scholarly journals Practical Method of Predicting Slope Failure Based on Velocity Value (SLO Method) From Slope Stability Radar

2019 ◽  
Vol 1 (1) ◽  
pp. 143-150
Author(s):  
Fery Andika Cahyo ◽  
Audi Farizka ◽  
Ahmad Amiruddin ◽  
Rachmat Hamid Musa
Keyword(s):  
Slope Stability ◽  
Slope Failure ◽  
Maximum Velocity ◽  
Practical Method ◽  
Radar Data ◽  
Time Stamp ◽  
Time Data ◽  
The One ◽  
Log Linear ◽  
Inverse Velocity

Predicting slope failure is one of the most sought after feature from Slope Stability Radar (SSR). An accurate slope failure prediction will potentially give an ample time to manage risk related with slope stability, wherein the evacuation ofequipment or personal would be executed on a timely manner. The renownedmethod to predict failure among geo-mechanical practitioner is utilizing inversevelocity method, in which collapse will be predicted to happen when the extension of inverse velocity line is intercepted at predefined value that is usually only fractal above zero. The tenet of this method is, if one has acquired the knowledge of inverse velocity value from previous collapses, the next collapse could be predicted based on it with the pretext that both share the same nature and geological feature. The same can be said for predicting collapse based on velocity value. Set of maximum velocity value from several previous collapses will be averaged to determine predefined assumption to predict the next collapse. This paper will demonstrate an alternative method to predict collapse that will use velocity value instead of inverse velocity. This method is called SLO method as proposed by Azania Mufundirwa.This paper will specifically exemplify the practical steps to produce the failureprediction from slope stability radar data, and discuss the characteristic of theprediction yield by this method. Velocity chart with velocity calculation period of60 minutes is first established from particular pixel deemed as the one that showing the most distinguished progressive deformation trend. The velocity data will then be an exported and reprocess as such that the time data will be converted into unit time stamp number. The designated time stamp will then be accumulated, in which the onset of failure, will be regarded as time 0 reference. Log linear chart will be generated in which X-axis will be occupied by velocity value, while Y-axis will depict Velocity x Accumulated time (SLO chart). Collapse can subsequently be predicted by intercepting the predefined assumption of velocity during collapse with the log linear curve from the SLO chart. Two methods, mathematical & graphical, will be presented in this paper in order to give in depth understanding as to how one can predict collapse event with velocity value. Taking account on the study case from iron ore mining, SLO method yielded prediction of failuretime on 10:58 PM 31st January 2016, meanwhile the real failure occur on 11:32 PM 31st January 2016.

scholarly journals SLO VS INVERSE VELOCITY METHOD: A STUDY TO EXAMINE EFFECTIVE APPROACH TO PREDICT SLOPE FAILURE

2020 ◽  
Vol 1 (1) ◽  
pp. 525-532
Author(s):  
Maria Christine Rosaria ◽  
Rania Salsabila ◽  
Muhammad Khalif Arda ◽  
Fery Andika Cahyo ◽  
Rachmat Hamid Musa
Keyword(s):  
Slope Stability ◽  
Real Time ◽  
Slope Failure ◽  
Regression Line ◽  
Failure Prediction ◽  
Maximum Velocity ◽  
Time Deformation ◽  
Recent Method ◽  
Inverse Velocity Method ◽  
Inverse Velocity

