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Recent content by EireChch

  1. EireChch

    How to confirm stone columns where installed successfully?

    In soft soils, stone columns offer very little improvement. Only in generally firm CLAY and granular material do they offer some improvement in the ground between the columns. A plate load test on top of the column on confirms the E' of the column material. This can be checked against the...
  2. EireChch

    Plaxis 3d modelling

    hhm Eric, Plaxis has been proven to be extremely accurate (in geotechnical terms) for modelling most things! There has been lost of case studies of predicted movement vs monitored movement , which have shown very good agreement. I am not sure what would be more accurate, possibly discrete...
  3. EireChch

    Mohr-Coulomb -graphical/equation

    your question probably needs some context. you can present shear stress graphically and with the typical shear stress equation.....
  4. EireChch

    Waler Connection

    Thanks gents
  5. EireChch

    Stepped Cantilever Retaining Wall

    your approach for the tiered walls is right, just apply the weight of the wall above on to the lower wall and design accordingly. You seem to have lots of embedment depth which is a help, is this correct, or just indicative? You could look at using modular block walls like ALLAN block or...
  6. EireChch

    Modular Block Wall With Geogrid Into Bedrock

    When I said pin it to the wall I meant a bodkin type join which is more or less the same as a pipe anchor. Hooking the individual cells to a single point etc would definitely be a bad idea. If you are confident in pinning/fixing the geogrid to the rock face then you must be sure it’s stable...
  7. EireChch

    cohesion based on SPT N-value

    anytime your talking about cohesion you need to specify drained or undrained. Undrained cohesion can be estimated by strouds correlation and others similar to it
  8. EireChch

    Modular Block Wall With Geogrid Into Bedrock

    I cant see why drilling and grouting a hook into the rock isnt possible. Its unusual but can be designed and detailed properly . You could go down the other route in assessing reduced pressures due to the presence of rock within you Ka wedge.
  9. EireChch

    Waler Connection

    Has anyone got any good pictures of waler beam connections, and also walers connected to a very non straight run of sheet piles. Putting together a presentation and need inspiration. TIA
  10. EireChch

    The minimum number of piles required for static load test

    Sorry I completely mis interpreted your question. In the UK, there is no minimum standard on number of piles to be tested. For a lot of projects, static pile testing is too expensive given the size of the project and and cost of testing. Generally it developed on a project by project basis...
  11. EireChch

    Sheet Pile Design - Causeway with Tire Pressures as Strip Loads, Retained by SSPs, and Faced with Concrete Blocks

    yes, still applicable. The theta c angle is a function of the passive soils friction angle. The berm above is completely separate to it. It could be concrete, rubber tyres etc, all we are concerned with is the weight it provides.
  12. EireChch

    The minimum number of piles required for static load test

    There is no real minimum etc. Its all about the reaction you need. If you get it from 2 piles, no reason you cant use just 2.
  13. EireChch

    Sheet Pile Design - Causeway with Tire Pressures as Strip Loads, Retained by SSPs, and Faced with Concrete Blocks

    The blocks are acting as a berm to the wall. It would be far to conservative to not consider any support from them. I can see why the contractor wouldnt be happy. Pick up a copy of CIRIA c760 and read the section on berms and how to consider them in your analysis.
  14. EireChch

    Dodgy parameters?

    I think your gut is right. Mudstone, and most rocks are typically designed as drained materials. Provided the material is jointed, you can use the Hoek Brown criteria to calculate drained parameters. For a mudstone, id guess something like phi of 28 degrees, c' 50-100kPa. Thats a big shot from...
  15. EireChch

    Lateral earth pressure at rest for a standing cliff

    Very true GAC - its a global stability problem first, then a retaining wall design.
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