Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: "Hydrovac" for pier construction

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Is this a procedure where we could excavate small piers up to 10 deep under an existing building?  The existing soil is silty-sand with backfill densities ranging from 68 to  88 percent relative compaction.  Presently the water table is near the surface, but we can pump that down some.

Neil Moore, SE,SECB


At 02:39 PM 5/23/2006, Padmanabhan Rajendran wrote:
Yes. However, auger cast piles are typical for deep foundations. Hydrovac is used where the pier is not more than 10' deep.

Rajendran

Tripp Howard <tripphoward(--nospam--at)yahoo.com> wrote:
Have you considered using auger cast displacement piles?  Berkel and Morris-Shea Bridge both have a version.  Basically the auger has a blocking section on it that pushes the soil coming up the auger flights out into the surrounding soils so there's no waste to haul off or deal with.  Sounds like it would be a great idea for contaminated sites.

"Garner, Robert" <rgarner(--nospam--at)moffattnichol.com> wrote:
This is not totally relevant but we recently used a hydrovac truck to assist us in removing saturated, runny soils in an exploratory pit alongside the bay.  A backhoe loosened the soils and the hydrovac sucked them out and stored them in the rear tank of the truck.  This was an ordinary vacuum truck like you would use to clean out manholes, etc.  We had a rental Baker water tank on site so the hydrovac could empty its contents into the tank for segragating the water from the soils and later disposal of the soils (contaminated also).  The remaining soils in our pit remained saturated with significant pore water pressure so our little pit would not be good for supporting much.  Those hydrovacs can sure remove a lot of material in a short time, though.  And keep your feet away from that hose - it'll take your boot right off and turn your ankle a quick 90 degrees with a loud "snap"!
 
Bob Garner, S.E.
 

From: Padmanabhan Rajendran [ mailto:rakamaka(--nospam--at)yahoo.com]
Sent: Tuesday, May 23, 2006 1:13 PM
To: seaint(--nospam--at)seaint.org
Subject: "Hydrovac" for pier construction
 
In the refineries, it is becoming common to use the "hydrovac" technique for creating hole for a concrete pier construction. In essence it is water jetting method with high pressure water jet.  As the hole excavation progresses, a vacuum hose removes the loosened debris. The method is preferred because it is fast, requires minimum labor, does not create a mess and the excavated material,  which is usually defined hazardous, is removed in a compact way for suitable disposal.

Commonly used formulas for determining the vertical and lateral load bearing capacities for the concrete pier assume undisturbed soil. Are there any modified formulas for use with methods similar to "hydrovac"?

Any additional input from list members?

Thanks.

Rajendran 

Love cheap thrills? Enjoy PC-to-Phone calls to 30+ countries for just 2�/min with Yahoo! Messenger with Voice.
The information contained in the e-Mail, including any accompanying documents or attachments, is from Moffatt & Nichol and is intended only for the use of the individual or entity named above, and is privileged and confidential. If you are not the intended recipient, be aware that any disclosure, dissemination, distribution, copying or use of the contents of this message is strictly prohibited. If you received this message in error, please notify us.




Tripp



Be a chatter box. Enjoy free PC-to-PC calls with Yahoo! Messenger with Voice.