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Hitting with the pipes underground while construction
8

Hitting with the pipes underground while construction

Hitting with the pipes underground while construction

(OP)
I am working in power industry, and now contruction of FGD project ( Flue gas De sulphurisation ) is going on in our industry. Initially when Geo technical investigation performed, a fire water pipe underground got hit. And we dont have layout for the fire water pipes underground. And later we came to know that an industry nearby uses a water pipe which is going underground in our industry. And we dont know how many public utility pipes are going underground in our industry.

1. My first concern is: How to handle hitting issue with the fire water pipes in our industry whose layout we dont have.
2. My second concern is: There may be many industries located far from us like more than 30 KM, and they may also have water pipes below our industry serving them, and there may chance of hitting with those pipes.
3. My third concern is: How to handle construcion without damaging public utility pipes going underground in our industry.

Most important issue is: we dont know at what depths these pipes are there underground in our industry.

Kindly guide me how to handle above problems

RE: Hitting with the pipes underground while construction

Dig using hand shovels.

RE: Hitting with the pipes underground while construction

2
You don't appear to be from the United States. In the States there are laws that require one to call a utility locating service prior to digging. Here is an example. You may have something similar where you are located:

Locating Service

RE: Hitting with the pipes underground while construction

(OP)
The problem here is: The depth at which the pipes are buried we don't know, it may go as deep as possible. And the soil is also moisturous and watery in nature. Ground penetrating technique can go as deep as 1 metre if the soil is wet. But the pipes may be buried more than this depth (say 4 metre)

And we cannot use hand shovels as the Project covers large area, and using shovels may take more time to complete the project.

And also we don't have online facilities like "know below your ground" in our area.

Could you tell us any other alternative way of solving this issue.

RE: Hitting with the pipes underground while construction

K Baaru,

What material is the line pipe? If its metal then you should be able to attach a frequency generator to it and then scan the ground for the lines, even at 2m deep quite easily and cheaply.

Then try CAT scanning with a high quality scanner.

If you know anyone for whom the two welding rods technique works, get them to walk across the site in a grid pattern and mark anything they find. Then see if the dots join up. You might think its all very dodgy, but a lot of pipeline technicians swear by it to locate buried pipes and cables.

For other utilities, you need to check any records you can find, ask any white haired engineers from the utilities if they can remember where it went, look carefully all around the perimeter for marker posts, valve chambers, man holes etc.

Then it's time to start digging. A set of slit trenches 1.5m deep is not too hard to do if you do them in the right places - so around the perimeter of the site to start with and then try not to damage the utilities when you do....

Are you in India? Many persons digging should not be a big issue?

But why are you worried about pipes 4m deep? What are building?

Basically, if you suspect you have buried services on site but you don't know where then it becomes a risk you need to manage.
Scan and trial dig as much as you can to reduce that risk, but you won't reduce it to zero.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Hitting with the pipes underground while construction

(OP)
Sir/Madam,

I thank for the guidance given by you.

I agree with your points.

I need to add another some more information

That is, actually we are situated near sea area. And we find Rocky surface only below 9 metre. Hence we need to put piles deeper than 9 metres to withstand our building structure.

The project which is going on is heavy weight, such that we need to put thousands of piles near to each other with space between them 1 metre only.

And also the pipes underground are made up of metal as well as concrete, the concrete pipes are used, since we are situated near sea area to avoid corrosion.

Hence, could you tell me, whether ground penetration radar or any other instrument can detect metal and concrete pipes if they are at 3 metre depth in sea water area


RE: Hitting with the pipes underground while construction

GPR struggles beyond 1.5 to 2m but finds holes in the ground so material is irrelevant.

If though you dig a trench say 2m deep then you can run the machine along the base of the trench to find things 2m below that so a total of 4m below ground level.

But if these pipes are important to others then someone, somewhere will have at least some sort of knowledge as to where they are.

Finding that office or person only you can do as you know what those organisations are.

How old do you think those pipes are?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Hitting with the pipes underground while construction

(OP)
I think digging for 2 metre and running the machine along the trench will solve my problem.

The pipes may as old as 30 years (Concrete pipes), in case of metal pipe it may be 20 years old.

Thank you.

RE: Hitting with the pipes underground while construction

step 1 is utility research - there should be records filed of easements or right of way required for installation of the pipes.
step 2 is coordination with the utility owner - once you find the easements, you should be able to contact the utility owner and obtain records showing where the utilities are and how deep
step 3 is potholing - locate horizontally and then pothole to expose the top of the pipe, and measure the depth and confirm the type of pipe
step 4 is survey - accurate locations should be determined using survey

all of this should be done before any more digging

RE: Hitting with the pipes underground while construction

cvg - The OP hasn't said where he or she is, but I suspect India or similar location.

Records out there are not all they should be...

I do agree that at 20-30 years old, there should be good records of location. I thought the OP was going to say they were 40-50 years old....

If they are that young, then try looking at Google Earth and going all the way back on the history button - sometimes the route of pipelines shows up even a few years after they were built due to poor re-instatement.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Hitting with the pipes underground while construction

(OP)
Thank you very much sir/madam.

RE: Hitting with the pipes underground while construction

Not a fun situation. My guess is we all have had similar issues. I am in the states and have run into missing As-Built plans. I typically do research of other projects in the area and also meet with the utility owner(s). Basically exhaust efforts to find information on paper then reexamine the risk for the design.

RE: Hitting with the pipes underground while construction

I agree that records may be lacking. easements may have not been obtained and record drawings may be non-existant. these things are often, also lacking in more developed countries. however, the standard of care is to follow the stepwise approach, similar to what I posted and follow it to the extent possible. and once you start installation, hand potholing, ahead of the trenching operation, should be done to confirm that your alignment is clear.

RE: Hitting with the pipes underground while construction

Sometimes after you clear the disturbed surface layer, you can make out where pipes have been routed by noting soil material changes, discoloration, hardness and the like. Even finding something that appears as a straight line in the dirt can be a clue. See Indiana Jones techniques.

A black swan to a turkey is a white swan to the butcher.

RE: Hitting with the pipes underground while construction

In this case he's peppering the ground with 9+m long piles at 1m centres so short of digging out 9m of soil over huge area, you're going to hit something...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Hitting with the pipes underground while construction

Presumably the pipeline trenches were surface to depth, so there is probably some evidence to be found at shallow depths. Previous backfills are not that difficult to spot.

A black swan to a turkey is a white swan to the butcher.

RE: Hitting with the pipes underground while construction

2
As far as the actual exploratory excavations for locating the underground utilities, hydrovac excavation has typically been the method I have seen implemented. This is faster and less labor intensive than shovels and less damaging than traditional heavy equipment. Here is an example of this in use: https://www.youtube.com/watch?v=0FnEIQSO7bI

RE: Hitting with the pipes underground while construction

(OP)
I think the solutions which we have discussed will solve my problems.

Once again thanks a lot friends for taking conversation to next level.

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