What could be the reason?
What could be the reason?
(OP)
I am desigining an approximately 18-foot tall and segmental block retaining wall that has a 3 to 1 slope on the toe side. A wet pond is planned for construction at the toe of the above mentioned slope. I ran a slope stability analysis of the wall using SLIDE program for long term (when pond is filled with water), rapid drawdown and no water in the pond (end of wall construction) conditions. I used a friction angle of 28 degrees and zero cohesion for both retained and foundation soils in the analysis. For no water in the pond case, I got a factor of safety of 1.35. For the long term condition, I got a FS of 1.55. Can somebody tell the reason why I am getting low factor of safety under no water in the pond condition? Is it reasonable to consider the no water in the pond case as short term condition?
best regeards
best regeards





RE: What could be the reason?
RE: What could be the reason?
RE: What could be the reason?
Thank you very much for your quick replies.
For short term- yes, my critical circle lies within the retained fill and the circles match closely. Basically, the on-site soils are typically sands and silts. Therefore, I assumed friction angle of 28 degrees and zero cohesion. I totally agree with your reasoning. I attached my typical critical circles here. The minimum required factor of safety for short condition is 1.3, right? does my no water case come under short term? Or do you guys think my assumption is wrong?
Thanks a lot
RE: What could be the reason?
RE: What could be the reason?
RE: What could be the reason?
RE: What could be the reason?
RE: What could be the reason?
That may be OK for loose bone dry clean sand, but most likely above the water table it is higher, due to usual soil moist conditions.
Also, if the program just subtracts 62.4 from the non-submerged condition, that does not the result in the actual correct submerged unit weight in most cases.
Also, when the pond is full of water is a flat WT under the hillside correct?
Before you get excited about your current question, I'd examine other factors here that put a question in correctness of either result.