|
||||||||
In case a defect pre-exists in an embankment hydraulic structure (root, racoon-hole, etc.), the defect tends to widen when the structure is subject to a significant hydraulic head (> a few meters). Depending on the characteristics of the soil, etc., the leak associated with the defect can rapidly evolve into a breach, in the worst case in 4 hours.
The Hole Erosion Test apparatus used at geophyConsult has been developed by IRSTEA and re-creates the erosion phenomenom in a core (see the video presentation of the test by IRSTEA). To do so, an articial hole of 6 mm diameter is pre-drilled in the axis of the core and a controlled water flow is imposed in the conduit so that it can widen while the evolution of diameter is monitored. The test determines the resistance to ersion of the soil.The HET carried out at geophyConsult under IRSTEA licence agrees with the experimental AFNOR XP P94-065 standard (which geophyConsult, as one the pioneer users of the test, contributed to write). It enables to determine:
- the position of the soil in the Fell classification of soil erosion rates (which varies from « Extremely rapid » to « Extremely slow ») ;
- the τc parameter, which addresses the hydraulic conditions required to initiate the erosion process ;
- the Ie index, which can be used to calculate how fast a small erosion can lead to a major failure.
The test can be made on intact soils, provided they do not contain gravels of size greater than 5 mm, and provided they are delivered in cores of diameter greater than 8 cm and of height greater than 10 cm. It can also be carried out on reworked soils (provided at least 1.5 kg of soil is provided with).
The test cannot be carried out in situ.
Download link to the « Erosion » leafleft : click here.
© geophyConsult SAS – 22, rue des frères Lumière – 34 830 Jacou – France
Simplified joint-stock company registered under the French law with a capital of 10,000 € – Identification number : 521 005 041, RCS Chambéry
Contact : +33 6 95 38 85 09, administration@geophyconsult.com
Espace clients : Customer area :
Web site hosted by OVH Cloud – 2, rue Kellermann – 59100 Roubaix – France