Assessment of spalling occurrence using fuzzy probability theory and damage index in underground openings

Spalling is a kind of instability phenomenon of surrounding rock around underground openings subjected to high in-situ stress according to the development of extension fractures. Three kinds of spalling criteria have been presented so far; however, all spalling criteria have the range of values so that the fuzziness and vagueness of spalling criterion cannot be avoided. In this study, a new fuzzy probability model is proposed to predict the probability of spalling in a systematic way by using fuzzy probability theory. Many of the underground opening projects worldwide are evaluated with the proposed method. Prediction results expressed as the spalling probability agree well with the in-situ observations. In particular, a new fuzzy probability model considering all three evaluation indices of spalling by adopting weighting factors based on relative reliability among three evaluation indices is able to resolve erroneous prediction of spalling by choosing only one prediction method. Moreover, the more reasonable value of spalling probability could have been obtained by adopting the modified damage index to the newly proposed fuzzy probability model.

keywords: Brittle failure, spalling, fuzzy probability theory, damage index, 취성파괴, 스폴링, 퍼지확률이론, 손상지수, Brittle failure, spalling, fuzzy probability theory, damage index

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Article Contents

Vol.12 No.1

Assessment of spalling occurrence using fuzzy probability theory and damage index in underground openings

Abstract

Reference

(사)한국터널지하공간학회