Effect of loading rate on fracture characteristics of rock
来源期刊：中南大学学报(英文版)2010年第1期
论文作者：周小平 钱七虎 杨海清
文章页码：150 - 155
Key words：fracture toughness of rock; three-point bending round bar; loading rate; velocity of crack growth
Abstract: The three-point bending experiments were applied to investigating effects of loading rates on fracture toughness of Huanglong limestone. The fracture toughness of Huanglong limestone was measured over a wide range of loading rates from 9×10-4 to 1.537 MPa·m1/2/s. According to the approximate relationship between static and dynamic fracture toughness of Huanglong limestone, relationship between the growth velocity of crack and dynamic fracture toughness was obtained. The main conclusions are summarized as follows. (1) When the loading rate is higher than 0.027 MPa·m1/2/s, the fracture toughness of Huanglong limestone increases markedly with increasing loading rate. However, when loading rate is lower than 0.027 MPa·m1/2/s, fracture toughness slightly increases with an increase in loading rate. (2) It is found from experimental results that fracture toughness is linearly proportional to the logarithmic expression of loading rate. (3) For Huanglong limestone, when the growth velocity of crack is lower than 100 m/s, the energy release rate slightly decreases with increasing the growth velocity of crack. However, when the growth velocity of crack is higher than 1 000 m/s, the energy release rate dramatically decreases with an increase in the crack growth velocity.
基金信息：the National Natural Science Foundation of China
Program of New Century Talents of Ministry of Education; Project(CSTC, 2009BA4046
