Specialised subsidiaries

Soletanche Bachy has a number of specialist subsidiaries that exploit in-depth knowledge of particular technologies or market sectors.

Some subsidiaries are involved in Soletanche Bachy's core business – geotechnical work – in tunnels, piles, borehole drilling, marine and river projects and soil improvement. Others work in related markets, such as the environment, with treatment of polluted land testing of soils and man-made constructions by continuous measurements and geophysical investigations, along with the design and construction of specialist equipment for building foundations. All the subsidiaries benefit from the experience and expertise of the Group and its substantial research and development arm.

Balineau, marine and river works & special foundations.
Specialises in port, estuarine and river construction, including the installation of sheet piles and ground improvement by vertical drain systems.

Bessac, tunnelling equipment designers, manufacturers and contractors.
A specialist in tunnels for water, stormwater and sewerage and other services. CSM Bessac is both a general contractor for tunnel construction and a designer and manufacturer of tunnel boring machines.

Soletanche Bachy Fondations Spéciales, specialist for piling, micropiles, soil mixing, and drilling techniques.
Company specialising in the construction of all types of foundation, retaining, soil improvement, and specialised drilling techniques. Pioneering innovation in the foundations field with the invention of the STARSOL® process.

Soletanche Bachy Tunnels, constructs tunnels of large section by all type of processes.
A specialist in large tunnels, this company combines the total expertise of the Group: underground excavation, lining, all associated geotechnical works.

Sol Expert International : geotechnical studies, design of underground structures, technical assistance.
An engineering and technical assistance company specialising in applied geotechnics.


Sotem, a guaranteed maintenance of the underground railway.
A company specialising in grouting and sealing methods, developed particularly for the maintenance of the Paris Metro System infrastructure.

TEC System, plant & equipment design, manufacturing, maintenance and repairs, sales and service.
A designer and manufacturer of foundation equipment under the brands Domine, Bonne Espérance and SBC. TEC system also provides after-sales service for these brands and distributes spare parts for various types of equipment.