Snailz - Search Limits - Global Stability & Design Test Load 1

[Marlow18]

So I have two questions in regards to soil nail walls. I posted this in another category by accident but here goes. I've been looking into soil nail wall analysis and haven't been able to find a thread on this yet.

In regards to using Snailz, is there a benefit in limiting the search limit option? I was wondering if someone could point me in the direction to find how far back you need to search in terms of global stability and what justifies limiting your search limits. I know if you don't input it in the program, it automatically figures one for you (2 x H) but I want to know how that length is/should be chosen.

Another thing is picking the design test load. From the few equations I've encountered I keep coming up with values over 70 kips which seem a little too high. How do you calculate this value?

 

[PEinc]

Pick fairly wide apart search limits. Then, narrow them down as you see where the critical surface is approaching. It is an iterative process.
The 70 kip test load you refer to may be twice the nail design load. This should not be your test load. You can't accurately test a soil nail that does not have an unbonded length. Instead, pick a short bond length and then test this nail, using two-stage grouting or a sheathed unbounded length, to a load that represents twice the design bond stress. You don't want a test load that exceeds the allowable testing strength of the tendon. If you test a nail using two stage grouting where the ungrouted length is uncased, you may collapse the uncased hole when the test load is applied.

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