scholarly journals Combining TRIGRS and DEBRIS-2D Models for the Simulation of a Rainfall Infiltration Induced Shallow Landslide and Subsequent Debris Flow

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 890 ◽  
Author(s):  
Yu-Charn Hsu ◽  
Ko-Fei Liu
Keyword(s):  
Debris Flow ◽  
Depth Distribution ◽  
Shallow Landslide ◽  
Rainfall Infiltration ◽  
The Real ◽  
Hazard Zone ◽  
Before And After ◽  
Flow Motion ◽  
Debris Flow Hazard ◽  
Area And Volume

TRIGRS revealed the responses of the total pressure heads and factors of safety with a depth change under a rainfall infiltration occurring on the Daniao tribe’s hill. The depth distribution of the collapsed zone could be identified under the condition where the factors of safety Fs = 1, and the results could calculate the area and volume. Afterward, DEBRIS-2D used TRIGRS’s results to assess the hazard zone of the subsequent debris flow motion. In this study, the DTM variation analysis results from both of before and after the Daniao tribe’s landslide are used to validate TRIGRS’s simulation, the area and the volume of the collapse zone within 8% and 23% errors, respectively. The real disaster range was depicted from the aerial photo used to validate the hazard zone simulation of DEBRIS-2D within 25% errors. In spite of that, the hazard zone from the simulation still included the real disaster range. The combining method for a rainfall infiltration induced a shallow landslide and subsequent debris flow, which was well-matched on a real disaster range on the Daniao tribe’s hill. Therefore, we believe that the TRIGRS and DEBRIS-2D combining methods would provide a better solution for an assessment of a rainfall infiltration inducing shallow landslide and subsequent debris flow motion. TRIGRS could, therefore, provide the area and depth distribution of the collapsed zone, and DEBRIS-2D could use TRIGRS’s results for subsequent debris flow hazard assessment. Furthermore, these results would be of great help in the management of slope disaster prevention.

scholarly journals Applications of simulation technique on debris-flow hazard zone delineation: a case study in Hualien County, Taiwan

2010 ◽  
Vol 10 (3) ◽  
pp. 535-545 ◽  
Author(s):  
S. M. Hsu ◽  
L. B. Chiou ◽  
G. F. Lin ◽  
C. H. Chao ◽  
H. Y. Wen ◽  
...  
Keyword(s):  
Debris Flow ◽  
Yield Stress ◽  
Empirical Model ◽  
Water Conservation ◽  
Debris Flows ◽  
Sediment Concentration ◽  
Hazard Zone ◽  
Debris Flow Hazard ◽  
Debris Flow Disaster ◽  
Soil And Water

Abstract. Debris flows pose severe hazards to communities in mountainous areas, often resulting in the loss of life and property. Helping debris-flow-prone communities delineate potential hazard zones provides local authorities with useful information for developing emergency plans and disaster management policies. In 2003, the Soil and Water Conservation Bureau of Taiwan proposed an empirical model to delineate hazard zones for all creeks (1420 in total) with potential of debris flows and utilized the model to help establish a hazard prevention system. However, the model does not fully consider hydrologic and physiographical conditions for a given creek in simulation. The objective of this study is to propose new approaches that can improve hazard zone delineation accuracy and simulate hazard zones in response to different rainfall intensity. In this study, a two-dimensional commercial model FLO-2D, physically based and taking into account the momentum and energy conservation of flow, was used to simulate debris-flow inundated areas. Sensitivity analysis with the model was conducted to determine the main influence parameters which affect debris flow simulation. Results indicate that the roughness coefficient, yield stress and volumetric sediment concentration dominate the computed results. To improve accuracy of the model, the study examined the performance of the rainfall-runoff model of FLO-2D as compared with that of the HSPF (Hydrological Simulation Program Fortran) model, and then the proper values of the significant parameters were evaluated through the calibration process. Results reveal that the HSPF model has a better performance than the FLO-2D model at peak flow and flow recession period, and the volumetric sediment concentration and yield stress can be estimated by the channel slope. The validation of the model for simulating debris-flow hazard zones has been confirmed by a comparison of field evidence from historical debris-flow disaster data. The model can successfully replicate the influence zone of the debris-flow disaster event with an acceptable error and demonstrate a better result than the empirical model adopted by the Soil and Water Conservation Bureau of Taiwan.

