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单轴压缩条件下冻融灰岩裂隙扩容及损伤破坏分析
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作者 宋心怡 宋彦琦 +1 位作者 马宏发 杨江坤 《矿业研究与开发》 CAS 北大核心 2024年第2期122-128,共7页
为研究冻融灰岩单轴压缩下裂隙应变演化及渐进损伤特征,开展了0次、10次、20次、40次灰岩冻融单轴压缩试验,建立了基于裂隙体应变特征的冻融灰岩损伤本构方程,结合PFC2D数值模拟分析了冻融灰岩的损伤破坏模式。结果表明:经历40次冻融循... 为研究冻融灰岩单轴压缩下裂隙应变演化及渐进损伤特征,开展了0次、10次、20次、40次灰岩冻融单轴压缩试验,建立了基于裂隙体应变特征的冻融灰岩损伤本构方程,结合PFC2D数值模拟分析了冻融灰岩的损伤破坏模式。结果表明:经历40次冻融循环后,灰岩的单轴抗压强度、弹性模量、泊松比由原来的109.88 MPa、65.38 GPa、0.225分别降至70.36 MPa、46.62 GPa、0.197;冻融10次、20次、40次灰岩裂隙体应变极值分别增至0.0106, 0.0146, 0.0269。基于体积应变拐点法及位移回归分析法得到的冻融灰岩扩容应力值随冻融循环次数增加而降低,两种方法所得结果的相对误差低于10%。基于裂隙体应变特征的理论应力-应变曲线与试验曲线具有较好的一致性,所建的损伤本构方程适用于低冻融次数灰岩。基于PFC2D所得的冻融灰岩单轴压缩破坏模式为劈裂破坏和“劈裂-剪切”破坏。 展开更多
关键词 冻融循环 力学参数 裂隙体应变 扩容应力 损伤本构
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Crack initiation stress and strain of jointed rock containing multi-cracks under uniaxial compressive loading: A particle flow code approach 被引量:16
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作者 范祥 KULATILAKE P H S W +1 位作者 陈新 曹平 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第2期638-645,共8页
The ratio of crack initiation stress to the uniaxial compressive strength(SCI,B/SUC,B) and the ratio of axial strain at the crack initiation stress to the axial strain at the uniaxial compressive strength(B,UCB,CI,A,A... The ratio of crack initiation stress to the uniaxial compressive strength(SCI,B/SUC,B) and the ratio of axial strain at the crack initiation stress to the axial strain at the uniaxial compressive strength(B,UCB,CI,A,A/SSSS) were studied by performing numerical stress analysis on blocks having multi flaws at close spacing's under uniaxial loading using PFC3 D. The following findings are obtained: SCI,B/SUC,B has an average value of about 0.5 with a variability of ± 0.1. This range agrees quite well with the values obtained by former research. For joint inclination angle, β=90°,B,UCB,CI,A,A/SSSS is found to be around 0.48 irrespective of the value of joint continuity factor, k. No particular relation is found betweenB,UCB,CI,A,A/SSSS and β; however, the average B,UCB,CI,A,A/SSSS seems to slightly decrease with increasing k. The variability ofB,UCB,CI,A,A/SSSS is found to increase with k.Based on the cases studied in this work,B,UCB,CI,A,A/SSSS ranges between 0.3 and 0.5. This range is quite close to the range of 0.4to 0.6 obtained for SCI,B/SUC,B. The highest variability of ± 0.12 forB,UCB,CI,A,A/SSSS is obtained for k=0.8. For the remaining k values the variability ofB,UCB,CI,A,A/SSSS can be expressed within ± 0.05. This finding is very similar to the finding obtained for the variability of SCI,B/SUC,B. 展开更多
关键词 jointed rock multi flaws uniaxial loading PFC3D model crack initiation stress(SCI B) axial strain at crack initiation
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