×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

excavating utility trench beside settled footing

excavating utility trench beside settled footing

excavating utility trench beside settled footing

(OP)
Hello, I thought that this could be interesting problem to share.
A utility trench (almost 50 m long) with depth of 2 m is proposed at horizontal offset of 2 - 3 m from a wall of 3 storeys house . Unfortunately, the wall has been reported to have cracks due to both structural issues and foundation settlement. Horizontal offset between the problematic wall and trench can't be increased. As understood there 2 to 2.5 m of compacted fill overlaying firm to silty clay at subject site. The excavation of trench may compromise the stability of the wall . Conceptual solution options:

First obtain more accurate soil profile at site and information on the depth of the foundation of the wall with respect to depth of the trench. Solution options would be :


1- Lower the burial depth of the utility to the minimum possible (1.5 m ) and if the depth of trench is shallower than the depth of the wall foundation ( wall foundation settlement is not likely to happen). Even with the shallow trench of 1.5 m , structurally support the trench side (soldier timber piles system) without causing any tangible vibration (more than 5 mm/sec) (Utilize experienced excavation contractor)

2-If you can't figure out the depth of the wall foundation or if it is shallower than minimum trench depth (1.5m) , use proper trenchless technique ( that results in minimum gaps between drilled hole and pipe) to install the utility pipe in the subject trench.

3-other option is just fix the problem of the settled wall before excavation of the trench

Your thoughts and discussion on this matter will be appreciated

RE: excavating utility trench beside settled footing

Get legal advice as to reducing liabilities. Get detailed before and after info on the existing house, with photos, measurements, including measurement of cracks with a system capable of many repeat measurements. Finding foundation depth may take actual limited excavation test pits. I'd not trust hand augers or probes. If some noticeable work the house owner could do to help him and incidentally help this job, be sure to mention that in a written communication. Oh yes, keep detailed records, even showing time of day, weather. Establish a reference line with stationing for reference purposes. Tie all photos, etc. to that reference system. If possible do some elevation observations of the building and possibly any affected landmarks.

RE: excavating utility trench beside settled footing

The crack width measuring method I use is a pencil line across the crack and a small cross on each side placed a given distance apart. Record this distance and sny off-set of the lines on eachside.

RE: excavating utility trench beside settled footing

Option 3 is better!

RE: excavating utility trench beside settled footing

(OP)
Maybe option 3 cant be done as it may cause significant delay of the project

RE: excavating utility trench beside settled footing

User10...are you concerned about doing it right or doing it fast? Doing it right works. Doing it fast doesn't always work.

RE: excavating utility trench beside settled footing

(OP)
oldestguy , thanks for your good thoughts

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

eBook - Manufacturing the Cars of Tomorrow
In this ebook, we'll explore how additive manufacturing is going to transform the way cars are made. This includes commentary from thought leaders such as Ford's CTO, Ken Washington, Customer case studies of ways 3D printing is being used today, and a variety of part examples where 3D printing is already impacting how automobiles are made. Download Now
White Paper - Smart Manufacturing for Semiconductor
New technologies and approaches present great opportunities for semiconductor manufacturers to achieve high levels of innovation, yield and improvement. This white paper explores some of these cutting-edge technologies and how they can be applied effectively in the semiconductor industry. Read about how Smart Manufacturing is transforming the semiconductor industry. Download Now
White Paper - Analysis and Simulation in Aircraft Structure Certification
Organizations using simulation and analysis tools effectively see the benefits in their ability to achieve certification faster and with drastically less total cost than those who do not maximize these tools. Read this White Paper to learn about how digital tools such as analysis and simulation help in aircraft structure certification. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close