scholarly journals Simulation of Slope Failure Distributions Due to Heavy Rain on an Island Composed of Highly Weathered Granodiorite Based on the Simple Seepage Analysis

2021 ◽  
Vol 16 (4) ◽  
pp. 626-635
Author(s):  
Takatsugu Ozaki ◽  
Akihiko Wakai ◽  
Go Sato ◽  
Takashi Kimura ◽  
Takanari Yamasaki ◽  
...  
Keyword(s):  
Laboratory Tests ◽  
Slope Failure ◽  
Water Movement ◽  
Heavy Rain ◽  
Prediction Equation ◽  
Soil Test ◽  
Seepage Analysis ◽  
Rainfall Seepage ◽  
Heavy Rains

To fully and rapidly develop a real-time early warning judgment system for slope failure at the time of heavy rains including overseas, it is necessary to predict water movement in the soil at the time of rainfall. In addition, to apply the system to a place where insufficient geotechnical and geological data have been amassed, it is necessary to evaluate the risk of slope failure based on physical properties obtained from a simple soil test. Therefore, in this study, the authors set Gogoshima Island in Ehime Prefecture as a study site and evaluated the water movement over time in the soil during heavy rain using a simple prediction equation of rainfall seepage process. Soil properties were determined through simple in-situ and laboratory tests. As a result, it was found that the factor of safety for slope failure in the head and wall of a valley dissecting the hillside slope composed of granodiorite in which weathering has progressed can be planarly evaluated using the simple prediction equation.

scholarly journals SLOPE FAILURE RISK ASSESSMENT MODELING USING TOPOGRAPHIC DATA AND NUMERICAL CALCULATION OF SOIL CONSERVATION BY TREE ROOT SYSTEMS

2019 ◽  
Vol IV-2/W5 ◽  
pp. 217-222
Author(s):  
T. Mori ◽  
T. Sugiyama ◽  
I. Hosooka ◽  
M. Nakata ◽  
K. Okano ◽  
...  
Keyword(s):  
Risk Assessment ◽  
At Risk ◽  
Slope Failure ◽  
Forest Type ◽  
Heavy Rain ◽  
Root Systems ◽  
Topographic Data ◽  
Relative Risk Assessment ◽  
External Forces ◽  
Heavy Rains

<p><strong>Abstract.</strong> In Japan, the frequency of sudden heavy rain events has recently increased, causing slope failures that in turn increase rates of damage to transit infrastructure such as railways and roads. To reduce this damage, there is a need to identify locations near railroad tracks that are at risk of slope failure. Thus, an assessment that predicts whether or not damage will occur due to external forces such as heavy rains is required, rather than a simple relative risk assessment based on identifying locations similar to those damaged in previous events. In this study, we developed a method for time series stability assessment of slopes during heavy rains using digital topographic data. This method uses topographic data to estimate topsoil thickness, which contributes to stability, and soil strength, which is affected by the root systems of vegetation on slopes. Using differences in these parameters between tree species and forest type, we were able to calculate slope stability and simulate slope failure during rainfall. The simulations allowed us to evaluate locations along routes where previous failures occurred, and to identify at-risk locations that have not yet experienced slope failure. This approach will improve forest management based on risk assessments for intensifying heavy rains.</p>

scholarly journals Behavior analysis by model slope experiment of artificial rainfall

2016 ◽  
Vol 16 (3) ◽  
pp. 789-800 ◽  
Author(s):  
Min Cheol Park
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Slope Failure ◽  
Initial Conditions ◽  
Matric Suction ◽  
Slope Stability Analysis ◽  
Seepage Analysis ◽  
Porewater Pressure ◽  
Model Slope ◽  
Rainfall Seepage

Abstract. In this study, we performed a model slope experiment with rainfall seepage, and the results were compared and verified with the unsaturated slope stability analysis method. In the model slope experiment, we measured the changes in water content and matric suction due to rainfall seepage, and determined the time at which the slope failure occurred and the shape of the failure. In addition, we compared and verified the changes in the factor of safety and the shape of the failure surface, which was calculated from the unsaturated slope stability analysis with the model experiment. From the results of experiment and analysis, it is concluded that the unsaturated slope stability analysis can be used to accurately analyze and predict rainfall-induced slope failure. It is also concluded that in seepage analysis, setting the initial conditions and boundary conditions is very important. If engineers will use the measured porewater pressure or matric suction, the accuracy of analysis can be enhanced. The real-time monitoring system of porewater pressure or matric suction can be used as a warning of rainfall-induced slope failure.

scholarly journals Laboratory and In Situ Determination of Hydraulic Conductivity and Their Validity in Transient Seepage Analysis

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1131
Author(s):  
Soonkie Nam ◽  
Marte Gutierrez ◽  
Panayiotis Diplas ◽  
John Petrie
Keyword(s):  
Hydraulic Conductivity ◽  
Field Measurements ◽  
Natural Soil ◽  
In Situ Tests ◽  
Seepage Analysis ◽  
Soil Deposits ◽  
Seepage Modeling ◽  
Sample Disturbance

This paper critically compares the use of laboratory tests against in situ tests combined with numerical seepage modeling to determine the hydraulic conductivity of natural soil deposits. Laboratory determination of hydraulic conductivity used the constant head permeability and oedometer tests on undisturbed Shelby tube and block soil samples. The auger hole method and Guelph permeameter tests were performed in the field. Groundwater table elevations in natural soil deposits with different hydraulic conductivity values were predicted using finite element seepage modeling and compared with field measurements to assess the various test results. Hydraulic conductivity values obtained by the auger hole method provide predictions that best match the groundwater table’s observed location at the field site. This observation indicates that hydraulic conductivity determined by the in situ test represents the actual conditions in the field better than that determined in a laboratory setting. The differences between the laboratory and in situ hydraulic conductivity values can be attributed to factors such as sample disturbance, soil anisotropy, fissures and cracks, and soil structure in addition to the conceptual and procedural differences in testing methods and effects of sample size.

Heart rate recording method validated by whole body indirect calorimetry in 10-yr-old children

1996 ◽  
Vol 81 (3) ◽  
pp. 1169-1173 ◽  
Author(s):  
A. Bitar ◽  
M. Vermorel ◽  
N. Fellmann ◽  
M. Bedu ◽  
A. Chamoux ◽  
...  
Keyword(s):  
Heart Rate ◽  
Indirect Calorimetry ◽  
Laboratory Tests ◽  
Prediction Equation ◽  
Whole Body ◽  
Healthy Children ◽  
Recording Method ◽  
Mean Differences ◽  
Best Fit ◽  
Heart Rate Recording

The aim of the study was to validate the heart rate (HR) recording method against whole body indirect calorimetry in prepubertal children. Nineteen 10.5-yr-old healthy children (10 boys, 9 girls) participated in this study. HR and energy expenditure (EE) were recorded through laboratory tests. Individual relationships between HR and EE were computed (equation established in laboratory). Several models were tested and validated from 24-h measurements of EE and HR by whole body indirect calorimetry. The best fit was obtained with individual polynomial relationships. Mean differences between predicted (equation established in laboratory) and measured total daily EE averaged 7.6 +/- 20.1%. The causes of the differences and the means of improving the accuracy of the prediction equation are discussed.

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