摘要
压缩条件下,不同规则程度玄武岩柱的强度和变形存在差异,且其破裂机理亦存在区别。构建不同规则程度的玄武岩柱图像,然后将细观损伤力学、统计强度理论、连续介质力学相结合,基于RFPA^(3D)-CT的数字图像处理,将玄武岩柱图像转化为有限元网格模型,并分别赋予节理、岩石的材料力学参数,并考虑节理及岩石的非均质。开展不同侧压条件下的玄武岩柱数值试验,以研究其强度变形特性,及其破裂机理、累计声发射数、损伤破裂特征。研究表明:侧压0 MPa、6 MPa情况下,随着柱体不规则程度的增加,玄武岩柱的抗压强度基本呈先微增(或增加)再减小的趋势;玄武岩柱的等效变形模量呈波动变化(或先增加再减小)的趋势;随着柱体不规则程度的增加,或者随着侧压的增加,玄武岩柱抗压强度,趋于横观各向同性;分析了侧压0 MPa、6 MPa条件下不同规则程度玄武岩柱的应力场演化过程。在累计声发射数方面,从加载过程中峰值应力所对应的累计声发射数出现的先后顺序,及其量值由小到大的角度来看,分别为柱体不规则、中等规则、基本规则和完全规则;从损伤的角度,分析了侧压0 MPa、6 MPa条件下不同规则程度玄武岩柱的损伤破裂特征。
Under compression,the strengths and deformations of columnar jointed basalts(CJBs)with different regular degrees are different,and the failure mechanisms are also not the same.The images of CJBs with different regular degrees are constructed.Then,by combining meso-damage mechanics,statistical strength theory and continuum mechanics,the images of CJBs are converted into finite element mesh models based on RFPA^(3D)-CT digital image processing,and mechanical parameters of joint and rock materials are assigned,respectively,in which the heterogeneity of joint and rock is considered.Further,numerical tests of CJBs under different lateral pressures are carried out to study the strength and deformation characteristics,fracture mechanism,acoustic emission(AE)accumulation and damaged fracture characteristics.The results show that:Under lateral pressures of 0 MPa and 6 MPa,with the growth of column irregularity,the compressive strength(CS)of CJBs shows a trend of slight increase(or increase)first and then decrease.The equivalent deformation modulus(EDM)of CJBs fluctuates(or increases firstly and then decreases).With the growth of column irregularity or lateral pressure,the CS of CJBs tends to be transversely isotropic.The evolution processes of stress field of CJBs with different regularities under lateral pressures of 0 MPa and 6 MPa are investigated.In terms of AE accumulation,the sequence and magnitude of AE accumulations,corresponding to peak stresses in the loading process,are in order of irregular,moderately regular,basically regular and completely regular columns,respectively.From the point view of damage,the damaged fracture characteristics of CJBs with different regular degrees under lateral pressures of 0 MPa and 6 MPa are analyzed.
作者
王永艺
陈甜甜
龚斌
王婷婷
唐春安
Wang Yongyi;Chen Tiantian;Gong Bin;Wang Tingting;Tang Chunan(State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian,Liaoning 116024,P.R.China;School of Resources and Civil Engineering,Northeastern University,Shenyang 110819,P.R.China;State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2022年第S02期642-658,共17页
Chinese Journal of Underground Space and Engineering
基金
国家自然科学基金(42102314,41941018)
重庆大学煤矿灾害动力学与控制国家重点实验室重大项目(2011DA105287—FW201802)
中国地质大学地质过程与矿产资源国家重点实验室开放基金(GPMR202002)
中国科学院西北生态环境资源研究院冻土工程国家重点实验室开放基金(SKLFSE202013)
关键词
压缩条件
规则程度
玄武岩柱
破裂机理
数值模拟
compression condition
regular degree
basalt columns
fracture mechanism
numerical simulation
