An Experimental Investigation on Flow Velocity in Fine-grained Copper Tailings with High Water Content under Vacuum Preloading

Document Type : Original Article

Authors

1 Civil Engineering Department, Engineering Faculty, Ferdowsi University of Mashhad, Mashhad, Iran

2 Civil engineering Department, Engineering Faculty, Ferdowsi University of Mashhad. Iran

Abstract

Assessment of flow velocity through a porous space is one of the important issues in geotechnical engineering problems. Mine tailings are extracted in the form of slurry due to their high water content. Therefore, layers deposited in the dam reservoir have a high compressibility coefficient and experience significant strains under material self-weight in the long term. Adopting an appropriate improvement technique can accelerate the drainage velocity to increase the amount of materials stored behind the tailings dam in a short time. In this experimental study, vacuum preloading is utilized to improve the Sungun copper tailings samples, and the effects of water content and the vacuum pressure intensity on flow velocity and vertical strain rate are evaluated. The observations indicate that flow velocity is directly proportional to the water content and suction magnitudes, and an exponential function with a very good approximation (R2 > 0.98) can express variations in the drained water volume and vertical strain of the samples. Besides, vacuum preloading continues until the sample attains a specific void ratio. Furthermore, several correlations are proposed to calculate the flow velocity and the average degree of consolidation under vacuum preloading. Finally, the proposed relationships are verified through the results of the Oedometer test and in-situ vacuum preloading improvement project.

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Asas Journal
Volume 24, Issue 68
Autumn 2022
December 2022

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History

  • Receive Date: 11 April 2022
  • Revise Date: 11 August 2023
  • Accept Date: 11 September 2023

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