Abstract
The aim of this article is to review and analyse the different hypotheses assumed in the calculation methods for flexible systems used in slope stabilisation.
These systems are formed by a membrane (cable net or high-resistance wire mesh) and anchored bolts. Several manufacturers and independent researchers assume that the membrane can stabilise the slope by exerting a normal pressure, which leads to an increase in the shear resistance of the ground: This system behaviour is denominated ‘active’. The two main conditions that flexible systems have to fulfil to be considered active (to avoid detachment or sliding from being produced) are that the membrane should be pre-tensioned when installed and that the slope must have a convex curvature. None of the manufacturers-installers verify the membrane's pre-tension force and moreover, in many cases, the membrane does not have a convex curve, but may be planar or even have a concave one. Additionally, the force applied on bolts to tighten them does not usually exceed 50 kN. Thus, these systems do not work actively, but passively; which means they are able to retain a mass of soil or a rock piece when the sliding has already occurred, but they are unable to prevent it.
Therefore, current design methods used by manufacturers and researchers can be incorrect, leading to extra installation costs in the flexible system in some cases or even an unsafe solution in others.
These systems are formed by a membrane (cable net or high-resistance wire mesh) and anchored bolts. Several manufacturers and independent researchers assume that the membrane can stabilise the slope by exerting a normal pressure, which leads to an increase in the shear resistance of the ground: This system behaviour is denominated ‘active’. The two main conditions that flexible systems have to fulfil to be considered active (to avoid detachment or sliding from being produced) are that the membrane should be pre-tensioned when installed and that the slope must have a convex curvature. None of the manufacturers-installers verify the membrane's pre-tension force and moreover, in many cases, the membrane does not have a convex curve, but may be planar or even have a concave one. Additionally, the force applied on bolts to tighten them does not usually exceed 50 kN. Thus, these systems do not work actively, but passively; which means they are able to retain a mass of soil or a rock piece when the sliding has already occurred, but they are unable to prevent it.
Therefore, current design methods used by manufacturers and researchers can be incorrect, leading to extra installation costs in the flexible system in some cases or even an unsafe solution in others.
| Original language | English |
|---|---|
| Pages (from-to) | 129-145 |
| Number of pages | 17 |
| Journal | Engineering Geology |
| Volume | 122 |
| Issue number | 3-4 |
| Early online date | 2 Aug 2011 |
| DOIs | |
| Publication status | Published - 10 Oct 2011 |
| Externally published | Yes |
Bibliographical note
NOTICE: this is the author’s version of a work that was accepted for publication in Engineering Geology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Engineering Geology, 122, (2011)DOI: 10.1016/j.enggeo.2011.05.014
© 2011, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Keywords
- Slope stabilisation
- Cable nets
- Wire meshes
- Passive systems
- Active systems