(Sub)Global Rock Slope Stability: Using Rock Mass Indices to Characterize and Manage Rockfall Risk

GeoRisk 2011 ◽  
2011 ◽  
Author(s):  
Brian Bruckno
2011 ◽  
Vol 08 (02) ◽  
pp. 209-228 ◽  
Author(s):  
HEHUA ZHU ◽  
XIAOYING ZHUANG ◽  
YONGCHANG CAI ◽  
GUOWEI MA

The meshless methods are particularly suitable for modeling problems with discontinuities such as joints in rock mass. The meshless Shepard and least squares (MSLS) method is a newly developed meshless method, which overcomes some limitations with other meshless methods. In the present paper, the MSLS method is extended for modeling jointed rock mass and the joint is modeled as discontinuity governing the near-field stress. A substantial high rock slope by the dam shoulder of Jinping Hydropower Station is analyzed by the developed method. Safety factors are evaluated based on the stress results along potential slip surfaces and compared with the conventional slice methods. The results demonstrate the feasibility of using the MSLS method in rock slope stability analysis and also reveal some interesting differences from the conventional slice methods. Some findings and outstanding issues demonstrated in this study are discussed in the end, which can be the topics for future development.


2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
K. Ma ◽  
N. W. Xu ◽  
Z. Z. Liang

A high-resolution microseismic (MS) monitoring system was implemented at the right bank slope of the Dagangshan hydropower station in May 2010 to analyse the slope stability subjected to continuous excavation. The MS monitoring system could real-time capture a large number of seismic events occurring inside the rock slope. The identification and delineation of rock mass damage subject to excavation and consolidation grouting can be conducted based on the analysis of tempospatial distribution of MS events. However, how to qualitatively evaluate the stability of the rock slope by utilizing these MS data remains challenging. A damage model based on MS data was proposed to analyse the rock mass damage, and a 3D finite element method model of the rock slope was also established. The deteriorated mechanical parameters of rock mass were determined according to the model elements considering the effect of MS damage. With this method, we can explore the effect of MS activities, which are caused by rock mass damage subjected to excavation and strength degradation to the dynamic instability of the slope. When the MS damage effect was taken into account, the safety factor of the rock slope was reduced by 0.18 compared to the original rock slope model without considering the effect. The simulated results show that MS activities, which are subjected to excavation unloading, have only a limited effect on the stability of the right bank slope. The proposed method is proven to be a better approach for the dynamical assessment of rock slope stability and will provide valuable references for other similar rock slopes.


2015 ◽  
Vol 19 (2) ◽  
pp. 147-152 ◽  
Author(s):  
Davood Fereidooni ◽  
Gholam Reza Khanlari ◽  
Mojtaba Heidari

<p>This paper explores the applicability of a modified Q classification system and its component parameters for analysis and conclusion of site investigation data to estimate rock slope stability. Based on the literature, Q classification system has high applicable potential for evaluation of rock mass quality. Therefore, in this study, it was used with RMR and SMR rock mass classification systems to assess stability or instability of different rock slopes along the Hamedan-Ganjnameh-Tuyserkan road, Hamedan province west of Iran. Furthermore, a modified rock mass classification system namely Slope Quality Rating (SQR) was proposed based on the correction of the Q classification parameters and calculating some new parameters such as dip and strike of discontinuities and the method of rock excavation or blasting. For this purpose, the SMR and RMR rock mass classifications were also needed. By measuring SQR for different rock slopes, it will be possible to measure Slope Mass Rating (SMR).</p><p> </p><p><strong>Evaluación del sistema Q modificado de clasificación del macizo rocoso para el análisis de estabilidad de pendiente de roca</strong></p><p> </p><p><strong>Resumen</strong></p>Este artículo explora la aplicabilidad del sistema de clasificación Q modificado y sus parámetros para analizar y determinar la información estimada de estabilidad de pendiente de roca en el sitio determinado de estudio. Según la literatura, el sistema de clasificación Q tiene un alto potencial de aplicabilidad paral a evaluación de la calidad del macizo rocoso. En este estudio además se utilizó el sistema Q junto con los sistemas Índice de Masa de Pendiente (SMR) y Clasificación Geomecánica de Bienawski (RMR) para evaluar la estabilidad e inestabilidad de diferentes pendientes rocosas en la carretera Hamedan-Ganjnameh-Tuyserkan, de la provincia de Hamedan, en el Oeste de Irán. Además, se propone el Índice de Calidad de Pendiente (SQR), un sistema de clasificación de macizo rocoso modificado, a partir de la corrección de los parámetros de clasificación Q y el cálculo de nuevos parámetros como pendiente y caída de las discontinuidades y el método de excavación o explosión de la roca. Para esta propuesta también se utilizaron las clasificaciones SMR y RMR. La medición SQR en diferentes pendientes hizo posible el cálculo del sistema SMR.</p>


