基于Hoek-Brown的岩石横观各向同性屈服准则研究  

Yield criterion research on intact rock transverse isotropy based on Hoek-Brown citerion

作　　者：郑艳妮 张强[3] 张升[1,2] 贾朝军 雷明锋[1] ZHENG Yan-ni;ZHANG Qiang;ZHANG Sheng;JIA Chao-jun;LEI Ming-feng(School of Civil Engineering,Central South University,Changsha,Hunan 410075,China;National Engineering Laboratory for High Speed Railway Construction,Central South University,Changsha,Hunan 410075,China;China Institute of Water Resources and Hydropower Research,Beijing 100048,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南大学高速铁路建造技术国家工程实验室,湖南长沙410075 [3]中国水利水电科学研究院,北京100048

出　　处：《岩土力学》2022年第1期139-151,共13页Rock and Soil Mechanics

基　　金：国家自然科学基金青年基金项目(No.52008403);中南大学研究生自主探索创新项目(No.2021zzts0233)。

摘　　要：为了描述岩石强度的各向异性特征,通过引入材料的微结构张量,考虑单轴抗压强度σ_(cβ)随层理倾角β而变化,提出了基于微结构张量的修正Hoek-Brown屈服准则。开展不同层理倾角(0°、15°、30°、45°、60°、75°和90°)的页岩试样不同围压(0、5、10、15和20 MPa)下的三轴压缩试验,结果显示,页岩峰值强度与层理倾角β呈“U”形曲线关系,在围压较低时呈“肩”形曲线关系,弹性模量E_(t)和泊松比ν对围压不敏感,其平均值随层理倾角β的变化关系分别呈倒“U”形、“肩”形。页岩的微观和宏观破坏图像表明,其破坏模式受围压和层理倾角双重控制。试验值与模型预测值的对比表明,修正的Hoek-Brown屈服准则可较好地对页岩强度的各向异性进行模拟。同时,采用Koteshwar千枚岩、Koteshwar板岩、绿泥石片岩等层状结构岩石的单轴和三轴压缩试验数据,进一步验证了提出的修正Hoek-Brown屈服准则对多数具有层理结构的横观各向同性岩石峰值强度模拟具有普遍适用性,并对屈服准则在试验数据较多和较少情况下的峰值强度模拟效果进行了评价。In order to describe the anisotropy characteristics of rock strength,a modified Hoek-Brown yield criterion based on the microstructure tensor is proposed,in this process,the microstructure tensor of the material is introduced,considering the change of uniaxial compressive strengthσ_(cβ)with the bedding dipβ.Conventional triaxial compression tests are conducted on shale samples with different bedding orientations(0°,15°,30°,45°,60°,75°and 90°)under different confining pressures(0,5,10,15 and 20 MPa).The results show that the peak strength of shale and the bedding dipβhave a"U"-shaped curve relationship.When the confining pressure is low,it shows a"Shoulder"-shaped curve relationship.Elastic modulus E_(t)and Poisson’s ratioνare not sensitive to confining pressure,and the relationship between their average value and the bedding dip angleβis inverted"U"shape and"shoulder"shape,respectively.The micro and macro failure modes of shale are further discussed,and the results show that its failure mode is controlled by both confining pressure and bedding dip.The comparison between experimental data and fitting results indicates that the modified Hoek-Brown yield criterion can simulate the anisotropy of shale strength satisfactorily.Meanwhile,the experiment data of uniaxial and triaxial compression tests on Koteshwar phyllite,Koteshwar slate and chlorite schist are conducted to further verify the application of the proposed modified Hoek-Brown yield criterion in the simulation of most transversely isotropic rock with bedding structure.The simulation effect of the peak strength of the yield criterion is evaluated in the case of more and less test data.

关 键 词：层状页岩 横观各向同性 HOEK-BROWN 屈服准则 

分 类 号：TU452[建筑科学—岩土工程]