Our Identity
We cultivate our technical excellence with complete independence.
At the heart of the challenges of construction and sustainable development, our geotechnical engineering firm positions itself as a key player, committed to supporting its clients in the successful delivery of ambitious projects. Drawing on recognised expertise and an innovative approach, our mission is clear: to provide geotechnical solutions that reconcile performance, safety, and environmental responsibility.
Through our vocation — “High added-value geotechnical engineering for innovative and responsible projects” — we strive to do everything in our power to meet our partners’ challenges, whether they involve urban construction, complex infrastructure, or sustainable development schemes. Through this vocation, we aspire to be a trusted partner, committed to delivering projects that durably transform our territories.
Our DNA
A lived and nurtured company culture
Geotechnics is a complex discipline at the crossroads of natural sciences, exact sciences, and construction techniques — one that is constantly evolving. Analytical tools and construction methods continue to advance in response to projects set within an ever more demanding environment, with two principal geotechnical concerns: ensuring the stability of structures and their proper functioning, while also optimising projects.
Since its founding by François Schlosser, terrasol has grown in a measured and deliberate manner, cherishing a culture of technical mastery and innovation, scientific rigour and ethics, team availability and agility, a desire to do things well, and the means to continuously do better.
This culture is carried forward from one generation of engineers to the next, through the accumulation of knowledge fed by the remarkable diversity of projects handled by terrasol, the in-house training of staff, and the involvement of all engineers in R&D.
A proudly claimed and widely valued independence
Since its inception, terrasol has chosen to remain financially independent by being wholly owned by its engineers, and technically independent by focusing its activity exclusively on geotechnical engineering, without encroaching upon ground investigation work.
Its integration in 1999 into the Setec Group — built on identical values of financial independence and ethics — has enabled terrasol to reinforce its total independence from construction companies and financial groups.
As a result, our engineers are able to prescribe, in good conscience and free from any pressure, precisely the level of ground investigation required, and to propose the most technically optimal solutions.
Engineers & Citizens in everyday practice
Our teams, acutely aware of the challenges facing the world, are committed to addressing the issues that engineering is called upon to tackle in relation to the act of building:
- Reducing the environmental footprint of geotechnical structures
- Ensuring their resilience in the face of climate disruption
- Managing their maintenance and lifecycle
- Making the most of the opportunities offered by the digital transition
- Passing on knowledge and ingenuity across generations of engineers
Our Strategic Priorities
We are expanding our international presence by adapting our expertise to local specificities.
Through strong partnerships, we support diverse projects in complex geotechnical contexts.
We design geotechnical solutions that are resource-efficient and adapted to climate variability.
The optimisation of materials and the adaptability of structures strengthen the durability of our projects.
This approach ensures both technical performance and environmental responsibility.
Mastery of digital tools and ground data improves the precision of our studies.
We exploit field data and model geotechnical behaviour to optimise our solutions.
This strategy reinforces our capacity for innovation and forward planning.
Our Values
Technical excellence lies at the heart of our commitment to geotechnical engineering.
It is expressed through sharp expertise, the use of advanced analytical methods, and scientific rigour applied to every project.
By ensuring precise studies, innovative solutions, and sound management of geotechnical risks, we guarantee the reliability and longevity of infrastructure.
This pursuit of excellence guides our teams daily in delivering high-quality services that meet the most demanding standards and are tailored to the specific challenges of each site.
The culture of proportionate need is grounded in an optimised and responsible approach to geotechnical engineering.
It consists in proposing solutions that are fit for purpose — neither over-specified nor insufficient — whilst taking into account technical, economic, and environmental constraints.
By accurately analysing soil characteristics and project requirements, we ensure relevant recommendations that guarantee the safety and longevity of structures whilst avoiding unnecessary additional costs.
This approach combines performance, durability, and restraint to effectively meet our clients’ actual needs.
The spirit of knowledge transfer is an essential value in geotechnical engineering, safeguarding the continuity and evolution of expertise.
It rests on the sharing of experience, continuous training, and the mentoring of new generations of engineers.
By fostering the exchange of knowledge between seasoned experts and emerging talent, we strengthen our collective expertise and ensure the constant improvement of our practices.
This commitment preserves a high level of competence, drives innovation, and enables us to respond aptly to the technical challenges of today and tomorrow.
Key Dates
Foundation of terrasol by Professor F. Schlosser
terrasol joins the Setec Group
Opening of a regional office in Lyon
Opening of a regional office in Bordeaux
Opening of a regional office in Vitrolles
Certifications
OPQIBI certification in our specialist fields is a recognition of our expertise and our commitment to quality in geotechnical engineering. It attests to our competence in carrying out rigorous studies that comply with the requirements of the sector. This qualification gives our clients the assurance of reliable, optimised services tailored to the technical demands of their projects, ensuring risk management and a sustainable approach to infrastructure.
10 – Ground Engineering
- 1001: Study of standard geotechnical projects
- 1002: Study of complex geotechnical projects
- 1003: Geological study
- 1005: Hydrogeological study
11 – Earthworks – Roads – Underground Networks
- 1106: Study of earthworks with ground improvement
12 – Civil Engineering – Structural & Finishing Works
- 1201: Study of complex foundations
Quality and safety are at the core of terrasol’s processes, which are QSE-certified. For geotechnical engineering services carried out by the Paris and Lyon offices, terrasol is also certified for Nuclear Safety.
- ISO 9001 – Quality Management
- ISO 45001 – Occupational Health and Safety
- ISO 14001 – Environmental Management
- ISO 19443 – Nuclear Safety
These certifications reflect our constant drive for improvement, operational rigour, and responsibility in the face of current and future challenges in our sector. They are not an end in themselves, but a lever for pursuing our mission with ever greater mastery, ethics, and impact.
In concrete terms, they represent:
- Official recognition of the robustness of our processes
- An additional guarantee for our partners and clients
- A structuring framework that reinforces our culture of safety, quality, and sustainability
- An enhanced capacity to support sensitive projects, particularly in the nuclear sector, with Safety as an absolute priority