Abstract In tropical/subtropical regions, weathering is quite intense and can influence engineering activities by degrading rock materials and masses. In the context of quartzite, which is a competent rock for engineering purposes, weathering grade categorization is challenging as quartz, being practically immune to chemical weathering, is the chief mineral constituent of this rock. Consequently, the evaluation of salient mechanical behaviors of quartzitic materials under triaxial compression with reference to weathering grades does not seem to have gained much attention in the past. With due need, this paper investigates the said issues. Weathered quartzite blocks collected from Ghatshila (India) were used for this study. The weathering grades (Grade II and Grade IV) were categorized following the common 6-fold classification which were subsequently substantiated by microscopic study and physical indices (effective porosity, dry density and ultrasonic P-wave velocity). Conventional triaxial tests were performed on the weathered quartzitic materials at five confining pressures (0, 2, 4, 6, 8 MPa). Loss of elasticity with increasing weathering intensity and/or confining pressure became apparent. In case of Grade IV quartzite, crack initiation occurred at a much lower stress percentage of the corresponding peak strength than that in case of Grade II quartzite. With the increase in confining pressure, the crack initiation stress increased in case of Grade IV materials. Failure patterns of weathered quartzite under triaxial compression were also examined. The plausible explanations for various observations relating to both weathering grade categorization and evaluation of mechanical behavioral patterns of the quartzitic materials are elucidated in this paper. Research highlights <UnorderedList Mark="Bullet"> <ItemContent> Weathered quartzitic materials from Ghatshila (India) were investigated. </ItemContent> <ItemContent> Mechanical behaviors under triaxial compression were evaluated. </ItemContent> <ItemContent> Loss of elasticity with increasing weathering intensity and/or confining pressure became apparent. </ItemContent> <ItemContent> Crack initiation occurred at a lower stress in Grade IV quartzite than in Grade II quartzite. </ItemContent> <ItemContent> Crack initiation stress increased with confining pressure for Grade IV materials. </ItemContent> </UnorderedList>

Mechanical behavioral response of quartzitic materials to triaxial compression with reference to weathering grades

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发表日期：

2026年5月11日

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Arindam Basu,
Tukuni Das

摘要

Abstract

In tropical/subtropical regions, weathering is quite intense and can influence engineering activities by degrading rock materials and masses. In the context of quartzite, which is a competent rock for engineering purposes, weathering grade categorization is challenging as quartz, being practically immune to chemical weathering, is the chief mineral constituent of this rock. Consequently, the evaluation of salient mechanical behaviors of quartzitic materials under triaxial compression with reference to weathering grades does not seem to have gained much attention in the past. With due need, this paper investigates the said issues. Weathered quartzite blocks collected from Ghatshila (India) were used for this study. The weathering grades (Grade II and Grade IV) were categorized following the common 6-fold classification which were subsequently substantiated by microscopic study and physical indices (effective porosity, dry density and ultrasonic P-wave velocity). Conventional triaxial tests were performed on the weathered quartzitic materials at five confining pressures (0, 2, 4, 6, 8 MPa). Loss of elasticity with increasing weathering intensity and/or confining pressure became apparent. In case of Grade IV quartzite, crack initiation occurred at a much lower stress percentage of the corresponding peak strength than that in case of Grade II quartzite. With the increase in confining pressure, the crack initiation stress increased in case of Grade IV materials. Failure patterns of weathered quartzite under triaxial compression were also examined. The plausible explanations for various observations relating to both weathering grade categorization and evaluation of mechanical behavioral patterns of the quartzitic materials are elucidated in this paper.

Research highlights

Weathered quartzitic materials from Ghatshila (India) were investigated.

Mechanical behaviors under triaxial compression were evaluated.

Loss of elasticity with increasing weathering intensity and/or confining pressure became apparent.

Crack initiation occurred at a lower stress in Grade IV quartzite than in Grade II quartzite.

Crack initiation stress increased with confining pressure for Grade IV materials.