Building on Organic Soils 2

[DocDirt]

We will be building a lightly loaded commercial warehouse (1 storey). Organic layer about 15 ft thick is present below 20 ft from proposed floor level. Building loads will not structurally affect the organics. We are concerned about settlement due to secondary effects such as volume change to decomposition. The organics are below water table and we think that they will not oxidize( aerobic) as it happens in most swamps settling. However we are concerned with the anerobic reduction of volume causing settlement.
Need Help in estimating settlements. Then we can decide on foundation options.
Any help?

 

[fattdad]

DocDirt - any index data yet? I'd like to see Atterberg limits and natural moisture contents.

f-d

¡papá gordo ain’t no madre flaca!

 

[DocDirt]

Dear F-D
I am on vacation and the testing is in still in progress. I have the following information which I am providing of the top of my head
Tube from Boring A - Natural Water Content = 270% LL= about 200 Pl could not be determined as it was too fibrous peat. Dry Density = 27 pcf.( Material found in borings from 23 to 33 ft)
Tube from Boring B- Natural Water Content = 60% LL= 90 PL= 50 Dry Density = 70 pcf Material is Organic. ( Material found in borings from 18 to 30 ft)
Tube from Boring C -Natural Water Content = 70% LL= 90 PL= 50 Dry Density = 55 pcf Material is organic. ( Material found in borings from 15 to 30 ft)
Boring D - ( Material found in borings from 13 to 30 ft)
Boring E- No organic/peat Encountered
Tube from Boring F-Natural Water Content = 65% LL= 80 PL= 40 Dry Density = 70 pcf Material is organic.( Material found in borings from 28 to 40 ft)
Boring G - ( Material found in borings from 18 to 35 ft)

Organic contents seem to vary from 2 to 5% in Organics and from 5 to 10% in peat.
LL, Pl are air dried.
I will be back on 1/22.

Study is a feasibility study.
DocDirt