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Pore structure and liquid flow velocity distribution in water-saturated porous media probed by MRI 被引量:3
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作者 吴爱祥 刘超 +2 位作者 尹升华 薛振林 陈勋 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第5期1403-1409,共7页
Magnetic resonance imaging (MRI) was used to probe the structure and flow velocity within the interparticle space of a packed bed of agar beads under water-saturated condition. The images of the velocity field at th... Magnetic resonance imaging (MRI) was used to probe the structure and flow velocity within the interparticle space of a packed bed of agar beads under water-saturated condition. The images of the velocity field at three different flow rates were obtained. To determine the pore-parameter of the porous media, the internal structure of the bed was also obtained using image processing technique. The results show that the porosity of the sample is 31.28% and the fitting curve for the distribution of pore equivalent diameter follows Gaussian distribution. The velocity profiles do shift as the flow rate varies and the solution flow through the void space is not a homogeneous flow in any pores. The velocity distributions within the pore are roughly parabolic with the local maximum being near the center. About half of the velocity components are in the class of 0-1 cm/s. The frequency of lower velocity components is lower at higher flow rate, but to higher velocity components, it is just the opposite. 展开更多
关键词 magnetic resonance imaging porous media flow velocity POROSITY pore equivalent diameter
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软土地区旋挖扩底钻孔灌注桩施工技术研究
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作者 陆天一 《中文科技期刊数据库(全文版)工程技术》 2023年第4期160-164,共5页
就大多数改扩建工程而言,有着施工场地受限、施工工期紧、环保及文明施工要求高等特点。与常规钻孔灌注桩相比,旋挖扩底钻孔灌注桩有着施工占地较小,采用履带式设备、各道工序相对独立因而施工便捷、无大量泥浆产生利于环保等优点。旋... 就大多数改扩建工程而言,有着施工场地受限、施工工期紧、环保及文明施工要求高等特点。与常规钻孔灌注桩相比,旋挖扩底钻孔灌注桩有着施工占地较小,采用履带式设备、各道工序相对独立因而施工便捷、无大量泥浆产生利于环保等优点。旋挖成孔工艺主要存在两个问题,一是由于软土地区上层土层以淤泥质土为主,而旋挖成孔工艺在取土过程中容易在孔内产生真空效应,极易产生塌孔现象;二是桩基底部一定范围内需进行扩底,扩孔质量难以控制且极易产生塌孔及缩径问题。本文结合新川沙河段桥梁桩基实际施工情况,从泥浆指标、旋挖速率、提钻速度、成孔时间、工序衔接等方面进行研究总结,探索软土地区的旋挖扩底灌注桩施工技术。 展开更多
关键词 钻孔灌注桩 软土地区 旋挖成孔 泥浆 成孔速率
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