scholarly journals Evaluation of failure of slopes with shaking-induced cracks in response to rainfall

Landslides ◽  
2021 ◽  
Author(s):  
Jiawei Xu ◽  
Kyohei Ueda ◽  
Ryosuke Uzuoka
Keyword(s):  
Main Crack ◽  
Rainfall Intensity ◽  
Slip Surface ◽  
Deformation Pattern ◽  
Rain Event ◽  
Main Scarp ◽  
Surface Location ◽  
Triggering Mechanisms ◽  
Different Levels ◽  
Centrifuge Model Tests

AbstractCentrifuge model tests on slopes subject to shaking and rainfall have been performed to examine the response of slopes with shaking-induced cracks to subsequent rainfall and evaluate the corresponding landslide-triggering mechanisms. The failure pattern of the slope subject to shaking and then rainfall was found different from that of the slope subject to only rainfall. When shaking caused cracks on the slope shoulder and rupture line below, the mobilized soil slid along the slip surface that extended to the rupture line, the main crack became the crown of the undisturbed ground once the slope was subject to a subsequent rain event, and the progression of the landslide was related to the rainfall intensity. During the landslide caused by light rainfall, the main scarp kept exposing itself in the vertically downward direction while the ground behind the main crack in the crack-containing slope remained undisturbed. The detrimental effect of cracks on soil displacement was more evident when the slope was exposed to heavy post-shaking rainfall, resulting in a rapid and massive landslide. Additionally, the volume of displaced material of the landslide, the main scarp area on the upper edge, and the zone of accumulation were larger in the crack-containing slope subject to heavy rainfall, in comparison with those in the crack-free slope. The deformation pattern of slopes with shaking-induced cracks during rainfall was closely related to rainfall intensity and the factor of safety provided a preliminary estimation of slope stability during rainfall. Moreover, even when subjected to the same rainfall, the slopes with antecedent shaking-induced cracks displayed different levels of deformation. The slope that experienced larger shaking had greater deformation under the following rainfall, and the shaking-induced slope deformation also controlled the slip surface location. Finally, the velocity of rainfall-induced landslide could be greatly influenced by the prior shaking event alone. Despite being under light rainfall, the slope that has encountered intense previous shaking exhibited an instant landslide.

scholarly journals Error in the Sampling Area of an Optical Disdrometer: Consequences in Computing Rain Variables

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
R. Fraile ◽  
A. Castro ◽  
M. Fernández-Raga ◽  
C. Palencia ◽  
A. I. Calvo
Keyword(s):  
Rainfall Intensity ◽  
Rain Event ◽  
Rain Intensity ◽  
Sampling Area ◽  
The Real ◽  
Efficient Sampling ◽  
Real Value ◽  
Effective Sampling Area ◽  
Reflectivity Factor

The aim of this study is to improve the estimation of the characteristic uncertainties of optic disdrometers in an attempt to calculate the efficient sampling area according to the size of the drop and to study how this influences the computation of other parameters, taking into account that the real sampling area is always smaller than the nominal area. For large raindrops (a little over 6 mm), the effective sampling area may be half the area indicated by the manufacturer. The error committed in the sampling area is propagated to all the variables depending on this surface, such as the rain intensity and the reflectivity factor. Both variables tend to underestimate the real value if the sampling area is not corrected. For example, the rainfall intensity errors may be up to 50% for large drops, those slightly larger than 6 mm. The same occurs with reflectivity values, which may be up to twice the reflectivity calculated using the uncorrected constant sampling area. TheZ-Rrelationships appear to have little dependence on the sampling area, because both variables depend on it the same way. These results were obtained by studying one particular rain event that occurred on April 16, 2006.

scholarly journals Effectiveness of Three Post-Harvest Rehabilitation Treatments for Runoff and Sediment Reduction on Skid Trails in the Hyrcanian Forests

2020 ◽  
Vol 41 (2) ◽  
pp. 309-324
Author(s):  
Meghdad Jourgholami ◽  
Masoumeh Ahmadi ◽  
Farzam Tavankar ◽  
Rodolfo Picchio
Keyword(s):  
Leaf Litter ◽  
Sediment Yield ◽  
Rainfall Intensity ◽  
Regression Equations ◽  
Negative Effects ◽  
Diverse Range ◽  
Straw Mulch ◽  
The Impact ◽  
Different Levels ◽  
Runoff And Sediment Yield

