估算异性岩石不连续面峰值剪切强度的经验公式  

Empirical criterion for evaluating the peak shear strength of discontinuity with different joint wall strengths

作　　者：张志飞 黄曼 唐志成[1] ZHANG Zhi-fei;HUANG Man;TANG Zhi-cheng(Faculty of Engineering,China University of Geosciences,Wuhan,Hubei 430074,China;School of Civil Engineering,Shaoxing University,Shaoxing,Zhejiang 312000,China;Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province,Shaoxing University,Shaoxing,Zhejiang 312000,China)

机构地区：[1]中国地质大学(武汉)工程学院,湖北武汉430074 [2]绍兴文理学院土木工程学院,浙江绍兴312000 [3]绍兴文理学院浙江省岩石力学与地质灾害重点实验室,浙江绍兴312000

出　　处：《岩土力学》2023年第2期507-519,共13页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.42177165,No.41672302,No.41572299);浙江省重点研发计划项目(No.2019C03104)。

摘　　要：长江三峡库区广泛发育着两侧岩性不同的不连续面(称为异性不连续面),研究其峰值剪切强度可为相关岩体的稳定性分析和评价提供理论依据。采用高强石膏浇注3组不同形貌且上、下壁面强度不同的不连续面试件,并在不同常法向应力下进行剪切试验。引入不连续面壁组合系数λ来综合量化不连续面壁的抗压强度和基本摩擦角对异性不连续面峰值剪切强度的影响,λ越小,上、下不连续面壁强度差异越大。异性不连续面的峰值剪切强度随λ的增加呈非线性增加,且在高法向应力下更为显著。在Barton公式的基础上,通过多元回归分析建立了估算异性不连续面峰值剪切强度的经验公式。采用天然和人工锯齿形异性不连续面的直剪试验结果对新公式做了进一步验证,试验剪切强度与新公式预测值吻合较好。简要分析了新公式在软硬互层岩质边坡稳定性评价中的应用。最后,讨论了Wu公式的适用性以及新公式的优点和不足。Discontinuities with different rock types are widely distributed on the Three Gorges reservoir area of Yangtze River,and the study of their peak shear strengths can provide a theoretical basis for the stability analysis and evaluation of rock masses.Three groups of rock-like specimens with different surface morphologies and upper and lower joint wall strengths were cast by high-strength gypsum,and then directly sheared under different constant normal stresses.The joint wall strength combination coefficient(λ)is introduced to quantify the comprehensive influence of the compressive strength and basic friction angle of the discontinuity wall on the peak shear strength of discontinuities with different joint wall strengths.The smallerλis,the greater the strength difference between the upper and lower discontinuity wall is.The peak shear strength of rock discontinuities with different joint wall strengths increases non-linearly with increasingλ,which is more significant at higher normal stress.Based on Barton criterion,an empirical criterion for estimating the peak shear strength of discontinuities with different joint wall strengths has been established by multiple regression analysis.The new criterion is further verified by the direct shear test results of the natural and artificial tooth-shaped discontinuities with different joint wall strengths,and tested shear strengths are in good agreement with predicted values by the new criterion.The application of the new criterion in the stability evaluation of soft and hard inter-bedded rock slopes is briefly analyzed.Finally,the applicability of Wu’s equation and the advantages and disadvantages of the new criterion are discussed.

关 键 词：异性岩石不连续面 剪切强度准则 不连续面壁组合系数 

分 类 号：TU452[建筑科学—岩土工程]