Shattering a Half-Century Misconception: The Truth About “Class II Rocks”

主講人 : 蔡明 教授

The classification of rocks into “Class I” and “Class II” has long shaped how we interpret and utilize post-peak stress–strain curves in rock mechanics. But do Class II rocks truly exist? In this talk, we will revisit this fundamental question.

We begin with a historical overview of servo-controlled rock testing machines and trace the development of stiff testing systems. After highlighting key pioneering contributions, we critically discuss common misconceptions surrounding the Class I/Class II dichotomy. Drawing on recent experimental evidence, we explore the mechanisms that produce apparent Class II post-peak behavior.

Key factors—including machine stiffness, loading control mode, confining pressure, rock type, and specimen geometry (especially the height-to-diameter ratio)—are examined for their influence on post-peak stress–strain responses. We also address how misinterpretations of Class II behavior have fueled persistent misunderstandings in the rock mechanics community.

This session is intended for anyone studying or working with rock behavior under stress—whether in the laboratory, the field, or numerical simulations. Join us to challenge conventional views and gain a clearer understanding of the physical mechanisms that govern rock deformation.

主講人簡介：

蔡明教授現(xiàn)為加拿大勞倫森大學終身教授和地質(zhì)力學講席教授。他擁有逾 30 年學術(shù)、科研及工業(yè)界從業(yè)經(jīng)驗，主要研究方向包括：脆性巖石破壞、巖石試驗、數(shù)值模擬、沖擊地壓條件下的巷道支護設(shè)計，以及深部采礦工程巖體穩(wěn)定性評價。其學術(shù)成果在全球采礦與巖土工程領(lǐng)域具有深遠影響力，已發(fā)表學術(shù)論文260 余篇，谷歌學術(shù)總引用量超17000 次，工程咨詢報告50 余篇，相關(guān)研究成果已成為行業(yè)標桿規(guī)范。目前是國際權(quán)威學術(shù)刊物Rock Mechanics and Rock Engineering, Tunnelling and Underground Space Technology, Canadian Geotechnical Journal等多個期刊編委。憑借開創(chuàng)性學術(shù)貢獻，蔡明教授榮獲 2017 年加拿大巖土工程學會富蘭克林獎，2025 年加拿大礦業(yè)、冶金與石油學會（CIM）巖石力學獎。