References
Provence Opera building
FRANCE, 1992
Heavy duty, composite material ground soil anchors.
Introduction to the project
The construction of an underground car park for the PROVENCE-OPERA Building in Paris required the installation of a peripheral diaphragm wall, the stability of which, as a temporary measure, was assured by a covering slab and three rows of temporary anchors. One side of the excavation is situated along Rue Joubert, underneath which a railway tunnel for the SNCF EOLE project was foreseen. The ground anchors for the lowest two rows on this side of the site intersect the future works.
Building permission for the development on the PROVENCE-OPERA site was granted only on the express condition that no elements would be installed in the ground that could impede tunnelling machines excavating the proposed tunnel.
Bachy proposed the installation of destructible, non metallic ground anchors of a composite material and this allowed the condition referred to above to be fully satisfied.
Development of the process
Preliminary tests
The installation of ground anchors with composite, non metallic strands required the development of a stressing system adapted to the mechanical properties of the strands.
After a laboratory development phase site trials were organised to meet the following principal objectives:
- confirmation of satisfactory functioning of the proposed anchoring system,
- confirmation of the behaviour of the bond length of the anchor in the ground bearing in mind the relatively low modulus of elasticity of the strand material,
- development of appropriate installation methodology,
- observation of the behaviour of the composite material ground anchors related to time.
The ground anchor system developed and implemented at the PROVENCE- OPERA site has significantly widened the range of application for anchors where possible physical or legal problems arise from leaving permanently in place in the ground high strength steel strands or other ferrous items.
Techniques
A diaphragm wall is a reinforced concrete wall that is made in situ. The trench is prevented from collapsing during excavation, reinforcing and casting by the use of supporting bentonite slurry. The slurry forms a thick deposit (the cake) on the walls of the trench which balances the inward hydraulic forces and prevents water flow into the trench. A slurry made of polymers can also be used.
A ground anchor is a load transfer system designed to transfer the forces applied to it to a competent stratum. An anchor is said to be temporary if it has a lifespan of under two years and permanent if the lifespan is over two years.
Ouvrages
Soletanche Bachy undertakes the whole of a project from feasibility studies, through design to the complete construction on a turnkey basis.
Major urban excavations are one of the specialist activities of Soletanche Bachy. Such excavations are required for basements to buildings that are usually part of the foundations of the structure and also used for under-street car parks, cut and cover tunnels for roads, rail, metro and storm water tank...
Voyage au coeur de l'ingénierie de pointe
Find out more about our expertise by:
