The case of Kakia Skala, National Highway Athens

The case of "Kakia Skala", National Highway Athens-Korinthos, Greece

Forepoling is used wherever it is dangerous to expose even small areas of soil or rock
for a short time. To be more accurate the time available for support, after excavation
(stand-up time) is so little that support must be secured prior to excavation.

Forepoling is used usually in the following cases:

Running ground, such as water-bearing sand or silt
Fragmented or squeezing rock

Figure 1:The steel piles drilled into the
fragmented rock before the first
excavation

Bellow are some photos of the drilling project and machine. The holes are drilled
with a slight inclination. Then the steel piles are inserted into the hole and are filled
with cement. The piles have many holes from which the cement comes out and bonds
the pile with the ground. In the picture above you can see the piles before pumping
of cement.

The total length of piles is 12m.

References

T.M. Megaw, J.V. Bartlett, "Tunnels, planning, design, construction",Ellis Horwood
International Edition, 1983.