Ground-based skidding operations can lead to soil compaction and displacement, which could cause negative effects on forest soil. Hence, some efforts such as forestry best management practices (BMPs) must be implemented in the prone area to mitigate these possible impacts. Several materials and treatments have been adopted to suppress these adverse effects by increasing the ground cover. However, the effects of mulch treatments on runoff and sediment yield are inconclusive with a diverse range of effectiveness. For these reasons, in this research mulch treatments were tested as to determine how the application of organic mulch amendments such as straw and leaf litter and contour-felled logs would alleviate the runoff and sediment yield on machine operating trails and ensure successful hillslope stabilization. The aims of the study were to analyse and compare the effectiveness of leaf litter (LM) and straw mulch (SM) rate and different distances of contour-felled logs (CFL) to mitigate the runoff and sediment yield, and examine the impact of rainfall intensity on effectiveness of litter mulch, straw mulch, and contour-felled logs. Totally, 30 bounded runoff plots in the machine operating trails and four treatments including litter mulch (LMR1: 0.62, LMR2: 1.24, and LMR3: 1.86 kg m-2), straw mulch (SMR1: 0.45, SMR2: 0.92, and SMR3: 1.34 kg m-2), contour-felled logs (CFL10: 10, CFL20: 20, and CFL30: 30 m), and untreated area were established in triplicate with 4 m width and 100 m length. During the study period, the runoff and sediment yield in the untreated trails (U) were 2.36 mm and 11.84 g m-2. Straw (from 41.5 to 60.6%) and litter mulch (from 38.1 to 55.1%), and contour-felled logs treatments (from 70.8 to 88.1%) significantly decreased the runoff, compared to U treatment. Results show that mulch treatments with three different levels of Litter Mulch Rate, LMR1, LMR2, and LMR3 decreased mean sediment by 46.6, 64.0 and 71.8%, in the treatments with three different levels of Straw Mulch Rate, SMR1, SMR2, and SMR3 decreased mean sediment by 42.9, 62.1, and 69.9%, and in the treatments with three different distances of Contour-Felled Logs, CFL10, CFL20, and CFL30 decreased mean sediment by 90.6, 94.7 and 88.3% comparing to U, respectively. The relationships of the runoff and sediment responses to increasing mulching rate of litter and straw followed as negative logarithmic curves, but the decreasing-increasing trends were observed in runoff and sediment yield as the distance between contour-felled logs increased from 10 to 30 m. Polynomial regression equations were developed for predicting the runoff and sediment yield as a function of the application rate of litter and straw mulch and the distance between contour-felled logs, and rainfall intensity. We concluded that contour-felled logs treatment was more effective than both litter and straw mulch to mitigate the runoff, runoff coefficient, and sediment yield on machine operating trails. As a management measure, it could be possible to propose that the contour-felled logs with a distance of 20 m be prescribed to protect the machine operating trails from the negative effects of surface waterflow.

scholarly journals Hydrologic Performance of an Extensive Green Roof in Syracuse, NY

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1535
Author(s):  
Mallory Squier-Babcock ◽  
Cliff I. Davidson
Keyword(s):  
New York ◽  
Soil Moisture ◽  
Rainfall Intensity ◽  
Green Roof ◽  
Rain Event ◽  
Climate Conditions ◽  
Extensive Green Roof ◽  
Peak Runoff ◽  
Roof Design ◽  
Hydrologic Performance

Green roof performance reported in literature varies widely—the result of differences in green roof design and climate, as well as limitations in study design and duration. The need exists for full-scale studies under real climate conditions to inform the design, modeling, and planning of new green roof installations. The purpose of this study is to quantify hydrologic performance of a large green roof and characterize its dominant physical processes. To achieve this, a 5550 m2 extensive green roof in Syracuse, New York, designed to hold a 25.4 mm rain event, is monitored for 21 months. Over the monitoring period, the roof retains 56% of the 1062 mm of rainfall recorded. Peak runoff is reduced by an average of 65%. Eleven events exceed 20 mm and are responsible for 38% of the rainfall and 24% of the annual retention. Retention in the summer is lower than that in the fall or spring, as a result of greater rainfall intensity during the period sampled. Soil moisture during winter months remains high, reducing the ability of the roof to retain rainfall volume from new events. Comparison of seasonal data demonstrates the strong influence of rainfall intensity on runoff and the effect of initial soil moisture on event retention.

scholarly journals Water dynamics at the urban soil-atmosphere interface—rainwater storage in paved surfaces and its dependence on rain event characteristics

