I need to have someone come dig a tunnel to access a "Y" connection in the sewer line that needed to be replaced. Access from above is too problematic and messy.
The quote I got is $187 per foot of digging. They will need to dig down several feet beyond the footing, then dig a horizontal tunnel six feet over to the location of the pipe. Because we are in Miami and near the beach, the soil is all sandy, I guess when they tunnel, the compacted sand above the tunnel will fall? This means more dirt will be removed from the tunnel. Now when they finished repairing or replacing the drain line, they told me they can just throw the dirt back into the tunnel and all will be ok.
I wonder how you will throw the dirt back into the tunnel to fill the space below the slab and above the footing? Can this really be done? Does it not require some sort of a sand/dirt pump? Even if this is doable it will not be compacted right?
Will this cause the line to be "suspended" and not resting on dirt and will that cause future failure - possibly the weight of water going through may create a back pitch? Will the foundation settle as a result of this dig?
Thanks for any comments,
O