Do i need to stabilize the soil i am not depend on it???

[Balageotech]

Dear Expert,

we are developing a industrial structure G+2 with plan dimension of 45x75m (150ft x 220ft). where we have 80 m/s wind speed and 0.20g seismic acceleration.

We are having the soil profile for 50m and as follows,

Layer 1(0 to 15m): silty sand, N= 4(average)
Layer 2(15 to 25): silty clay, N=10(average)
Layer 3 (25 to 35): Siltiy sand, N= 7(average)
Layer 4 (35 to 50) ; Sand , N=50(Average)

the loading intensity from the superstructure column is 10t/m2. Hence we suggested to go for pile foundation with 45m depth. Being the site is high seismic zone we asses the site has medium to high liquefaction potential.

As the ground level slab (factory slab) needs to carry 6 t/m2 with settlement restricted to 12mm, we have suggested to use structural slab system supporting piles below at every 5m spacing. Now the entire building designed such way to not having any contact with soil other than pile and the pile are taken to hard strata.

Now the question is, after doing this all, do I need to go for soil stabilization or improvement as I am not taking any advantage strength available in the soil below??

Please post your comment.

Regards
Bala

 

[EireChch]

If your slab is fully self supporting between piles you don't need to worry about the soils beneath liquefying. You will however need flexible fittings for your services i.e. Wastewater etc.

 

[SlideRuleEra]

Be sure to design the piling system to that it does not depend on lateral support from the (liquefied) soils.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[Mccoy]

Before the onset of liquefaction lateral displacement (due to wind or earthquake) of piles might be significant in the top layers of soft soil. And the shallowest layers are those where the pile tends to be displaced the most.
What may be done is a preliminary calculation of lateral displacement of piles in the natural soil conditions (soil not improved).
Also, another issue is sliderula's remarks about liquifyiable layers not giving contribution to lateral resistance of piles in vertical bearing capacity.

http://www.mccoy.it