DYNAMIC CRACK PROPAGATION OF GRANITE SUBJECTED TO BIAXIAL CONFINING PRESSURE AND BLAST LOADING
TO GREAT UNDERSTANDING THE DYNAMIC CRACK PROPAGATION OF ROCK UNDER IN-SITU STRESS AND BLASTING, THE STATIC-DYNAMIC LOADING EXPERIMENTAL PLATFORM WAS BUILT. WITH DIFFERENT CONFINING PRESSURE (0MPA, 2MPA, 4MPA, 6MPA, 8MPA) AND DIFFERENT RATIOS (K) OF HORIZONTAL-TO-VERTICAL PRESSURE (0, 0.25, 0.5, 0.75, 1), NINE TEXTS HAVE BEEN CARRIED OUT IN QUADRATE GRANITE SAMPLES. THE DYNAMIC STRAIN GAUGES AND HIGH-SPEED (HS) CAMERA WERE USED TO MEASURE STRAIN FIELD AND OBSERVE CRACK GROWTH. ACCORDING TO EXPERIMENTAL RESULTS, THE CENTROSYMMETRIC DAMAGE ZONE IS GENERATED AROUND BOREHOLE WHEN K=1, CIRCUMFERENCE COMPRESSIVE STRESS IS FORMED BY CONFINING PRESSURE, AND IT REDUCES THE CIRCUMFERENCE TENSILE FAILURE BY BLAST LOADING. THE NUMBER AND SIZE OF THE BROKEN RADIUS SIGNIFICANTLY REDUCE WITH CONFINING PRESSURE INCREASES. AS K DECREASE FROM 1 TO 0, THE TENSILE STRESS CONCENTRATION IS OBVIOUSLY AROUND BOREHOLE IN THE VERTICAL DIRECTION, AND RADIAL CRACKS GROW FROM THE STRESS CONCENTRATION ZONE AND DEVELOP INTO BOUNDARY UNDER TENSILE STRESS WAVE FROM BLAST LOADING. FROM THE NUMERICAL ANALYSIS BASED ON JOHNSON-HOLMQUIST IN AUTODYN, CRACK BRANCHING APPEAR NEAR FREE BOUNDARY AND BECOME OBVIOUSLY, MEANWHILE THE RADIAL CRACKS GROW AND RUN THROUGH SAMPLE BY REFLECTED WAVE. COMPARED TO THE EXPERIMENTAL RESULTS, THE EVOLUTION AND FINAL SHAPE OF CRACKS ARE AGREE WITH THE EXPERIMENTAL RESULTS, THE CENTRAL DAMAGE AREA IS LESS THAN LATTER BECAUSE JWL EQUATION NEGLECT THE GAS LOADING IN NUMERICAL CALCULATION.
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License [CC BY] that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).