I have a situation. There is a 45deg excavation near the existing sign board which is on a short pile. Just wondering how far digging can go without damaging the pile?
There are two things you have to take into account:
1.It should bigger than 5B B=diameter of pile (better to see some literature)
2.Vibration effect caused of your digging
GeoPaveTraffic is right.
The following questions need to be answered before the geotechnical engineer can give an answer:
1. what kind cohesive soil it is, fill, soft clay, firm clay, stiff clay or hard clay?
2. where is the ground water regime?
3. how deep is the excavation?
4. how long will it open?
5. what is the season for construction?
6. is the original design sono-tube allow for short term side exposure (structural engineer's verification)?
7. is the excavation to be backfilled?
8. any surcharge/vibration/slope near the site?
9. other considerations may affect the excavation, say underground utilities, previously man-made trenches or buried features, etc.?
If the excavation is really shallow, in the good soil, temporary, no high water table, to be backfilled right away, you probably worry little. If some or all unfavorable factors kick in (most cases), you will need a full review by an geotechnical engineer.