Geotechnical Bore Holes

[Walter2992]

This may seem like a basic question, but I would like to get some information on the standard procedures for backfilling bore holes after the completion of the drilling. This is with respect to holes completed for foundation design, which are immediately filled after the test is complete. Are there standards or regulations that apply? We are having drilling done in a public area, and want to ensure that this procedure is done correctly.

 

[Rendang71]

Dear Walter2992,

I used to work for SI company in Bahrain. Whenever we completed the boreholes, it was a mandatory to grout the holes using cement grout (mixture cement and water only). This is prescribed by the Water Resources Directorate (WRD) to maintain the aquifer. What we did, 1 bag of cement was mixed with 1 big drum of water and the mixture was pumped from the bottom of the borehole till it reached the ground surface. May this help you.

Regards,

Rendang71

 

[fattdad]

whatever method you use in a public space, be sure to return to the site and perform maintenance as the backfill will settle over time. I'd stop by weekly for at least a month to make sure there are no trip hazzards or such.

Grouting is a good idea, but no guarantee that the grout won't settle in the hours after placement (i.e., as you are driving home).

f-d

¡papá gordo ain’t no madre flaca!

 

[molerat2210]

My presciption for backfilling boreholes in public space roadway areas:

Backfill with cuttings up to -3 feet.
Mix two bags of Sacrete and pour in to hole up to -3"
Come back later and pound in cold patch.

Many deep, sloppy holes filled in DC by this method. No settlement.

 

[Dirtguy4587]

Depends on the specific purpose. Most of the projects I'm involved in are in areas where the water table is near surface. Typically, I prescribe backfill with cuttings to -3m, then bentonite chips to surface.

In cases where the borehole is collapsing/flowing, I've even grouted to surface, using a bentonite grout.

 

[Grouser]

Most state environmental agencies have requirements for abandoning/closing of water wells. This often includes geotechnical boreholes. Check with them and the municipality that may have jurisdiction. Most holes must be grouted closed and reported as such by the driller. Failure to do so is a violation of state law.

Please protect the environment as much as possible.

Cheers