Saturated soils.
Saturated soils.
(OP)
My geo tech wants me to include a special provision in a contract telling the contractor not to work on a slide if the soil is saturated. He offers no ideas on how the contractor is to know when the soils are saturated. I could use embankment control stakes but if it's moving I'm in trouble anyway. What do I require to measure saturation 20' under a roadbed?





RE: Saturated soils.
Just an idea ............. What do others think?
Andy Machon
RE: Saturated soils.
or measure movement using:
slope indicators (inclinometers)
settlement/heave measurement devices
stress meters or strain gauges
to prevent saturation, the water must be diverted from the site. Best to prevent the saturation in the first place.
RE: Saturated soils.
I might be taking CVG's comment too far, but let's not keep dumping on the contractor. Everyone on a construction project has duties AND responsibilities. If we ALL lived up to our own, instead of trying to shift them to someone else, construction would be more of a TEAM effort.
RE: Saturated soils.
It seems that after I rejected the first two options from the soils engineer that it's now my problem to deal with and be responsible for. His idea was to build a bypass through a 50' rock bluff and bypass the traffic until the road could be rebuilt. I have about $600,000 to spend I'm guessing that would cover the bypass
P.S. If I knew where the water was coming from maybe I could divert it. Limited budgets mean limited borings.
RE: Saturated soils.
I have to admit that after reading you latest post, a different light is shed on your question. My first reaction was to suggest writing into the specifications the requirement that the contractor hire a geotechnical firm to do the required monitoring. That way the costs of the monitoring become part of the construction cost rather than the design cost, just as you suggest.
But then I wondered how do YOU decide what the parameters of the monitoring are going to be without first having a geotechical firm tell you? (Bye the way, from what you said in your first post, I would change geotechs!) If that is the case, just leave the whole thing back in the design phase. The monitoring effort should be part of the ongoing project inspection costs and you preserve the "arms length" relationship between design and construction.
This may seem harsh, but I am always skeptical of an Owner who has enough money to do the construction phase, but not enough money to do the complete design or construction inspection phases. In the end, it ALWAYS costs someone more than it should when things are done skimpy.
One last suggestion, can you put in dewatering wells or a cutoff wall to dewater the area?
RE: Saturated soils.
RE: Saturated soils.
The boring showed saturated soils, not free water, at varying depths. The embankment runs along a hill side so a pore pressure type well would not acurately display the level of saturation or the present of flowing water.
If dewatering is pratical let me know what I need to read. If it is not too technical I can work it out for myself.
This is very important to me and I really appreciate your help. If anyone has specs that I could use please attach them to an email (msword format
RE: Saturated soils.
RE: Saturated soils.
From practical points of view, dewatering and monitoring well should work if your base is not too deep and there is not any adjencent structure. That should not be too expensive because it does not need complicated equipment.
If that does not work, you may have to use some kind of retaining structures and dewatering system.
The contractor should make a test excavation first to see what happened.
RE: Saturated soils.
I think is quite easy. Take one boring mashine on site and perform STP test every one meter depends on your site(say 10 meters). From split spoon samples get the labo test on saturation and other GP properties of your soil.Labo should know what to do.
Saturation S=Vw/Vv * 100(%)
Vw- volume of water
Vv-volume of voids
Saturated soil is between 95-100%. If the area is landslide you have to take the core also to distinguish failure plane.Be aware of liquefaction problems related to earthquake!!!