To analyze the effects of a time-varying viscosity on the penetration length of grouting,in this study cement slur-ries with varying water-cement ratios have been investigated using the Bingham’sfluidflow equation and ...To analyze the effects of a time-varying viscosity on the penetration length of grouting,in this study cement slur-ries with varying water-cement ratios have been investigated using the Bingham’sfluidflow equation and a dis-crete element method.Afluid-solid coupling numerical model has been introduced accordingly,and its accuracy has been validated through comparison of theoretical and numerical solutions.For different fracture forms(a single fracture,a branch fracture,and a fracture network),the influence of the time-varying viscosity on the slurry length range has been investigated,considering the change in the fracture aperture.The results show that under different fracture forms and the same grouting process conditions,the influence of the time-varying viscosity on the seepage length is 0.350 m.展开更多
从受激布里渊散射耦合波导方程出发建立了多模光纤布里渊频移、泵浦波、斯托克斯波和声波场理论模型,分析对比了多模光纤与单模光纤布里渊散射谱的频移、增益、线宽和受激布里渊散射阈值,并进一步分析了光纤长度、衰减系数、数值孔径对...从受激布里渊散射耦合波导方程出发建立了多模光纤布里渊频移、泵浦波、斯托克斯波和声波场理论模型,分析对比了多模光纤与单模光纤布里渊散射谱的频移、增益、线宽和受激布里渊散射阈值,并进一步分析了光纤长度、衰减系数、数值孔径对多模光纤受激布里渊散射阈值的影响。结果表明,多模光纤多个模式布里渊散射谱叠加造成其总的布里渊散射谱展宽,不再满足洛伦兹分布,其线宽增加至原来数倍、峰值增益和频移降低;渐变折射率多模光纤SBS阈值一般在80 m W以上,远大于单模光纤;纤芯直径相同时,相比于阶跃折射率多模光纤,数值孔径对渐变折射率多模光纤SBS阈值的影响较大,后者更易发生受激布里渊散射效应。理论计算与已报道测量结果的比较验证了理论分析的正确性。文中研究为建立基于多模光纤的布里渊散射分布式传感系统奠定了理论基础。展开更多
基金supported by the National Natural Science Foundation of China(Grant Numbers:U22A20234,42277170)the Key Research and Development Project of Hubei Province(Grant Number:2020BCB073).
文摘To analyze the effects of a time-varying viscosity on the penetration length of grouting,in this study cement slur-ries with varying water-cement ratios have been investigated using the Bingham’sfluidflow equation and a dis-crete element method.Afluid-solid coupling numerical model has been introduced accordingly,and its accuracy has been validated through comparison of theoretical and numerical solutions.For different fracture forms(a single fracture,a branch fracture,and a fracture network),the influence of the time-varying viscosity on the slurry length range has been investigated,considering the change in the fracture aperture.The results show that under different fracture forms and the same grouting process conditions,the influence of the time-varying viscosity on the seepage length is 0.350 m.
文摘从受激布里渊散射耦合波导方程出发建立了多模光纤布里渊频移、泵浦波、斯托克斯波和声波场理论模型,分析对比了多模光纤与单模光纤布里渊散射谱的频移、增益、线宽和受激布里渊散射阈值,并进一步分析了光纤长度、衰减系数、数值孔径对多模光纤受激布里渊散射阈值的影响。结果表明,多模光纤多个模式布里渊散射谱叠加造成其总的布里渊散射谱展宽,不再满足洛伦兹分布,其线宽增加至原来数倍、峰值增益和频移降低;渐变折射率多模光纤SBS阈值一般在80 m W以上,远大于单模光纤;纤芯直径相同时,相比于阶跃折射率多模光纤,数值孔径对渐变折射率多模光纤SBS阈值的影响较大,后者更易发生受激布里渊散射效应。理论计算与已报道测量结果的比较验证了理论分析的正确性。文中研究为建立基于多模光纤的布里渊散射分布式传感系统奠定了理论基础。