动载作用板岩断裂韧度与裂纹扩展特征试验研究  

Experimental Study on Fracture Toughness and Crack Propagation Characteristics of Slate under Dynamic Loading

作　　者：张建国 杨文 汪海波[2] 拜晓亮 张翌炜 樊永强[1] 邢永杨 杨永斌[1] 杨波 闫高文 薛文飞 段聪 刘振江 ZHANG Jian-guo;YANG Wen;WANG Hai-bo;BAI Xiao-liang;ZHANG Yi-wei;FAN Yong-qiang;XING Yong-yang;YANG Yong-bin;YANG Bo;YAN Gao-wen;XUE Wen-fei;DUAN Cong;LIU Zhen-jiang(China Communications Second Highway Engineering Bureau Limited Company,Xi′an 710000,China;School of Civil Engineering and Architecture,Anhui University of Science and Technology,Huainan 232001,China)

机构地区：[1]中交第二公路工程局有限公司,西安710000 [2]安徽理工大学土木建筑学院,淮南232001

出　　处：《爆破》2025年第1期37-43,55,共8页Blasting

基　　金：安徽省爆破器材与技术工程实验室开放基金(AHBP2022A-02)。

摘　　要：为探究动载作用下天然板岩的断裂韧度,论文采用板岩制作直切槽半圆盘弯曲试样(NSCB),利用直径50 mm分离式霍普金森压杆(SHPB)试验系统进行了动态冲击试验,同时使用高速摄像机记录了其裂纹扩展过程,研究了不同冲击气压和预制裂纹长度下板岩的动态断裂韧度及裂纹扩展速度。结果表明:试件的动态断裂韧度与冲击气压和加载率呈现正相关,而随着预制裂纹长度的增加动态断裂韧度先增加后减小,根据拟合结果,当预制裂纹长度为7.45 mm时试件的动态断裂韧度达到最大值,0.2、0.3和0.4 MPa三种冲击气压下对应的动态断裂韧度最大值分别为2.99、3.57和4.14 GPa·m^(1/2);试件的破坏过程可以分为动态损伤、裂纹孕育、裂纹形成、裂纹扩展和试件断裂五个阶段;试件主裂纹的扩展速度波动较大,而预制裂纹长度对试件裂纹扩展速度的影响较小。研究揭示了不同工况下板岩试件动态断裂行为的差异,对该类岩性地下工程支护、爆破参数设计具有一定的参考意义。To investigate the fracture toughness of natural slate under dynamic loading,dynamic impact tests were conducted on notched semi-circular bending slate specimens by a 50 mm diameter split Hopkinson pressure bar testing system and the crack growth process was recorded by the high-speed cameras.Furthermore,the dynamic fracture toughness and crack propagation rate of slate under different impact pressure and prefabricated crack lengths were studied.The results show that the dynamic fracture toughness of the specimen is positively correlated with the impact pressure and loading rate,and the dynamic fracture toughness first increases and then decreases with the rise of the prefabricated crack length.According to the fitting results,the dynamic fracture toughness of the specimen reaches the maximum value when the prefab crack length is 7.45 mm.The maximum values of dynamic fracture toughness at 0.2,0.3 and 0.4 MPa were 2.99,3.57 and 4.14 GPa·m^(1/2),respectively.The failure process of the specimen can be divided into five stages:dynamic damage,crack propagation,crack formation,crack propagation,and specimen fracture.The propagation speed of the main crack of the specimen greatly fluctuates,while the prefabricated crack length has little effect on the propagation velocity of the specimen.The study revealed the differences in dynamic fracture behavior of slate specimens under different working conditions.

关 键 词：板岩 NSCB SHPB 预制裂纹 动态断裂韧度 

分 类 号：TU458[建筑科学—岩土工程]