基于裂纹长度幂律排布的损伤砂岩强度模型  

Strength model for damaged sandstone based on power-law distribution of crack length

作　　者：石浩 宋雷[2,3] 王敦显[4] 王国柱 黎明镜 龙伟 陈贵武[2,3] SHI Hao;SONG Lei;WANG Dunxian;WANG Guozhu;LI Mingjing;LONG Wei;CHEN Guiwu(School of Civil Engineering and Architecture,Anhui University of Science and Technology,Huainan,Anhui 232001,China;State Key Laboratory for Geomechanics&Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;School of Mechanics&Civil Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;Xuzhou Metro Group Co.,Ltd.,Jiangsu 221000,China)

机构地区：[1]安徽理工大学土木建筑学院,安徽淮南232001 [2]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116 [3]中国矿业大学力学与土木工程学院,江苏徐州221116 [4]徐州地铁集团有限公司,江苏徐州221000

出　　处：《中国矿业大学学报》2022年第2期263-272,共10页Journal of China University of Mining & Technology

基　　金：安徽理工大学高层次引进人才科研启动基金项目(2021yjrc16);国家自然科学基金项目(41974164);中央高校基本科研基金项目(2018ZDPY08)。

摘　　要：本文采用二维颗粒流软件(PFC^(2D))生成预裂纹长度服从幂律排布的缺陷砂岩试件,通过改变幂律指数和预制裂纹数量,对砂岩强度特性进行了研究;在此基础上,根据Mori-Tanaka方法进行理论推导,建立了与单位面积裂纹数量及裂纹长度相关的损伤砂岩强度模型.研究结果表明:1)幂律指数越大,试件中长裂纹的占比越小,并且试件单轴抗压强度随预制裂纹总长度的增加而减小;2)当预制裂纹数量保持恒定时,砂岩试件抗压强度随幂律指数的增加而增大;当幂律指数保持恒定时,试件抗压强度随着预制裂纹数量的增加而减少;3)本文建立的强度模型可以较好地描述缺陷岩石的强度演化规律.即当预制裂纹数量处于50~600范围内时,随着幂律指数由1.1增至6.0,试件单轴抗压强度由减速降低逐渐变为近线性减小趋势;4)相对于单位面积裂纹数量,试件强度对裂纹平均半长变化的敏感性更强.Particle Flow Code software(PFC^(2D))was used in this paper to generate the defected specimens with the power-law distribution of pre-cracks length.Then the power-law index and the number of pre-cracks were changed to statistically study their influences on the strength characteristics of sandstone.On this basis,the strength model of damage sandstonerelated to the number of cracks per unit area and the crack length was established according to the Mori-Tanaka method.The results show that the higher the power-law index,the smaller the proportion of long cracks in the specimen,as well as the uniaxial compressive strength of sandstone specimendecreases with the total length of the pre-cracks.When the number of pre-cracks remains constant,the uniaxial compressive strength of sandstone increases with the power-law index,while when the power-law index remains constant,the compressive strength decreases with the number of pre-cracks.The strength model was established based on the Mori-Tanaka method in this paper,which can be used to describe the strength evolution of damaged rock very well.That is,when the number of pre-cracks is in the range of 50 to 600,the compressive strength of the specimen gradually decreases from deceleration to a nearly linear decrease as the power rate index increases from 1.1 to 6.0.Relative to the number of cracks per unit area,the strength of the specimen is more sensitive to the change of the average half-length of the cracks.

关 键 词：预制裂纹数量 预制裂纹长度 幂律指数 强度预测模型 强度敏感性 

分 类 号：TU45[建筑科学—岩土工程]