An Approach to the Forecasting of Debris Flow Hazard by Storms from Large Waste-Dump at Open Pit Mines

2014 ◽  
Vol 1065-1069 ◽  
pp. 2337-2341
Author(s):  
Xiao Fei Jing ◽  
Ke Hui Liu ◽  
Zhi Yong Cai ◽  
Xiao Zhou
Keyword(s):  
Debris Flow ◽  
Flow Control ◽  
Open Pit ◽  
Waste Dump ◽  
Research Project ◽  
Open Pit Mines ◽  
Flow Motion ◽  
The Impact ◽  
Debris Flow Hazard ◽  
Debris Flow Disaster

In order to explore the impact of debris flow in large waste-dump which under the situation of rainstorm could cause disasters to the downstream region of the life and property; the research project has chosen a large waste-dump as the engineering background in Jiuzhaigou, Sichuan. According to the theory of the debris flow motion, we have made a deep analysis about the possibilities that waste-dump could cause debris flow disaster under the different frequency of rainstorm; and carried on the forecast analysis about the scope and degree of the calamity in the downstream which caused by the debris flow. The results can provide a reference for debris flow control in the lower reaches.

scholarly journals Spatial variability and potential impacts of climate change on flood and debris flow hazard zone mapping and implications for risk management

2008 ◽  
Vol 8 (3) ◽  
pp. 539-558 ◽  
Author(s):  
H. Staffler ◽  
R. Pollinger ◽  
A. Zischg ◽  
P. Mani
Keyword(s):  
Risk Management ◽  
Debris Flow ◽  
Spatial Variability ◽  
Case Studies ◽  
Climate Changes ◽  
Hazard Mapping ◽  
Hazard Zone ◽  
Debris Flow Hazard ◽  
River Catchments ◽  
Protection Structures

Abstract. The main goals of this study were to identify the alpine torrent catchments that are sensitive to climatic changes and to assess the robustness of the methods for the elaboration of flood and debris flow hazard zone maps to specific effects of climate changes. In this study, a procedure for the identification and localization of torrent catchments in which the climate scenarios will modify the hazard situation was developed. In two case studies, the impacts of a potential increase of precipitation intensities to the delimited hazard zones were studied. The identification and localization of the torrent and river catchments, where unfavourable changes in the hazard situation occur, could eliminate speculative and unnecessary measures against the impacts of climate changes like a general enlargement of hazard zones or a general over dimensioning of protection structures for the whole territory. The results showed a high spatial variability of the sensitivity of catchments to climate changes. In sensitive catchments, the sediment management in alpine torrents will meet future challenges due to a higher rate for sediment removal from retention basins. The case studies showed a remarkable increase of the areas affected by floods and debris flow when considering possible future precipitation intensities in hazard mapping. But, the calculated increase in extent of future hazard zones lay within the uncertainty of the methods used today for the delimitation of the hazard zones. Thus, the consideration of the uncertainties laying in the methods for the elaboration of hazard zone maps in the torrent and river catchments sensitive to climate changes would provide a useful instrument for the consideration of potential future climate conditions. The study demonstrated that weak points in protection structures in future will become more important in risk management activities.

Estimation of spatial soil depth and its application for shallow landslides and debris flow assessment: case study at Mt. Jiri, S. Korea

2020 ◽  
Author(s):  
Minseok Kim ◽  
Jisu Kim ◽  
Hyun-Joo Oh ◽  
Jinkwan Kim
Keyword(s):  
Debris Flow ◽  
Depth Distribution ◽  
Soil Depth ◽  
Critical Role ◽  
Model Performance ◽  
Absolute Error ◽  
Shallow Landslide ◽  
Test Method ◽  
Coefficient Of Determination ◽  
Gps Rtk

<p>Soil depth plays critical role in prediction studies reflecting hydrologic mechanism such as shallow landslide and debris flow although there are many parameters. Thus, many researchers are studying the estimation of soil depth distribution using various methods such as a kriging and artificial neural networks (ANNs) since it is not easy to get a detailed soil depth distribution in field. The aims of this study are 1) to estimate detailed spatial distribution of soil depth (various methods such as ANNs, Kriging, s- and z-model, and c-model) and, 2) to apply them for assessment of shallow landslide instability and debris flow. To do this, soil depth of 760 points using knocking pole test method and elevation datasets using GPS-RTK were collected at Mt Jiri, South Korea. To analysis the accuracy of each estimated soil depth distribution, the lowest root mean square error (RMSE), mean absolute error (MAE) and the highest values of the coefficient of determination (R<sup>2</sup>) were applied and, ANNs method showed reasonable result better than did others. In the effect of shallow landslide instability and debris flow assessment with the each soil depth distribution results, soil depth distribution using an ANNs method also showed high simulated model performance by modified success ratio (MSR). These results indicated that ANNs can be one of the methods to estimate the soil depth distribution for improvement of accuracy of shallow landslide instability mapping and debris flow assessment.</p>

Real-life Field Studies of the NOx Removing Properties of Photocatalytic Surfaces in Roskilde and Copenhagen Airport, Denmark

