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基于裂纹系的砼轴拉构件亚临界扩展研究
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作者 郑涛 王桂尧 张永杰 《应用力学学报》 CAS CSCD 北大核心 2024年第6期1317-1326,共10页
普通混凝土构件存在多裂纹的特点,现有的单裂纹模型仅反映了构件的抗裂能力,而没有反映构件内部在极限荷载之前既已发生的有害的裂纹发展情况。针对这一问题,提出采用裂纹系模型研究混凝土构件的亚临界扩展过程。为简化,选取轴拉构件为... 普通混凝土构件存在多裂纹的特点,现有的单裂纹模型仅反映了构件的抗裂能力,而没有反映构件内部在极限荷载之前既已发生的有害的裂纹发展情况。针对这一问题,提出采用裂纹系模型研究混凝土构件的亚临界扩展过程。为简化,选取轴拉构件为研究对象,以缝端微裂纹区模型为基础建立了楔形的单裂纹模型,并以几何分布参数——裂纹平均间距、裂纹初始长度及其数量百分比为框架建立了由单裂纹模型串式排列而成的裂纹系模型。采用该模型模拟了轴拉构件的受拉试验和断裂试验,结果表明选取合适的参数后模型能够准确反映混凝土宏观断裂过程和微观裂纹扩展过程,并且对于含预制裂缝试件,裂纹总数为实际数量的裂纹系模型结果与现有单裂纹模型结果吻合。采用该模型的分析表明,混凝土亚临界扩展过程源于混凝土初始裂纹系由长到短逐级开展;其真实起裂点远早于通常试验观测到的起裂点,其失稳点——失稳韧度可以通过减小混凝土初始裂纹系最小长度提高。 展开更多
关键词 断裂 裂纹系模型 统计学参数 亚临界扩展 混凝土断裂 试验模拟
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Crack evolution behavior of rocks under confining pressures and its propagation model before peak stress 被引量:11
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作者 ZUO Jian-ping CHEN Yan LIU Xiao-li 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第11期3045-3056,共12页
The understanding of crack propagation characteristics and law of rocks during the loading process is of great significance for the exploitation and support of rock engineering.In this study,the crack propagation beha... The understanding of crack propagation characteristics and law of rocks during the loading process is of great significance for the exploitation and support of rock engineering.In this study,the crack propagation behavior of rocks in triaxial compression tests was investigated in detail.The main conclusions were as follows:1)According to the evolution characteristics of crack axial strain,the differential stress?strain curve of rocks under triaxial compressive condition can be divided into three phases which are linear elastic phase,crack propagation phase,post peak phase,respectively;2)The proposed models are applied to comparison with the test data of rocks under triaxial compressive condition and different temperatures.The theoretical data calculated by the models are in good agreement with the laboratory data,indicating that the proposed model can be applied to describing the crack propagation behavior and the nonlinear properties of rocks under triaxial compressive condition;3)The inelastic compliance and crack initiation strain in the proposed model have a decrease trend with the increase of confining pressure and temperature.Peak crack axial strain increases nonlinearly with the inelastic compliance and the increase rate increases gradually.Crack initiation strain has a linear relation with peak crack axial strain. 展开更多
关键词 crack strain crack propagation behavior crack propagation model stress strain relationship
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