Scenario Simulation of The Geohazard Dynamic Process of Large-Scale Landslides: A Case Study of The Xiaomojiu Landslide Along The Jinsha River

Abstract Large-scale landslides often cause severe damage due to their long run-out distances and having disaster chain effects. Scenario simulation has been adopted in the current work to analyze the Xiaomojiu landslide dynamic processes, such as sliding velocity, deposition characteristics, and flood outburst after a landslide-dam failure using Particle Flow Code (PFC-3D) which introduced the changeable friction coefficient and the HEC-RAS software. The landslide characteristics and topography data were obtained via field investigation, whereas high-resolution topographic data (0.17 m) was obtained using an Unmanned Aerial Vehicle (UAV). The results showed that: 1. The landslide presents a scallop shape with a length of 1566 m, a width ranging from 809~1124 m, and an area of 1.34×106 m2. The average thickness and volume of the sliding body is approximately 40 m, 5.1×107 m3. The InSAR deformation analysis showed that the Xiaomojiu landslide has a maximum annual displacement rate of 60 mm/y, and a maximum accumulation deformation of 180 mm since November 25, 2017. 2. From the landslide simulation results, the failure process of the Xiaomojiu landslide lasted for 65 s with a maximum velocity of 78.2 m/s. The deposited area is approximately 2023 m long, 900 m wide, with a maximum height of approximately 149 m. 3. After the landslide blocks the Jinsha River, a landslide-dammed lake with an elevation of 2940 m and a storage capacity of 4.13×109 m3 is formed. The maximum peak flow rate of the breach is 12051.7 m3/s, 43451.4 m3/s, 148635.6 m3/s, and 304544.7 m3/s for the landslide-dammed failure degrees of 15%, 25%, 50%, and 75%, respectively. These results provide a scientific reference for the risk analysis and mitigation of the landslide.

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A Preliminary Study of the Failure Modes and Process of Landslide Dams Due to Upstream Flow

Water ◽

10.3390/w11061115 ◽

2019 ◽

Vol 11 (6) ◽

pp. 1115 ◽

Cited By ~ 3

Author(s):

Xinghua Zhu ◽

Jianbing Peng ◽

Cheng Jiang ◽

Weilong Guo

Keyword(s):

Large Scale ◽

Failure Modes ◽

Mine Waste ◽

Failure Process ◽

Landslide Dam ◽

Experimental Tests ◽

Field Investigation ◽

Dam Failure ◽

Experimental Conditions ◽

Landslide Dams

In the process of mineral development, large-scale flash floods (or debris flows) can be induced by the failure of landslide dams formed by the disorganized stacking of mine waste. In this study, the modes and processes of mine waste dam failures were explored using 13 experimental tests based on the field investigation of landslide dams in the Xiaoqinling gold mining area in China. Our 13 mine waste dam experiments exhibited three failure modes: (i) Piping, overtopping, and erosion; (ii) overtopping and soil collapse; and (iii) overtopping and erosion. In addition, the failure processes of the landslide dams included impoundment, seepage, overtopping, and soil erosion. Different experimental conditions would inevitably lead to different failure processes and modes, with the failure modes being primarily determined by the seepage characteristics. Overtopping was the triggering condition for dam failure. The landslide dam failure process was determined based on the particle size of the mine waste and the shape of the dam. These findings will provide a scientific reference for the prevention and mitigation of natural hazards in mining areas.

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Catastrophic landslide affected by topography: a case study in Guizhou, China

10.5194/egusphere-egu21-13750 ◽

2021 ◽

Author(s):

Jian Guo

Keyword(s):

