This study experimentally analyzes the nonlinear flow characteristics and channelization of fluid through rough-walled fractures during the shear process using a shear-flow-visualization apparatus.A series of fluid fl...This study experimentally analyzes the nonlinear flow characteristics and channelization of fluid through rough-walled fractures during the shear process using a shear-flow-visualization apparatus.A series of fluid flow and visualization tests is performed on four transparent fracture specimens with various shear displacements of 1 mm,3 mm,5 mm,7 mm and 10 mm under a normal stress of 0.5 MPa.Four granite fractures with different roughnesses are selected and quantified using variogram fractal dimensions.The obtained results show that the critical Reynolds number tends to increase with increasing shear displacement but decrease with increasing roughness of fracture surface.The flow paths are more tortuous at the beginning of shear because of the wide distribution of small contact spots.As the shear displacement continues to increase,preferential flow paths are more distinctly observed due to the decrease in the number of contact spots caused by shear dilation;yet the area of single contacts in-creases.Based on the experimental results,an empirical mathematical equation is proposed to quantify the critical Reynolds number using the contact area ratio and fractal dimension.展开更多
落锤撕裂试验(DWTT)被广泛用于评价管线钢的抗脆性断裂能力。因为异常断口的出现,使API RP 5L3标准的应用遇到一定的困难。首先评述了分层裂纹与异常断口的特点、成因以及异常断口改进的评判方法。随后,分析了提高DWTT性能所采用的成分...落锤撕裂试验(DWTT)被广泛用于评价管线钢的抗脆性断裂能力。因为异常断口的出现,使API RP 5L3标准的应用遇到一定的困难。首先评述了分层裂纹与异常断口的特点、成因以及异常断口改进的评判方法。随后,分析了提高DWTT性能所采用的成分设计、控轧控冷工艺等技术方案及其内在理论依据,并给出了提高管线钢DWTT断口剪切面积的若干建议。展开更多
Shear velocity is an important index for evaluating soil dynamic properties of the site. In this paper, the statistical relation of shear velocity with soil properties is set up by statistical analysis of shear veloci...Shear velocity is an important index for evaluating soil dynamic properties of the site. In this paper, the statistical relation of shear velocity with soil properties is set up by statistical analysis of shear velocities and relevant soil properties measured in Tianjin and Shanghai. The obtained formula has some referential value for the evaluation and classification of the site in offshore areas of China.展开更多
基金This study has been partially funded by National Key Research and Development Program of China(Grant No.2020YFA0711800)the National Natural Science Foundation of China(Grant No.51979272)the Natural Science Foundation of Shandong Province,China(Grant No.ZR2021QE069).
文摘This study experimentally analyzes the nonlinear flow characteristics and channelization of fluid through rough-walled fractures during the shear process using a shear-flow-visualization apparatus.A series of fluid flow and visualization tests is performed on four transparent fracture specimens with various shear displacements of 1 mm,3 mm,5 mm,7 mm and 10 mm under a normal stress of 0.5 MPa.Four granite fractures with different roughnesses are selected and quantified using variogram fractal dimensions.The obtained results show that the critical Reynolds number tends to increase with increasing shear displacement but decrease with increasing roughness of fracture surface.The flow paths are more tortuous at the beginning of shear because of the wide distribution of small contact spots.As the shear displacement continues to increase,preferential flow paths are more distinctly observed due to the decrease in the number of contact spots caused by shear dilation;yet the area of single contacts in-creases.Based on the experimental results,an empirical mathematical equation is proposed to quantify the critical Reynolds number using the contact area ratio and fractal dimension.
文摘落锤撕裂试验(DWTT)被广泛用于评价管线钢的抗脆性断裂能力。因为异常断口的出现,使API RP 5L3标准的应用遇到一定的困难。首先评述了分层裂纹与异常断口的特点、成因以及异常断口改进的评判方法。随后,分析了提高DWTT性能所采用的成分设计、控轧控冷工艺等技术方案及其内在理论依据,并给出了提高管线钢DWTT断口剪切面积的若干建议。
文摘Shear velocity is an important index for evaluating soil dynamic properties of the site. In this paper, the statistical relation of shear velocity with soil properties is set up by statistical analysis of shear velocities and relevant soil properties measured in Tianjin and Shanghai. The obtained formula has some referential value for the evaluation and classification of the site in offshore areas of China.
