(1. College of Civil Engineering，Shaoxing University，Shaoxing，Zhejiang 312000，China；2. Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province，Shaoxing，Zhejiang 312000，China；3. Zhejiang Rockinnov Technology Co.，Ltd.，Shaoxing，Zhejiang 312000，China)
Abstract：In this paper，the size effect of basalt samples and green sandstone samples in a small size range of 20–50 mm in diameter was studied. The compositions of mineral particles inside the samples were observed by a high-precision 3D profilometer，and the size，shape and distribution of the pores inside the samples were obtained by a CT scanner. The influence of the sample size on the uniaxial compressive strength，the elastic modulus and the failure mode was analyzed. It is found that，within the small size range，the size，shape and distribution of the pores in different rock samples have an influence on the size effect. The size effect curves of green sandstone and basalt samples conform to exponential and logarithmic distributions respectively. Combining the existing conclusions on larger size rock samples，it is pointed out that the segmental fitting method can better reflect the size effect of rocks. It is also shown that，with increasing the sample diameter，the modulus of elasticity of the samples tends to gradually increase and the overall failure mode of the samples changes from splitting failure to monoclinic shear failure and then to X-shaped conjugate oblique shear failure.
张 明，卢裕杰，杨 强. 准脆性材料的破坏概率与强度尺寸效应[J]. 岩石力学与工程学报，2010，29(9)：1 782-1 789.(ZHANG Ming，LU Yujie，YANG Qiang. Failure probability and strength size effect of quasi-brittle materials[J]. Chinese Journal of Rock Mechanics and Engineering，2010，29(9)：1 782-1 789.(in Chinese))
[3]
PRATT H R，BLACK A D，BROWN W S，et al. The effect of specimen size on themechanical properties of unjointed diorite[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1972，9(4)：513-529.
[5]
路新景，李志敬，房后国，等. 岩石单轴抗压强度优势尺寸及尺寸效应[J]. 人民黄河，2011，33(4)：109-111.(LU Jingxin，LI Zhijng，FANG Houguo，et al. Dominant size and size effect of rock uniaxial compressive strength [J]. People¢s Yellow River，2011，33(4)：109-111.(in Chinese))
[7]
杨圣奇，苏承东，徐卫亚. 岩石材料尺寸效应的试验和理论研究[J]. 工程力学，2005，22(4)：112-118.(YANG Shengqi，SU Chengdong，XU Weiya. Experimental and theoretical study on size effect of rock materials[J]. Engineering Mechanics，2005，22(4)：112-118.((in Chinese))
[10]
张后全，徐建峰，贺永年，等. 灰岩单轴压缩实验室尺度效应研究[J]. 岩石力学与工程学报，2012，31(增2)：3 491-3 496. (ZHANG Houquan，XU Jianfeng，HE Yongnian，et al. Laboratory scale effect of uniaxial compression of limestone[J]. Chinese Journal of Rock Mechanics and Engineering，2012，31(Supp.2)：3 491-3 496. (in Chinese))
[11]
ZHANG Q，ZHU H，ZHANG L，et al. Study of scale effect on intact rock strength using particle flow modeling[J]. International Journal of Rock Mechanics and Mining Sciences，2011，48(8)：1 320-1 328.
[13]
梁正召，张永彬，唐世斌，等. 岩体尺寸效应及其特征参数计算[J]. 岩石力学与工程学报，2013，32(6)：1 157-1 166.(LIANG Zhengchao，ZHANG Yongbin，TANG Shibin，et al. Rock size effect and its characteristic parameters calculation[J]. Journal of Rock Mechanics and Engineering，2013，32(6)：1 157-1 166.(in Chinese))
[15]
薛华庆，胥蕊娜，姜培学，等. 岩石微观结构CT扫描表征技术研究[J]. 力学学报，2015，47(6)：183-188.(XUE Huaqing，XU Ruina，JIANG Peixue，et al. Study on CT scanning characterization technology of rock microstructure[J]. Journal of Mechanics，2015，47(6)：183-188.(in Chinese))
[1]
严 妍，郑永来，曹宏泰. 常规三轴条件下不均匀岩石的强度尺寸效应[J]. 低温建筑技术，2017，234(12)：136-139.(YAN Yan，ZHENG Yonglai，CAO Hongtai. Size effect of strength of inhomogeneous rock under conventional triaxial conditions[J]. Low Temperature Building Technology，2017，234(12)：136-139.(in Chinese))
[4]
王连山，孙东生，郑秀华，等. 三种典型岩石轴抗压强度的尺寸效应试验研究[J]. 地质力学学报，2017，23(2)：327-333.(WANG Lianshan，SUN Dongsheng，ZHENG Xiuhua，et al. Experimental study on size effect of compressive strength of three typical rock shafts[J]. Journal of Geomechanics，2017，23(2)：327-333.(in Chinese))
[6]
WEIBULL W. A statistical theory of the strength of materials[M]. Stockholm：Generalstabens Litografiska Anstalts Fo?Rlag，1939，151：1-29.
[8]
GRIFFITH A A. The theory of rupture[J]. Proceedings of the International Congress Applied Mechanics，1924：55-63.
[9]
刘宝琛，张家生. 岩石抗压强度的尺寸效应[J]. 岩石力学与工程学报，1998，17(6)：611-614.(LIU Baochen. Size effect of rock compressive strength[J]. Chinese Journal of Rock Mechanics and Engineering，1998，17(6)：611-614.(in Chinese))
[12]
孙 超，刘 芳，蒋明镜，等. 岩石抗压强度的尺寸效应及端部约束的离散元数值模拟[J]. 岩石力学与工程学报，2014，33(增2)：3 421-3 428.(SUN Chao，LIU Fang，JIANG Mingjing，et al. Discrete element numerical simulation of size effect and end restraint of rock compressive strength[J]. Chinese Journal of Rock Mechanics and Engineering，2014，33(Supp.2)：3 421-3 428.(in Chinese))
[14]
陈卫忠，杨建平，邹喜德，等. 裂隙岩体宏观力学参数研究[J]. 岩石力学与工程学报，2008，27(8)：1 569-1 575.(CHEN Wei Zhong，YANG Jian Ping，ZOU Xi De，et al. Macromechanical parameters of fractured rock masses[J]. Journal of Rock Mechanics and Engineering，2008，27(8)：1 569-1 575.(in Chinese))
[16]
BIENIAWSKI Z T. The effect of specimen size on compressive strength of coal[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1968，5(4)：325-335.
[17]
冯增朝，赵阳升. 岩体裂隙尺度对其变形与破坏的控制作用[J]. 岩石力学与工程学报，2007，27(1)：78-83.(FENG Zengchao，ZHAO Yangsheng. The controlling effect of fracture scale on deformation and failure of rock mass[J]. Journal of Rock Mechanics and Engineering，2007，27(1)：78-83.(in Chinese))
2021, Vol. 40 