ABSTRACT Provided with accurate and quasi real time deformation data, there are at least 2 methods that can be utilized to predict a slope failure. Inverse velocity method, coined by Fukuzono, aims at the interception of inverse velocity line to zero value at X time axis as the prediction of slope failure. More recent method called SLO, develop by Mufundirwa, puts emphasize on interception of acceleration regression line with X velocity axis. This paper is intended first and foremost to establish well-structured comparison between the two aforementioned methods. By using the same set of displacement data that show progressive deformation trend from Slope Stability radar, both SLO & Inverse Velocity method will be put into trial. Not only the accuracy of the failure prediction time, but also the comparison between the R2 attribute will be examine to reveal which method that yield better data statistically. One of the selected study case, from several which is presented on the paper, reveal that SLO method give failure prediction closer with the actual failure compared to Inverse Velocity method. The actual failure is happening at 21:59 AM January 1st 2016. SLO method generates failure prediction 10 minutes prior the actual failure, while Inverse Velocity generates failure prediction plus 68 minutes after the failure. R2 value for SLO method and Inverse Velocity method respectively are 0.710 & 0.630. Apart from this results comparison, a more in depth examination toward the nature of both methods delivers pro & con of each method. SLO method seems more accurate but having a constraint in which if there are no previous database of maximum velocity during collapse, prediction is almost impossible to make. Inverse Velocity method could address this flaw by projecting the inverse velocity line to zero value for the very least. Further explanation about the flaw and advantages of both methods will be conveyed in more detail on the later part of this paper.   Key words: Failure Prediction, SLO, Inverse Velocity, SSR  ABSTRAK Dengan adanya pengambilan data deformasi yang akurat dan mendekati “real time”, terdapat setidaknya dua metode yang dapat digunakan untuk memprediksi longsor. Metode inverse velocity, yang dikembangkan oleh Fukuzono, adalah metode yang menggunakan perpotongan grafik inverse velocity dengan titik nol sebagai acuan atau nilai dari prediksi longsor. Metode lain yang lebih baru dibandingkan metode inverse velocity adalah metode SLO yang dikembangkan oleh Mufundirwa. Metode ini lebih ditekankan pada perpotongan antara grafik akselerasi dengan nilai kecepatan pada sumbu X. Tujuan utama dari paper ini adalah penyajian perbandingan yang terstruktur antara kedua metode tersebut. Penelitian terhadap metode SLO dan inverse velocity menggunakan data deformasi progresif yang sama dari Slope Stability Radar. Tidak hanya keakuratan prediksi waktu longsor, tetapi perbandingan nilai R2 pun akan menentukan metode yang lebih efektif secara statistik. Pada salah satu studi kasus, dari beberapa kasus yang dibahas di paper ini, menunjukkan bahwa metode SLO memberikan prediksi waktu longsor yang lebih mendekati waktu longsor yang sebenarnya jika dibandingkan dengan metode inverse velocity. Longsor yang sebenarnya terjadi pada tanggal 1 Januari 2016, pukul 21:59. Metode SLO menghasilkan prediksi longsor 10 menit lebih awal dari waktu longsor yang sebenarnya, dimana metode inverse menghasilkan prediksi longsor 68 menit setelah waktu longsor. Nilai R2 untuk metode SLO dan inverse velocity adalah 0.71 dan 0.63. Di samping perbandingan kedua hasil di atas, pemahaman lebih mendalam tentang sumber dari kedua metode tersebut memunculkan hasil plus dan minus dari masing-masing metode. Metode SLO memang terlihat lebih akurat namun metode ini membutuhkan data kecepatan maksimal saat kejadian longsor sebelumnya. Jika tidak ada, maka prediksi hampir tidak mungkin untuk dibuat. Sebaliknya, kelemahan tersebut tidak terdapat pada metode inverse velocity karena dapat diproyeksikan pada titik nol. Penjelasan lebih dalam mengenai kelebihan dan kekurangan dari kedua metode tersebut akan dibahas selanjutnya pada paper ini. Kata kunci: Prediksi longsor, SLO, Inverse velocity, SSR

scholarly journals Integrated Analysis Method for Stability Analysis and Maintenance of Cut-Slope in Urban

2021 ◽  
Author(s):  
Mincheol Park ◽  
Heuisoo Han ◽  
Yoonhwa Jin
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Slope Failure ◽  
Slope Stability Analysis ◽  
Velocity Curve ◽  
Integrated Analysis ◽  
Cut Slope ◽  
Analysis Method ◽  
Cut Slopes ◽  
Inverse Velocity

