Completed the Pico del Buitre's geotechnical study

2009-Jul-30 13:58
Pico del Buitre's geotechnical study

Pico del Buitre's geotechnical study

The Pico del Buitre's geotechnical study has determined that the project area is located on a rock mass of middle Jurassic age - Upper Jurassic. All excavation may be made by conventional mechanical means using hammer from time to time. All the material extracted is suitable for the manufacture of artificial gravel or unpaved direct use or fills all - one. The land has no aggressiveness toward concrete, so it is not necessary the use of concrete sulforresistetes according to EHE.

In this study we have identified 5 geotechnical units within the affected zone, which in summary way are:

  • From 0.0 to 5.0 m: highly fractured gray bioclastic limestones
  • 5.0 to 7.0 m: moderately fractured limestones sandy ocher
  • From 7.0 to 8.0 m: Shales very porous yellow limestone, weakly karstified
  • From 8.0 to 9.5 m: red sandy limestone, very porous and resistant
  • From 9.5 to 22.0 m: gray calcareous marl, slightly fractured and highly resistant

These units are arranged in layers that appear like subhorizontal dips locally affected by several shortcomings, one of which passes through the affected area altering significantly the geological and geophysical field in the first 9 meters.

According to the geophysical surveys, we have identified two areas with different mechanical properties. The area south of fault line, defined as Zone 1, has a low modulus of deformation of the solid in the first 7 to 9 m deep and low electrical resistivity, indicating high porosity. In this area, the main telescope will be placed. Zone 2, north of the fault, shows significantly higher modules and high resistivities are not detected within areas affected by construction projects.

According to these features of the land, the building conditions in Zone 2 that affect smaller telescope, control building, tunnels and generators as well as deposits, are optimal, with higher allowable pressures, higher or equal in all cases to 5.0 kg/cm2. In Zone 1, where the main telescope will be built and the service building will be recommended not to exceed a design pressure of 3.5 kg/cm2.

In the case of the main telescope it's also recommended to make an oversight about the excavation to verify the exact nature of the geophysical anomalies detected in the southern area in the bottom of excavation to take specific measures for treatment if it's necessary.