Inclined reinforced wall motorway sections
Location of work/project:
SOUTH OF FRANCE MOTORWAY, A7
The aim of the project was to widen, in 3 circulation ways, a section of A7 French motorway between Lyon and Marseille.
In Vienne, the railway follows the motorway downwards.
It was decided to create a reinforced soil structure with Guintalu® process in order to maintain the road without touching the railway. The process Guintalu® consists in building, with reinforcement geotextile and vegetalized facing, a retaining structure made of soil reinforced.
The main particularity of the structure (because of the railway located just below), is the unusual shape of the cross section. The space and the length of the geotextiles layers are designed to obtain the maximum tensile effort for the different potential slip circles. In this case, the minimal security coefficient to rupture is 1,5.
• 9 to 11 m high
• 5 to 7.5 m width
• 130° gradient
Backfilling materials :
• friction angle = 40°
• density = 20 kN/m3
Ground formation :
• friction angle = 30° to 40°
• cohesion = 5 to 28 kPa
Reinforcement geotextile • • • Notex® 100/50 (100 kN/m MD and 50 kN/m CD)
• Size and layout of the geotextile :
• Lower part : space between layers = 0,3 m, length = 3 to 5 m
• Medium part : space between layers= 0,60 m, length = 5 m
• Upper part : space between layers = 0,25 m, length = 7,50 m