In the process of constructing roads for the development of the city, cut-slopes are made by excavating mountains. However, these cut-slopes are degraded in strength by time-deterioration phenomenon, and progressive slope failure is caused. This study developed an integrated analysis method for stability analysis and maintenance of cut-slopes in urban. The slope stability analysis was performed using the finite element model, and the progressive slope failure by time-dependent deterioration was quantified by using the strength parameters of soil applying the strength reduction factor (SRF). The displacements until the slope failure by slope stability analysis were quantified by cumulative displacement curve, velocity curve, and inverse velocity curve and, applied to the slope maintenance method. The inverse-velocity curve applied to the prediction of the time of slope failure was regressed to the 1st linear equation in the brittle material and the 3rd polynomial equation in the ductile material. This is consistent with the proposed formula of Fukuzono and also shows similar behavior to the failure case in literature. In the future, integrated analysis method should be improved through additional research. And it should be applied to cut-slope to prevent disasters.

scholarly journals The Hydromechanical Interplay in the Simplified Three-Dimensional Limit Equilibrium Analyses of Unsaturated Slope Stability

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 73
Author(s):  
Panagiotis Sitarenios ◽  
Francesca Casini
Keyword(s):  
Analytical Solution ◽  
Slope Stability ◽  
Slope Failure ◽  
Failure Modes ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Three Dimensional ◽  
Stability Limit ◽  
Smooth Transition

This paper presents a three-dimensional slope stability limit equilibrium solution for translational planar failure modes. The proposed solution uses Bishop’s average skeleton stress combined with the Mohr–Coulomb failure criterion to describe soil strength evolution under unsaturated conditions while its formulation ensures a natural and smooth transition from the unsaturated to the saturated regime and vice versa. The proposed analytical solution is evaluated by comparing its predictions with the results of the Ruedlingen slope failure experiment. The comparison suggests that, despite its relative simplicity, the analytical solution can capture the experimentally observed behaviour well and highlights the importance of considering lateral resistance together with a realistic interplay between mechanical parameters (cohesion) and hydraulic (pore water pressure) conditions.

scholarly journals An Inverse Source Problem for the Generalized Subdiffusion Equation with Nonclassical Boundary Conditions

2021 ◽  
Vol 5 (3) ◽  
pp. 63
Author(s):  
Emilia Bazhlekova
Keyword(s):  
Boundary Conditions ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Stability Estimates ◽  
Inverse Source Problem ◽  
Time Data ◽  
Final Time ◽  
Generalized Eigenfunction ◽  
The One ◽  
Initial Boundary Value

An initial-boundary-value problem is considered for the one-dimensional diffusion equation with a general convolutional derivative in time and nonclassical boundary conditions. We are concerned with the inverse source problem of recovery of a space-dependent source term from given final time data. Generalized eigenfunction expansions are used with respect to a biorthogonal pair of bases. Existence, uniqueness and stability estimates in Sobolev spaces are established.

scholarly journals Analysis on the Evolution and Microphysical Characteristics of Two Consecutive Hailstorms in Spring in Yunnan, China

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 63
Author(s):  
Sidou Zhang ◽  
Shiyin Liu ◽  
Tengfei Zhang
Keyword(s):  
Wind Speed ◽  
Cloud Model ◽  
Global Analysis ◽  
Maximum Velocity ◽  
Western Pacific Subtropical High ◽  
Convective Cloud ◽  
Radar Data ◽  
Reanalysis Data ◽  
Cloud Water ◽  
High Level

By using products of the cloud model, National Centers for Environmental Prediction (NCEP) Final Operational Global Analysis (FNL) reanalysis data, and Doppler weather radar data, the mesoscale characteristics, microphysical structure, and mechanism of two hail cloud systems which occurred successively within 24 h in southeastern Yunnan have been analyzed. The results show that under the influence of two southwest jets in front of the south branch trough (SBT) and the periphery of the western Pacific subtropical high (WPSH), the northeast-southwest banded echoes affect the southeastern Yunnan of China twice. Meanwhile, the local mesoscale radial wind convergence and uneven wind speed lead to the intense development of convective echoes and the occurrence of hail. The simulated convective cloud bands are similar to the observation. The high-level mesoscale convergence line leads to the development of convective cloud bands. The low-level wind direction or wind speed convergence and the high-level wind speed divergence form a deep tilted updraft, with the maximum velocity of 15 m·s−1 at the −40~−10 °C layer, resulting in the intense development of local convective clouds. The hail embryos form through the conversion or collision growth of cloud water and snowflakes and have little to do with rain and ice crystals. Abundant cloud water, especially the accumulation region of high supercooled water (cloud water) near the 0 °C layer, is the key to the formation of hail embryos, in which qc is up to 1.92 g·kg−1 at the −4~−2 °C layer. The hail embryos mainly grow by collision-coalescence (collision-freezing) with cloud water (supercooled cloud drops) and snow crystal riming.

