Quick screen shot of some rough and ready calcs, hopefully not too hard to follow. The above seems to work in Wallap but i cant get a hand calc to get an embedment depth/FoS thats in the ballpark. For 2D features, 1024x768 screen resolution. 1 GB hard disk space for program installation. So for a Phi of 21 degress and a post hole width 0.5m, at 2m spacing, Kp = 2.11, and Kp (mod) = 2.11 * (0.5 * 3 / 2) = 1.58. For 2D features, Intel® Pentium® 4 or better, or AMD Opteron or Athlon 64 or better (GeoStudio is optimized for multi-core Intel processors.) For 3D features, Intel® i5 or better. Kp is then factored to Kp (mod) which is Kp * (d * 3 / post spacing). The Wallap method is to ignore the active thrust below excavation line due to soil arching (this is done by setting Ka to 0) and then to factor down the passive resistance as each post is only receiving its passive pressure from a 3d width of soil in front of the post. However when doing a hand calc as a check, adopting the typical cantilever wall approach doesn't work as its not a continuous wall below the excavation line. Wallap gave an embedment depth of 2.7m for 1.4m height with a Fos of 2. I have had this checked by a senior engineer and he confirmed it. I have done a king post analysis in Wallap and followed the methodology provided and it works ok. Thanks SRE - thats what i was assuming too.