Complex Terrain ◽

Large Scale ◽

Shallow Water Equation ◽

Maximum Velocity ◽

Field Investigation ◽

Guizhou Province ◽

Future Research ◽

Low Velocity ◽

Runout Distance ◽

Rainfall Analysis

<p>In mountainous areas, large-scale landslides usually cause serious disasters. A large number of studies have found that complex terrain may affect the landslides dynamic, which may be one of the significant factors in catastrophic events. However, the mechanism is rarely explored. On July 23, 2019, a large-scale landslide occurred in Jichang town, Shuicheng County, Liupanshui City, Guizhou Province in China. The landslide, which moved along two gullies, resulted in strong punching-shear, induced scarping on vegetation and large destruction of houses and finally formed a deposit with a volume of 2&#215;106 m3. This research aims to understand the effect of topography on landslide kinematics. To achieve this aim, a detailed field investigation was first carried out with an unmanned aerial vehicle (UAV) aerial photography survey, resident interviews, and field sampling. The rainfall analysis indicate the effective rainfall within seven days before landslides was 70.14 mm which exceeded the rainfall threshold of 54.3 mm in this region, which finally triggered the landslide. Traditional soil mechanics tests were then performed to identify the soil properties of the source material. Combined with numerical simulation using the nonlinear shallow water equation, the whole process of landslides was divided into four stages: instability stage, acceleration stage, transformation stage and impact and accumulation stage. The simulations results show the landslide block slid with a low velocity of 8 m/s for about 100 m. Then, Froude number of landslide increase from 2 to 3 when passing the high and steep terrain, indicating that landslide change to inertial dominated with potential same Froude behavior of classic debris flow. The rupture mass slid with the peak velocity of 23 m/s and diverged in two gullies and ran out for about 600 m. The maximum velocity is 23 m/s in east gully while only 15 m/s in west gully. Compared with deep and incised valleys in west, shallow and straight valley in east decrease the deposit depth, further increase the velocity of landslide material with increased runout distance. This research may provide a fast flow path of back analyzing geo-hazards on complex terrain and serve as a basis for future research on long runout landslides.&#160;</p>

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Large-Scale Field Test Study on Failure Mechanism of Non-Cohesive Landslide Dam by Overtopping

Frontiers in Earth Science ◽

10.3389/feart.2021.660408 ◽

2021 ◽

Vol 9 ◽

Author(s):

Liang Li ◽

Xingguo Yang ◽

Jiawen Zhou ◽

Jieyuan Zhang ◽

Gang Fan

Keyword(s):

Large Scale ◽

Discharge Channel ◽

Failure Process ◽

Field Tests ◽

Landslide Dam ◽

Development Stage ◽

Dam Failure ◽

Process Time ◽

Scale Field ◽

Large Scale Field

In recent years, landslide lake disasters occur frequently in southwest mountainous areas of China. Considering the influence of dam size and discharge channel location, three large-scale field tests were carried out in a natural river to study the failure process and mechanism of non-cohesive soil landslide dam, and the process and mechanism of non-cohesive landslide dam breach were analyzed. The results show that the dam size and discharge channel location have a significant influence on the breach mechanism of the landslide dam. The dam failure process can be divided into three stages: the initiation stage, the development stage and the failure stage. When the discharge channel is located close to the bank, the width of the breach is smaller, and the volume of the residual dam body is larger. The more stable the dam body is, the longer the breach process time is, and the smaller the peak discharge is. This study can provide a scientific reference for the emergency disposal and risk assessment of landslide dam.

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Universal Masking to Control Healthcare-Associated Transmission of SARS-CoV-2

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2021.127 ◽

2021 ◽

pp. 1-24

Author(s):

Eliza R. Thompson ◽

Faith S. Williams ◽

Pat A. Giacin ◽

Shay Drummond ◽

Eric Brown ◽

...

Keyword(s):

Large Scale ◽

Infection Prevention ◽

Index Patient ◽

Field Investigation ◽

Point Prevalence ◽

Control Measures ◽

Prevention Measures ◽

Infection Control Measures ◽

Va Health Care System ◽

Healthcare Associated

Abstract Objective: To assess extent of a healthcare-associated outbreak of SARS-CoV-2 and evaluate effectiveness of infection control measures, including universal masking Design: Outbreak investigation including 4 large-scale point-prevalence surveys Setting: Integrated VA Health Care System with 2 facilities and 330 beds Participants: Index patient and 250 exposed patients and staff Methods: We identified exposed patients and staff and classified them as probable and confirmed cases based on symptoms and testing. We performed a field investigation and assessment of patient and staff interactions to develop probable transmission routes. Infection prevention interventions implemented included droplet and contact precautions, employee quarantine, and universal masking with medical and cloth facemasks. Four point-prevalence surveys of patient and staff subsets were conducted using real-time reverse-transcriptase polymerase chain reaction for SARS-CoV-2. Results: Among 250 potentially exposed patients and staff, 14 confirmed cases of Covid-19 were identified. Patient roommates and staff with prolonged patient contact were most likely to be infected. The last potential date of transmission from staff to patient was day 22, the day universal masking was implemented. Subsequent point-prevalence surveys in 126 patients and 234 staff identified 0 patient cases and 5 staff cases of Covid-19, without evidence of healthcare-associated transmission. Conclusions: Universal masking with medical facemasks was effective in preventing further spread of SARS-CoV-2 in our facility in conjunction with other traditional infection prevention measures.

