Fuzzy approach in preliminary design of weak rock slopes for lignite mines

Yardımcı, Ahmet Güneş
Slope mass rating (SMR) system, which is an enhanced version of rock mass rating (RMR), is a useful tool to be utilized for the preliminary stability analysis of rock slopes. Parameter scoring systems of both conventional RMR and SMR systems are based on crisp set theory. Common problems of conventional classification systems are assigning sharp boundaries for ranges, the same values for both upper and lower limits of ranges and presence of uncertainties as a result of complex nature of rock. These problems give rise to misleading final scores for rock or slope masses. In the scope of this study, the above mentioned problems of rock mass and slope mass classification systems will be aimed to be overcame by application of fuzzy set theory to RMR and SMR systems. For the preliminary stability assessment, slope performance chart suggested by Bieniawski was investigated in terms of its suitability to weak rock conditions. Later, the chart of Bieniawski was modified based on the back analysis data taken from real failure cases. Critical slope angles considering rock mass failure were determined from this chart using conventional and fuzzified RMR scores. After that, the SMR was used to investigate the structural failure mechanisms. Finally, SMR system was fuzzified similar to RMR by considering real failure cases. The result obtained from conventional and fuzzy systems were compared. It was observed that the fuzzified SMR and RMR produced more representative results than conventional RMR and SMR.


Assessment of rock slope stability by slope mass rating (SMR): A case study for the gas flare site in Assalouyeh, South of Iran
AZARAFZA, Mohammad; Akgün, Haluk; ASGHARI-KALJAHI, Ebrahim (2017-10-01)
Slope mass rating (SMR) is commonly used for the geomechanical classification of rock masses in an attempt to evaluate the stability of slopes. SMR is calculated from the RMR89-basic (basic rock mass rating) and from the characteristic features of discontinuities, and may be applied to slope stability analysis as well as to slope support recommendations.
Probabilistic-numerical modeling of stability of a rock slope in Amasya-Turkey
Gheibie, Sohrab; Akgün, Aykut; Department of Mining Engineering (2011)
Rock slope stability is considered as one of the most important fields in rock engineering. Developments of computation facilities and increase in application of sophisticated mathematical concepts in engineering problems have also affected the methods of slope stability analysis. In recent years, the numerical modeling methods have extensively applied instead of limit equilibrium methods. Also, the probabilistic methods are considered in rock slope designs to quantify the uncertainties of input effecting v...
Fuzzy Rock Mass Rating: Soft-Computing-Aided Preliminary Stability Analysis of Weak Rock Slopes
YARDIMCI, AHMET GÜNEŞ; Karpuz, Celal (2018-01-01)
Rock mass classification systems are the most commonly used empirical tools in preliminary design of rock slopes. In spite of numerous advantages, these systems lack the common drawbacks of classification systems originated from uncertainties. These drawbacks may lead to similar or so close quality scores for different rock mass properties. Fuzzy Sets is a rising trend in describing Geomechanical problems by including the expert opinion. Especially in the case of weak rocks it allows prediction of more real...
Portal slope stability assessment of a proposed highway tunnel in northeastern Turkey
Sopaci, E.; Akgün, Haluk (2009-01-01)
This paper presents an application of the rock mass classification systems, namely, Geomechanics Classification System (RMR), Geological Strength Index (GSI) and the newly adapted A-RMR for the characterization of the rock masses surrounding the portals of the Ordu Peripheral Highway Tunnel. In order to characterize the rock masses, which mainly consist of flysch (mostly alternation of sandstone, marl and siltstone) and pyroclastics (agglomerate and tuff), engineering geological investigations have been car...
Stability Analysis and Optimized Slope Angle for the Iron Ore Open-Pit Mine
Akdağ, S.; Başarır, H.; Karpuz, Celal; Özyurt, M. (2015-04-17)
With an increase in the overall slope height of open pit mines, stability analysis and amount of stripping waste rock becomes progressively difficult. It is necessary to optimize the overall slope angle by increasing it as much as possible with ensuring the mining safety. After comprehensive geotechnical investigation and rock mechanical laboratory tests, the combined use of limit equilibrium and numerical modeling analysis methods increases reliability and accuracy of the stability analysis. With the optim...
Citation Formats
A. G. Yardımcı, “Fuzzy approach in preliminary design of weak rock slopes for lignite mines,” M.S. - Master of Science, Middle East Technical University, 2013.