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design of soldier piles for c phi soil 1

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kaushalaggarwal

Geotechnical
Mar 1, 2015
4
Hello,
I am designing a soldier pile system but I got stuck at a point. The type of the soil that I have is silty clay with phi less than 10 and c=50kn per square metres. I have seen two threads here on soldier piles and the other one was on whether to consider phi in unconfined undrained test or not?
The first one says take advantage of the cohesion of the soil and just design for the granular part. Is it reasonable to consider this for such a low value of phi. The other one says that for unconfined undrained test phi should be considered zero for the design purpose.
Now I am totally confused.. Pls help
Thanks in advance
 
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Well I am considering the first option to take advantage of the cohesion of the soil and design for the granular part only. But my question is it reasonable to do so for such a low value of the phi?????
 
Technically, if the soils have P.I. value of 10 or more and you limit your cohesion to 15 kPa and then you put a water pressure in your tension crack depth, then yes, you can use C and Phi values for earth pressure calculations. Be careful with ML & MH soils plus sites with high GWT. Practically, I ignore cohesion in backfill soils and use no more than 15 kPa in passive soils in earth retention projects.

 
@ fixedearth
What if I design it by considering a purely cohesive soil???? The is soil CL and ML type with no water table.
 
Here is a loading diagram for what you are thinking. Alternatively, you can use a simplified rectangular distribution on the active and passive sides. Refer to Foundation Engineering books by Jumikis and Teng for more discussion.

 
I know this dates me but way back in the 60s or possible the early 70s Hugh Golder and John Seychuk (of Golder) wrote a nice paper on soldier piles that were being used for the Spadina Line in Toronto. It was a PanAm geotechnical conference. I have the paper but it is in deep storage more than 10k km from here.
 
@ fixed earth
I am using the same earth pressure diagram as you have mentioned for purely cohesive soil.I just want to know whether it is correct or not for the type of soil I have.One more thing I want to discuss, on one side of the excavation there is a eight storey building so, while designing I have got 13m depth of the soldier pile for 6m depth of excavation that means the total pile length would be 19m and I want to reduce it. I am considering a tie. Can you pls tell me in the moment equation whether we will consider the moment due the tension in tie or not????
 
BigH - Are you referring to 4th Pan American conference paper of 1967?

Kaush- When you have 8 story building, you need to bring in a qualified shoring design firm. It is not something we can solve in a forum.

 
FixedEarth - That sounds about right - it is of the Toronto Spadina line. While the paper may seem a bit non-numerical (considering today's fixation on FEM), it is a good practical paper that stood the test of time in the construction of the line. Seychuk and I go back a ways - even got a nod from Vic Milligan once after he saw John and I talking again . . .
 
Dear friends, you can use Timber pile design manual for your professional works. i have attached some suitable download link for the purpose.
: bridge modeling
: beam modeling
: subroutine writing in ABAQUS
: seismic loading in concrete structures
: blast loading and soil-structure interaction modeling
: soil modeling in ABAQUS
: weld modeler plugin in ABAQUS
: soil plasiticity
:advanced soil plasticity
: soil elasticity and plasticity
: Advanced FEM book
: suitable book including lab test by True triaxial test
:constitutive modelling in geomechanics
: Constitutive Relations under Impact Loadings Experiments,
Theoretical and Numerical Aspects
:multiscale geomechanics
: Constitutive Modeling of Soils and Rocks
: soil mechanics - Nova
timber pile design
: dilatancy in soils
: ground improvement book
uploadboy.com/nxxy2lg35psr.html :tripartite template
:N-H spectrum lecture
 
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