含裂隙岩体点触探破坏机制研究  

Failure mechanism of rock with pre-existing surface crack under cone penetration test

作　　者：毛芮 房凯[1,2] 赵同彬[1,2] 刘念武[3] MAO Rui;FANG Kai;ZHAO Tongbin;LIU Nianwu(College of Energy and Mining Engineering,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;School of Civil and Architecture,Zhejiang Sci-Tech University,Hangzhou,Zhejiang 310018,China)

机构地区：[1]山东科技大学能源与矿业工程学院,山东青岛266590 [2]山东科技大学矿山灾害预防控制省部共建国家重点实验室培育基地,山东青岛266590 [3]浙江理工大学建筑工程学院,浙江杭州310018

出　　处：《岩石力学与工程学报》2022年第6期1183-1192,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51974171);山东省自然科学基金资助项目(ZR2019QEE015)。

摘　　要：岩石点触探试验是间接评估岩体力学特性的重要方法,在其原位应用过程中,岩体的触探特性会受到原位裂隙的重要影响。为了明确岩体裂隙对点触探试验的影响范围,揭示含裂隙岩体点触探的破坏机制,量化不同裂隙对点触探指标的影响,进行一系列含裂隙岩体的室内点触探试验,并通过数值模拟对其破裂机制进行了研究。试验结果表明:点触探加载点下方的影响区域内存在裂隙时会改变点触探破坏模式和强度特性。当裂隙延伸至加载压头附近时,点触探加载下岩体会发生从加载点向该裂隙端部的剪切破坏,裂隙内端的位置决定了点触探的强度及裂纹扩展路径,基于剪切破坏的极限平衡原理可建立点触探强度与剪切路径的对应关系。为了进一步阐明含裂隙点触探破裂规律,通过数值模拟分析了裂隙内端延伸至压头附近不同区域条件时点触探特性,根据破坏模式界定了触探加载点下方的裂隙影响范围,通过定义弱化系数量化了影响区域内不同裂隙对点触探强度的影响程度。同时基于岩体裂隙扩展路径耗能规律,对多裂隙条件下的点触探破裂特性进行了探讨。Rock cone penetration test is used to evaluate the mechanical properties of in-situ rock indirectly,while the rock failure pattern and mechanical behavior would be severely affected by the pre-existing cracks contained in the in-situ rock mass.To clarify the influence mechanism of the cracks on the cone penetration test and to quantify the effect of the pre-existing cracks on the cone penetration indexes,series of cone penetration tests and numerical simulations were conducted.The test results show that there exists an influence area of cracks below the cone indenter.When the surface crack extends to the vicinity of the loading indenter,shear failure plane generates and propagates from the indenter to the inner tip of the crack.The position of the crack inner tip dominates the cone penetration strength and the crack propagation path,and the correspondence between the cone penetration strength and the shearing path can be established based on the shear limit equilibrium.Additionally,numerical simulations were carried out to analyze the cone penetration behaviors in the case of the crack inner tip extending to different positions near the indenter.Based on the numerical analysis results,it is found that the affected area of the pre-existing crack can be determined according to the failure pattern.Moreover,the weaken coefficient is also defined to quantify the effect of different pre-existing cracks on the penetration strength.Based on the energy dissipation of different fracture paths,the fracture characteristics with multiple cracks under cone penetration test were also discussed.

关 键 词：岩石力学 点触探试验 破坏机制 裂隙 破坏模式 

分 类 号：TU45[建筑科学—岩土工程]