Here is a high, solid mountain.  We are going to make a tunnel through it.
It is hard to see from the outside, but mountains are filled with various layers of rock and it is important to analyze the characteristics of the channel where the tunnel will pass before construction.

A column should be installed in the mountain to survey the shape of the place
we are planning to bore and how hard it is using a computer. 
Wow!  You can see which spots are hard and which spots are weak!
When you have a solid plan, an opening (portal) is made and gunpowder is used to blow up the tunnel.

Boom!  The tunnel has an opening now! 
Then, excavators and trucks come to bore the tunnel.
We keep surveying the condition of surface (tunnel face) while boring the tunnel to decide
how to reinforce it.

It seems like the strata here are not firm enough.  They must be reinforced and made harder.
Supports (steel ribs) should be installed to hold the tunnel and concrete (shotcrete) is sprinkled to firm the walls!

Finally, bolts (rock bolts) are installed to prevent collapsing.
Then, exploding and digging are repeated and the tunnel face is firmly fixed.
The repetition of this process finally creates a tunnel through the mountain.
In the final stage, the groundwater that flows through the mountain is drained away and steel
re-bars are installed on the tunnel walls.  Concrete is poured and finished safely and stably.
Ta-dah!  A sturdy tunnel is completed through this strong-looking mountain!

Hyundai E&G builds the tunnels that connect the world and people with the world’s most magnificent technology!