巴西劈裂试验对岩石抗拉强度影响因素研究  

Experimentalstudy on the influence of rock tensile strength based on Brazilian test

作　　者：刘天宇[1,2] 万文[1,2] 王亚[1,2] 罗世林[1,2] 唐劲舟 LIU Tianyu WAN Wen WANG Ya LUO Shilin TANG Jingzhou(School of Resource,Environment and Safety Engineering, Hunan University of Science and Technology, Xiangtan 411201, China Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines, Hunan University of Science and Technology, Xiangtan 411201, China)

机构地区：[1]湖南科技大学资源环境与安全工程学院,湖南湘潭411201 [2]湖南科技大学煤矿安全开采技术湖南省重点实验室,湖南湘潭411201

出　　处：《矿业工程研究》2016年第4期1-7,共7页Mineral Engineering Research

基　　金：国家自然科学基金资助项目(51274097;51174088);湖南省自然科学基金资助项目(2015JJ2067);湖南省教育厅资助项目(13A020)

摘　　要：在巴西劈裂试验中选用最基本的垫条加载的加载方式条件下,对不同厚径比的茅口灰岩岩石试件采用不同的加载速率进行巴西圆盘劈裂试验.通过试验数据分析发现,在相同的厚径比下,随加载速率的提高,岩石的抗拉强度小幅增加;当采用相同的加载速率时,茅口灰岩抗拉强度均随厚径比的增加而减小,存在一定的尺寸效应.运用FLAC3D数值分析软件,针对垫条加载进行了不同厚径比及加载速率的巴西劈裂数值模拟试验,结果表明水平拉应力最大值位于圆盘轴线上端面中心点,即圆盘开始起裂的位置位于端面中心点附近.随着加载速率增加,圆盘端面中心点等效应力增大;随着厚径比增加,圆盘端面中心点等效应力减小.最后提出了在垫条加载下抗拉强度的修正公式,消除厚径比及加载速率对岩石抗拉强度的影响,并验证了修正公式的有效性.The research of spacer of Maokou limestone under different loading loading thickness-to-diameter ratios, with the increase same loading rate, with the increase of loading Brazilian splitting test uses different thickness-to-diameter ratios rate. Results show that several characteristics： at the same of loading rate, stress-line drop phenomenon disappears. At the rate, tensile strength decreases and presents the linear relation with the increase of thickness size. Having discussed the influence of different factors through FLAG3D, this paper finds that the first fracture starting point is at the center of the disc ends, which proves that the disc is broken from the center. The more close to the ends, the higher of the horizontal stress. The larger of the thickness-to- diameter ratios, the lower of the horizontal stress of the central point of the specimens. Tensile strength increases with the increase of loading rate. Finally, tensile strength correction formula are presented, It eliminates the influence of the thick diameter ratio and loading rate on rock tensile strength, and the validity of the modified formula is verified.

关 键 词：巴西劈裂 垫条加载 厚径比 加载速率 抗拉强度 

分 类 号：TD313[矿业工程—矿井建设]