Optimized Based on Cloud Model Extension Assessment of Slope Stability

2010 ◽  
Vol 163-167 ◽  
pp. 2709-2714
Author(s):  
Feng Guo ◽  
Wei Ya Xu ◽  
Fei Xu
Keyword(s):  
Slope Stability ◽  
Cloud Model ◽  
Assessment Model ◽  
Actual State ◽  
Hydropower Project ◽  
Model Extension ◽  
Project Construction ◽  
The One ◽  
Cloud Model Theory

Evaluation of slope stability in the hydropower project construction is extremely important. This Cloud Model will be introduced to the matter-element extension, the extension assessment is proposed based on the sutra field division of the slope stability assessment model. This method combines the Cloud Model theory and the advantages of the extension assessment .On the one hand, the division of the sutra field by means of Cloud Model can overcome the "hard" division of the evils. On the other hand,with different values of Cloud Drops as a sutra field, the statistical results of Cloud Drops can be used as last stable assessment results. Project case study shows that compared with the conventional method, results of the method of extension are more accurate, which fully accorded with the actual state, proving optimized based on Cloud Model extension assessment of slope stability feasible and effective.

scholarly journals Deep permafrost evolution in unstable slopes during the Holocene

2018 ◽  
Author(s):  
Julien Seguinot
Keyword(s):  
Slope Failure ◽  
Time Lag ◽  
Great Influence ◽  
Ground Surface ◽  
Heat Diffusion ◽  
Failure Initiation ◽  
Finite Element Software ◽  
Hand Model ◽  
The One ◽  
Ice Pressure

Large alpine landslides dynamics are generally associated with Quaternary glacier retreat. Some recent datations demonstrate that several thousand years can separate the slope failure initiation from ice pressure unloading. The current study addresses the question whether the persistence of deep permafrost could produce this time lag. A model of deep permafrost evolution is developed, including heat diffusion, phase change and a ground surface transfer function. It is numerically implemented by a 1D finite difference code on the one hand and into a 2D finite element software on the other hand. Model results reveals the great influence of porosity and near-ground processes in permafrost evolution, and illustrates the possible persistence of a permafrost core into the slope.

scholarly journals Characteristics of ground motion and threshold values for colluvium slope displacement induced by heavy rainfall: a case study in northern Taiwan

2016 ◽  
Vol 16 (6) ◽  
pp. 1309-1321 ◽  
Author(s):  
Ching-Jiang Jeng ◽  
Dar-Zen Sue
Keyword(s):  
Slope Stability ◽  
Heavy Rainfall ◽  
Slope Failure ◽  
Drainage System ◽  
Threshold Value ◽  
Slope Instability ◽  
Disaster Prevention ◽  
Strain Gages ◽  
Slope Displacement ◽  
Northern Taiwan

Abstract. The Huafan University campus is located in the Ta-lun Shan area in northern Taiwan, which is characterized by a dip slope covered by colluvium soil of various depths. For slope disaster prevention, a monitoring system was constructed that consisted of inclinometers, tiltmeters, crack gages, groundwater level observation wells, settlement and displacement observation marks, rebar strain gages, concrete strain gages, and rain gages. The monitoring data derived from hundreds of settlement and displacement observation marks were analyzed and compared with the displacement recorded by inclinometers. The analysis results revealed that the maximum settlement and displacement were concentrated on the areas around the Hui-Tsui, Zhi-An, and Wu-Ming buildings and coincided with periods of heavy rainfall. The computer program STABL was applied for slope stability analysis and modeling of slope failure. For prevention of slope instability, a drainage system and tieback anchors with additional stability measures were proposed to discharge excess groundwater following rainfall. Finally, threshold value curves of rainfall based on slope displacement were proposed. The curves can be applied for predicting slope stability when typhoons are expected to bring heavy rainfall and should be significant in slope disaster prevention.

