文献类型：期刊文献

英文题名：Research on Rock Strength Test Based on Electro-Hydraulic Servo Point Load Instrument

作者：Zhou, Xiaoxia[1];Qiao, Lei[1];Wu, Faquan[1];Wang, Zhaoyuan[1];Chen, Yinhong[1];Wu, Jie[2]

机构：[1]Shaoxing Univ, Key Lab Rock Mech & Geohazards Zhejiang Prov, Shaoxing 312000, Peoples R China;[2]Zhejiang Rock Innovat Technol Co Ltd, Shaoxing 312000, Peoples R China

年份：2022

卷号：12

期号：19

外文期刊名：APPLIED SCIENCES-BASEL

收录：SCI-EXPANDED(收录号：WOS:000866718600001)、、Scopus(收录号：2-s2.0-85139947602)、WOS

基金：The project presented in this article was supported by the National Natural Science Foundation of China (41831290) and the Key Research and Development Project of Zhejiang Province (2020C03092).

语种：英文

外文关键词：electro-hydraulic servo point load instrument; loading rate; size effect; standard point load strength; uniaxial compressive strength

外文摘要：A new electro-hydraulic servo point load instrument was designed to address the problem that the existing point load instrument cannot be loaded continuously and uniformly; different loading rates (using three loading rates: 0.1, 0.5, 1.0 kN/s) were conducted on fine-crystalline granite, coarse-crystalline granite, and siltstone (each rock sample contains four sizes: 20(3), 30(3), 40(3), 50(3) mm(3)) for point load tests. Firstly, the influence of loading rate on the axial stress distribution of rock sample loading was investigated in conjunction with the rock strength damage theory. Next, the influence of rock sample size and loading rate on different standard point load strength evaluation methods was analyzed to find a reasonable evaluation method and loading rate and range of rock sample size. Finally, the relationship between standard point load strength and uniaxial compressive strength was analyzed on this basis to obtain its empirical conversion formula. The results show that: (1) With the increase in the loading rate of point load, the tensile and compressive stresses in the loading axis increase, and the compressive stresses near the center of the loading axis of the rock sample are more influenced by the loading rate; the standard point load strength increases with the increase in the loading rate, but the increase in the standard point load strength decreases when the loading rate increases to a certain range. (2) With the increase in size, the standard point load strength solved by method I, method III, and method IV has an obvious size effect, while the size effect of standard point load strength solved by method II is not obvious. (3) The conversion factors of fine-crystalline granite, coarse-crystalline granite, and siltstone were obtained by zero-intercept linear regression analysis as 16.80, 15.32, and 14.60, respectively, which indicated that the conversion factors of rocks with high strength were higher than those of rocks with low strength. The present research results can provide theoretical support for revising the existing point load strength calculation equations.