Earth moving requires tools or machinery. These too;s can be small or large, and simple or complex. They include cranes, dump trucks, bobcats, graders, backhoes, trenchers, tractors, pipe layers, roller compactors, front-end loaders, drag lines, truck-mounted drills and shovels – just to name a few.
Having access to equipment is not the same as being able to use it properly.
Proper use of equipment depends upon knowing the equipment, it's applications and it's limitations; as well as a level of skill that only comes with experience. A skilled operator, for instance, can achieve more in an hour with the right tool, than an unskilled operator would in a day with the wrong tool.
Bobcat are small scale earth moving machines which are useful on sites where there is not a lot of space to get a larger machine into. They are used widely by landscapers working in urban areas and by plumbers, nurseries, etc. The bobcat has been responsible for many fatalities in the past. This may be due to the unskilled level of operators or due to carelessness by individuals who mistake its small size as an indication of its harmlessness. BEWARE!!! When working around these and all earth moving or heavy equipment - your first mistake can often be your last.
Can be used to describe a bucket and lift-arm assembly designed for use on the front of a tractor; with hydraulic cylinders that raise and lower the lift arms, and tip the bucket so that it may be dumped in the elevated position; or is a self-propelled machine mounted either on wheels (or on crawlers) and equipped with a front-mounted bucket to dig, lift, haul, and dump into stockpiles. A variety of attachments are available enabling such a machine to do other types of work, such as ripping, scraping or ditching.
Tractor is the generic term used to describe the basic power unit that will drive the earth moving implement. They might be wheeled or tracked and are usually set up with a number of hydraulic options for the operator to fix implements.
The backhoe is used for digging. It is very useful for operations such as pipe laying or trench digging. The backhoe's standard equipment is a narrow bucket on the rear end and a loader on the front. The operator effectively makes either device the working end by simply rotating his chair and operating a different set of controls. The excavator bucket is rigidly attached to a hinged pole on the boom that is drawn backward to the machine when in operation. The backhoe bucket is deep though not necessarily large and it hangs in a J shape. The bucket is driven hydraulically and can be lowered below the level of the tractor base. Backhoes often have feet or anchors, which are essential when digging deeply as this tends to destabilise the tractor.
These are used to break up hard ground or rock. They are often fitted to backhoes initially to soften up the ground first before then being attacked with a backhoe or shovel.
Also known as a “dozer”, they are a heavy, driver-operated machines used for clearing and grading land, usually having continuous treads and a broad hydraulic blade in front.
Two distinct features characterize the bulldozer: the long, vertical steel blade in the front of the vehicle and the rotating twin tracks, which facilitate the bulldozer movement. The tracks give excellent ground hold and mobility through very rough terrain. Wide tracks help distribute the bulldozer's weight over large area, decreasing pressure, and preventing the machine from sinking in sandy or muddy ground.
There are many implements that can be attached to a bulldozer and these are designed for a specific job. There are implements used to scrape, grade, rip or push rock and soil.
Dozer blades usually come in three varieties:
- A Straight Blade ("S-Blade"): this blade is short and has no lateral curve, no side wings, and can be used for fine grading.
- A Universal Blade ("U-Blade"): is a tall and quite curved blade. It has large side wings to carry more material.
- The "S-U" combination blade: is shorter, has less curvature, and smaller side wings. This blade is typically used for pushing piles of large rocks, such as at a quarry.
Alternately a bucket may be used for lifting soil but is not really effective in soil or rock that has not been loosened already. The bulldozer is often used as a compacting device on dams or farm lanes but is not entirely suited to these tasks. The bulldozer is used in many industrial applications such as construction, waste management, and farming.
The use of detonating explosives occurs when large amounts of solid or rock materials are required to be loosened. In the case of mines, where larger machinery is not practical, detonating explosives are used to extensively. Many coal mines use explosives to loosen the rock and coal. In surface mining, holes are drilled through the overburden, loaded with explosives, and discharged, shattering the rock in the overburden. Special explosives, called permissible explosives, must be used. These explosives produce little or no flame and explode at low temperatures to prevent secondary explosions of mine gases and dust.
One important explosive used in mining is called ANFO (a mixture of ammonium nitrate and fuel oil). Its use has revolutionised certain aspects of open-pit and underground mining because of its low cost and relative safety. To obtain and use explosives, an operator requires a qualification and training due to the dangerous nature of the task.
The shovel is generally used for large scale earth moving operations. They are frequently employed in mines, dam construction, etc. They are dragged or pulled through the material to be moved. They can be either operated by a crane like technique, where the bucket is placed in the desired position and then hydraulically maneuvered using steel cables. It can also be attached to a large tractor unit and used to scrape or drag material in on site operations.
DIFFERENT WAYS OF MOVING AND SHAPING EARTH
Cut and Fill
The concept behind cut and fill procedure is that material that is cut from one area of a project may be required as fill in another area of the same project. Thus, costs of removal and acquisition of materials are cut. Even though the cut and fill equation will rarely be exactly proportional, and hence some material will have to be either carted away or brought onto the site, cut and fill is an extremely cost effective procedure.
Excavating means to hollow out, or remove and thus create a hole. Excavators, also called diggers, can be used for various tasks other than digging holes by using various attachments. These include digging trenches, moving large objects, grading and landscaping and removing vegetation.
Contouring is the manipulation of material to create rises and falls as required by the plans of the project. A grader may used to take layers of material from the inside corner of a turning lane for instance. The purpose being that surface water will drain away down the slope.
Swales are channels cut or built along a contour, on sloping ground, to catch water. Swales are used in some areas of agriculture & horticulture (e.g. permaculture) to trap water runoff and to utilise the valuable resource. They are usually raised earth constructions designed to trap water long enough to ensure water is permitted to penetrate into the soil. This ensures rainwater and surface run off is saved and used by plants. They are regarded as semi-permanent in that they will last for a couple of years without much maintenance, after which time they naturally level out.
In many projects, levelling is achieved by the Cut and Fill procedures outlined above. Where the existing level is quite good a grader may be used to administer the final accuracies. A grader working in this manner will have its blade set at a certain angle and simply move across the ground to be levelled. Spots that are high are then scraped off and deposited by the grader in areas that are low.
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