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  1. DougHole

    Ground response

    I second what rubudiman says. thank you mccoy for all your tips and explanations. I never got taught site response in my engineering degree and am teaching myself on the job and at home
  2. DougHole

    At rest (ko) wedge?

    to clarify further and to give some context around the question.... I have a stepped 2 level basement ret wall that will be propped by the slabs at ground level, -1 level and -2 level. the upper basement wall is 3m high the lower basement wall is 3m high the distance between the upper and lower...
  3. DougHole

    Ground response

    awesome, thanks! i will try order some copies. i take it they're a bit lower level than Kramer?
  4. DougHole

    Ground response

    i find Kramers book very confusing...i am yet to find a good document or post that explains site response well. i am keen to figure out the difference between linear, non-linear, equivalent liner, total/effective stress site response methods and when to use which one
  5. DougHole

    At rest (ko) wedge?

    Hokie66 - to clarify, i meant the distance back from the wall that the wall supports i.e. for a wall designed for active pressures, the soil in the active wedge is defined by (45 deg + phi/2) e.g. for a clay with a friction angle of 30 deg, the active wedge angle would be 45 + 30/2 = 60 deg from...
  6. DougHole

    At rest (ko) wedge?

    We can calculate the active (ka) wedge distance and passive (kp)mwedge distance behind/in front of a wall. is there such thing as an "at-rest" (ko) wedge and if so, how do i calculate it?
  7. DougHole

    Site response for dummies for liquefaction analysis

    i was just wondering what the difference is between the following analysis methods used to calculate the CSR for a liquefaction analysis in a site response analysis: 1. linear total stress (SHAKE?) 2. non-linear total stress 3. non-linear effective stress what does the "linear" thing mean...
  8. DougHole

    Cantilevered Soldier Pile Wall - Sanity Check

    Looks ok for overturning but deflections could govern. what is at the top of the wall? A WALLAP analysis would take about 15 mins if you have that software
  9. DougHole

    Pile retaining wall design methods - US/Canada

    ok thanks. It sounds very much like WALLAP which is what i am used to using.In WALLAP, the basement floor slab props and temp props (raking/anchors, etc.) are modelled as springs. you put in your free length, youngs modulus, pre-stress, angle, cross sectional area, etc. and it calculates an...
  10. DougHole

    Sensitivity of clays

    my apologies - in my example i should have said Sr=100kPa/30kPa = 3.33
  11. DougHole

    Pile retaining wall design methods - US/Canada

    thanks Avscorreia - can you clarify what you mean by "beam model with uncoupled elasto-plastic springs, taking into account the construction sequence (using a VBA program in an Excel spreadsheet) to get a better force envelope in the wall and to check the evolution of anchor forces;"?
  12. DougHole

    Pile retaining wall design methods - US/Canada

    Hi guys, just out of curiosity, just wondering what everyone in the US and Canada are using for piled wall basement design? By this i mean bored reinforced concrete piles spaced at generally less than 3D centres e.g. 600 mm diameter piles at 1800 mm centres? and temporary props (raking...
  13. DougHole

    Sensitivity of clays

    similar to BigH, the only time i ever calculate a sensitivity ratio is following measuring an Su in a shear vane test (e.g. 100 kPa) and then a remoulded shear vane (30kPa) and then dividing one by the other. so in this example, Sr=0.3 or 30%. I guess you could get a sensitivity during a...
  14. DougHole

    lateral spreading analysis

    Hi EireChch What is the difference between "shaking induced slope displacement" and "lateral spreading from liquefiable ground"? with my situation, it is a slope into a river which i guess is a "free face". My liq analyses, indicated that i had liquefiable soils between 6-8 m below ground...
  15. DougHole

    electrical resistivity in gypseous soil

    do you mean a weinner four pin method? There is a good British Standard that outlines electrical resistivity testing methods. i don;t have the name of it at hand i'm afraid. From the results (in ohm metres), you can determine the corrosivity potential of the soils. Sorry can't help in the...
  16. DougHole

    lateral spreading analysis

    i am doing a newmark sliding block analysis ("Jibson 2007") for a slope to estimate the lateral displacement under seismic conditions. To do this, i need to determine the yield acceleration. This is usually done by tweaking the acceleration coefficient in Slope/W until the FoS is 1.0. i have...
  17. DougHole

    Time period from undrained to drained

    i have been using c' of 6 kPa and phi' of 31 deg and su of 100 kPa. The c' probably sounds high but it is a reasonable value based on local geology. When i run the undrained with su of 100 kPa the FoS is very high (>3). The contractor wants to cut the slope and build his structure which may take...
  18. DougHole

    Time period from undrained to drained

    In slope stability analyses, we generally use drained parameters (c', phi) for long term assessment of slopes and undrained parameters (Su) for short term assessment. After how many days/weeks/months/years does a material go to a "drained" conditions. let's assume for this question that we...
  19. DougHole

    Grout to ground bond stresses in Green Bay, WI

    If you have some undrained shear strength readings in the clay from pilcon shear vanes tests (or pocket pens or torvanes) then you could use an alpha.Cu chart to get a design bond in the clay. The alpha value ("adhesion") is based on Tomlinson's chart but you can also find it in the Canadian...
  20. DougHole

    Slope stability

    Without knowing the details of your project, i would try the following combination of parameters... silt: use phi'= 27,29,31,33 deg combined with c' of 1, 2, 5, 10 and 15 kPa. clay: use phi' of 24,26,28 and c' of 1,2,5, and 10 kPa You will find the c' makes a big difference to the FoS.

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