摘要
自组织临界理论为无序和非线性复杂系统的行为特征和演化模式提供了新的解释,基于该理论探讨岩石破裂演化的规律。考虑到体型对其破坏特征的影响,制作了立方体和圆柱体两种体型岩石试件,开展单轴压缩和声发射试验,分析岩石破裂演化过程中自组织临界点前后的声发射信息,根据声发射能量概率密度、声发射空间定位及等候时间的分布,对临界指数k、余震分布指数α和等候时间分布指数δ等参数进行统计。结果表明:不论是立方体还是圆柱体试样,其破坏过程均是一个由低能值的无序稳定态向高能值的有序非稳定态发展的自组织过程,体型对其破坏的自组织过程影响较小,立方体试件相对圆柱体试件,前者从受压到自组织第一临界点(体积膨胀起始点)的持续时间相对较久,且由第一到第二临界点(峰值强度点)的自组织演化过程更迅速,其破坏更具规律性,破坏预测优于后者;立方体试件在受压过程中趋于多向应力状态,对岩石内部裂缝的发展具有一定的限制作用,破裂全过程的临界指数较大,圆柱体试件的局部屈服弱化特征较明显,在受压作用下更容易导致裂隙的发展,破裂全过程的临界指数较小;对于岩石的Omori定律分布统计指数α,立方体试件破裂自组织演化过程中第二阶段声发射余震分布的α值大于1,而圆柱体试件的α值小于1,表明立方体试件在第二临界点出现前已进入了临界失稳状态;在大的等候时间差范围内(>0.1s),试件破裂自组织演化过程第二阶段的临界指数相对第一阶段较大,意味着新裂纹出现的频率随着破裂的自组织演化而加剧,声发射能量的临界特征可以较好反映岩石破裂过程中的内部响应。
Self-organizing criticality theory provides a new interpretation for the behaviour characteristics and evolution patterns of disordered and non-linear complex systems.Based on this theory,the law of fracture evolution with different rock types was discussed.Considering the influence of body shape on the failure characteristics,uniaxial compression test and acoustic emission(AE) test were carried out on two rock specimens,i.e.cube and cylinder.The acoustic emission information before and after the self-organized critical point during the evolution of rock fracture was analyzed.According to the distributed of the probability density of AE energy,the spatial positioning of AE event and the AE waiting time,and their critical exponent k,productivity exponent α of after shock distribution,and waiting time distribution exponent δ were analyzed statistically.The results show that the failure processes of both cube and cylinder specimens are self-organization processes from disordered stable state of low energy value to ordered unstable state of high energy value.The body shape has little effect on the self-organization process of its destruction.Comparing with cylindrical specimens,the first phase of cubic specimens from compression to the first critical point of self-organization,volume expansion point,lasts relatively longer,and the self-organization evolution process from the first critical point to the second critical point of self-organization,speak strength point,is also faster.The failure of the cubic specimen is more regular,which is more conducive to failure prediction.Cubic specimen is isotropic in the process of compression,which restricts the development of cracks so the critical index of the whole process of fracture is larger.While the local yield weakening characteristic of cylindrical specimen is obvious,which makes the development of cracks under compression easier and its critical index is smaller.For the productivity exponent α of Omori law of rocks with different sizes,the value α of the second st
作者
孙冰
唐文福
曾晟
侯珊珊
方耀楚
SUN Bing;TANG Wen-fu;ZENG Sheng;HOU Shan-shan;FANG Yao-chu(School of Civil Engineering,University of South China,Hengyang,Hunan 421001,China;School of Resources,Environment and Safety Engineering,University of South China,Hengyang,Hunan 421001,China;State Key Laboratory of Deep Rock Mechanics and Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221000,Chian)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2022年第9期2525-2538,共14页
Rock and Soil Mechanics
基金
湖南省自然科学基金资助项目(No.2021JJ30575)
国家自然科学基金资助项目(No.51204098)。
关键词
岩石破裂过程
自组织临界性
声发射能量
幂律分布
临界指数
rock fracture process
self-organizing criticality
acoustic emission energy
power law distribution
critical index
