科研之友
微信
新浪微博
Facebook
分享链接
摘要
An optical sensor was designed to measure the fine solid particles concentration contained in a fluid flow. This sensor is composed of four light-emitting diodes and four associated light-dependent resistors, allowing the measurement of fluid transparency. Given the small device dimensions, it can be placed close to the particles exit from the specimen. The optical sensor is able to instantaneously measure a large range of clay or silt concentrations in the effluent, without a significant influence of flow rate. The presence of sand grains in fluid flow can be detected. The use of this sensor with a specific triaxial device allows precise characterization of the initiation and development of the suffusion process on clayey sand specimens. It is shown that suffusion of clay particles induces a decrease of hydraulic conductivity, which is due to a diffuse process of eroded particles filtration. Clay suffusion and filtration processes are influenced by grain-size distribution and also by grain shape of the coarse fraction. Under a high hydraulic gradient, clay suffusion can be accompanied by sand erosion. The critical value of mean pore velocity to initiate clay suffusion was determined for the types of soils.
- 出版日期2011-12
