Saturated Soil, Settlement Problem?
Saturated Soil, Settlement Problem?
(OP)
We're building a shrimp hatchery in Nicaragua (Light Gage Stainless Steel Structure, Reinforced Concrete Tanks), the site is about 350 meters from the beach, today we ran into this problem, over the last week or so, we cut the area of work to remove the top layer of the soil (black mud, highly expansive soil, about 0.85 meters deep), then we started to backfill with stone, throughout the week it rained a lot (we can expect more rain since it's that time of the season), today we found some water so we decided to explore some more and found out that below the first layer backfill was very humid, so we decided to dig a trench, and a couple of hours later the trench filled with water.
My major concern is because of the concrete tanks and the drainage pvc pipes, a little of settlement could be a disaster, i walked through the trench but the soil below felt stable, hard; since it rained a lot i'm sure the lower layers of soil are saturated, but i'm not sure if it's safe to keep filling and compacting. I need help with this one.
My major concern is because of the concrete tanks and the drainage pvc pipes, a little of settlement could be a disaster, i walked through the trench but the soil below felt stable, hard; since it rained a lot i'm sure the lower layers of soil are saturated, but i'm not sure if it's safe to keep filling and compacting. I need help with this one.





RE: Saturated Soil, Settlement Problem?
RE: Saturated Soil, Settlement Problem?
RE: Saturated Soil, Settlement Problem?
RE: Saturated Soil, Settlement Problem?
RE: Saturated Soil, Settlement Problem?
RE: Saturated Soil, Settlement Problem?
Perhaps the bigger issue is have you performed a geotechnical investigation with borings? You say settlement would be disastorous. There may well be compressible layers below the firm surface layer you describe. This may be a an upper dessicated layer with softer soils below. The loading from the rockfill and structures may induce settlement if there are compressible layers below.
RE: Saturated Soil, Settlement Problem?
RE: Saturated Soil, Settlement Problem?
the site elevation, and the nature and condition of the
native material underlying the new fill.
If the water entering the trenches is a result of precipitation,
then the impact on a well-compacted fill should be minimal.
However, if the water entering the trenches is a result of
consolidation/drainage of the underlying native soils,
then future settlement is definitey an issue.
Hopefully a geotechnical exploration was completed during the design stage of this project.
As Moe suggests, you need good geotechnical data, including water table measurements,
and Standard Penetration Test (SPT) borings, Cone Penetration Test (CPT) borings or similar.
In the absence of other data, you might consider digging a deeper test pit to observe the underlying soils.
Such a test pit should be located outside of the footprint of your proposed construction.