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!

*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.

Jobs

Landslide debris barrier design - frestanding timber wall

Landslide debris barrier design - frestanding timber wall

(OP)
We have considered a building platform near the base of a moderate to steep slope that has experienced past landslope instability.  Soil instability is limited to silt/clay flows due to saturation.  
Does anybody know of any literature with respect to determining landslide impact forces for a mobilised soilmass with respect to design of a freestanding timber wall built to take the impact of the slide and protect the structure directly downslope.
Also, does anybody know of any literature that considers how to derive the pressure applied to the wall with respect to its design under dynamic conditions.

RE: Landslide debris barrier design - frestanding timber wall

If you have a landslide condition, you need to hire a local geotechnical engineer who is experienced in performing slope stability analyses.

RE: Landslide debris barrier design - frestanding timber wall

(OP)
We are the local geotech engineer, and we have run slope stability analyses to determine the volume of the failure mass.   I'm interested in determining the design of a freestanding retaining wall as an option to protect the building platform from the debris flow.   Normally, we'd design an earthbund upslope of the platform to collect the materials, but on this site they are a little tight for available land area.

RE: Landslide debris barrier design - frestanding timber wall

Does your slope stability program allow you to add a stabilizing force to the slope so that the FS becomes acceptable?

RE: Landslide debris barrier design - frestanding timber wall

(OP)
Yes, we use SLIDE and US Army Corps methods to determine lateral forces required to prevent a mass from mobilising (or achieve a required FoS for a slope.   
What I am trying to determine is design of a wall at the base of a slope to collect debris that has mobilised from the top of the slope.   I am tring to determine the force that would be applied to the wall at the moment of impact as it would not just be something as simple as F = M x A.
Normally, for a wall design we adopt Pa = Ka x Gamma x Height^2 x (pole spacing) to determine loads on each pole - with the load applied at H/3.   Obviously all of this changes with the nature of the load being applied by a debris flow.

RE: Landslide debris barrier design - frestanding timber wall

I think there is a lot more to your problem than impact forces.  If you can visualize say a snow avalanche and what it does, it would seem that more importantly you need to design a wall of sufficient height to hold a whole lot more material than just the thickness of the flow. How much volume of soil will finally stop at your wall? and what will its final stabilized shape look like?  It won't look so neat if that wall is over-topped by a massive flow volume.

RE: Landslide debris barrier design - frestanding timber wall

(OP)
Thanks oldestguy.   We have already determined runout angles based on the soils present at the site and we have indications of flow volumes.   At the proposed wall position it wouldn't need to be any more than 2 metres high to collect the slump volume and prevent the soil mass impacting the proposed dwelling.   
Slump volume is about 800 cubic metres (20 metres wide x 3 metres deep x 15 metres up slope), mobilised from say 30 to 50 metres upslope.   We aren't talking massive volumes, just small scale landslips.  
 
 

RE: Landslide debris barrier design - frestanding timber wall

I would suggest looking into gabions.  There has been a substantial number of free standing rockfall and avalanche structures built around the world.  The impact energy these structures can withstand is incredible (10000kJ+)

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!


Resources


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