improved by increasing the water velocity, reducing the inflating gas flow and adding frother and collector. Reducing the inflating gas flow can reduce the apparent gas velocity of the fluidized-bed, while increasing the water velocity and adding the frother will reduce the bubble size through the shear effect of the upflowing fluid and the reduction of the surface tension, and the adding of the collector will make the adhesion of the bubble to the particles and reduce the floating speed of the bubble. With the increase of water velocity and inflating gas flow, the ash content of concentrate first decreases and then increases, but the tailling ash content has a slightly different trend. Too high inflating gas flow will disturb the fluidized-bed and lead to serious mixing，then the tailling ash content will increase. The appropriate addition of collector and frother will further reduce the ash content of concentrate, which is due to the adhesion of flotation bubbles on the surface of coarse particles, reducing its apparent density and strengthening the density separation effect. However, excessive addition of agents may lead to the occurrence of flotation entrainment and increase the ash content of concentrate. Finally, a semi-industrial test of fluidized bed flotation with a diameter of 200 mm was carried out, and the best separation index was obtained with 1.0-0.25 mm coarse slime as feed at water velocity of 15 L/min, inflating gas flow of 1.5 L /min, collector of 200 g/t and frother of 400 g/t. Ash content and yield of concentrate were 9.34% and 90.13%, and tailling ash content and yield were 38.51% and 9.87%, respectively. This study is of great significance for the realization of fluidized-bed stability control and efficient recovery of coarse slime in fluidized bed flotation process.

Pneumoconiosis is a systemic disease mainly caused by diffuse fibrosis (scar) of lung tissue due to long-term inhalation of productive mineral dust in occupational activities and retention in the lungs. The mineral dust concentrration can be effectively controlled using water-based mineral dust reduction technique. Therefore, the investigation into water-clay mineral dust interaction is useful for pneumoconiosis prevention and treatment. In this study, the adsorption performances for water molecules in kaolinite clay mineral were investigated. The findings reveal that the performances of water molecules adsorption in kaolinite clay mineral can be divided into primary adsorption and secondary adsorption. Under the lower vapour pressure, water molecules are primarily fixed in primary sites. At the higher vapour pressure condition, the secondary adsorption sites become the utilizable main adsorption centers. Primary adsorption is monolayer adsorption, while water molecules adsorption in secondary adsorption centers is occurred by the formation of water clusters.

The Shanshucao landslide is a recent landslide that occurred in the China Three Gorges Reservoir area. It is next to the Daling Hydropower Station landslide, one of the geological hazard professional monitoring points in the China Three Gorges Reservoir. The Shanshucao landslide had not shown a significant deformation during recent decades until September 2nd, 2014. On that day, the Shanshucao landslide abruptly started to move at around 9 a.m. local time, stopped at 13:19 p.m., and caused a 43.2×104m³ landslide mass which slipped into the Luogudong River, the secondary branch of Yangtze River. Fortunately, the local government gave an efficient early warning and organized a successful emergency evacuation. Nobody was injured or killed in this landslide failure event. The Daling Hydropower Station and its attached buildings were eradicated by the landslide. Posterior to the failure, a newborn free surface occurred on the dip slope. The remaining body of the landslide poses a great threat to the safety of both the village and the Three Gorges Reservoir operation. Subsequently, an emergency monitoring system has been placed on the slope to observe any subsequent deformation. By applying the kinematic model, this article will give a general outlook on the failure event and investigate the geological features which caused the slope instability. Also, the two inclined blocks models are introduced in the back analysis and show a good comparison to the site observation results. This article will provide guidance and suggestion for the stability analysis of similar highly weathered bedded landslides in the China Three Gorges Reservoir area. [ABSTRACT FROM AUTHOR]

