摘要
为了解决岩石Ⅱ型断裂韧度的准确测量问题,提高对工程裂隙岩体稳定评价的可靠性,采用颗粒离散单元法,从微观裂纹、声发射及块体特征角度出发,结合断裂韧度计算,对短芯压缩(SCC)试样进行了数值研究。结果表明:随着切槽间距比(C/H)的增加,试样破坏模式会由纯剪向拉剪混合过渡;声发射模式前震-主震-后震型(C/H≥0.3)的转变与块体破坏特征也验证了这一结果;当C/H=0.2时,计算所得的断裂韧度与室内试验测得的值相符,验证了所采用方法对于Ⅱ型断裂韧度测试的准确性。借助离散单元法阐明了短芯压缩试样的破裂特征,从裂纹扩展的角度明确了切槽间距变化对破坏形态及破坏模式影响的规律,可为实验室精确测量岩石Ⅱ型断裂韧度提供参考。
In order to solve the problem of accurate measurement of rock modeⅡfracture toughness and improve the reliability of stability evaluation of engineering fractured rock mass,a detailed numerical study of short core compression(SCC)samples was carried out from the perspective of micro-crack,acoustic emission and block characteristics,combined with fracture toughness calculation by particle discrete element method.The results show that the failure mode of the sample changes from pure shear to tension-shear mixture with the increase of the ratio of slot spacing(C/H).The foreshock-mainshock-aftershock(C/H≥0.3)transformation and block failure characteristics of acoustic emission models also confirm the result.When C/H=0.2,the calculated fracture toughness is consistent with that measured in laboratory experiment,which verifies the accuracy of modeⅡfracture toughness test in this case.With the help of discrete element method,the fracture characteristics of short core compression samples are elucidated,and the effect of groove spacing on the failure form and failure mode is determined from the angle of crack growth,which could provide some reference for accurate measurement of rock modeⅡfracture toughness in lab.
作者
张加明
曹卓康
付岩
刘丰
ZHANG Jiaming;CAO Zhuokang;FU Yan;LIU Feng(School of Civil Engineering,Tianjin University,Tianjin 300072,China;State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 300072,China)
出处
《河北科技大学学报》
CAS
北大核心
2023年第4期393-402,共10页
Journal of Hebei University of Science and Technology
基金
国家自然科学基金(52079091)。
关键词
岩土力学
Ⅱ型断裂韧度
离散元
裂纹扩展
破裂过程
微裂纹
rock and soil mechanics
modeⅡfracture toughness
discrete element
crack growth
fracture process
micro-crack