2020 ◽  
Vol 01 ◽  
Author(s):  
Henrik Jensen ◽  
Pernille D. Pedersen
Keyword(s):  
Air Quality ◽  
High Stability ◽  
Reference Site ◽  
Real Life ◽  
Field Studies ◽  
The Real ◽  
Before And After ◽  
Parking Lot ◽  
Photocatalytic Concrete

Aims: To evaluate the real-life effect of photocatalytic surfaces on the air quality at two test-sites in Denmark. Background: Poor air quality is today one of the largest environmental issues, due to the adverse effects on human health associated with high levels of air pollution, including respiratory issues, cardiovascular disease (CVD), and lung cancer. NOx removal by TiO2 based photocatalysis is a tool to improve air quality locally in areas where people are exposed. Methods: Two test sites were constructed in Roskilde and Copenhage airport. In Roskilde, the existing asphalt at two parking lots was treated with TiO2 containing liquid and an in-situ ISO 22197-1 test setup was developed to enable in-situ evaluation of the activity of the asphalt. In CPH airport, photocatalytic concrete tiles were installed at the "kiss and fly" parking lot, and NOx levels were continuously monitored in 0.5 m by CLD at the active site and a comparable reference site before and after installation for a period of 2 years. Results: The Roskilde showed high stability of the photocatalytic coating with the activity being largely unchanged over a period of 2 years. The CPH airport study showed that the average NOx levels were decreased by 12 % comparing the before and after NOx concentrations at the active and reference site. Conclusion: The joined results of the two Danish demonstration projects illustrate a high stability of the photocatalytic coating as well as a high potential for improvements of the real-life air quality in polluted areas.

scholarly journals A Repeatable and Reproducible Digital Method to Quantify the Cement Excess and Enamel Loss after Debonding Lingual Multibracket Appliance Therapy

2021 ◽  
Vol 11 (3) ◽  
pp. 1295
Author(s):  
Alba Belanche Monterde ◽  
Alberto Albaladejo Martínez ◽  
Alfonso Alvarado Lorenzo ◽  
Adrián Curto ◽  
Jorge Alonso Pérez-Barquero ◽  
...  
Keyword(s):  
Measurement Technique ◽  
Measurement Method ◽  
Dental Arch ◽  
Micro Computed Tomography ◽  
Morphometric Measurement ◽  
Before And After ◽  
Repeatability And Reproducibility ◽  
Lingual Brackets ◽  
Multibracket Appliance ◽  
Area And Volume

The aim of the present study is to present a repeatable, reproductible, and accurate morphometric measurement method for measuring and quantifying the area and volume of cement that remains after fixed lingual multibracket appliance debonding, enamel loss after fixed lingual multibracket appliance debonding, and the volume of cement used to adhere fixed lingual multibracket appliances. Ten conventional lingual brackets were cemented in 10 extracted teeth embedded into an epoxy resin model simulating a dental arch. This model was scanned before and after bonding the lingual brackets, after debonding, and after polishing the surfaces. We also performed a Micro-Computed Tomography scan of the lingual brackets used. Afterward, the standard tessellation language (STL) digital file was aligned, each tooth was segmented individually, and the file was re-aligned using engineer morphometry software. Inter-operator and intra-operator comparative analyses were performed using the ANOVA test, and the repeatability and reproducibility of the morphometric measurement technique were analyzed using Gage R&R statistical analysis. Repeatability showed 0.07% and 0.16% variability associated with the area and volume measures, respectively, while reproducibility showed 0.00% variability associated with the area and volume measures, respectively. In conclusion, the morphometric measurement technique is a repeatable, reproductible, and accurate morphometric measurement method for quantifying the area and volume of cement that remains after fixed lingual multibracket appliance debonding, enamel loss after fixed lingual multibracket appliance debonding, and the volume of cement used to adhere fixed lingual multibracket appliances.

Contact Width Analysis of Corrugated Metal Gasket Based on Surface Roughness

2013 ◽  
Vol 856 ◽  
pp. 92-97 ◽  
Author(s):  
Shigeyuki Haruyama ◽  
Didik Nurhadiyanto ◽  
Ken Kaminishi
Keyword(s):  
Surface Roughness ◽  
The Real ◽  
Real Contact ◽  
Contact Width ◽  
Before And After ◽  
Optimizing Design ◽  
Roughness Evaluation ◽  
Helium Leakage ◽  
Corrugated Metal ◽  
Important Design

Contact width is important design parameter for optimizing design of new metal gasket. The contact width was found have relationship with helium leak quantity. Increasing axial force, the contact width will increase and helium leakage will decrease. This study we conducted the surface roughness evaluation of 25A-size metal gasket before and after use. The results denote the real contact width after contact with flange having different surface roughness. The real contact width for the flange having smoother surface roughness is wider than the rougher one.

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