Numerical simulation of stress distribution

The Rogun hydropower plant is being constructed in Tajikistan, in the valley of the Vakhsh River. The construction site is located in a narrow gorge separating the Vakhsh and Surkh-Ku ridges. Most of the hydroelectric complex structures are located within a single tectonic block, which is bounded by two faults - Ionakhsh and Gulizindan, which are proximal to the Vakhsh regional fault. The study of stress distribution around the diversion tunnel was carried out by numerical simulation, which aimed to identify the stress distribution in the strongly dislocated heterogeneous rock massif before and after the tunnel creation. The underground cavity of the tunnel is a significant factor influencing the natural stress field of the rock massif. An area with critical values of the strength coefficient in the working roof, caused by the presence of a weak layer of Lower Cretaceous siltstones, is revealed in the tunnel location. The size of this area reaches two tunnel diameters. The change of stresses and their concentration around the underground working can cause deformations in the roof (collapse or rock bumps)

Numerical simulation of stress distribution

The Rogun hydropower plant is being constructed in Tajikistan, in the valley of the Vakhsh River. The construction site is located in a narrow gorge separating the Vakhsh and Surkh-Ku ridges. Most of the hydroelectric complex structures are located within a single tectonic block, which is bounded by two faults - Ionakhsh and Gulizindan, which are proximal to the Vakhsh regional fault. The study of stress distribution around the diversion tunnel was carried out by numerical simulation, which aimed to identify the stress distribution in the strongly dislocated heterogeneous rock massif before and after the tunnel creation. The underground cavity of the tunnel is a significant factor influencing the natural stress field of the rock massif. An area with critical values of the strength coefficient in the working roof, caused by the presence of a weak layer of Lower Cretaceous siltstones, is revealed in the tunnel location. The size of this area reaches two tunnel diameters. The change of stresses and their concentration around the underground working can cause deformations in the roof (collapse or rock bumps)

Shallow Landslide Susceptibility Mapping in Sochi Ski-Jump Area Using GIS and Numerical Modelling

The mountainous region of Greater Sochi, including the Olympic ski-jump complex area, located in the northern Caucasus, is always subjected to landslides. The weathered mudstone of low strength and potential high-intensity earthquakes are considered as the crucial factors causing slope instability in the ski-jump complex area. This study aims to conduct a seismic slope instability map of the area. A slope map was derived from a digital elevation model (DEM) and calculated using ArcGIS. The numerical modelling of slope stability with various slope angles was conducted using Geostudio. The Spencer method was applied to calculate the slope safety factors (Fs). The pseudostatic analysis was used to compute Fs considering seismic effect. A good correlation between Fs and slope angle was found. Combining these data, sets slope instability maps were achieved. Newmark displacement maps were also drawn according to empirical regression equations. The result shows that the static safety factor map corresponds to the existing slope instability locations in a shallow landslide inventory map. The seismic safety factor maps and Newmark displacement maps may be applied to predict potential landslides of the study area in the case of earthquake occurrence

Application of GIS-based bivariate statistical methods for landslide potential assessment in Sapa, Vietnam

Актуальность. Прогнозирование и минимизация последствий стихийных бедствий являются важнейшими задачами для правительств во всем мире, включая Вьетнам. Оползни являются одним из наиболее распространенных видов стихийных бедствий во Вьетнаме, особенно в северных горных провинциях, что приводит к значительным человеческим жертвам и материальному ущербу. В этом исследовании для оценки потенциального развития оползней в районе Шапа, провинция Лаокай, применялись статистические методы, с использованием геоинформационных систем (ГИС). Для решения поставленной задачи было отобрано девять факторов, определяющих оползневую восприимчивость на рассматриваемой территории: высота над уровнем моря, расстояние до дорог, крутизна склонов, расстояние от разломов, среднемесячное количество осадков, вертикальное расчленение рельефа, землепользование, тип коры выветривания и расстояние до эрозионной сети. Основная цель исследования заключается в подготовке карт потенциального развития оползней для района Шапа. Кроме того, выполненные работы продемонстрировали эффективность использованных статистических методов при оценке восприимчивости территории к оползневому процессу. Объектом исследования является оползневая восприимчивость в районе Шапа провинции Лаокай (Вьетнам). Методы: статистические методы с использованием ГИС, включая метод соотношения частотностей (англ. Frequency Ratio method - FR), метод анализа оползневой восприимчивости (англ. Landslide Susceptibility Analysis method - LSA) и метод статистического индекса (англ. Statistical Index method - SI). Результаты. Были построены карты потенциального развития оползней для исследуемой территории, которая была разделена на пять зон: очень низкого потенциала, низкого потенциала, среднего потенциала, высокого потенциала и очень высокого потенциала. Площадь под кривой ошибок была использована для оценки достоверности этих моделей. Проценты успеха моделей для тренировочных данных составляют 74,60 % (FR), 70,82 % (LSA) и 76,36 % (SI). Проценты прогнозирования моделей для данных тестирования составляют 77,01 % (FR), 74,36 % (LSA) и 78,11 % (SI). Оценка эффективности моделей показала, что все три метода являются эффективными для оценки потенциального развития оползневого процесса в районе исследования. Результаты исследований имеют исключительно важное значение для планирования землепользования и экономического развития, а также для минимизации ущерба от оползней.The relevance. Predicting and minimizing the impact of natural disasters are critical tasks for governments worldwide, including Vietnam. Landslides are one of the most frequent types of natural disasters in Vietnam, especially in the northern mountainous provinces, resulting in significant loss of life and property. In this study, the GIS-based bivariate statistical methods were applied for assessing landslide potential in Sapa district, Laocai province, Vietnam. For assessing landslide susceptibility, nine landslide-related factors were selected, including elevation, distance to roads, slope, distance to faults, average monthly precipitation, relative relief, land use, crust weathering, and distance to drainage. The main aim of this study is to prepare landslide potential maps for the study area. In addition, the study also demonstrated the effectiveness of bivariate statistical methods for landslide susceptibility assessment. Object of the study is the landslide susceptibility in Sapa district, Laocai province, Vietnam. Methods: GIS-based bivariate statistical methods including frequency ratio, landslide susceptibility analysis, and statistical index. Results. Landslide potential maps were prepared using GIS-based bivariate statistical methods. The study area is divided into five landslide potential zones: very low, low, moderate, high, and very high. The area under the curve of the receiver operating characteristic (AUCROC) was used to evaluate the performance of these models. The success rates of the models for the training data are 74,60 % frequency ratio, 70,82 % landslide susceptibility analysis and 76,36 % statistical index. The prediction rates of the models for the testing data are 77,01 % frequency ratio, 74,36 % landslide susceptibility analysis and 78,11 % statistical index. The performance evaluation of the models revealed that all three techniques are efficient in assessing landslide potential in the study area. Study results are critical for land use planning and economic development, as well as minimizing landslide-related damage

Abstracts of The Second Eurasian RISK-2020 Conference and Symposium

This abstract book contains abstracts of the various research ideas presented at The Second Eurasian RISK-2020 Conference and Symposium.The RISK-2020 Conference and Symposium served as a perfect venue for practitioners, engineers, researchers, scientists, managers and decision-makers from all over the world to exchange ideas and technology about the latest innovation developments dealing with risk minimization