scholarly journals Combined rock slope stability and shallow landslide susceptibility assessment of the Jasmund cliff area (Rügen Island, Germany)

2009 ◽  
Vol 9 (3) ◽  
pp. 687-698 ◽  
Author(s):  
A. Günther ◽  
C. Thiel
Keyword(s):  
Slope Stability ◽  
Landslide Susceptibility ◽  
Slope Failure ◽  
Rock Slope ◽  
Shallow Landslide ◽  
Material Strength ◽  
Spatial Integration ◽  
Inventory Data ◽  
Susceptibility Analysis ◽  
Susceptibility Model

Abstract. In this contribution we evaluated both the structurally-controlled failure susceptibility of the fractured Cretaceous chalk rocks and the topographically-controlled shallow landslide susceptibility of the overlying glacial sediments for the Jasmund cliff area on Rügen Island, Germany. We employed a combined methodology involving spatially distributed kinematical rock slope failure testing with tectonic fabric data, and both physically- and inventory-based shallow landslide susceptibility analysis. The rock slope failure susceptibility model identifies areas of recent cliff collapses, confirming its value in predicting the locations of future failures. The model reveals that toppling is the most important failure type in the Cretaceous chalk rocks of the area. The shallow landslide susceptibility analysis involves a physically-based slope stability evaluation which utilizes material strength and hydraulic conductivity data, and a bivariate landslide susceptibility analysis exploiting landslide inventory data and thematic information on ground conditioning factors. Both models show reasonable success rates when evaluated with the available inventory data, and an attempt was made to combine the individual models to prepare a map displaying both terrain instability and landslide susceptibility. This combination highlights unstable cliff portions lacking discrete landslide areas as well as cliff sections highly affected by past landslide events. Through a spatial integration of the rock slope failure susceptibility model with the combined shallow landslide assessment we produced a comprehensive landslide susceptibility map for the Jasmund cliff area.

scholarly journals Spatial and Temporal Evolution of the Infiltration Characteristics of a Loess Landslide

2020 ◽  
Vol 9 (1) ◽  
pp. 26 ◽  
Author(s):  
Dongdong Yang ◽  
Haijun Qiu ◽  
Yanqian Pei ◽  
Sheng Hu ◽  
Shuyue Ma ◽  
...  
Keyword(s):  
Slope Stability ◽  
Slope Failure ◽  
Temporal Evolution ◽  
Infiltration Rate ◽  
Middle Part ◽  
Loess Landslide ◽  
Infiltration Rates ◽  
Disturbed Soil ◽  
Landslide Body ◽  
Over Time

Infiltration plays an important role in influencing slope stability. However, the influences of slope failure on infiltration and the evolution of infiltration over time and space remain unclear. We studied and compared the infiltration rates in undisturbed loess and disturbed loess in different years and at different sites on loess landslide bodies. The results showed that the average initial infiltration rate in a new landslide body (triggered on 11 October 2017) were dramatically higher than those in a previous landslide body (triggered on 17 September 2011) and that the infiltration rates of both landslide types were higher than the rate of undisturbed loess. The initial infiltration rate in the new landslide body sharply decreased over the 4–5 months following the landslide because of the appearance of physical crusts. Our observations indicated that the infiltration rate of the disturbed soil in a landslide evolved over time and that the infiltration rate gradually approached that of undisturbed loess. Furthermore, in the undisturbed loess, both the initial and quasi-steady infiltration rates were slightly higher in the loess than in the paleosol, and in the previous landslide body, the infiltration rate was highest in the upper part, intermediate in the middle part, and lowest in the lower part. This study can help us to better understand the evolution process of infiltration in undisturbed loess, previous landslides, and new landslides.

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