点荷载强度指标间接确定岩石的单轴抗压强度,具有独特的优势,被认为是一种现场测定、估算单轴抗压强度的最佳方法。通过总结大量国内外相关文献发现,目前的研究成果受岩石材料各向异性、数据模糊对应、仪器笨重、缺乏试验验证4个方面的影响,仍存在局限性。利用自行研制的便携式点荷载仪,针对各向同性的类岩石材料进行不同强度、不同尺寸、一一对应的点荷载指标和单轴抗压强度对应关系试验研究。试验结果表明:试验数据均服从正态分布规律,集中趋势明显;不同尺寸的测试结果证实,类岩石材料的点荷载指标具有明显的尺寸效应;结合实测数据,通过绘制P-D2e关系曲线的修正方法得到相关系数最高为0.97,说明不规则样品的点荷载指标能够很好地统一到标准等效尺寸。采用统计分析方法建立点荷载指标和单轴抗压强度的线性方程,对应关系的相关系数为0.994,说明修正后的点荷载指标能够更好地建立相关性、提高精确度。通过不规则试件的点荷载测试验证上述关系式误差在15%以内。
Abstract
The point load intensity index is considered as the optimum method for measuring and estimating uniaxial compressive strength as it is of unique advantage by indirectly determining the uniaxial compressive strength of rock. By summing up a large number of literatures in China and abroad, we found that current research results are limited by the anisotropy of rock materials, fuzzy correspondence of data, heavy equipment and lack of experimental verification. In this paper, we researched the correlation between point load index and uniaxial compressive strength of rock-like isotropic material of different sizes and strengths by using a portable instrument for point load test. According to test results we conclude that the test data follows the normal distribution law with obvious central tendency; size effect of rock-like material on point load index is apparent; according to P-D2e curve, the highest correlation coefficient is 0.97, indicating that the point load index of irregular samples can be rectified to that of standard equivalent size. Furthermore, the relational expression between point load index and uniaxial compression strength is established, with a correlation coefficient up to 0.994, which suggest that the rectified point load index well reflects the correlation and improves calculation accuracy. Finally, through point load test of irregular specimens, the error of the proposed relational expression is verified within 15%.
关键词
类岩石材料 /
点荷载指标 /
单轴抗压强度 /
尺寸效应 /
统计方法
Key words
point loading index /
uniaxial compressive strength /
rock-like material /
size effect /
statistical method
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参考文献
[1] FRANKLIN J A. ISRM Suggested Method for Determining Point Load Strength[J]. International Journal of Rock Mechanics and Mining Sciences,1985,22(2):51-60.
[2] ASTM D5731, Standard Test Method for Determination of the Point Load Strength Index of Rock and Application to Rock Strength Classifications[S]. Pennsylvania: American Society for Testing and Materials, 2016.
[3] AZIMIAN A, AJALLOEIAN R, FATEHI L. An Empirical Correlation of Uniaxial Compressive Strength with P-wave Velocity and Point Load Strength Index on Marly Rocks Using Statistical Method[J]. Geotechnical and Geological Engineering, 2014, 32(1): 205-214.
[4] DIAMANTIS K, GARTZOS E, MIGIROS G. Study on Uniaxial Compressive Strength, Point Load Strength Index, Dynamic and Physical Properties of Serpentinites from Central Greece—Test Results and Empirical Relations[J]. Engineering Geology, 2009, 108(3): 199-207.
[5] KARAKUL H. Investigation of Saturation Effect on the Relationship Between Compressive Strength and Schmidt Hammer Rebound[J]. Bulletin of Engineering Geology and the Environment, 2017, 76(3): 1143-1152.
[6] BROCH E, FRANKLIN J A. The Point Load Strength Test[J]. International Journal of Rock Mechanics and Mining Sciences, 1972, 9: 669-676.
[7] GOUDIE A S. Schmidt Hammer in Geomorphological Research[J].Progress in Physical Geography,2006,30(2):703-716.
