摘要
岩体作为一种具有自承载能力的天然非均质材料,其失效过程具有显著不确定性。为了建立一个能够用于评估岩石材料失效的损伤准则,结合强度准则与统计损伤力学理论,建立材料临界损伤与塑性变形之间的关系,将塑性指标g引入损伤演化方程,推导出2种岩石损伤失效准则,并采用2种岩石17组三轴压缩试验结果对所建立的损伤失效准则进行了对比论证分析,论证了其合理性和准确性;同时,依据所建立的损伤失效准则,建立一种非均质材料损伤等级划分参考标准,并给出各损伤等级临界值计算方法,探索岩石材料在不同围压下的损伤失效行为。研究结果表明:(1)试验结果实测值均处于所建立的损伤失效准则理论预测值99%的置信带内,预测精度高;(2)材料塑性指标g越大,均质性越差,岩石压拉比越小;临界损伤Dcr越大,材料抗损伤性能越好,其结构性破坏对轻微损伤越不敏感;(3)随围压的增加,岩石材料失效时的损伤速率呈快速下降趋势,围压对材料的损伤具有抑制作用;(4)可将岩石材料的渐进失效过程划分为:I级(基本完好)、II级(轻微破损)、III级(中度破坏)、IV级(严重破坏)4个损伤等级,其损伤等级的界限值与材料的均质性直接关联。以上研究成果可定量评估不同围压环境下岩石材料的损伤状态和损伤极限,并为工程岩体损伤失效性分析提供重要理论指导。
As a natural non-homogeneous material with self-bearing capacity,the failure process of rock masses has significant uncertainties.To establish a damage criterion that can be used to evaluate the failure of rock materials,the relationship between the critical damage and the plastic deformation was established by combining the strength criterion and statistical damage mechanics theory,and the plasticity index g was introduced into the damage evolution equation to derive two types of rock damage failure criteria.Triaxial compression tests on 17 sets of samples from two types of rocks were carried out to verify the reasonability and accuracy of the developed criteria.At the same time,based on the damage failure criteria established in the paper,a reference standard for the classification of the damage class of non-homogeneous materials was established,and the calculation method for the critical value of each damage class was given to explore the damage failure behavior of rock materials under different surrounding pressures.The results show that the test results are all within the 99%confidence band of the theoretical prediction values by the damage failure criterion established in the paper,indicating that the prediction accuracy is high.The larger the material plasticity indexγ,the worse the homogeneity,and the smaller the rock compression and the tension ratio.The larger the critical damage Dcr,the better the damage resistance of the material,and the less sensitive the structural damage is to minor damage.With increasing the surrounding pressure,the damage rate of the rock material decreases rapidly,showing that the surrounding pressure has a suppressive effect on the damage of the material.The progressive failure process of rock materials can be divided into four damage levels including basically intact,minor breakage,moderate damage and severe damage,and the boundary values between the damage levels are directly related to the homogeneity of the materials.The above research results can quantitatively assess the damage state and damage limit of rock materials under different surrounding pressure environments,and give important theoretical guidance for the analysis of engineering rock damage failure.
作者
秦庆词
李克钢
李明亮
刘博
QIN Qingci;LI Kegang;LI Mingliang;LIU Bo(Faculty of Land Resource Engineering,Kunming University,of Science and Technology,Kunming,Yunnan 650093,China;Yunnun Key Laboratory of Sino-German Blue Mining and Utilization of Special Underground Space,Kunming,Yunnan 650093,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2021年第9期1812-1825,共14页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金面上项目(41672303)
云南省高校科技创新团队支持计划。
关键词
岩石力学
非均质性
临界损伤
失效准则
损伤等级
塑性指标
rock mechanics
non-homogeneity
critical damage
failure criterion
damage class
plasticity index
作者简介
秦庆词(1991-),男,2016年毕业于昆明理工大学采矿工程专业,现为博士研究生,主要从事岩石损伤力学方面的研究工作。E-mail:1457186548@qq.com;通讯作者:李克钢(1978-),男,现任教授、博h生导师。E-mail:106146135@qq.com。
