Temporary retaining for deep excavation for padestrian underpass
Temporary retaining for deep excavation for padestrian underpass
(OP)
We have one project which need excavation for padestrian underpass. The underpass is below the road level about 20 meter and the length of the underpass is about 15m. So i'm thinking to use sheet piles to drive in and then strut with king post. i'm estimated the driven will need about 40m from the existing road level so that after excavation max.20 meter it will still have about 20 meter penetrate inside the soil.(let said).
So im thinking sheet pile is suitable for this case? Appreciate your suggestion.
So im thinking sheet pile is suitable for this case? Appreciate your suggestion.





RE: Temporary retaining for deep excavation for padestrian underpass
By its temporary nature, shoring is designed to minimal factors of safety, yet you can't afford to have it fail. Normally shoring is written into the contract as a performance item, giving the GC a lot of leeway in its design. Basically, it's a means and methods item, where you don't care how its done as long as it meets certain parameters.
RE: Temporary retaining for deep excavation for padestrian underpass
As JedClampett notes this depth seems beyond routine use of sheet pile.
Perhaps a solider pile /lagging application is best.
And on second reading, it seems like you need to go down 20m and then say burrow under the road? Thereby keeping the road open?
Another option may be to use tunnel liners, ring beams, or, again, solider piles. The liners can be used in a vertical application (shafts) as well as a horizontal application (tunnels).
See this link for examples: http://www.bortunco.com/index.html
Regards,
![[pipe] pipe](https://www.tipmaster.com/images/pipe.gif)
Qshake
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RE: Temporary retaining for deep excavation for padestrian underpass
RE: Temporary retaining for deep excavation for padestrian underpass
BigH, Do you have a copy of NUS conference? Appreciate if you can share it with me. Thanks.
RE: Temporary retaining for deep excavation for padestrian underpass
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Temporary retaining for deep excavation for padestrian underpass
For supporting the wall you can either use concrete slabs with kingpost (top-down construction method) or permanent ground anchors / wall to wall steel struts (conventional bottom-up construction method).
Normal vertical spacing for ground anchors/wall to wall struts is about 3 -4 m, whereas for concrete slabs is about 6 m.
I can't comment on penetration depth since no boring log available.
RE: Temporary retaining for deep excavation for padestrian underpass
RE: Temporary retaining for deep excavation for padestrian underpass
I would think given the depth and length tunneling might be the easiest way to go.
Out of curiosity, are there access stairs at each end? I am having trouble visualizing the condition where a 15m long tunnel is located 20m under ground.
RE: Temporary retaining for deep excavation for padestrian underpass
for dcarr82775, there should be access at the end but this is only a preliminary concept/method to be use so this will not a main issue.
The width of the underpass pedestrian is about 4meter plus so i think only useing wall strut is sufficient.
Due to this is not a very long tunnel so we are not consider for the pipe jacking or use TBM for safe cost purpose.
RE: Temporary retaining for deep excavation for padestrian underpass
RE: Temporary retaining for deep excavation for padestrian underpass
You give no information with rregards to what the permanent structure is going to look like.
I would expect that using something more permanent like diaphragm walls to also act as the temporary shoring may be a better solution.
RE: Temporary retaining for deep excavation for padestrian underpass
www.PeirceEngineering.com