12d Model software was used by Aurecon in Thailand for the civil design of
three Solar Farm projects located in the Tak and Sukhothai Provinces in Northern
Thailand. These projects consist of Photo Voltaic solar panels spread over an
area of approximately 575,000 m2 in Tak and 150,000 m2 in Sukhothai, with a
combined generating capacity of 34 MW.
These Solar Farms will alleviate pressure on existing electrical networks and
strengthen Thailand’s target for renewable energy. 12d Model was used for the
design of the earthworks, roads and surface drainage.
The solar farms are located on gently sloping to steep terrain. Layers of hard
rock also existed below the soil. The challenge was to regrade the land to a
consistent and gradual slope that would make the foundations easier to
The aspect of the grade of the sites had to be such that each
panel faced south, with no shadow effect from adjacent panels. In Thailand, the
optimum slope of each panel is 15° south, with a constant surface gradient of
less than 2%.
All of the sites were previously used as farms, and there was no established
drainage. Runoff from neighbouring properties needed to be cut-off, and
effective drainage was required at each site to prevent flooding. As much of the
electrical cabling is underground, the control of flooding was extra important.
Aurecon’s client for this project was Bouygues Energies and Services. The client
was interested in cost savings and wanted cut and fill volumes optimised. They
also wanted to limit cut in the underlying rock. Rock on the site was hard and
is both costly and time-consuming to remove.
Aurecon’s 12d team leader for the project was Keerakiat Khamsee. Using 12d Model
for the topographical survey and geotechnical report, the team was able to
create TINs of the existing levels and the underlying rock layers. TINs are a
form of vector-based digital geographic data and are constructed by
triangulating a set of vertices (points). They produce a 3D surface that can be
used to determine volumes. Closely spaced range files of 0.5m were used to
accurately estimate the soil volumes and rock volumes.
Using experience, good design principles and some trial and error, the final
excavation surfaces were created. Slopes and berms were set up to control
drainage. The final design levels were then adjusted to balance cut and fill
volumes, reduce excavation in hard rock and making sure that the aspect of the
final surface maximised the solar gain in the Photo Voltaic Panels.
Several iterations were developed and refined, prior to completing the Final For
Using 12d Model, Aurecon was able to optimise the design to
achieve the project objectives of maximising solar power from the Photo Voltaic
panels, controlling stormwater run-off, balancing cut and fill, and limiting
excavation in hard rock. Aurecon worked closely with Bouygues Energies and
Services to complete the project on time and within budget.
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