Effect of water on fracture of rocks under diametral compression

Va Kalachev,Dv Zaitsev,An Kochanov,Yua Kostandov,Pe Panfilov

doi:10.1088/1755-1315/134/1/012023

Abstract

The researchers study the effect of water on the strength of small-size specimens made of metamorphic rocks (carbonaceous quartzite, serpentine) and an analog of sedimentary rocks (sand-and-cement mixture, or artificial sandstone) exposed to diametral compression. It is found that the specimens exhibit the same brittle deformation behavior after water storage for a day. All specimens show reduced strength while quartzite and serpentine feature a decrease in deformability down to failure. Microscopic fracturing is viscoelastic and independent of water. It is suggested that the influence of water on the deformation behavior of the specimens can be explained by the Rebinder effect.

Highlights

Water environment has a considerable influence on mechanical properties of rocks
This study focuses on the influence exerted by water on the mechanical properties and fracturing behavior in small-size specimens of rocks in indirect tensile tests (Brazilian testing)
The specimens of quartzite and serpentinite were shaped as disks with a diameter of 5 mm and a thickness of 3 mm; the artificial sandstone disk had a diameter of 11 mm and was 5 mm thick

Summary

Published under licence by IOP Publishing Ltd

The testing was terminated when the stress–strain curve acquired a dog-leg reflective of initiation of a critical fracture in a specimen. For each type of rocks, two groups of 10 specimens each were tested. The curves of initial specimens and specimens held in water exhibited the same behavior. It can be concluded that the specimens subjected to the tensile load behaved as a brittle material irrespective of being held in water or not. The strength characteristics of the test rocks after the day-long water storage reduced. Failure of initial sandstone specimen and after water storage on a macroscale (a), (c) and on a microscale (b), (d). Failure of initial serpentinite specimen and after water storage on a macroscale (a), (c) and on a microscale (b), (d)

Artificial sandstone air

Conclusion