[8] KABILAN N, MUTTHARA M, SIVA A, et al. Prediction of Uniaxial Compressive Strength Using Point Load Index for Jointed Rocks[J]. Journal of Mechanical and Civil Engineering,2016,13: 1-7.
[9] KAHRAMAN S, GUNAYDIN O, FENER M. The Effect of Porosity on the Relation between Uniaxial Compressive Strength and Point Load Index[J]. International Journal of Rock Mechanics & Mining Sciences,2005,42(4):584-589.
[10]KAYA A, KARAMAN K. Utilizing the Strength Conversion Factor in the Estimation of Uniaxial Compressive Strength from the Point Load Index[J]. Bulletin of Engineering Geology and the Environment, 2016, 75(1): 341-357.
[11]KAHRAMAN S, GUNAYDIN O. The Effect of Rock Classes on the Relation Between Uniaxial Compressive Strength and Point Load Index[J]. Bulletin of Engineering Geology and the Environment, 2009,68(3):345-353.
[12]TANDON R S, GUPTA V. Estimation of Strength Characteristics of Different Himalayan Rocks from Schmidt Hammer Rebound, Point Load Index, and Compressional Wave Velocity[J]. Bulletin of Engineering Geology and the Environment, 2015,74(2):521-533.
[13]BIENIAWSKI Z T. The Point Load Test in Geotechnical Practice[J]. Engineering Geology,1975,9(1):1-11.
[14]READ J R L, THORNTEN P N, REGAN W M. A Rational Approach to the Point Load Test[C]∥Institution of Professional Engineerings New Zealand,Third Australia-New Zealand Conference on Geomechanics, Wellington, May 12-16, 1980: 35-39.
[15]GHOSH D K, SRIVASTAVA M. Point-load Strength: An Index for Classification of Rock Material[J]. Bulletin of the International Association of Engineering Geology, 1991,44(1): 27-33.
[16]CHAU K T,WONG R H C.Uniaxial Compressive Strength and Point Load Strength of Rocks[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1996,33(2):183-188
[17]QUANE S L, RUSSEL J K. Rock Strength as a Metric of Welding Intensity in Pyroclastic Deposits[J]. European Journal of Mineralogy, 2003, 15(5): 855-864.
[18]AKRAM M, BAKAR M Z A. Correlation Between Uniaxial Compressive Strength and Point Load Index for Salt-range Rocks[J]. Pakistan Journal of Engineering and Applied Sciences, 2007, 1: 1-8.
[19]王 茹, 唐春安, 王述红. 岩石点荷载试验若干问题的研究[J]. 东北大学学报,2008,29(1):130-134.
[20]SABATAKAKIS N, KOUKIS G, TSIAMBAOS G. et al. Index Properties and Strength Variation Controlled by Microstructure for Sedimentary Rocks[J]. Engineering Geology, 2009, 97: 80-90.
[21]SINGH T N, KAINTHOLA A, VENKATESH A. Correlation Between Point Load Index and Uniaxial Compressive Strength for Different Rock Types[J]. Rock Mechanics and Rock Engineering, 2012, 45(2): 259-264.
[22]LI D, WONG L N Y. Point Load Test on Meta-Sedimentary Rocks and Correlation to UCS and BTS[J]. Rock Mechanics and Rock Engineering, 2013,46(4):889-896.
[23]CARGILL J S, SHAKOOR A. Evaluation of Empirical Methods for Measuring the Uniaxial Compressive Strength[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts,1990, 27(6): 495-503.
[24]GRASSO P, XU S, MAHTAB A. Problems and Promises of Index Testing of Rocks[J]. Rock Mechanics,1992,33:879-88.
[25]ULUSAY R, TURELI K, IDER M H. Prediction of Engineering Properties of a Selected Litharenite Sandstone from Its Petrographic Characteristics Using Correlation and Multivariate Statistical Techniques[J]. Engineering Geology, 1994,38(1/2):135-157.
