Agua Negra Binational Tunnel

Client: Dirección Provincial de Vailidad | Location: Argentina and Chile | Year Completed: In Progress

Agua Negra Binational Tunnel

RIZZO performed the in-depth geological, geotechnical, and hydrogeological drilling studies for the feasibility stage of the Agua Negra Binational Tunnel.

This Binational project is being developed in the surroundings of Agua Negra's border crossing, linking Argentina and Chile, through National Roads No. 150 in San Juan and No. 41 in the IV Region of Chile. This project is located in the Los Andes Range, and consists of a double tunnel 9 miles (14.5 km) long.

RIZZO's work required completing a total of 3.85 miles (6.15 km) of drilling and specific studies that are not usually carried out in Argentina due to the diameter of the required drillings (HQ 4") with total core recovery by means of NQ (63 mm).

Geophysical Prospecting

RIZZO completed a program of measurements of borehole profiles and 3-D core rendering, using the latest technology relating to well-logging geophysics for small drilling diameters. Field equipment carried out the measurement of boring trajectories (gyroscope); measurement of the boring internal diameter (caliper); structure orientation and core reconstruction virtually by means of well acoustic and optical television sets; measurement of rock density (Gamma-Gamma) and porosity (Neutron-Neutron); lithology characterization and differentiation by means of Natural Gamma; measurement of water quality (pH, Temperature, Conductivity, Redox); and measurement of vertical flows (Flowmeter). The sonic log recordings allowed us to obtain complete wave and density along each borehole, and the 4 Dynamic Modules of the Rock Mass.

This information helped develop the Geological profile and set the parameters of the modulation of the future tunnel design.

Geotechnical Studies

RIZZO personnel performed core control and handling tasks, RQD measurements, radioactivity measurement of each core sample, and routine pH, conductivity, temperature, O2 and radon saturation on sludges, methane, and CO2 and radon gas at wellheads. RIZZO utilized special equipment to perform Dilatometric Tests on rocks at depths greater than 0.37 miles (.6 km), measuring the tension deformation values of rock.

Hydrogeological Tests

RIZZO carried out different hydrogeological tests in each boring like Lugeon or packer tests, hydraulic fracturing, short-term, long-term and step-drawdown pumping, drill stem tests (DST), slug tests, and repeat formation tests (RFT).

Remote Camps Developed

Given the height where the work was completed, 2.5 to 3 miles (4 to 4.8 km) above sea level, the installation of four different camps was necessary. The mains camps were fully equipped for a permanent 50-person workforce to live and carry out its activities during the project. On the operational sites, other strategic camps were set up and used for material storage, as a permanent communication center, and as a first aid center and shelter. These sites also had the necessary accommodations to provide lodging, and included satellite communication, water, food, dry clothes for staff, equipment, and heliport rescue capability, in the event a storm would have isolated them.

© 2014 Paul C. Rizzo Associates Inc.