2014 ◽  
Vol 59 (3) ◽  
pp. 609-620 ◽  
Author(s):  
Marek Cała ◽  
Michał Kowalski ◽  
Agnieszka Stopkowicz

Abstract The purpose of this paper was to perform the 3D numerical calculations allowing slope stability analysis of Hyttemalmen open pit (location Kirkenes, Finnmark Province, Norway). After a ramp rock slide, which took place in December 2010, as well as some other small-scale rock slope stability problems, it proved necessary to perform a serious stability analyses. The Hyttemalmen open pit was designed with a depth up to 100 m, a bench height of 24 m and a ramp width of 10 m. The rock formation in the iron mining district of Kirkenes is called the Bjornevaten Group. This is the most structurally complicated area connected with tectonic process such as folding, faults and metamorphosis. The Bjornevaten Group is a volcano-sedimentary sequence. Rock slope stability depends on the mechanical properties of the rock, hydro-geological conditions, slope topography, joint set systems and seismic activity. However, rock slope stability is mainly connected with joint sets. Joints, or general discontinuities, are regarded as weak planes within rock which have strength reducing consequences with regard to rock strength. Discontinuities within the rock mass lead to very low tensile strength. Several simulations were performed utilising the RocLab (2007) software to estimate the gneiss cohesion for slopes of different height. The RocLab code is dedicated to estimate rock mass strength using the Hoek-Brown failure criterion. Utilising both the GSI index and the Hoek-Brown strength criterion the equivalent Mohr-Coulomb parameters (cohesion and angle of internal friction) can be calculated. The results of 3D numerical calculations (with FLA3D code) show that it is necessary to redesign the slope-bench system in the Hyttemalmen open pit. Changing slope inclination for lower stages is recommended. The minimum factor of safety should be equal 1.3. At the final planned stage of excavation, the factor of safety drops to 1.06 with failure surface ranging through all of the slopes. In the case of a slope angle 70° for lower stages, FS = 1.26, which is not enough to provide slope stability. Another series of calculations were therefore performed taking water table lowering into consideration, which increases the global safety factor. It was finally evaluated, that for a water table level of 72 m the factor of safety equals 1.3, which is enough to assure global open-pit stability.


2012 ◽  
Vol 594-597 ◽  
pp. 2267-2271
Author(s):  
Ping Chen ◽  
Ming Chen ◽  
Jian Kong ◽  
Yu Liu

The rock slope stability under blasting excavation disturbance is an important study content in the fields of hydropower, mining, transportation and other research field. Basing on a potential slip rock mass of the left slope of Jinping-Ⅰ Hydropower Station, using Sarma method of the limit equilibrium analysis and orthogonal experimental design, the paper analyzed the main factors which affect the slope stability, and studied the sensibilities of the slope stability to various factors under blasting disturbance. The results indicate that the slope stability under blasting disturb is very sensitive to the change of internal correlative of potential slip rock mass. The slope stability under blasting disturb is less sensitive to the change of external correlative factors which are result from the blasting.


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