Songzhizhai mine pool
There are two modes of transportation, one is rail transportation (that is, there are rails in the tunnel, like the railway), the other is trackless transportation, that is, ordinary large trucks
one is self use. Because of the huge subway project, we need to dig here and fill there sometimes
The second is to take them away and sell them. The country's land policy is very strict now. Earth rock is a good thing. It can be sold to buyers who need it. It can sell for a lot of money The third is temporary storage. Make a wasteland or a hill in the suburbs and store the soil there for future use or sale 
extended data:
in the process of excavation, about 25% of the soil will be squeezed in all directions. When the drill bit is drilled in, the density of the earth rock around the 360 degree edge of the drill bit will increase, and part of the soil will be lost in the process of excavation; Internal digestion & quot; It's too late
shield machine is usually used in subway tunnel construction. We all know that the shallow soil on the surface is relatively soft, so once it is pushed away, there will be a certain degree of instability
so the shield machine will use a quarter of the soil when we dig the tunnel to consolidate the tunnel, so the tunnel will be more solid. Obviously, this is a kind of internal consumption, so the cost of outward transportation is saved