裂隙灰岩拉剪破坏裂纹扩展规律与断裂机制  

Crack Propagation Law and Fracture Mechanism of Tension-shear Damage for Fissure Limestone

作　　者：张研[1,2] 王峻峰 王自成 叶玉龙 ZHANG Yan;WANG Jun-feng;WANG Zi-cheng;YE Yu-long(School of Civil Engineering,Guilin University of Technology,Guilin 541004,China;Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin 541004,China)

机构地区：[1]桂林理工大学土木工程学院,桂林541004 [2]广西岩土力学与工程重点实验室,桂林541004

出　　处：《科学技术与工程》2024年第31期13504-13511,共8页Science Technology and Engineering

基　　金：国家自然科学基金(52068016,42067041);广西自然科学基金(2020GXNSFAA159118,2020GXNSFAA159125);水利工程岩石力学广西高等学校高水平创新团队及卓越学者计划(202006);广西岩土力学与工程重点实验室项目(桂科能20-Y-XT-01)。

摘　　要：为了探究裂隙灰岩体发生拉剪破坏后的裂纹扩展规律与断裂机制,以裂隙灰岩为研究对象,开展拉剪断裂试验,并基于ABAQUS软件建立相对应模型。通过分析得到不同加载位置下裂隙尖端发生断裂破坏过程的应力云图变化,利用J积分与位移外推法计算得到Ⅰ、Ⅱ型应力强度因子。结果表明:随着加载步数的增加,加载点正下方、裂纹尖端处与底部临空区易形成应力集中区并相互贯通,数值模型与物理试验裂纹扩展路径基本一致,加载距离的增加使得裂纹起裂角与水平方向最远扩展距离变小。利用J积分法与位移外推法计算不同加载距离下应力强度因子K_(Ⅰ)、K_(Ⅱ)值,相对误差在5%以内,计算结果准确度较高。所建立的模型能够较好地反映试验真实断裂情况,其分析结果可为危岩崩塌预报防治提供重要的理论参考。In order to explore the crack propagation law and fracture mechanism of tension-shear damage for fissure limestone,the tension-shear fracture test was carried using based on fissure limestone,and the corresponding model was also established using ABAQUS.The change of stress cloud diagram of the fracture damage process occurring at the fracture tip under different loading positions was obtained.The stress intensity factors for type Ⅰ and Ⅱ were calculated by using J-integral and displacement extrapolation method.The results show that the stress concentration zone is formed directly below the loading point,at the tip of the crack and at the bottom of the protruding area which are connected with each other.The crack propagation path for numerical model basically coincide with physical test.With the increase of loading distance,the crack initiation angle and the farthest spreading distance in horizontal direction become smaller.The values of stress strength factor K_(Ⅰ) and K_(Ⅱ)for different loading distances are calculated based on J-integral and displacement extrapolation method.The relative error is less than 5%and the calculation result is accurate.The real fracture situation of the test can be reflected better by the model established in this paper,and an important theoretical basis can be provided by its analysis results for the prevention and control of dangerous rock collapse.

关 键 词：裂隙灰岩 拉剪破坏 裂纹扩展规律 断裂机制 应力强度因子 

分 类 号：TU456[建筑科学—岩土工程]