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Sustainable Spatial Energy Planning of Large-Scale Wind and PV Farms in Israel: A Collaborative and Participatory Planning Approach

Energies ◽

10.3390/en14030551 ◽

2021 ◽

Vol 14 (3) ◽

pp. 551

Author(s):

Sofia Spyridonidou ◽

Georgia Sismani ◽

Eva Loukogeorgaki ◽

Dimitra G. Vagiona ◽

Hagit Ulanovsky ◽

...

Keyword(s):

Large Scale ◽

Wind Farms ◽

Field Investigation ◽

Participatory Planning ◽

Energy Planning ◽

Environmentally Sustainable ◽

Selection Processes ◽

Planning Framework ◽

Planning Approach ◽

Near Future

In this work, an innovative sustainable spatial energy planning framework is developed on national scale for identifying and prioritizing appropriate, technically and economically feasible, environmentally sustainable as well as socially acceptable sites for the siting of large-scale onshore Wind Farms (WFs) and Photovoltaic Farms (PVFs) in Israel. The proposed holistic framework consists of distinctive steps allocated in two successive modules (the Planning and the Field Investigation module), and it covers all relevant dimensions of a sustainable siting analysis (economic, social, and environmental). It advances a collaborative and participatory planning approach by combining spatial planning tools (Geographic Information Systems (GIS)) and multi-criteria decision-making methods (e.g., Analytical Hierarchy Process (AHP)) with versatile participatory planning techniques in order to consider the opinion of three different participatory groups (public, experts, and renewable energy planners) within the site-selection processes. Moreover, it facilitates verification of GIS results by conducting appropriate field observations. Sites of high suitability, accepted by all participatory groups and field verified, form the final outcome of the proposed framework. The results illustrate the existence of high suitable sites for large-scale WFs’ and PVFs’ siting and, thus, the potential deployment of such projects towards the fulfillment of the Israeli energy targets in the near future.

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Rising Planetary Boundary Layer Height over the Sahara Desert and Arabian Peninsula in a Warming Climate

Journal of Climate ◽

10.1175/jcli-d-20-0645.1 ◽

2021 ◽

Vol 34 (10) ◽

pp. 4043-4068

Author(s):

Liming Zhou ◽

Yuhong Tian ◽

Nan Wei ◽

Shu-peng Ho ◽

Jing Li

Keyword(s):

Boundary Layer ◽

Relative Humidity ◽

Planetary Boundary Layer ◽

Large Scale ◽

Arabian Peninsula ◽

Climate Model ◽

Statistical Significance ◽

Maximum Height ◽

Sahara Desert ◽

Sensible Heat

AbstractTurbulent mixing in the planetary boundary layer (PBL) governs the vertical exchange of heat, moisture, momentum, trace gases, and aerosols in the surface–atmosphere interface. The PBL height (PBLH) represents the maximum height of the free atmosphere that is directly influenced by Earth’s surface. This study uses a multidata synthesis approach from an ensemble of multiple global datasets of radiosonde observations, reanalysis products, and climate model simulations to examine the spatial patterns of long-term PBLH trends over land between 60°S and 60°N for the period 1979–2019. By considering both the sign and statistical significance of trends, we identify large-scale regions where the change signal is robust and consistent to increase our confidence in the obtained results. Despite differences in the magnitude and sign of PBLH trends over many areas, all datasets reveal a consensus on increasing PBLH over the enormous and very dry Sahara Desert and Arabian Peninsula (SDAP) and declining PBLH in India. At the global scale, the changes in PBLH are significantly correlated positively with the changes in surface heating and negatively with the changes in surface moisture, consistent with theory and previous findings in the literature. The rising PBLH is in good agreement with increasing sensible heat and surface temperature and decreasing relative humidity over the SDAP associated with desert amplification, while the declining PBLH resonates well with increasing relative humidity and latent heat and decreasing sensible heat and surface warming in India. The PBLH changes agree with radiosonde soundings over the SDAP but cannot be validated over India due to lack of good-quality radiosonde observations.

