Tunnel projects face three key issues and challenges – geological complexities, poor contracting practices and safety issues. Of these, geological complexities pose the maximum risk to tunnel projects and have impacted the largest number of projects in the country. While the latter two risks can be dealt with using best practices available in the industry, the former risk can only be mitigated to a certain extent.
Some of these issues can be mitigated by taking timely action and with coordination between the contractor and the implementing agency. Other issues, which occur due to external factors such as change in design due to thrust zones and seismicity, need to be considered by the nodal agencies to reduce the burden on contractors. In this regard, measures such as fair risk sharing contracts, and timely support from subcontractors and agencies will improve the current scenario. In recent years, the industry has taken several measures to mitigate these risks, which have become best practices for other projects to follow.
Almost every aspect of a tunnelling project from its conception to commissioning is influenced by the geology of the area. The majority of the tunnelling projects face issues arising from geological surprises and inadequate investigations.
Detailed geological investigation is needed to plan the methodology and determine the requirement of construction equipment. The extent of investigation varies from project to project depending upon its geology, project features, location, etc. Typically, a thorough geological investigation requires two-three years. In contrast, typically a contractor gets only one-two months to submit tenders and hence has no time to have any major investigation conducted. In recent years, availability of the latest technology, equipment, instruments, software, information and data has increased the accuracy and speed of surveys and investigation.
Poor investigation results in hold-ups for several days, even weeks. Some projects have been delayed for as long as five-seven years due to changed conditions. Insufficient investigations also result in geological variations that are not factored into the methodology and tender documents resulting in delays and disputes, improper tunnel alignment with very low cover zone, non-availability of quarry for aggregates, and improper assessment of bridges/roads to transport heavy equipment to project sites.
Some of the sectors where geological complexities have hampered tunnel construction are the hydropower and water and sewerage sectors.
Deficiencies in contract documents and contracting practices
Overall, the processes for selection of contractors and consultants are very weak for most construction projects including those for tunnelling. Moreover, the contracts are drafted on age-old norms and leave a lot of room for ambiguity and disputes. Even the Fédération Internationale Des Ingénieurs-Conseils (FIDIC) conditions are compromised in some cases.
The roles and responsibilities of various parties and risk sharing among the parties are not clearly defined in the contract documents. Further, the contracts do not clearly spell out the methodology for working out rates for extra items and deviations in design or construction requirements and this becomes a major reason for disputes in an ongoing project.
Any deviations in contracts related to escalation, extra items, extra quantities, change of specifications, time overruns and extensions, etc. also result in disputes since they are not clearly specified in the contract documents. In addition, contract administration is very poor.
India has a long way to go with regard to safety in tunnel construction and maintenance. There are no specific guidelines or specifications for such tunnel projects. Several tunnel projects have had major safety issues resulting in a negative impact on the morale of the team and a loss in project momentum. Further, compensation for accidents is not commensurate with the risks and hence finding manpower to work in these conditions becomes difficult.
These risks and challenges are unique to tunnelling projects and depend on the geology of the project, location, developer agency, contractor, and contracting terms and conditions. They can lead to considerable time and cost overruns if adequate attention is not paid during the pre-construction phase, especially during geological investigations and setting of the terms and conditions in the contract. Any neglect at this stage can have grave consequences, including abandonment of projects.