AnaAnt
Civil/Environmental
- Mar 24, 2012
- 41
Hi!
I read few articles and books that describe this soil property.
I dont know if this could be even called soil property since its an mathematical model wich tries to imitate soil behaviour under pressure.
Anyway the formula as we know it is k=pressure/settlement (kN/m2) / m.
As I understood "k" only represents elastic behaviour of soil wich only happens for small deformation (settlements).
Now this is where I get confused.
Small deformations (settlements). How small?
Many authors describe "k" as an tagent to pressure/settlement curve. Is this related to my previous question?
I think it could be couse for small settlements the pressure/settlement curve is prety much linear. But I could be wrong...
Wich field or laboratory test could most accuractly predict "k" value?
Ive seen many graphs from Plate Load Test wich are basicly pressure/settlement graphs. Are they reliable?
I have many doubts here.
First of all, the pressure bulb from small plate and foundation are VERY much different. If the soil properties dont change with depth then its ok.
Second, PLT is only for soils that dont undergo consolidation! So only reliable for soils that only undergo instant settlement. No long term settlements!
Ive found few formulas from "Bowels" that try to coolerate bearing capacity and "k" value.
Can these be safely used while designing?
Ive read aslo few forum discussions where experts say that "k" value should vary under a raft foundation and that one value shouldnt be used under the whole plate. I dont understand this? Why?
If "k" is used based on the elastic behaviour I dont see any problem of using one value for design process.
Please help.
Ana
I read few articles and books that describe this soil property.
I dont know if this could be even called soil property since its an mathematical model wich tries to imitate soil behaviour under pressure.
Anyway the formula as we know it is k=pressure/settlement (kN/m2) / m.
As I understood "k" only represents elastic behaviour of soil wich only happens for small deformation (settlements).
Now this is where I get confused.
Small deformations (settlements). How small?
Many authors describe "k" as an tagent to pressure/settlement curve. Is this related to my previous question?
I think it could be couse for small settlements the pressure/settlement curve is prety much linear. But I could be wrong...
Wich field or laboratory test could most accuractly predict "k" value?
Ive seen many graphs from Plate Load Test wich are basicly pressure/settlement graphs. Are they reliable?
I have many doubts here.
First of all, the pressure bulb from small plate and foundation are VERY much different. If the soil properties dont change with depth then its ok.
Second, PLT is only for soils that dont undergo consolidation! So only reliable for soils that only undergo instant settlement. No long term settlements!
Ive found few formulas from "Bowels" that try to coolerate bearing capacity and "k" value.
Can these be safely used while designing?
Ive read aslo few forum discussions where experts say that "k" value should vary under a raft foundation and that one value shouldnt be used under the whole plate. I dont understand this? Why?
If "k" is used based on the elastic behaviour I dont see any problem of using one value for design process.
Please help.
Ana