View Full Version : thoughts and ideas on trenching
12-19-2002, 11:12 AM
Hi.....found this forum today and it seemed like a good place to get some feedback.
I have a section of airfield taxiway that needs the taxiway lights replaced, about 7000 feet of concrete encased 2" conduit will be installed at a depth of 30" and the balance of trench will be filled with slurry up to asphalt subgrade and then patch-paved.
My options right now are trenching with my Vermeer 5750 ride on trencher,or my Case 580M bachoe. The backhoe bucket width is 12" while the trencher makes a nice 8-10" cut. Problem with the trencher is the spoil being deposited on the trench edges. None of the spoil will be used ,so as far away from the cut as possible is desirable. The 12-14 " backhoe cut deposits the spoil nicely away from the ditch, but hurts us on concrete and slurry costs.
I have trenched some with the Vermeer,shoveling the spoil back into the chain and letting it spoil on just one side,but this is gonna kill me on time as my feet per minute is slower to keep up with the chain digging.
I'm thinking a mini excavator would do nice...perhaps a Bobcat or something with a 9" bucket. Any ideas or experiences?
Thanks in advance....
Welcome to Lawnsite. Its been a long time now, but I remember using Vermeer trenchers & a couple of similar jobs. I believe I remember that a Vermeer trencher we used had a type of plow set behind the chain that would plow the spoils further from the trench, allowing your 580 to come along & scoop them up & away. After reading your question, I'm thinking this may have been an add on attachment that allowed us to do that type of job, instead of the usual trenching where we'd push the spoils back in over a layer of stone or other. The company I was working for had a few different Vermeers, so its possible that one was a certain model for this situation, but maybe the attachment option is possible? Other wise, a mini X such as the Bobcat you mention would be great for that job, based on watching a friend use his. One could fly through with that & just drop it beside the trench far enough away & since you already have the Case, that could scoop & load dump trucks to haul it away?? Or the mini could dump right into the bucket of the 580 real fast and maybe keep a good pace that way?? I would think that those 2 methods would go faster than the Mini X loading the trucks along side?? Probably faster for the Mini to drop it on the ground & not wait for the 580 to dump it on second thought. Anyway, that's how I'd do it based on what I know LOL. Good luck & have fun with it.
12-20-2002, 02:23 AM
Ahh....this Vermeer has the "crumber bar" that trails along behind the digging chain,supposedly pulling the loose dirt left over from trenching. I bet I could rig up a V-plow or something to push the spoil away from the ditch. The 580M Case has a 4-1 bucket,so clamming up the spoil is no big deal. Actually,we are not hauling off any excess dirt...just loosing it in the unpaved taxi-way shoulder area.
I would rather use the 580 to dig the whole deal as the trench is cleaner,straighter and easier on the electricians to place the conduit and pour the duct bank. We are pouring slurry on top of the duct so we don't have to mess with compaction tests.
Another PITA is the asphalt where trench runs....it is sawcut at 16", but the paving is old,old old and crumbles from baking in the CA. desert heat for the last 30 years. If you look at it wrong...it breaks.
Will be glad when this job is over....over 40,000 feet of ditch opened up and hundreds of taxiway lights installed. Can't forget those 115 degree summer days when the backhoe controls were too hot to touch and the trencher would dig 25 feet and have to be shut down to let the hydraulic system cool down.
Thanks for the welcome and the idea about the plow....I was thinking conveyors or perhaps a different machine all together to get this last section done and over with. ;)
12-22-2002, 11:00 PM
Why don't you just bore under the runway? Minimal disturbance... There are companies that do this type of work. Check it out.
12-24-2002, 05:53 PM
Boring isn't going to leave a concrete encased conduit.
When I built golf courses, I had to install a pretty good chuck of drainage pipe along the way. Some as large as 48" in dia.
I found the rpm on mini x's plus the limited bucket size to be way too slow for quantity work. The digging depth,reach and operator comfort were also questionable. It seemed some of the larger operators got tired quicker in the smaller machine.
What we ended up doing was using JD 590/690 excavators with narrow buckets - we were able to reach and maintain over 1000 linear feet installed per day easier this way.
In your instance, if the crumbler bar idea works I would go with it. Dependent upon subsoil type and consistency, it seems to me a trencher would leave a nicer trench than a mini x. Use to 580 to move the spoils to your levelling site.
Good luck with your project.
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