2020 ◽  
Author(s):  
Thomas Nehls ◽  
Andre Peters ◽  
Fabian Kraus ◽  
Yong Nam Rim
Keyword(s):  
Rainfall Intensity ◽  
Water Dynamics ◽  
Urban Hydrology ◽  
Temperate Climate ◽  
Rain Event ◽  
Rainfall Distribution ◽  
Event Distribution ◽  
Rain Events ◽  
Hydrology Modeling ◽  
System Characteristics

Abstract Purpose The surface store governs the rainwater partition, e.g., water storage and evaporation on paved surfaces, especially for low-intensity and low-sum rain events, which account for the greatest part of the total rainfall in a temperate climate city like Berlin, Germany. The surface store S is a fixed value, dependent on surface relief and pore system characteristics. Contrary, in this study, the surface storage was assumed to depend also on the rain intensity, thus being variable from event to event. Materials and methods The surface store filling dynamics for dense (DP), porous (PP), and highly infiltrative (IP) paving materials were studied in a rainfall simulator. Irrigation intensities p ranged from 0.016 to 0.1 mm min−1 which represent the 25 to 88% quantiles of the rain event distribution in Berlin, Germany (1961 to 1990). Results and discussion Three surface stores can be separated: storage until initial runoff, Sf, at maximum filling, Sm, and for steady-state runoff, Seq—all of them can be regarded as effective stores depending on the aim of its use. The equilibrium store varies from 0.2 to 3 mm for DP, PP, and IP for the investigated rainfall intensities. Conclusions For all pavers, the surface store depends on rainfall intensity, which was shown experimentally and confirmed by numerical simulation of the infiltration. We introduce a simple and robust method to describe Sf, Sm = f(p) for different pavers. Pavers can evaporate a multiple of their surface store per day, depending on the rainfall distribution, which implicates the need for high temporal resolutions in urban hydrology modeling. Pavers can evaporate a multiple of their surface store per day, depending on the rainfall distribution. That implicates the need for high temporal resolutions in urban hydrology modeling.

Identification of slip surface location by TLS-GPS datafor landslide mitigation case study: Ciloto-Puncak, West Java

2015 ◽  
Author(s):  
Vera Sadarviana ◽  
Hasanuddin Z. A. ◽  
Joenil K. ◽  
Djoko Santoso ◽  
Irwan G. ◽  
...  
Keyword(s):  
Slip Surface ◽  
West Java ◽  
Landslide Mitigation ◽  
Surface Location

scholarly journals The Effect of Rainfall Intensity to Landslide Run-Out Prediction and Velocity: A Parametric Study on Landslide Zones in West Java-Indonesia

2021 ◽  
Vol 56 (3) ◽  
pp. 540-548
Author(s):  
S. Feranie ◽  
T. M. Khoiriyah ◽  
F.D.E. Jabbar ◽  
A. Tohari
Keyword(s):  
Parametric Study ◽  
Rainfall Intensity ◽  
Slip Surface ◽  
Landslide Risk ◽  
Lumped Mass ◽  
Mass Model ◽  
West Java ◽  
Landslide Volume ◽  
Surface Development ◽  
Lumped Mass Model

Assessment and management of landslide risk require the knowledge of landslide run-out distance and velocity. However, the landslide volume as the basis for calculating landslide run-out distance and velocity is governed by slip surface development during rainfall. Thus, it is necessary to understand how rainfall characteristics influence landslide run-out and velocity. This paper presents a parametric study to clarify the effect of rainfall intensity on landslide run-out and velocity of two steep volcanic cut-hillslopes in West Java, Indonesia. The landslide volumes were estimated from the potential sliding surface obtained from slope stability analysis under a rainfall infiltration. The landslide run-out and velocity were then calculated using an energy conservation formula in a lumped mass model. This study shows that the slip surface developed at a different depth in each slope, depending on the rainfall intensity. As a result, the landslide run-out and velocity of both cut-hillslope are significantly different and, in general, decrease to reach a constant value with increasing rainfall intensity. Thus, the results of this study can be used as a guideline to assess the rainfall-induced landslide movement, especially in cut-hillslopes.

scholarly journals Estimation of a Landslide Slip Surface Location by a Fuzzy Inference Method

Landslides ◽  
1995 ◽  
Vol 32 (1) ◽  
pp. 1-7_1
Author(s):  
Hiroyuki YOSHIMATSU ◽  
Saburo NAKAMURA
Keyword(s):  
Fuzzy Inference ◽  
Slip Surface ◽  
Inference Method ◽  
Surface Location

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

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