If you need any explaination about this form contact ammar.aljer@univ-lille.fr

Activity Name:

N-OT04 Overtopping Test (Artificial burrow)

Activity Numbre:

172

Activity type

Strength test

Involved Workpackage

Flood defences
Emergency response
Knowledge infrastructure

Objective

Longer artificial burrows in the higher part of the slope were drilled.

Activity Brief descriptor

This test was executed on a ‘test section with a uniform vegetation cover’, with only few bare spots, irregularities and holes. Artificial burrows in the higher part of the slope were drilled. The slope is 1:2,5.

Linked to theme(s):

Breaching
Animal- & vegetation-induced anomalies
Erosion processes
Temporary levee repairs
Levee survey & monitoring technique
Prolonged collaboration

Activity Time

Start Date:

None

End Date:

None

Active time length:

Days:

2

Hours:

None

Other:

Location

Levee stretch:

VI

Coordinates/ Latitude (WGS):

None

Coordinates/ Longitude (WGS):

None

Coordinates/ Altitude (mTAW):

12.0

Descriptor:

Landward slope of levee

Other references:

Data

This activity has no data

Relationships with other activities

Detaled information about the activity

Pre-conditions

Levee slope is visually in good condition.

Activity Descriptor

The following wave sets were consecutively applied: 0,5m60lsm and 1m190lsm (twice), 2m50lsm (30’) and 1m190lsm (2x 15’).

Equipments

this activity does not have equipments

Monitoring & Sensors

this activity does not have sensors

Limits

During Activity

When after 3 sets of wave no failure of the cover was imminent, 2 longe(r) artificial burrows were created, adjacent in the higher part of the slope, again with a diameter 10 cm but by increasing the total length of the pipe (inlet of pipe at an angle of 45°, outlet of pipe at an angel of -12,5°). Both pipes were connected within the sandy core. Applying wave set ‘2m50lsm’ for 30 minutes both pipes showed washout of sand. Continuing with the wave set ‘1m190lsm’, transport of sand remained and after 15’, sudden, a pit was formed at the inlet of 1 pipe. Gradually this pit eroded further and found connection to the other pipe inlet.

Post-activity conditions

At the end, a step of 3m by 4m with a cliff of 1 m height was formed. The outlet pipes were still in place.

Immediate Results

Pipes connecting to the sandy core and having sufficient lenght can give rise to sudden collapse of the cover layer.

Results /Conclusion

Infrastructure Knowledge

Other key information