Minimum Depth of Excavation

What, the civil engineer of this project doesn't know? What about the architectural engineer?

There is no way to answer such a question from here with the complete lack of pertinent information.

Or is this homework?

Wait there is an answer, the minumum depth will be called out on the foundation plans.

About 4m...? Just a guess...

You do your own thinking, we might critique it but we are not doing your homework for you. We tend to help people who try but not lazy rascals who try to get their homework done for them.

I see your being beaten up about this being home work.

Please google "india building collapse", there are so many deaths caused by bad engineering, bad materials, monsoons washing out foundations......

So learn the correct way to prevent any more human life loss and take the study of structural design as critical to your future. Unless you want to learn this the HARD way. There is no room for mistakes here.

7 floors of what type of construction? What loading per square foot is the building (both live and dead load)? Define "rock" sedimentary, igneous, or metamorphic? How thick? What is the underlying rock layers. You can build on igneous rock over limestone that has sink holes in it. Or soft sand stones, shales, that will "flow" from foundation pressure.

Is the building on a hillside?

Just what are you learning. And this is not my area of study, but I know enough to ask lot's of questions and what the specifications are.

You present a single sentence question that is flawed. You can't expect an answer from this question. Oh, maybe that was the homework.

ROCK just 2m below!

Easy ANSWER TO YOUR question : 2m + Anchor bolt holes .

BUT,BUT, what shape is this rock below? And its 3D situation?

What is shape is this 7 Storey Building you want to build ON IT? And its mass ?

POST BOTH please .

Only then can anybody comment --- what you need to do.

Define rock.

Describe flood and washout circumstances.

What are the earthquake resistance requirements.

Is that area flat or angled at what degree.

What is he rock slab supported on.

And these questions did not came from a civil engineer.

So I might have missed some.

First you need to learn structural engineering spend few years designing structural elements and structures then master geotechnical engineering ,Staad or E-Tabs structural design software you will find the solution for your question with in no time

Not enough information given, and this obviously appears to be yet another homework problem. Egads, will it ever end?

Does the building require a basement?

Is the ledge rock sound, or does it need to be ripped down to sound structural sound rock?

Bearing capacity of the ledge rock and underlying rock? Is it sufficiently strong enough to support the 7-story building and the imposed design loads?

Type of proposed construction?

Do your own research while completing your homework assignment!

The question of how deep can only be answered as follows:

1.- You need a soil survey to determine what the ground and underground conditions are.

2.- You need a qualified engineer to design the foundations, since in my tiny mind, a 7 story building may need a quite deep foundation.

3.- Next have a company design the building, including foundations and ground requirements.

4.- And last, since you did not give any information, details of the requierements all we can assume is that you have no experience and should not be doing this if you are a professional, and if you are a student - DO YOUR OWN HOMEWORK -

It should be as deep, wide, and long, as the structural, and the geotechnical, and the relevant Codes, say it should be...

He plainly asks "What should be the minimum depth of excavation" he is clearly asking how deep to dig not what the depth of the foundation should be

From that we can say the answer is "the maxim depth of the foundation" the hole he excavates can't be smaller than the foundation.

You can't dig a hole 2 meters deep & put a 3m deep foundation in it.