Geotech

ARQ was responsible for the Geotechnical investigation for the road centreline and Wind Turbine generators foundation conditions. The geotechnical investigation included test pits, rotary core drilling, DPSH’s, CSW and Electrical resistivity testing. ARQ compiled a report detailing the geotechnical findings, including an interpretation of all the field and laboratory test results and recommended foundation solutions.

The investigation comprised four phases conducted simultaneously and one additional phase conducted consequently on the discovery of cavities across the site. These phases are discussed below.

• Phase 1. The test pit investigation was conducted to determine the in-situ soil conditions and the suitability of the material to be used as fill or layer works in the access roads to the wind turbine generators,
• Phase 2. Rotary core drilling was conducted to determine the thickness and geotechnical properties of the various in-situ layers in order to provide meaningful foundation recommendations for the wind turbines,
• Phase 3. The Dynamic Probe Super Heavy (DPSH) investigation was conducted to determine an empirical indication of consistency of the soil.
• Phase 4. Continuous Surface Wave (CSW) testing was conducted to obtain the small strain stiffness (G₀) profile of the in situ strata (up to a maximum depth of 20m) which may be directly used for design purposes.  This primarily allows the design engineers to derive optimal, cost-effective designs for the foundations.
• Phase 5. Electrical resistivity test were conducted at nineteen of the wind turbines positions to measure how strongly the soil resists the flow of electric current. The Dipole-Dipole electrical resistivity test was performed to provide an indication of possible cavities present below the surface, as well as the extent of these cavities.

Project details