Excessive inhalation of mineral dust can cause irreversible damage such as diffuse fibrosis of lung tissue. Water-based dust reduction technology can effectively control the dust concentration. The study of the interaction of water-clay mineral dust is helpful to the prevention and treatment of pneumoconiosis by water-based dust removal technology. To better understand the underlying adsorption mechanisms of water molecules on clay mineral dust, the detailed adsorption thermodynamics analysis is necessary. In this paper, we research the thermodynamics of adsorption of water molecules on swelling clay of montmorillonite and non-swelling clay of illite. First, the adsorption isotherms of water molecules on montmorillonite and illite at 293–313 K were measured by gravimetric method. Then, the key thermodynamic variables, including entropy change (ΔS), surface potential (Ω), isosteric heat of adsorption (Qst) and variation of Gibbs free energy (ΔG), were analyzed. Results illustrate that the adsorption amount for water molecules on illite is one order of magnitude smaller than that on montmorillonite, suggesting that swelling clay plays a dominant role in water molecules adsorption process. For water molecules adsorption on montmorillonite, the contribution of secondary adsorption to total adsorption (a2/a) is always less than 30%. For water molecules adsorption on illite, the contribution of primary adsorption to total adsorption (a1/a) is greater than a2/a at the low pressure region, while a2/a can exceed 60% at the high pressure region. The difference in the uptakes of water molecules adsorption on non-swelling and swelling clays is mainly resulted from the difference in primary adsorption on two clays. The Henry’s constant (KAA) for montmorillonite is in the range of 21.37–75.08 mmol/g/kPa, which is evidently larger than the KAA values of 0.34–0.98 mmol/g/kPa for illite. Compared with non-swelling clay, the adsorption spontaneity degree for water molecules on swelling clay is higher, and the interaction of swelling clay-water molecules is stronger. Meanwhile, the movement of adsorbed water molecules in swelling clay is more confined than that in non-swelling clay. These findings can offer meaningful guidelines for the prevention and treatment of pneumoconiosis.

In recent years, unmanned aerial vehicles (UAVs) have become widely used in emergency investigations of major natural hazards over large areas; however, UAVs are less commonly employed to investigate single geohazards. Based on a number of successful investigations in the Three Gorges Reservoir area, China, a complete UAVbased method for performing emergency investigations of single geo-hazards is described. First, a customized UAV system that consists of a multi-rotor UAV subsystem, an aerial photography subsystem, a ground control subsystem and a ground surveillance subsystem is described in detail. The implementation process, which includes four steps, i.e., indoor preparation, site investigation, on-site fast processing and application, and indoor comprehensive processing and application, is then elaborated, and two investigation schemes, automatic and manual, that are used in the site investigation step are put forward. Moreover, some key techniques and methods - e.g., the layout and measurement of ground control points (GCPs), route planning, flight control and image collection, and the Structure from Motion (SfM) photogrammetry processing - are explained. Finally, three applications are given. Experience has shown that using UAVs for emergency investigation of single geo-hazards greatly reduces the time, intensity and risks associated with on-site work and provides valuable, high-accuracy, high-resolution information that supports emergency responses. [ABSTRACT FROM AUTHOR]

The primary objective of this research is to study the relationship between surface movement and hydrological triggers of a large and active landslide in the Three Gorges Reservoir (the Shuping landslide). When the landslide was reactivated in June 2003 owing to the impoundment of the Three Gorges Dam, measurement of surface movement began through the use of manual global positioning system (GPS) monitoring. Since June 2012, near-real-time data with fine temporal resolution have been collected through the use of continuous automatic GPS. In total, more than 10 years of surface movement have been recorded for the Shuping landslide. Patterns of surface movement have been spatially identified first, and then subsequently over time. A fast moving zone can be spatially identified from the primary deformation zone. The temporal evolution of the landslide consists of a typical stepwise progression in time with short periods of fast movement (FM) and longer periods of slower movement. Eight of the former have been identified. The hydrological conditions and triggering factors can be understood by performing detailed correlations between displacements and daily fluctuations of reservoir water levels and rainfall records. The results indicate that any continuous rapid drawdown of the reservoir water level from approximately 160 to 145 m will definitely trigger FM. Generally, there is a lag time of approximately 6 days after the water level is reduced. In addition, there is a definite correlation between fast velocity and the rate of drawdown. Meanwhile, prolonged and periodic intense rainfalls have a slightly relevant effect on the movement of this landslide. This shows that long-term and near-real-time monitoring are invaluable for the understanding of landslide movements and their hydrological triggers. [ABSTRACT FROM AUTHOR]