Hi all, I am new to this site and am looking for some advice regarding a medium size industrial site development we are doing this fall. I have been in the construction industry my whole life but only on the earthwork side for 7 years. There are a few specifics i would like to ask your opinions on. Please see the details below. Site development size is 7 acres. We will be stripping to topsoil down to a good clay base, digging a water retention pit, building up 8" of base clay, and finally grading the site with 8" of top gravel. This site has a few particulars that i am interested in exploring. The site has an unusual amount of topsoil. between 8" to 12". This is a very rich section of land. Typically we only remove 4"-6" of topsoil, so this creates the unusual problem of have a tremendous amount of topsoil for removal. The client would like to know if there is any way that we could reuse the topsoil by mixing it in our fill cut. He has access to recycled concrete in large amounts and i am been told it is possible to mix topsoil with recycled concrete and clay to generate a suitable base in our fill cut. I have not heard of this before but here is was has been presented to me. I will be talking to our geotechnical guys too but wanted to hear any thoughts from you all first. 1: Remove 6" of topsoil off site for resale.... 2: Remove balance 4"to 6" of topsoil and stockpile on site for reuse later. 1/2 for cut fill blending. 3: mix topsoil on site at a ratio of 1 topsoil, 1 cement fill, & 1 clay (from the retainage pit) for the 8" fill 4: pack base and install 8" of topbase...i will leave these details out. So my main question is do you think it is possible to reuse the topsoil in this matter? Has this been done? Have you ever heard of re-blending in topsoil in the fill layer in small quantities. This would represent savings for the client, but i am curious to know of any experience with this from individuals on the forum. Thanks a bunch for any information. Jerad
I'm gonna say not a good fill. I'm not 100% sure what your topsoil looks like but I'm going to guess that it has alot of organics in it. This is absolutely terrible for fill. I'd be trying to sell it.
That is totally an engineering question for a soils engineer (probably, a civil engineer) engaged only by the client to answer. I'm in an allied business (well, commercial real estate appraisal) and I see far too many of my peers basing their conclusions on guesses they have made when they should have engaged, or caused the client to engage, an expert in that field, whether it's engineering, wetlands identification, asbestos removal, or any of a myriad of things. Neill
I have blended topsoil into fill lifts and also bridged over unsuitable soils including heavy organic topsoil depending on the fill depth. All with geotechnical approval. It can very well be done depending on how much organics are in the topsoil, fill depth, etc. However YOU do not need to be the one that determines any blending of topsoil or using any fill not deemed suitable by the project geotechnical engineer. You need to have the project engineer of record steer the course on how this project needs to go pertaining to using topsoil in the fill. Don't be pressured by the client to save money that ends up leaving you open to liability later down the road. Documentation is your best friend in this situation.
As the contractor you don't really want to figure things out like that. I had a job go sideways in the bid process cause the builder was to cheap to pay the engineer to do a take off on the volume of material we were to do our own estimates and my number was different than his that was a simple question Your question pertains a ton of liability My answer is this whatever the engineer specifies
Thank you all for the responses. Nice having other opinions. The client has been in communication with the geotechnical engineers and sounds like they are coming up with a plan that will include a portion of the topsoil as fill as per the clients request. Thanks again.
And this gets that monkey off your back. Well-done!