doi:10.16186/j.cnki.1673-9787.2023070006

Received:2023-07-05

Revised:2023-09-28

Online Date:2023-10-19

Improvement and verification of crack propagation prediction theory for rock mate-rials under compressive load（Online）

LI Xiulei1, DIAO Hang2, CHEN Chen2, HUANG Feng2, LING Tianqing2, ZENG Bin1

1.School of River & Ocean Engineering，Chongqing Jiaotong University，Chongqing  400074，China;2.School of Civil Engineering，Chongqing Jiaotong University，Chongqing  400074，China

Abstract:In order to improve the accuracy of crack propagation prediction for rock materials，the traditional maximum circumferential stress criterion（MTS criterion） disregards the non-singular stress term（T stress） in the crack tip's stress field and the crack geometrical properties.On the basis of the conventional MTS criterion，a new fracture criterion for non-closed fractures in rocks is established by accounting for the effects of T-stress and fracture geometry properties on the fracture tip stress field. Uniaxial compression tests were conducted using rock specimens with non-closed fractures in the center，then the predicted values of the criterion were compared with the cracking angle（θ） measured in the experiment to check the reasonablenessof the proposed criterion. The results of the research indicate that only considering fracture geometry fea⁃tures，long crack width ratio（b/a） increase the stress intensity factor（K_I） increase.When the geometric characteristics of crack and T stress are introduced simultaneously，the increase of crack width ratio（b/a）caused the crack angle θ to be reduced and the maximum peripheral stress (σ_θ)_max to be increased.With theintroduction of T stress，the crack starting angle（θ） and the crack starting load are closer to the actualvalue，then the T stress plays an important role in suppressing the crack starting，while the crack startingangle（θ） gradually transitions from positive to negative cracking with the increase of the crack dip angle（β）.The crack initiation criterion considering T stress and crack geometry can more accurately predict the crackinitiation angle（θ） in the range of 0° to 60° of the crack dip angle（β）.

Key words:fracture criterion;non-closed cracks;stresscrack geometric propertiescrack initiation angles

CLC：TU45