Preprints
https://doi.org/10.5194/se-2016-42
https://doi.org/10.5194/se-2016-42
08 Mar 2016
 | 08 Mar 2016
Status: this preprint was under review for the journal SE but the revision was not accepted.

Visualization and Quantification of the Penetration Behavior of Bentonite Suspensions into the Pore Network of non-cohesive Media by using μ-CT Imaging

Britta Schoesser, Atefeh Ghorbanpour, Matthias Halisch, and Markus Thewes

Abstract. Bentonite suspensions are an essential tool for different construction techniques in horizontal and vertical drilling, in diaphragm and bored pile walls as well as in pipe jacking and tunneling. One of the main tasks of the suspension is to prevent the surrounding ground from collapsing during the excavation process of trenches, drill holes or tunnels. In order to maintain the soil stability close to the excavation, the bentonite suspension has to counteract against the earth and water pressure. Therefore, the pressure acting in the suspension has to counter the groundwater pressure and to be transferred into an effective stress to support the soil skeleton.

The creation of a pressure transfer mechanism can be achieved in two ways. A direct relation exists between the mechanism of the pressure transfer and the penetration behavior of the bentonite suspension in the subsoil. The relation of the size of the bentonite particles in the suspension and the size of the pores in soft soil is decisive. In addition, the yield strength of the bentonite suspension is a determining factor.

Concerning the penetration behavior two theoretical models exist actually: formation of a filter cake and entire penetration into the pore space. If the pore space is smaller than the size of the bentonite particles, a filtration process takes place. Here, the bentonite particles agglomerate gradually at the entrance of the pore space and create a thin nearly impermeable layer. This membrane is named filter cake. If the pore space is larger than the size of the bentonite particles, the suspension penetrates into the subsoil up to a certain depth.

These models have a more theoretical character due to missing visual evidence concerning the interaction of the bentonite suspension in the pore space. Here, the micro CT technique delivers a valuable contribution to this research.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Britta Schoesser, Atefeh Ghorbanpour, Matthias Halisch, and Markus Thewes
 
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
 
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
Britta Schoesser, Atefeh Ghorbanpour, Matthias Halisch, and Markus Thewes
Britta Schoesser, Atefeh Ghorbanpour, Matthias Halisch, and Markus Thewes

Viewed

Total article views: 1,603 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
1,053 454 96 1,603 88 104
  • HTML: 1,053
  • PDF: 454
  • XML: 96
  • Total: 1,603
  • BibTeX: 88
  • EndNote: 104
Views and downloads (calculated since 08 Mar 2016)
Cumulative views and downloads (calculated since 08 Mar 2016)

Cited

Saved

Latest update: 22 May 2024
Download
Short summary
In summary, the µ-CT technique delivers a valuable contribution for the research on the interaction of bentonite suspensions penetration the pore space of non-cohesive media. This study shows the missing visual evidence concerning the theoretical interaction models of the bentonite suspension in the pore space on microscale. The Imaging results have been cross-validated with laboratory experiments and are in good agreement with each other.