Ground Loss Around Excavations
Ground Loss Around Excavations
(OP)
I am trying to my self some shoring basics. Question is how does ground loss due to the bending of the shoring? Does this increase the lateral pressure at the maximum bending point since there is now more soil? In long term shoring do we have to compensate for transported dirt or water (by air) to fill the area the ground loss was previously before or does a safety factor cover that? Yes there are many books but they really don't answer straight forward.





RE: Ground Loss Around Excavations
I am struggling to fully understand your language but I will give it a go.
settlement at ground level is usually about half of the horizontal movement of the shoring (from CIRIA)
The deflection of the sheets e.t.c. actually reduces the bending moment in the sheets due to the load taking the stiffer path and arching to the stiffer strut points. Load on the struts is not reduced by this though. The UK guide 'timber in excavations' allows a reduction of 25 to 50% to allow for this arching action in timber walings.
Long term these pressure will eventually consolidate with time and even out the pressure.
Clay is even more dependent and the value of cohesion chosen depends on if the drained or undrained shear strength is more relevant.
You can also get overconsolidated clays which tend to exert more pressure.
Not sure what the last questions are about.
Try
http://pdhengineer.com/