The design guide I use is EuroSoilStab 2002. I've designed soil cement columns in Tidal Flat deposits (Cu=10kPa) before. The method is based in a combined soil stiffness and differs totally from pile design. The only difference here is Peat suffers from secondary compression ie increase in...
Im designing deep Soil/ cement mixed columns (1.5m diameter) 12m deep at 2.8m centres in fibrous peat. Loading from a 10m x 10m raft foundation is 120kPa (SLS). My question is will the fibrous peat between the columns undergo secondary compression or will the adhesion between the peat and the...
UCS, CBR and PLT are all useful for verification, UCS is the go to test to get a quick idea of the undrained shear strength but elastic modulus is very conservative because the sample is not constrained. Plate load test will give good values for Modulus of subgrade reaction (good for designing...
wouldn't you be better suited using bearing capacity instead of subgrade modulus (unless you are modelling a slab rather than a pad). Subgrade modulus is a measurement of displacement with load so if you have heave then the value would be shown as negative as the displacement is going up...
Rule of thumb use 20kN/m3 to 22kN/m3 which is a bit less than concrete 24kN/m3. Bearing in mind a well graded material will be denser than single sized aggregate.
Thanks Mike,
That's very helpful and I'm going to look into the use of fully softened strength parameters which I confess I've never come across before. Every day is a school day.
Regards,
Rob.
2. Adverse jointing would only be applicable if the structure was founded on a rock slope / cutting where the dip angle and dip direction of the rock joint were in the same plane as the cutting.
Considering the dead and live load of the crane is only part of the problem. There will be different load cases dependent on the skew and reach of the boom. The worst load case has to be determined and designed for with a suitable factor of safety.
Yes typically Cu values only for undrained short term modelling and phi values only for drained long term values. However effective stress triaxial test results on OC clays will often give you a c and phi value; in which case would you just use the phi value or would you redraw the failure...
http://mapapps.bgs.ac.uk/geologyofbritain/home.html
In the UK we have the British Geological Survey website that has an interactive map (see link above). From there you can view the superficial and bedrock geology and you can view historical boreholes for the Site you are working on. Is there...
The Geotech has probably an idea of the ground conditions on the site from local knowledge or boreholes logs. Example if the SPT N value is 10 in a clayey soil he may suggest the safe bearing capacity is 120kPa based on correlations between SPT N values and undrained shear strength.
Hi guys, just wondering if anyone uses c' and phi' parameters together for design (retaining wall, slope stability etc). If so how much cohesion would you use and why if not why not.
Regards
Rob.
Undrained (total stress) for clay soils in the short term (temporary works) which generally use Cu (kPa) and phi = zero. Use drained for granular soils short term and long term.
Drained (effective stress) for long term clayey soils where Cohesion is usually zero (kPa) and phi is the drained...
