|Design of complex tunnel portals||References_4717|
Advanced numerical analyses of tunnel portals are needed in case of several complex design conditions. Lombardi Ltd. provides studies in this field, using both commercial 2D and 3D numerical software as well as in-house developed softwares. Lombardi has gained specific experience by dealing with design cases of considerable complexity.
A study of particular relevance was the analysis of the portal of three tunnels located within a large slope of cohesionless soil. In this case, the close to limit equilibrium condition of the slope itself, as well as the diagonal entrance direction of the tunnels, called for 3D numerical modelling. The effects of the excavations on the slope stability were evaluated and the tunnel lining was designed, taking into account the staggered excavation start of the tunnels. Additionally, due to the high seismicity of the site area, seismic analyses were performed.
For the design of portal supports, a particular case to be studied was the entrance of a double tube road tunnel through a railway embankment. Because of the diagonal entrance direction of the tunnels, the use of permanent soil anchors in the design of the retaining structure would have interfered with the nearby tube, and was therefore not allowed. Therefore, the final design provided a support structure to withstand the long term earth pressure. The complex portal geometry required 3D numerical modelling. Furthermore, considering the tunnels passing underneath an existing railway line, possible settlements at the railtrack level had to be verified.
|Preliminary design of TBM||References_4931|
The selection of the excavation method is a key aspect for the design of tunnels. The mechanized excavation by means of Tunnel Boring Machines (TBM) is possible and convenient only in specific geomechanical conditions. The preliminary TBM design becomes therefore relevant in order to define the main features of the TBM, determining the feasibility of this methodology, and considering schedules and costs.
The main characteristics of the TBM, i.e. advancement thrust, cutter head torque, shield geometry, cutter head properties and power of the hydraulic equipment, can be established by studying the geological framework and carrying out a proper geomechanical analysis. Other relevant aspects as the drilling machinery for the grouting works and geological investigations as well as the equipment required for the backfilling of the annular void can also be defined at this stage.
In specific geomechanical conditions, advanced calculations (typically 3D) could be required. The performance of such models must take into account the interaction between mechanized excavation and the geological setting.
Lombardi Ltd. has been actively involved in this engineering framework, carrying out successfully the preliminary TBM design regarding multiple underground works: highway, railway and hydraulic tunnels, rocky and soil ground, with high overburden or in urban areas.
|CERN - High Luminosity LHC||References_5745|
The High Luminosity LHC (HL-LHC, also HI-LUMI) is a project aiming to upgrade the LHC after 2026, increasing its peak luminosity by a factor five over nominal value. The project is located at the so-called Point 5, beside the existing structures of the Compact Muon Solenoid (CMS) experiment, near the village of Cessy, on French ground.
The HILUMI Project consists in the construction of four new buildings on the surface and of different underground structures, listed here under:
- Vertical shaft of approx. 85 m depth, internal Dia. 7 m
- Cavern at the food of the vertical shaft; L x B X H = 56 x 19.3 x 17.5 m
- Tunnel of approx. 300 m length, Section B x H = 8.5 x 7.9 m
- 4 side tunnels, 2 of which with access to the existing LHC
- Large diameter vertical cores connecting the side tunnels and the existing
Further to the design activities, which include Preliminary, Tender and construction design, the contract embraces also the Site Supervision until the closing of the Defects Liability.
Part of the assignment are also al the civil inner structures, such the elevator pit and stairs system in the shaft and the steel mezzanines and the concrete chamber inside the cavern. The design has been carried out on BIM platform. The design activities have started on June 2016 with the Preliminary design and will end on March 2019, with the Construction design of the surface buildings. The site works will start on April 2018. The end of the underground works is planned by middle of 2022, the one of the surface building for the end of the same year. The most delicate part of the work is represented from the excavation of the vertical shaft, which will be carried while the LHC is operating.
