A Study of Rock Crack Fracture under Different Temperatures

Abstract

A series of critical fracture toughness of two kinds of rock materials under different temperature which varied from-50°C to 240°C are measured by I-II-III mixed mode fracture experiments adopting atypical three point bending specimens. Relative stress intensity factors of crack initiation are calculated by finite element method. Combining with calculated values, the experiment results show that, the mixed mode fracture toughness of the rocks decreases with the increase of temperature. The experimental and calculated results can be used in the design of deep underground engineering or disaster prevention and mitigation engineering.

Theoretical characterization of the temperature‐dependent mode I fracture toughness of rocks

“…In the past, many experimental studies have been carried out on the mode I fracture toughness of high temperature rocks, which indicate that the fracture toughness and most of other mechanical properties progressively degrade with the increase of temperature overall. [17][18][19][20][21][22] However, some studies show that the change trend is not always monotonous. Meredith et al 23 measured the mode I fracture toughness of Westerly granite and Black gabbro at temperatures from 20 C to 400 C in a vacuum.…”

“…Experiment is the most basic method to study the effect of temperature on fracture toughness of rocks. In the past, many experimental studies have been carried out on the mode I fracture toughness of high temperature rocks, which indicate that the fracture toughness and most of other mechanical properties progressively degrade with the increase of temperature overall 17–22 . However, some studies show that the change trend is not always monotonous.…”