Rizzo Associates and the Agua Negra...

Rizzo Associates and the Agua Negra Tunnel

This international engineering and consulting firm is performing the in-depth Geological, Geotechnical, and Hydrogeological Drilling Studies for

the feasibility stage of the Agua Negra Binational Tunnel.

Agua Negra Binational Tunnel

The Agua Negra Binational Tunnel Project is being developed in the sur-roundings 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 in Quebrada San Lorenzo, Provincia de San Juan, on the Argentinean side, and Quebrada Río Colorado on the Chilean side, and consists of a double tunnel that is 14.5 km (9miles) long.

The main objectives of the 14.5 km-long road project are to allow a sub-stantial reduction in the altitude of the crossing that currently exists at 4,753 MASL; to avoid approximately 50 km of mountain road with haz-ardous stretches; and to make it passable for automobiles and all types of transportation vehicles year-round.

The stage that began in January of 2009 involved Phases I and II of the In-Depth Geological, Geotech-nical, and Hydrogeological Drilling and Test Studies for the Agua Negra Tunnel Project.

The Client, Dirección Provincial de Vialidad (DPV) of San Juan, awarded the contract to Ecominera SA and Rizzo Associates Argentina SA by means of a Public Bid. RIZZO is op-erationally responsible for the entire job, including all of the testing.

The RIZZO ASSOCIATES team in operation at 4600 msnm.

At the operation site (4,500 MASL) another strategic camp was set up in Quebrada San Lorenzo that was used for material storage, a permanent communication center, first aid cen-ter, and shelter. This camp also had all the accommodations needed to pro-vide shelter for staff and equipment if a storm isolated them.

In order to successfully develop the operations, it was necessary to draw upon all technical requirements to take advantage of the limited space and steep slopes in order to open new roads and build platforms and avalanche protection berms.

Characteristics of the Land

The geology of the San Juan Front Range presents a complex strati-fication including metamorphic, sedimentary, and igneous rocks that evolved between the Paleozoic and Quaternary eras. The Front Range is located in the Republic of Chile, near several potential locations for the west portal of the tunnel. These rock outcrops are lithologically characterized by rocks of the Choiyoi Group, and Permian, and Triassic vol-canic and hypabyssal rocks. On top of these there is another sequence of Tertiary volcanic and hypabyssal rocks, topped by Quaternary clastic sedimentary rocks, predominantly glacial in origin.

The geomorphology of this area is characterized by the U-shaped val-leys resulting from glacial erosion. The moraine glacial deposits from the Quaternary age are witnesses to the last glaciations in these valleys.

On the Chilean side, the area is char-acterized by rocks and deposits of similar age and lithology, but with steeper slopes (35º in average).

In the proposed locations for the dif-ferent tunnel alternatives there are outcrops of Choiyoi Group rock with intrusions of rhyolite, basalt and aplite dykes, sills, and veins.

Tectonically, the most relevant ele-ment of the area is the Río Colorado fault zone that is located in the Río Colorado (Chilean side); this is a su-perficial high-angle reverse fault.

Ecominera’s and Rizzo’s equipment and staff carrying out their tasks.

Rizzo’s staff conducting routine tests.

There are other important regional faults that directly affect the tunnel, like the Quebrada de San Lorenzo and Quebrada Amarilla faults (Argen-tinean side).

Challenges Found in High-Mountain Areas

From left to right (Front Row): Horacio Patt, Study Director; Hugo Riofrío, BS. Field Supervisor;

and José Fenoglio, Rizzo’s Office Manager, Cuyo Region.

Given the altitudes where the work was performed (4,300 to 4,900 MASL in the Argentinean side and 3,680 MASL in the Chilean side), the installa-tion of different camps was required.

The base camp was located in Arre-quintin (2,900 MASL) where the DPV has facilities. It was fully equipped for a permanent 50-person workforce to live and carry out its activities during the project. To this end, the camp was fitted with satellite communication and VHF, taking into account that the project was carried out 35 km from camp on a mountain road with intense tourist movement during summer months.

Technical Project and Characterization Studies

Rizzo’s staff during a storm.

According to the description given by José Fenoglio (RIZZO’s Office Manager, Cuyo Region), the project required very specific studies that are not usu-ally carried out in Argentina due to the diameter of the required drill

ings (PQ 4”) with total core recovery by HQ (63 mm). Special equipment and software had to be imported for both geophysical and hydrogeologi-cal tests.

