Earth Moving Plant
Discussion
How does a digger / dozer driver know where to dig / bulldoze?
Seems to me like you want the accuracy of a carpenter with his tape measure and pencil, but how do you do that on a muddy area where you're excavating / shaping in 3 dimensions, not just 2?
I don't believe it's just done by eye?
When you've been told to make a ramp up 3m+ tall embankment, how do you do it? How do you know it's strong enough and won't subside?
Seems to me like you want the accuracy of a carpenter with his tape measure and pencil, but how do you do that on a muddy area where you're excavating / shaping in 3 dimensions, not just 2?
I don't believe it's just done by eye?
When you've been told to make a ramp up 3m+ tall embankment, how do you do it? How do you know it's strong enough and won't subside?
I work for a Danish company making backhoes etc. and we were discussing this very topic the other week, due to a new gadget which gives a visualisation of the area to be dug, presented on a screen in the cab. Using GPS it shows exactly where to start/stop etc. also the front and rear diggers have cameras fitted, so the driver can be exact in starting position for the shovel. Very accurate apparently.
A lot of the new 'total station' topographical tools communicate with GPS-guided topographical equipment in the plant now; telling the driver precisely where (and how much) to cut and fill simply by 'reading' the topographical surveys.
GPS used in this equipment can be accurate to something like 10mm and I personally don't think it's too absurd that this activity could be automated one day for large-scale civils projects.
GPS used in this equipment can be accurate to something like 10mm and I personally don't think it's too absurd that this activity could be automated one day for large-scale civils projects.
Also, there's a definite skill in grading by eye. I recently hired a mini-digger to do my drainage at home and had a go at grading the garden afterwards using the digger, I found it absolutely impossible. Mind you, it was still tricky with a shovel!
Just noticed the part of your question about how you know it can support the weight - a Civil Engineer will do calculations, not dissimilar to those which a structural engineer might do for a new building. They will design/specify the make-up of the ground to support the required load, using both natural materials and more recently man-made (like geo-textiles e.g.).
Just noticed the part of your question about how you know it can support the weight - a Civil Engineer will do calculations, not dissimilar to those which a structural engineer might do for a new building. They will design/specify the make-up of the ground to support the required load, using both natural materials and more recently man-made (like geo-textiles e.g.).
Experience. A good digger driver can make the hardest job look easy.
The ground is marked out beforehand, and by positioning the boom square on the driver can follow his own line (because the painted one disappears with the first dig). Depth is roughly measured with the bucket, and more precisely by a man with a stick. Grading is all about balancing the levers so that the boom rises, the dipper dips, and the bucket turns all in sync to maintain a level.
Modern machines have all sorts of gizmodgetry to assist, but they can't replicate talent.
Ramps are made by filling a corner and compacting with the tracks. Where subsidence is likely the arm is used as a counterbalance or prop as appropriate. They can tip a surprising distance before passing the point of no return.
The ground is marked out beforehand, and by positioning the boom square on the driver can follow his own line (because the painted one disappears with the first dig). Depth is roughly measured with the bucket, and more precisely by a man with a stick. Grading is all about balancing the levers so that the boom rises, the dipper dips, and the bucket turns all in sync to maintain a level.
Modern machines have all sorts of gizmodgetry to assist, but they can't replicate talent.
Ramps are made by filling a corner and compacting with the tracks. Where subsidence is likely the arm is used as a counterbalance or prop as appropriate. They can tip a surprising distance before passing the point of no return.
Edited by johnny fotze on Monday 16th June 19:13
Profiles. These T-shaped bits of wood you see hammered into the ground on building sites.
You knock pieces of wood into the ground and nail on a cross piece 1 metre above the proposed finished level(if it's banking, the cross piece is nailed on at the finished angle).The banksman has a 1 metre high 'traveller' T-piece that is set down on the ground and sighted through any two of the fixed profiles to determine how much to dig away at that particular spot.
You knock pieces of wood into the ground and nail on a cross piece 1 metre above the proposed finished level(if it's banking, the cross piece is nailed on at the finished angle).The banksman has a 1 metre high 'traveller' T-piece that is set down on the ground and sighted through any two of the fixed profiles to determine how much to dig away at that particular spot.
ShaunTheSheep said:
When you've been told to make a ramp up 3m+ tall embankment, how do you do it? How do you know it's strong enough and won't subside?
In my experience the most common method of testing the load bearing capacity of the ground is to stamp on it and say "that's solid that is".Max_Torque said:
Have a close look at the blades and buckets of modern earth movers!
See the funny round white things at the end? Yup, that blade is steered from space to an accuracy of a few cm !! Modern tech eh! ;-)
Yep this. I saw a dozen large dozers excavate and grade the recent A14 Haughley Bypass using exactly the same method. Very clever, relatively simple, and a lot quicker than an engineer walking round with a level/dipping. See the funny round white things at the end? Yup, that blade is steered from space to an accuracy of a few cm !! Modern tech eh! ;-)
What about underwater excavations that you can't see I hear you ask?
Actually, a little bit similar to the ground scraper thingy with RTK GPS antennas on the corner of the shovel. The barge that a Backhoe is sat upon has the same GPS, also a Gyro or a second GPS unit to give you a vector. Laybacks and clever CAD voodoo tells the digger chap and the barge chap where each of them are.
Magic measuring things on the backhoe let you know what the arm is doing, and then with the application of an accurate tide value and via a 2D display in his cab the digger operator knows precisely where his bucket is relative to the tide and subsequently how deep he is supposed to dig.
A survey boat then pootles along afterwards to check the depth excavated matches the depth the Client is willing to pay for.
Don't ask how I know, it isn't as thrilling as it sounds, despite the digger being a bit big with a 90t lift capacity and a 20m3 bucket that can fit a couple of cars in.
Actually, a little bit similar to the ground scraper thingy with RTK GPS antennas on the corner of the shovel. The barge that a Backhoe is sat upon has the same GPS, also a Gyro or a second GPS unit to give you a vector. Laybacks and clever CAD voodoo tells the digger chap and the barge chap where each of them are.
Magic measuring things on the backhoe let you know what the arm is doing, and then with the application of an accurate tide value and via a 2D display in his cab the digger operator knows precisely where his bucket is relative to the tide and subsequently how deep he is supposed to dig.
A survey boat then pootles along afterwards to check the depth excavated matches the depth the Client is willing to pay for.
Don't ask how I know, it isn't as thrilling as it sounds, despite the digger being a bit big with a 90t lift capacity and a 20m3 bucket that can fit a couple of cars in.
Some of the GPS-linked systems in farm tractors/harvesters etc now are amazingly sophisticated too. They do things like show the operator a plan of the field and show exactly what he's already covered (with fertiliser, seed etc) or harvested and help plan the next turn so as to get the field done with incredible efficiency and accuracy (the turning circle at the end of the field may be such that it's more efficient to make your next pass a little distance across the field from the previous pass, the GPS helps keep each pass perfectly parallel even though they may not be right next to each other). Also things like working out how far whatever's in the back will manage to cover so that the guy driving the other tractor with fresh supplies can be at exactly the right place at the right time.
Gassing Station | General Gassing | Top of Page | What's New | My Stuff