HYBRID FINITE-DISCRETE ELEMENT MODELLING OF ROCK FRACTURE DURING CONVENTIONAL COMPRESSIVE AND TENSILE STRENGTH TESTS UNDER QUASI-STATIC AND DYNAMIC LOADING CONDITIONS

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DOI:

https://doi.org/10.1590/1679-78256123

Abstract

A HYBRID FINITE-DISCRETE ELEMENT METHOD IS PROPOSED TO MODEL THE ROCK FRACTURE UNDER STATIC AND DYNAMIC LOADING. THE KEY COMPONENT OF THE HYBRID FINITE-DISCRETE ELEMENT METHOD, I.E. TRANSITION FROM CONTINUUM TO DISCONTINUUM THROUGH FRACTURE AND FRAGMENTATION, WHICH MAKES THE HYBRID METHOD SUPERIOR TO THE TRADITIONAL CONTINUUM-BASED FINITE ELEMENT METHOD AND DISCONTINUUM-BASED DISCRETE ELEMENT METHOD, IS INTRODUCED IN DETAIL. AN EMPIRICAL RELATIONSHIP BETWEEN THE STATIC STRENGTHS AND THE DYNAMIC STRENGTHS DERIVED FROM THE DYNAMIC ROCK FRACTURE EXPERIMENTS IS IMPLEMENTED IN THE HYBRID METHOD TO MODEL THE EFFECT OF THE LOADING RATE. THE HYBRID METHOD HAS WELL MODELLED THE ROCK FRACTURE PROCESSES IN BRAZILIAN TENSILE STRENGTH (BTS) TEST AND UNIAXIAL COMPRESSIVE STRENGTH (UCS) TEST UNDER QUASI-STATIC LOADING. THE OBTAIN ROCK FRACTURES PATTERNS SHOW GOOD AGREEMENTS WITH THE EXPERIMENTAL RESULTS AND THE OBTAINED FORCE LOADING-DISPLACEMENT CURVES INDICATE A TYPICAL FAILURE PROCESS OF BRITTLE MATERIALS. THE HYBRID METHOD HAS MODELLED THE PURE MODE-I, PURE MODE-II AND MIXED-MODE I-II FRACTURE PROCESS AND THE OBTAINED FRACTURE TOUGHNESS USING DIFFERENT TEST METHODS SHOW A GOOD AGREEMENT WITH EACH OTHER. THEN THE HYBRID METHOD IS EMPLOYED TO MODEL THE DYNAMIC ROCK FRACTURE PROCESS IN UCS AND BTS TESTS. THE PROPOSED METHOD HAS WELL MODELLED THE DYNAMIC ROCK FRACTURE AND FRAGMENTATION PROCESSES AND CAPTURED THE EFFECT OF LOADING RATE ON ROCK STRENGTHS. IT IS CONCLUDED THAT THE HYBRID FINITE-DISCRETE ELEMENT IS A VALUABLE TOOL TO STUDY THE DYNAMIC ROCK FRACTURE AS IT TAKES THE ADVANTAGES OF THE CONTINUUM-BASED FINITE ELEMENT METHOD AND DISCONTINUUM-BASED DISCRETE ELEMENT METHOD, AND CONSIDER THE EFFECT OF THE LOADING RATE.

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Published

2020-08-07

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Articles