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Probabilistic Vulnerability Assessment of Transmission Lines Considering Cascading Failures

Processes ◽

10.3390/pr9111994 ◽

2021 ◽

Vol 9 (11) ◽

pp. 1994

Author(s):

Yanchen Liu ◽

Minfang Peng ◽

Xingle Gao ◽

Haiyan Zhang

Keyword(s):

Transmission Lines ◽

Large Scale ◽

Failure Process ◽

Power Grids ◽

Weak Links ◽

Cascading Failure ◽

Cascading Failures ◽

Stable Operation ◽

Chain Model ◽

Systems Research

The prevention of cascading failures and large-scale power outages of power grids by identifying weak links has become one of the key topics in power systems research. In this paper, a vulnerability radius index is proposed to identify the initial fault, and a fault chain model of cascading failure is developed with probabilistic attributes to identify the set of fault chains that have a significant impact on the safe and stable operation of power grids. On this basis, a method for evaluating the vulnerability of transmission lines based on a multi-criteria decision analysis is proposed, which can quickly identify critical transmission lines in the process of cascading failure. Finally, the proposed model and method for identifying vulnerable lines during the cascading failure process is demonstrated on the IEEE-118 bus system.

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Study of Vortex Systems as a Method to Weakening the Urban Heat Islands within the Financial District in Large Cities

Sustainability ◽

10.3390/su132313206 ◽

2021 ◽

Vol 13 (23) ◽

pp. 13206

Author(s):

Luis Rodriguez-Lucas ◽

Chen Ning ◽

Marcelo Fajardo-Pruna ◽

Yugui Yang

Keyword(s):

Rural Areas ◽

Large Scale ◽

Flow Characteristics ◽

Maximum Velocity ◽

Vortex Generator ◽

Urban Heat Islands ◽

Navier Stokes ◽

Specific Work ◽

Heat Islands ◽

Large Cities

This paper presents a new concept called the urban vortex system (UVS). The UVS couples a vortex generator (V.G.) that produces updraft by artificial vortex and a vortex stability zone (VSZ) consisting of an assembly of four buildings acting as a chimney. Through this system, a stable, upward vortex flow can be generated. The Reynolds Averaged Navier–Stokes (RANS) simulation was carried out to investigate the flow field in the UVS. The Renormalized Group (RNG) k–ε turbulent model was selected to solve the complex turbulent flow. Validation of the numerical results was achieved by making a comparison with the large-size experimental model. The results reported that a steady-state vortex could be formed when a vapor-air mixture at 2 m/s and 450 K enters the vortex generator. This vortex presented a maximum negative central pressure of −6.81 Pa and a maximum velocity of 5.47 (m/s). Finally, the similarity method found four dimensionless parameters, which allowed all the flow characteristics to be transported on a large scale. The proposed large-scale UVS application is predicted to be capable, with have a maximum power of 2 M.W., a specific work of 3 kJ/kg, buildings 200-m high, and the ability to generate winds of 6.1 m/s (20 km/h) at 200 m up to winds of 1.5 m/s (5 km/h) at 400 m. These winds would cause the rupture of the gas capsule of the heat island phenomenon. Therefore, the city would balance its temperature with that of the surrounding rural areas.

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Deep Convective Systems Observed by A-Train in the Tropical Indo-Pacific Region Affected by the MJO

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-12-057.1 ◽

2013 ◽

Vol 70 (2) ◽

pp. 465-486 ◽

Cited By ~ 20

Author(s):

Jian Yuan ◽

Robert A. Houze

Keyword(s):

Large Scale ◽

Deep Convection ◽

Active Phase ◽

Maximum Height ◽

Pacific Region ◽

Convective Envelope ◽

Convective Systems ◽

Mesoscale Convective ◽

Deep Convective Systems ◽

Cloud Tops

Abstract In the Indo-Pacific region, mesoscale convective systems (MCSs) occur in a pattern consistent with the eastward propagation of the large-scale convective envelope of the Madden–Julian oscillation (MJO). MCSs are major contributors to the total precipitation. Over the open ocean they tend to be merged or connected systems, while over the Maritime Continent area they tend to be separated or discrete. Over all regions affected by the MJO, connected systems increase in frequency during the active phase of the MJO. Characteristics of each type of MCS (separated or connected) do not vary much over MJO-affected regions. However, separated and connected MCSs differ in structure from each other. Connected MCSs have a larger size and produce less but colder-topped anvil cloud. For both connected and separated MCSs, larger systems tend to have colder cloud tops and less warmer-topped anvil cloud. The maximum height of MCS precipitating cores varies only slightly, and the variation is related to sea surface temperature. Enhanced large-scale convection, greater frequency of occurrence of connected MCSs, and increased midtroposphere moisture coincide, regardless of the region, season, or large-scale conditions (such as the concurrent phase of the MJO), suggesting that the coexistence of these phenomena is likely the nature of deep convection in this region. The increase of midtroposphere moisture observed in all convective regimes during large-scale convectively active phases suggests that the source of midtroposphere moisture is not local or instantaneous and that the accumulation of midtroposphere moisture over MJO-affected regions needs to be better understood.

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