[26]KAHRAMAN S. Evaluation of Simple Methods for Assessing the Uniaxial Compressive Strength of Rock[J]. International Journal of Rock Mechanics and Mining Sciences, doi: 10.1016/S1365-1609(01)00039-9.
[27]BASU A, KAMRAN M. Point Load Test on Schistose Rocks and Its Applicability in Predicting Uniaxial Compressive Strength[J]. International Journal of Rock Mechanics and Mining Sciences, 2010, 47(5): 823-828.
[28]HEIDARI M,KHANLARI G,TORABI-KAVEH M,et al. Predicting the Uniaxial Compressive and Tensile Strengths of Gypsum Rock by Point Load Testing[J]. Rock Mechanics and Rock Engineering, 2012, 45(2): 265-273.
[29]付志亮, 王 亮. 煤层顶底板岩石点荷载强度与拉压强度对比试验研究[J]. 岩石力学与工程学报,2013, 32(1): 88-97.
[30]KAHRAMAN S. The Determination of Uniaxial Compressive Strength from Point Load Strength for Pyroclastic Rocks[J]. Engineering Geology,2014,170(1):33-42.
[31]李安平, 刘洋树, 周 明, 等. 岩石点荷载强度与单轴抗压强度关系研究[J]. 有色金属,2014,66(3):53-59.
[32]TSIAMBAOS G, SABATAKAKIS N. Considerations on Strength of Intact Sedimentary Rocks[J]. Engineering Geology, 2004,72(3/4): 261-273.
[33]SANTI P M. Field Methods for Characterizing Weak Rock for Engineering[J].Environmental & Engineering Geoscience, 2006, 12(1): 1-11.
[34]KILIC A, TEYMEN A. Determination of Mechanical Properties of Rocks Using Simple Methods[J]. Bulletin of Engineering Geology and the Environment, 2008, 67(2): 237-244.
[35]张建明,唐志成,刘泉声. 点荷载强度指数估算与岩浆岩的单轴抗压强度的关系[J].岩土力学,2015,36(2):595-600.
[36]郭曼丽. 试论岩石点荷载试验的适用性[J].岩土力学,2003,24(3):488-492.
[37]郑达辉,王连俊,蔡铁仪,等.岩石点荷载强度的研究[C]∥全国第三次工程地质大会论文选集. 成都:成都科技大学出版社,1988:1075-1083.
[38]FRANKLIN J A. 测定岩石点荷载强度的建议方法[J].向桂馥,译.岩石力学与工程学报,1986,5(1):79-90.
[39]王祥厚, 李明勇, 佘洛斐, 等. 点荷载测定岩石强度使用不规则试件研究与探讨[J].岩土力学,1995,12(4):46-56.
[40]赵 奎, 金解放, 赵 康, 等.用岩石点荷载强度指标确定其单轴抗压强度的试验研究[J].矿业研究与开发,2005, (6):32-33, 88.
[41]王 赢, 孙成科, 张喜平, 等. 点荷载试验在岩基评价中的应用[J].港工技术,2013,(6):56-60.
[42]张国锋, 刘志双, 陈显坤, 等. 点荷载法测试易风化泥质岩强度的可靠性分析[J].岩土力学,2014,35(增1):292-299.
[43]戴洪军, 蔡升华, 郭纪中.点荷载强度试验中经验公式的分析[J].工程勘察,2001,(2): 43-47.
[44]杨 虎, 钟 波, 刘琼荪. 应用数理统计[M]. 北京:清华大学出版社,2006.
[45]杨 帆, 谢永利. 点荷载试验确定岩石强度指标的效果分析[J]. 广西大学学报(自然科学版),2013,38(1):138-144.
[46]曾伟雄, 林国赞. 岩石单轴饱和抗压强度的点荷载试验方法设计与探讨[J]. 岩石力学与工程学报,2003,22(4): 566-568.
基金
中央高校基础科研业务费专项(310821171125)
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