نوع مقاله : مقاله پژوهشی
نویسندگان
گروه مهندسی عمران. دانشکده مهندسی. دانشگاه فردوسی مشهد. مشهد. ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسنده [English]
Evaluation of flow velocity in a porous medium is one of the important subjects in geotechnical engineering. Mine tailings with high water content larger than the liquid limit in the form of slurry have high compressibility, hence, a suitable improvement method such as vacuum preloading is required to use materials in the tailings dam. The present study investigates the effect of sample water content and suction pressure level on time-dependent changes in flow velocity. The tests are performed on saturated samples of fine-grained tailings from the Sungun copper mine. The results show that the graphs of drained water volume and vertical strain of samples follow an exponential function of time with a very good approximation. Assuming Darcian flow through the test materials, relationships are presented to determine the flow velocity based on two approaches including the pore water discharge rate and vertical strain rate of samples. Then, results of the two approaches in calculating the flow velocity and interpreting laboratory observations are compared. The results also demonstrate that the flow velocity increases with sample water content and suction pressure. In addition, vacuum preloading continues until samples reach a certain void ratio. Furthermore, a new relation is proposed to calculate the average degree of consolidation for the layer based on the flow velocity ratio. Finally, the proposed relationship is accurately verified with the estimation of the volumetric compressibility coefficient for the data of the present study using the Oedometer test and a vacuum preloading improvement project on Dalian coast of China.
کلیدواژهها [English]
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