Tunnels and Major Underground Structures

The SGAI activities in the field of underground works date from the late 60s when the design was concentrated on the construction of the headrace tunnels of dams and reservoirs. Since then the business has gradually expanded, first within the tunnels for water aqueduct and sewerage networks, then developing for rail and road networks.

Subsequently, our desinges were applied also in the field of urban tunnels, both for the construction of underground lines and for the construction of underground car parks and buildings, also for the rehabilitation of existing structures.

Tunnels and Underground Construction Company: our Design

For the design of underground works SGAI uses the technical standards for construction as required by national, European or international laws, referring also to the "Design Guide Lines" published in the form of recommendations, from the group of cultural associations belonging to the National Project for the Statement of Underground Works. These guidelines date back to 1995 but they are still entirely valid for the articulation of the project phases as they do not conflict with existing laws.

Indicatively, excluding special issues related to the work in question, the design process follows a framework based on the following criteria:

• Identification of key issues and their articulation into topics that represent the different aspects of the problem to be analyzed and quantified in the course of the design;
• Summary description of the development;
• Indication of some of the most accredited criteria and methods.

How Tunnel And Underground Construction Company elaborate the topic

The level of elaboration of the topics depends on the particularity of the work and the design phase that is being conducted (Preliminary Design, Final Design, Executive Project).

The scheme is divided into the following main issues:

• General layout of the underground structure;
• Geological Survey;
• Geotechnical-geomechanical study;
• Forecast of the mechanical behavior of the mass;
• Design and verification of stabilization of the coating structure;
• Complementary projects and adaptation of the design solution;
• Verifications during construction and in operation.

All the aspects of our Underground and Tunnels Construction Design

All different design aspects are studied, analyzed and produced using tested calculation programs, some of which directly developed inside, so as to provide what serves for the execution of the works and follow, assist the client in the most appropriate technological choices for:

• Identify the excavation method, both of the traditional type (D & B, SCL), is mechanized (TBM), more suitable advancement in safety conditions for the operators and for the overall stability;
• Define the interventions of consolidation, drainage, support and final coating in order that the stability of the mass and the control of the induced displacements, are within the boundary of the excavation, both on the surface, they should be required for the mitigation of the effects related to the excavation.