Comparison of Internal and Surface Erosion Using Flow Pump Tests on a Sand-Kaolinite Mixture

Lakshmi N. Reddi, In Mo Lee, Mohan V.S. Bonala

Research output: Contribution to journalReview article

125 Citations (Scopus)

Abstract

The purpose of this paper is to assess the difference between surface and internal erosion processes using results from flow pump tests. Samples of 70% Ottawa sand + 30% kaolinite mixture were used with distilled water and NaCl solutions as permeants. Two kinds of tests were conducted, a surface erosion test where the permeant was pumped through a cylindrical hole of 7-mm diameter and an internal erosion test where the permeant was pumped through intact compacted samples in compaction permeameters. A simple capillary tube model was used to estimate the critical shear stresses needed to cause erosion in surface erosion experiments. It was found that although surface erosion critical shear stresses were exceeded in the intact soil samples, particle clogging in the pores and redeposition of eroded particles prevented mobilization of particles into the effluent stream. Erosion rates estimated using surface erosion parameters were significantly greater than those observed in internal erosion experiments. The results suggest that the fate of eroded particles, including particle redeposition and pore clogging, may govern the internal erosion process far more than the surface erodibility of the soil.

Original languageEnglish
Pages (from-to)116-122
Number of pages7
JournalGeotechnical Testing Journal
Volume23
Issue number1
Publication statusPublished - 2000 Mar

Keywords

  • Flow pump tests
  • Sand-kaolinite
  • Surface erosion

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology

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