The remnant part of the underground works will occur during the foreseen shut down period of the LHC for refurbishment and renewal works.
|Museum of Glacier Garden Lucerne||References_5417|
The Lucerne Glacier Garden will be renewed and extended until 2021 for a total of CHF 20 million. The existing extensions at the Swiss House will be demolished and a new building will be constructed further north. However, the main attraction of the museum extension is the planned adventure path inside the rock. It consists of a gallery passage, a cavern staged as a mountain lake and a shaft accessible via a staircase. Visitors can experience the geological formations and the special structures of the bedding planes and the joint surface of the Lucerne sandstone up close. Securing and covering should therefore be avoided wherever possible. The profile form follows, if possible, the geological structures.
The development of the underground components takes place in a separate gallery, which is not accessible to the visitors and, in the final state, includes part of the technical facilities of the museum as well as storage areas.
Due to the location right in the centre of the city and in proximity to the Lion Monument, special attention must be paid to the emissions by the planned drill-and-blast excavation. Extensive monitoring measures of the surrounding buildings are planned.
|Eigergletscher Top Station||References_6116|
The Grindelwald–Männlichen Gondola Cableway and Jungfrau Railways are building a V-cableway to access both the glacier of Eiger (Eigergletscher) and Männlichen. Starting from the joint terminal Grund in Grindelwald, a tri-cable aerial cableway will travel to Eigergletscher and ten-seater aerial gondolas will travel to Männlichen. This significantly shortens travel time to the Jungfraujoch as well as to the ski area, and considerably increases the transport capacity. The Jungfraubahnen’s project V-cableway comprises eight integrated components and an investment volume of about CHF 470 million.
Lombardi continues the design work and is as sub-contractor in charge of the final design (phase 51) and the technical construction management (phase 52) for the top station of the tri-cable aerial cableway at Eigergletscher.
The top station of the tri-cable aerial cableway will be located east of the existing chair lift Eigergletscher at around 2’330 meters above sea level. The space is limited and the terrain right above the planned station is steeply sloping if not overhanging, which results in a nearly 40 m deep excavation pit. The short summers and the exposed location will result in challenging weather conditions during construction.
The top station with a size of approximately 24 x 50 x 17 m (W x L x H) will be half excavated out of rock (cavern of 320-355 m2). The other half will be built as a frame above ground (excavated rock of 13‘000 m3). The top station and the Eigergletscher railway-station will be connected by two new tunnels (A = 20 - 30 m2, L = 40 m).
|Monaco Darse Nord||References_6943|
|ANDES Laboratory - HVAC Equipment||References_7099|
Preliminary study and tender design for the underground Physics laboratory. The work in question is located on the border between Argentina and Chile. The idea of the Physics laboratory stems from the opportunity created by the construction of the Auga Negra road tunnel that crosses the border between Chile and Argentina (Lombardi project in 2013).
Approximately in the center of the tunnel, with an overburden of about 3000 m, the CLAF (Centro Latino-Americano de Física) proposed the construction of a physics laboratory communicating with the tunnel (TAN).
The laboratory has a total volume of 67'607 m³ and includes various rooms dedicated to physical experiments, clean rooms and biology laboratories.
Water supply systems and water purification plants, treatment plants for waste water by bioreactors, compressed air, fire prevention systems and ventilation systems for air exchange, air conditioning as well as smoke and heat extraction systems have been planned. For the supply of water for human and fire-fighting purposes, shunts were created from the equipment of the road tunnel.
The air for the air-conditioning, hygienic changes for the extraction of smoke and heat and heat exchange aimed at air-conditioning takes place with the external environment, through 6 km of hydronic and aeraulic pipes that pass inside the safety adit of the road tunnel.
|City of Lucerne - Bicycle station at the Lucerne Station Square||References_5513|
Part of the preliminary project phase for the Lucerne underground station, sub-project traffic and environment, is to add 2’000 bicycle parking spaces within the perimeter of the train station. As part of the planned transformation of the Bahnhofstrasse the current above-ground bicycle parking spaces will be removed to boost the esthetics of the area.
Therefore, the City of Lucerne wants to realize a new bicycle station around the Lucerne station square. In a feasibility study, various locations and their development were analyzed in the greater area of the Lucerne railway station. The evaluation of the individual options was based on a broad list of criteria.
The best variant could then be further pursued in a preliminary project.