In recent years there has been a perception of a stagnation in the quality of site investigations, with geotechnical site investigations performed with unsuitable tools often leading to over- or under-designed geotechnical projects, dramatically increasing costs and/or risks.

But it is possible to innovate – even with relatively low investments – while simultaneously bridging the gap between "theoretical" and "practical" geotechnics, creating a virtuous collaboration between geotechnical consultants, researchers and contractors.

Geotechnical engineering in Italy must address a remarkably wide range of problems, many of which are shared with other countries: design and geotechnical-structural monitoring of infrastructure, including roads, bridges, dams, hydraulic works and transport systems, as well as the design and monitoring of residential, industrial and public buildings.

A particularly important Italian geotechnical challenge is the conservation of artistic, architectural and monumental heritage. Italy has thousands of historic towns, castles, towers, villas, churches, bridges and archaeological structures.

Many are affected by settlement, rotation, cracking, subsidence, flooding, landslides and seismic damage. Examples include the Leaning Tower of Pisa, the Colosseum, the historic centres of Venice, Bologna and Ravenna, the Rialto Bridge and many other old buildings of Venice. The preservation of these structures often requires highly specialised investigations and minimally invasive solutions.

Seismicity is another major issue. Unlike the UK, Italy is a highly seismic country. In several regions, particularly in the Po Valley, earthquakes may also trigger soil liquefaction. The 2012 Emilia-Romagna earthquake, for instance, showed that liquefaction can produce major damage even in areas where the direct structural effects of ground shaking may appear moderate.

Climate change

Long droughts may lower groundwater levels and cause settlement and cracking in buildings. These periods are increasingly followed by intense rainfall, floods, erosion, and consequently landslides and damage to levees. Other consequences include sea-level rise, coastal erosion, saltwater intrusion and increased pressure on hydraulic infrastructure.

Landslides represent one of the most widespread geotechnical hazards in Italy. A very large proportion (circa 66%) of European landslides occurs within the Italian territory. Mountain areas, historic villages and densely populated urban zones are frequently exposed to slope instability.

Recent events, such as the landslide at Niscemi in Sicily, are examples of a problem affecting much of the country.

Marine and coastal engineering is also important because Italy has more than 5,000 miles of coastline. Ports, breakwaters, piers, offshore structures and flood-defence systems require specialised investigations. Significant examples include the new Genoa breakwater (construction in progress) and the MOSE mobile barriers protecting Venice.

The energy transition is producing new geotechnical demands related to power plants, pipelines, wind farms, photovoltaic systems, energy-storage facilities, biomethane plants and data centres.

Many renewable-energy projects are under development, although offshore wind projects remain difficult because suitable wind conditions are often found where the seabed is relatively deep. Technical challenges are compounded by complex regulatory and administrative procedures.

Regulations

Over the last twenty to thirty years, theoretical geotechnics has developed considerably. New regulations are more demanding, numerical software is increasingly sophisticated, and concepts such as geotechnical models, BIM, digital twins and artificial intelligence are becoming more common.

Engineers now have a greater awareness of seismic risk, liquefaction, climate change, subsidence and the interaction between new construction and existing historic structures. However, the development of geotechnical site investigation has been much more limited. In many respects, field investigation practices remain conceptually similar to those used in the 1970s.

Percussion drilling

In Italy, percussion drilling has largely disappeared and has been replaced by simple core-barrel drilling driven by rods, even where double-core barrels or wireline systems would be more appropriate. High-quality samplers, such as Osterberg samplers, are rarely used.

The Standard Penetration Test continues to dominate down-hole testing, while mechanical-cone CPT tests are still performed. In some cases, software developed for CPTU data is even used to interpret mechanical CPT results.

This situation has produced a standardisation of investigation methods towards a "lowest common denominator", leaving limited space for innovation. There are several reasons for this.

First, drilling and testing companies face substantial bureaucratic, fiscal, contractual, regulatory and health-and-safety obligations.

These activities require considerable financial and managerial resources, leaving little funding for research and development. Public grants may be available, but they usually cover only part of the cost and require significant effort to obtain.

Second, the market does not always express a clear demand for innovative equipment.

Company managers must decide whether to invest in equipment that immediately increases productivity or in innovative systems that may produce benefits only in the long term. Without clear demand, short-term profitability is the safer choice.

Third and most important, a persistent gap exists between theoretical and practical geotechnics.

Academic literature and conferences focus on theory, while practical publications may simply list investigation methods or case histories without explaining how to combine them efficiently for a specific project. Case histories are useful, but they do not provide a general and clear guidance on how to design and optimise a complete investigation.

Dynamic interactions

The management of a geotechnical investigation is complex because many factors interact dynamically.

These include project data requirements, technical specifications, equipment availability, costs, contractual conditions, schedules, regulations, environmental and archaeological constraints, health and safety, supervision, quality control and unexpected ground conditions.

The crucial task is to convert the data required by the Designer into technically correct and economically realistic specifications. However, only a limited number of consultants have sufficient practical experience to combine project objectives, site conditions, equipment limitations, budget, time and data reliability.

As a result, specifications may contain inappropriate or impossible requirements based often on unrealistic budget.

When consultants ask drilling contractors for advice, they may naturally recommend the equipment they already own and that provides the best profitability. This does not encourage innovation. Conversely, when they prepare specifications without "practical" support, they may request unsuitable (obsolete, unavailable) methods.

Competition costs

Competition based mainly on price creates an additional obstacle. When clients do not recognise differences in data quality, innovation may be considered an unnecessary risk rather than an advantage.

Coming from a family drilling company and later graduating in civil engineering, I gained direct knowledge of both field investigation and design requirements.

Over several decades, I developed and used specialised systems including a micro-diaphragm wall machine (pictured above), custom CPTU equipment, environmental cones, CPTWD Cone Penetration While Drilling, RCPTU, the Pressiocone driven by a portable static penetrometer, permeameters, water samplers and special floating or jack-up platforms for nearshore investigations.

Furthermore, in 2017 I won the first prize in an engineering competition by presenting a new concept of geotechnical testing in complex landslide using the calculation of specific energy resulting from MWD applied to sonic drilling.

These systems were generally self-financed and developed either in response to project requirements or through personal curiosity (and a little courage). Their success depended not only on technical performance but above all on informing and educating clients through meetings, papers, seminars, and professional communication.

It should be noted that very often contracts were signed and relationships of trust were created thanks to the fact that customers appreciated the capacity for innovation and the ability to understand their needs, not necessarily because specific equipment had to be used.

Future innovation

Future innovation should include for instance improved sonic drilling, wider use of wireline systems, smarter down-hole tools, better Measurement While Drilling (MWD) systems (also applied to sonic drilling), more efficient pressure meter testing (possibly self-boring PMT), new cone sensors, improved vane tests, rational interpretation of SPT and dynamic penetration tests (instead than empiric), SPLT rebirth (screw plate load test) advanced liquefaction assessment and above all equipment designed for investigations beneath existing buildings, in difficult natural and urban environments, nearshore environment.

The central message is that geotechnical innovation requires stronger cooperation between designers, consultants, contractors, researchers.

Innovation should not be pursued only for technological novelty and to create a virtuous path. It should respond to real project needs, improve the reliability of geotechnical models (hence reducing overall cost and risk), increase safety and provide better value.

*Massimo Sacchetto graduated in Civil Engineering in 1984 and is certified specialist in geotechnics. He was the owner and technical director of drilling & testing companies from 1980 to 2015. He  now works as an independent consultant and designer.