Search

Reservoir landslide evolution is a complex multi-fields dynamic process which involves the interaction of the seepage field, stress field, displacement field and temperature field. After installing the stabilizing structure into landslide, the landslide and stabilizing structure will establish the landslide-stabilization system and lead to a more complex multi-fields evolution process under the reservoir operation. To study this complex problem, this paper designs and establishes a comprehensive in-situ multi-fields information monitoring platform which has been installed on Majiagou landslide in Three Gorges Reservoir area. The multi-fields information monitoring platform has four components: the landslide-stabilization system, the in-situ multi-field monitoring system, the data transmission and receiving system, and the database management system. The landslide-stabilization system includes Majiagou landslide and two experimental reinforced concrete piles. The in-situ monitoring system consists of landslide surface deformation monitoring system, experimental piles monitoring system and boreholes monitoring system. The landslide surface deformation monitoring system includes GPS stations and fiber lines. The experimental pile monitoring system consists of earth pressure cells around piles, stress and strain gauges on steel bars, and strain and temperature fiber sensors in piles. The borehole monitoring system includes boreholes with inclinometers, water pressure and water level gauges, fiber sensors. Therefore, the in-situ monitoring system can monitor the seepage, stress, displacement and temperature fields in the landslide, as well as the force and deformation in the experimental piles. Currently, the data transmission and management system is under construction and will be finished soon. Current monitoring results show that the landslide moves along three slip surfaces and the deformation of the experimental piles is influenced by reservoir operation. This platform can provide multi-fields data for scholars to study the evolution of landslide-stabilization system. [ABSTRACT FROM AUTHOR]

Capacity fading and voltage decay is one of the biggest obstacles for the practical application of Li‐rich layered oxides due to the serious surface‐related detrimental reactions. Herein, we develop a versatile and scalable method to construct a robust surface‐integrated structure. All the designed samples deliver outstanding capacity and voltage stability, among which the Zn‐treated sample possesses the best electrochemical performance. Its capacity retention is larger than 90 % after 400 cycles with a voltage decay ratio as small as 0.73 mV per cycle. What is more, the rules of surface‐integrated structure with different cations in terms of capacity and voltage stability is further deciphered by combining with density function theory (DFT) calculations. It is found that to obtain advanced Li‐rich layered oxide cathodes, cations in Li‐sites should firstly ensure the binding energy of the surface‐integrated structure in a lower level and then provide Bader charge for the nearest O atoms as small as possible. [ABSTRACT FROM AUTHOR]

Capacity fading and voltage decay is one of the biggest obstacles for the practical application of Li‐rich layered oxides due to the serious surface‐related detrimental reactions. Herein, we develop a versatile and scalable method to construct a robust surface‐integrated structure. All the designed samples deliver outstanding capacity and voltage stability, among which the Zn‐treated sample possesses the best electrochemical performance. Its capacity retention is larger than 90 % after 400 cycles with a voltage decay ratio as small as 0.73 mV per cycle. What is more, the rules of surface‐integrated structure with different cations in terms of capacity and voltage stability is further deciphered by combining with density function theory (DFT) calculations. It is found that to obtain advanced Li‐rich layered oxide cathodes, cations in Li‐sites should firstly ensure the binding energy of the surface‐integrated structure in a lower level and then provide Bader charge for the nearest O atoms as small as possible. [ABSTRACT FROM AUTHOR]

Abstract Landslides are often induced or activated by reservoir impoundment within the reservoir area. In this paper, a physical model test was conducted and compared with another published test to investigate the deformation characteristics and failure behavior of a colluvial landslide for conditions with and without reservoir impoundment. The laboratory landslide model represented the lower part of a landslide in the Three Gorges Reservoir area. A thrust load was applied to represent the upper part of the landslide. The thrust load, surface deformation, pore water pressure, and soil pressure were recorded during the experiments. The results show that the effect of the reservoir impoundment reduces the time to failure of the landslide and the load causing the failure. As expected, when water submerged the lower part of the landslide, the shearing resistance was reduced. The slip surfaces and failure behavior of the landslide under the two conditions are different. The entire landslide mass slid along the contact between the colluvium and the bedrock under reservoir impoundment. However, without a reservoir, the landslide slides partially along this contact, and multiple slip surfaces through the colluvium. Highlights • Physical model tests are used to evaluate the same landslide with and without reservoir impoundment. • The landslide with reservoir impoundment failed at a lower thrust load. • With reservoir impoundment, failure occurred along a weak basal sliding zone. • Without impoundment, multiple slip surfaces through the slope occurred. • Soil pressure measurements help to interpret the locations of slip surfaces. [ABSTRACT FROM AUTHOR]

Landslides often occur within the reservoir area behind dams. In China, a common strategy for stabilizing these landslides is to install large piles through the landslide and into the stable ground below. The piles interact with the landslide and constitute a landslide-stabilizing pile system. The deformation of this system under the reservoir operation is more complicated than the deformation of the landslide itself. Understanding the behaviour of this system is very important to the long-term safety of landslides stabilized with piles in reservoirs. The Majiagou landslide, which was selected as a case study, was triggered by the first impoundment of the reservoir behind the Three Gorges dam. A row of anti-slide piles was installed in the landslide in 2007, but monitoring results found these were ineffective at stabilizing the landslide. Subsequently, in 2011, two longer test piles and an integrated monitoring system were installed in the landslide to better understand the failure mode of the landslide and to measure the deformation characteristics of the landslide-stabilizing pile system. Monitoring results show that the Majiagou landslide is a translational landslide with three slip surfaces. The test piles provided local resistance and partially slowed down the sliding mass behind the piles, and the landslide deformation response to external factors decreased for a time. However, after 2 years, the deformation of the landslide-stabilizing pile system reverted to seasonal stepwise cumulative displacements influenced by cycles of reservoir drawdown and rainfall. The monitoring results provide fundamental data for evaluating the long-term performance of anti-slide piles and for assessing long-term stability of the stabilized landslide under the reservoir operation. [ABSTRACT FROM AUTHOR]

The physical model test of landslides is important for studying landslide structural damage, and parameter measurement is key in this process. To meet the measurement requirements for deep displacement in landslide physical models, an automatic flexible inclinometer probe with good coupling and large deformation capacity was designed. The flexible inclinometer probe consists of several gravity acceleration sensing units that are protected and positioned by silicon encapsulation, all the units are connected to a 485-comunication bus. By sensing the two-axis tilt angle, the direction and magnitude of the displacement for a measurement unit can be calculated, then the overall displacement is accumulated according to all units, integrated from bottom to top in turn. In the conversion from angle to displacement, two spline interpolation methods are introduced to correct and resample the data; one is to interpolate the displacement after conversion, and the other is to interpolate the angle before conversion; compared with the result read from checkered paper, the latter is proved to have a better effect, with an additional condition that the displacement curve move up half the length of the unit. The flexible inclinometer is verified with respect to its principle and arrangement by a laboratory physical model test, and the test results are highly consistent with the actual deformation of the landslide model. [ABSTRACT FROM AUTHOR]