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Probabilistic Analysis for Rock Slope Stability Due to Weathering Process  

Park, Hyuck-Jin (Dept. of Geoinformation Engineering, Sejong University)
Woo, Ik (Dept. of Coastal Construction Engineering, Kunsan National University)
Um, Jeong-Gi (Dept. of Energy Resources Engineering, Pukyong National University)
Publication Information
Economic and Environmental Geology / v.42, no.4, 2009 , pp. 357-366 More about this Journal
Abstract
Since weathering weakens the rock fabric and exaggerates any structural weakness, it affects mechanical properties as well as physical and chemical properties of rock. Weathering leads to a decrease in density, strength, friction angle and cohesion, and subsequently it affects negatively on the stability of rock slope. The purpose of the study is to investigate the changes of the rock slope stability caused by discontinuities which have different weathering grades. For that, the discontinuity samples which are divided into two different weathering grades are obtained from the field and tested their mechanical properties such as JCS, JRC and residual friction angle. In order to evaluate the effects on the stability of slope due to weathering, the deterministic analysis is carried out. That is, the factors of safety for planar failure are calculated for rock masses which have two different weathering grades, such as fresh and weathered rock mass. However, since the JRC and friction angle values are widely scattered and the deterministic analysis cannot consider the variation, the factors of safety cannot represent properly the stability of the rock slope. Therefore, the probabilistic analysis has been used to consider the scattered values. In the deterministic analysis, the factors of safety for the fresh discontinuity and weathered discontinuity are 1.25 and 1.0, respectively. The results indicate the fresh discontinuities are stable for planar failure and the weathered discontinuities are marginally stable. However, the probabilities of failure for the fresh discontinuity and weathered discontinuity are 25.6% and 45.9%, respectively. This shows that both discontinuities are analyzed as unstable in the probabilistic analysis.
Keywords
weathering; JRC(Joint roughness coefficient); JCS(Joint wall compressive strength); residual friction angle; probability of failure;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
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