Currently, 10 boreholes are being drilled; eight in Argentina and two in the Chilean side, thus completing a total of 5,000 meters of drilling. This task is under the authority of the company Ecominera S.A., headquar-tered in the province of San Juan.

Geophysical Prospecting

In terms of the high demand of information required, RIZZO is imple-menting a program of measurements including borehole profiles and 3-D core rendering, using the latest tech-nology relating to well-logging geo-physics for small drilling diameters.

Field equipment is carrying out the measurement of boring trajectories (gyroscope); measurement of the boring internal diameter (caliper); structure orientation and core recon-struction by means of well acoustic and optical television sets; measure-ment of rock density (Gamma-Gam-ma) and porosity (Neutron-Neutron); lithology characterization and dif-ferentiation by means of Natural Gamma; measurement of water qual-ity (pH, Temperature, Conductivity, Redox); and measurement of vertical flows (Flowmeter).

The sonic log recordings allow us to obtain complete wave and density measurements along each borehole, and the 4 Dynamic Modules of the Rock Mass.

Once the sonic wave and density log recordings are complete, the four Dynamic Modules of the Rock Mass, and a log of each one, are obtained: - Poisson’s ratio (m);- Shear Modulus (G);- Young’s modulus (E); and- Bulk modulus (K).

This information will be essential to set the modulation parameters of the future tunnel design, since it is

quantitative-type information that allows predicting the geomechanical behavior of rock masses and are directly applicable to the engineer-ing calculations, after the geological interpretation.

Routine measurements of Water Quality at the foot of the Glacial San Lorenzo, 4,900 MASL.

Each boring has a continuous control in place. RIZZO personnel are perform-ing core control and handling tasks, RQD measurements, and radioactivity measurements of each core sample. They are also taking routine pH, con-ductivity, temperature, O2, and radon saturation measurements on sludges, and methane, CO2, and radon gas measurements at wellheads.

By the end of 2009 and for the first time in Argentina, RIZZO imported a special piece of equipment to per-form Dilatometric tests on rocks at depths greater than 400 meters, that helped determine, besides the ten-

Geotechnical Studies

sion deformation values of rock, the “fluence” in the plastic deformation zone, and finally the rock shear stress at the depths of interest.

Hydrogeological Tests

RIZZO is currently performing hydro-geological tests on the borings using cutting-edge equipment and other units specially developed for this project. This equipment is capable of performing tests with very low static levels and small-diameter drillings. The experience of RIZZO’s hydro-geological professionals resulted in achieving the expected results in tests like Lugeon (Packer test); hydraulic fracturing; short-term, long-term, and step test pumping, Drill Stem tests, Slug test, and Repeat Formation tests.

For more information on the Agua Negra Binational Tunnel Project,

please contact José Fenoglio at [email protected].

Rizzo AssociatesE N G I N E E R S & C O N S U L T A N T S

www.rizzoassoc.com

RIZZO ASSOCIATES CHILE, S.A.

SANTIAGO OFFICEAv. Presidente Errázuriz 3724

Los Condes, SantiagoPhone: (56 2) 894 6975

Fax: (56 2) 369 5657Contact: [email protected]

RIZZO ASSOCIATES PERÚ, S.A.

LIMA OFFICECalle Luis Felipe Villarán 520

San Isidro, Lima 27, PerúPhone: (51 1) 221 6478


RIZZO ASSOCIATES ARGENTINA, S.A.

BUENOS AIRES OFFICE Av. Alicia Moreau de Justo 1148 - Piso 4°

(C1107AAX) Buenos Aires, ArgentinaPhone: (54 11) 4341 4514


RIZZO ASSOCIATES ARGENTINA, S.A.

MENDOZA OFFICEOlascoaga 131

(M5502ARC) Ciudad de Mendoza, ArgentinaPhone: (54 261) 524 1974


PAUL C. RIZZO ASSOCIATES, INC.CORPORATE HEADQUARTERS

500 Penn Center Boulevard, Suite 100Pittsburgh, Pennsylvania, 15235 US

Phone: +1(412) 856-9700Fax: +1(412) 856-9749

Contacts: [email protected] & [email protected]

US OFFICES California / Missouri / New York / Pennsylvania / South CarolinaINTERNATIONAL OFFICES Buenos Aires, Argentina / Mendoza, Argentina / Santiago, Chile / Lima, Perú

Plzen, Czech Republic / St. Petersburg, Russia / Abu Dhabi, UAE / Brisbane, Australia

Rizzo Associates and the Agua Negra...

Documents

Transcript of Rizzo Associates and the Agua Negra...